Rationing of work performed on machines with numerical control. Methods of rationing of certain types of work Software for rationing the load of CNC machines
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CENTRAL BUREAU OF REGULATIONS FOR LABOR OF THE USSR STATE COMMITTEE ON LABOR AND SOCIAL ISSUES
GENERAL MACHINE-BUILDING STANDARDS FOR TIME AND CUTTING MODES for standardizing work performed on universal and multi-purpose machines with a numerical program management
STANDARDS OF TIME
MOSCOW ECONOMY 1990
The standards for time and cutting conditions are approved by the Decree State Committee USSR for labor and social issues and the Secretariat of the All-Union Central Council of Trade Unions of February 3, 1988 N9 54 / 3-72 and are recommended for use in machine-building enterprises.
Validity of standards until 1994
With the introduction of this collection, the General Machine Building Standards for the time and cutting conditions for work performed on machine tools with program control (MGNII Labor, 1980) are canceled.
The time standards and cutting modes (4.1 and L) were developed by the Central Bureau of Labor Standards, the Chelyabinsk Polytechnic Institute. Lenin Komsomol, Ryazan and Minsk branches of the institute "Orgstakkinprom" with the participation of regulatory research organizations, engineering enterprises.
The first part contains the standards of auxiliary time for the installation and removal of the part associated with the operation; for control measurements; for the maintenance of the workplace; breaks for rest and personal needs; time standards for setting up equipment; for tool setting outside the machine; a method for calculating service standards, time standards and output during multi-machine maintenance.
The second part contains the standards for cutting conditions and all data on the calculation of the main time and machine-auxiliary time, i.e. to calculate the cycle time of the automatic operation of the machine according to the program.
The standards for time and cutting conditions are designed to calculate the time standards for work performed on the most common types of universal and multi-purpose equipment with numerical control (CNC) used in mechanical engineering in medium and small batch production.
The standards for time and cutting conditions cover the work of machine tool adjusters and CNC manipulators, CNC machine operators, and toolmakers.
The publication is intended for standard setters and technologists, as well as other engineering and technical workers involved in the development of control programs and the calculation of technically justified maintenance standards, time and output for CNC machines.
At the end of the collection, a feedback form is placed, which is filled in by the enterprise, the organization and sent to the address of the CENT. 109028, Moscow, st. Solyanka, d. 3, building 3.
Ensuring intersectoral regulatory and teaching materials on labor is carried out at the request of enterprises and organizations through the local bookselling network. Information about these publications is published in the Annotated thematic plans edition of the literature of the publishing house Economics” and Bookselling Bulletins.
011(01)-90 ISBN 5-282-00697-9
KB - 32 - 76 - 89
© Central Bureau of Labor Standards of the USSR State Committee for Labor and Social Affairs (CBNT), 1990
The piece time for assembly, adjustment and disassembly of the kit ipprumepm n.i d> * tali operation is determined by the formula
^"Un* = C^shlr1 G ^"|u pr 2 * ^H1U|g)* (1*1 M
where T shlchzh - piece time for assembly, adjustment and disassembly of a set of tools for detail operation, min; n is the number of customizable ingtrums mu per dtalso-operation, pcs.; T t ... T w>fa - piece time for assembly, configuration and ra:*Sx>rku different kind tool included in the kit, min.
1.8. Tariffication of work should be carried out according to the Unified Tariff and Qualification Handbook of Works and Professions of Workers (Issue 2, approved by the Decree of the State Committee of the USSR on Labor and Social Issues and the All-Union Central Council of Trade Unions of January 16, 1985 No. 17 / 2-541, taking into account subsequent additions and changes to it The discrepancy between the qualifications of the worker and the established category of work cannot serve as a basis for any changes in the norms of time calculated according to the collection.
1.9. With the improvement of CNC machines and control systems, as well as in those cases, the cost of enterprises has already reached higher)! labor productivity with high-quality performance of work, reducing correction factors can be set to the time standards.
In cases where the local norms of time in force at the enterprises are less than those calculated according to the standards, the current norms should be left unchanged.
1.10. The time standards are put into effect in the manner prescribed by the “Regulations on the organization of labor rationing in the national | (0) economy”, approved by the decree of the USSR State Committee on Labor and Social Issues and the Presidium of the All-Union Central Council of Trade Unions dated June 19, 1986 No. 226 / II-6.
L11. To explain the procedure for using the time standards, examples of the calculation of the preparatory and final time and the piece tool setting time are given below.
Examples of calculating the norms of time, cutting modes and the time of automatic operation of the mill according to the program are given in Part II of the collection in the relevant sections.
1.12. Examples of calculating the norms of the preparatory-final time and piece tool setting time
1.12.1. Examples of calculating the norms of the auxiliary-^ final time
Initial data
1. The name of the operation is turning and turret.
2. Machine - CNC turret lathe.
3. Model of the machine - 1P426DFZ (diameter of the processed bar - 65 mm).
4. Model of the CNC device - "Electronics NTs-ZG, program carrier - memory.
5. The name of the part is the booster piston.
6. Processed material - steel 45, weight - 0.5 kg.
7. The method of installing the part is in a collet chuck.
8. Working conditions: centralized delivery to workplace blanks, tools, fixtures, documentation and their delivery after processing a batch of parts; receiving briefing before starting to process the part. Group processing of parts is carried out (the collet chuck is not installed on the machine spindle).
The part processing program was compiled by a software engineer, entered into the memory of the CNC system by a turner-operator; the program contains 17 processed sizes.
9. Number of tools in setup - 5:
1. Cutter 2120-4007 T15K6 (grooving).
2. Cutter 2102-0009 (through thrust).
3. Special cutter (groove).
4. Cutter 2130-0153 T15K6 (cut-off).
5. Drill 2301-0028 (hole 010).
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Trial Processing 6 Detail accurate (has surfaces with tolerances for diameters over the 11th grade, grooves) for "four tools and four measured Map 29, 8.8 according to the diameter of the surfaces (two outer surfaces: pos. 27, 0 50.3 MO and O 203 MO; one groove b = 6; ind. G; note- single groove-groove 0 30 chan 2, 3 |
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Map 29, 8.8+t
note 1
Total preparatory and final time for a batch of parts
1. The name of the operation is turning and carousel.
4. Model of the CNC-N55-2 device, program carrier - punched tape.
5. Part name - flange. "l.
6. Processed material - ~ SCH20 cast iron, weight -1500 kg.
7. The installation method of the part is in four cams with boxes, each is fixed with six bolts on the faceplate of the machine.
8. Conditions of labor organization: the delivery of tools, fixtures, documentation, blanks to the workplace and their delivery after the processing of a batch of parts is carried out by the operator (adjuster).
The tool on the device for setting outside the machine is not pre-set.
9. Number of tools in setup - 4 (including one grooving cutter, tools 1 and 2 - from the previous setup):
1. Cutter 2102-0031VK8 (through).
2. Cutter 2141-0059 VK8 (boring).
3. Cutter 2140-0048 VK8 (boring).
4. Cutter NZH212-5043 (groove).
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Trial* processing Precision part (has surfaces with tolerances for diameters over the 11th qualifier, a groove) Grooving - one tool, one groove (08ООН9Х07ОО) boring and turning of external and internal surfaces - three tools, three changeable surface diameters - 0 1150h9.0 800H9, Map 30, pos 49, ind. a Map 30, pos. 5, inl. c, all Map 30, note 1 25,5 0,85 - 21,7 263 |
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I t o g o T
Total preparation and closing time per batch of parts
Tn-T u1 + Tn a + T yarv ^ 91.9
Initial data
1. The name of the operation is turning.
Z Machine - CNC lathe.
3. Machine model - 1P756DFZ (the largest diameter of the product installed above the bed is 630 mm).
4. Model of the CNC device - 2S85, program carrier - punched tape, memory.
5. Part name - flange.
6. Processed material - SCH25 cast iron, weight - 90 kg.
7. The method of installing the part is in a three-jaw chuck.
8. Conditions for the organization of labor: delivery * / to the workplace of tools, fixtures, documentation, blanks and their delivery after processing a batch of parts is carried out by the operator (adjuster). Group processing of parts is carried out (a sinful chuck is not installed on the machine spindle).
The part processing program was compiled by a software engineer, entered into the memory of the CNC system by a turner-operator. The program contains 20 processed sizes.
settings):
1. Cutter 2102-0005 (through thrust).
2. Cutter 2141-0604 (boring).
3. Cutter 2141-0611 (boring).
4. Cutter NZh 2126-5043 (groove).
5 Number of tools in setup - 4 (tools 1 and 2 - from the previous
Map, police, index
Time, missions
*1.0
1 Organizational preparation
Map 21. by 1). 2,3,4, incl. P
tions and their delivery after processing a batch of parts; receiving briefing before starting the processing of parts; The assembly of the tool is carried out in a special area for setting up tools of CNC machines.
9. Number of tools in setup - 25 (four tools: 1.12, 24.25 - from the previous setup):
1. End mill 6221-106.005 (planes 800x800).
2. Semi-finishing cutter (hole 0 259.0).
3. Finishing cutter (hole 0259DN9).
4. Semi-finishing cutter (hole 0169.0).
5. Finishing cutter (hole 0169.5H9).
6. Roughing cutter (hole 0 89).
7. Semi-finishing cutter (hole 0 89.5).
8. Finishing cutter (hole 0 90js6).
9. Roughing cutter (hole 0 79).
10. Semi-finishing cutter (hole 0 79.5).
1L Finishing cutter (hole 0 80js6).
12. Disc cutter 2215-0001VK8 (understatement 0 205).
13. Roughing cutter (hole 0 99).
14. Semi-finishing cutter (hole 0 99.5).
15. Finishing cutter (hole 0100js6).
16. Semi-finishing cutter (undercut 0130).
17. Drill 23004-200 (hole Ø 8.6).
18. Tap 26804Yu03 (K1/8" thread).
19. Drill 2301-0046 (hole 014).
20. Drill 2301-0050 (hole 015).
21. Zenker 2320-2373 No. 1VK8 (hole 015.5).
22. Reamer 2363-0050H9 (hole 015.95H9).
23. Reamer 2363-00550H7 (hole 016H7).
24. Drill 2317-0006 (centering).
25. Drill 2301-0061 (chamfers).
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Karga, position, index |
Time, min |
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Organizational preparation Total T P11 |
Map 25, pos. 1,3,4, ind. b |
4,0 + 2,0 + 2,0 8,0 |
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Setting up the machine * fixtures, tools, software devices: | |||
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set the fixture and shine |
Map 25, pos. 13 | ||
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move the table, the headstock is a zone convenient for adjustment |
Map 25, pos. 20 | ||
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set the initial operating modes of the machine (spindle speed) |
Map 25, pos. 21 | ||
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install tool blocks in the magazine and remove 21 tools |
Map 25, pos. 22 | ||
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insert the program medium into the reader and remove |
Map 25, resp 24 | ||
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check the operability of the reader and punched tape |
Map 25, resp 25 | ||
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set the initial X and Y coordinates (adjust the zero position) along the cylindrical surface |
Map 25, resp 29 | ||
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set the tool to the machining length (on the Z-axis for six tools: 1,7,12,16,24 and 25) |
Map 25, resp 30 | ||
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Total Т„ 2 | |||
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And |» O l O L F S II and s |
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In Trial office The detail is accurate (has surfaces with tolerances for lmams * t * ry over the I-th quality, a kanak) for four tools and three measured by dipmshru K; irta 2.4, 8.9 surfaces - e>*2c0hl0,<3 200Е17и канавка b = 10 тч. 6, чпл г Total T p lb Ka p. "2K, b.V + 1 SHSHSH'H.<ииС 1.1 |
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Total preparation time^final time per batch of parts
T "1 + T" 2 + T pr.ar
Example 5 Initial data
1. The name of the operation is vertical milling.
2. Machine - vertical milling with CNC.
3. Model of the machine - 6R13RFZ (with a table length of -1600 mm).
4. Model of the CNC device - NZZ-1M; program carrier - perforated tape.
5. Part name - bar.
6. Processed material - steel 45, weight -10 kg.
7. The method of installing the part is in a reconfigurable universal assembly device (USP).
8. Labor organization conditions: centralized delivery of blanks, tools, devices, documentation to the workplace and their delivery after processing a batch of parts; receiving briefing before starting to process parts.
9. Number of tools in the setup - 6 (tools 1 and 5 - from the previous setup):
1. Drill 2317-003 (centering).
2. Drill 22-2 (hole 0
3. Special end mill (for groove b = 20).
4. Cutter 2234-0007 (for groove b = 8H9).
5. Drill 6-1 (hole 0 6).
6. Countersink 2350-0106 VK6 (understatement 016).
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Trial Processing Slot milling L and AH9 and L slot * 634 Map 33, 192 |
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Total T pro60 _
Total preparation and closing time for a batch of parts
Toz 1 + T and # 2 + Tprobr
1.12.2. Example of calculating piece tool setting time
Initial data
1. The name of the operation is the assembly, adjustment and disassembly of a set of tools necessary for processing parts on a drilling-milling-boring machine.
2. Name of the device - BV-2027, with digital indication.
3. Characteristics of the machine - cone 7:24 No. 50.
4. Labor organization conditions: the delivery of tools and technical documentation to the workplace of a toolmaker is carried out by service production workers, the disassembly of a used tool is carried out by a toolmaker.
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Piece time, mi | |||||
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Applied tool |
Map, position, index |
kya us-groyku and collection * ku |
for disassembly | ||
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Drill 0 83, drill chuck, sleeve |
type of connection - 1 |
2,64 ■ 0,45 - 1,19 | |||
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2 Marks M10, adjustable thread-cutting chuck, holder |
type of connection - 2 |
3,15 * 0,65 = 2,05 | |||
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3 Spade drill 0 32, mandrel, sleeve |
type of connection - 1 | ||||
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4 Cutter mandrel adjustable for Map 38, oblique fastening, cutting, holder type of connection - 3, 0 boring hole - 80 mm | |||||
2. MULTIPLE SERVICE
2.1. To develop and improve the efficiency of multi-machine maintenance of machine tools with numerical control (CNC), the enterprise must create certain organizational and technical conditions that can significantly increase the productivity of operators and adjusters. Work on maintenance of CNC machines provides for the combination of the functions of the operator and the adjuster.
2.2. The most economically feasible form of labor organization in the areas of CNC machines is link (group). With a link (group) form, a certain service area is assigned to a link or a group of workers included in the brigade.
The experience of enterprises shows the advantage of the link form of labor organization in the maintenance of CNC machines, which ensures the best use of working time and equipment.
The best division of labor in servicing jobs of CNC machines is considered to be one in which the multi-machine operator and the adjuster have, along with the separated part of the common functions. General functions include the implementation of operational work, adjustment of machines; the function of setting up the equipment is carried out by the adjuster. This division of labor has economic and social benefits. The possibility of performing the same functions by two workers allows to reduce equipment downtime due to the coincidence in the need to service several machines and improve the use of working time. At the same time, the mastering of the adjustment functions by multi-machine operators increases the content of their work, creates opportunities for the growth of qualifications.
2.3. For the introduction of multi-machine maintenance and the rational use of working time, it is necessary to create a sufficient scope of work for each worker. Equipment, office equipment should be conveniently located, meet the requirements of the brigade form of labor organization. To do this, the design of the organization of jobs for multi-machine operators is carried out in accordance with the schemes presented in section 3.5. Preference should be given to schemes that ensure the full loading of the worker with active work, the shortest length of transitions within the workplace, and good visibility of all machines.
Distinguish between cyclic and non-cyclic maintenance of machines at a multi-machine workplace. In cyclic maintenance, the worker sequentially performs auxiliary work techniques, moving from machine to machine. With non-cyclic maintenance, the worker approaches the machine on which automatic work has ended, regardless of the location of the machines on the site.
2.4. Calculation of service rates
2.4.1. Service rates are set taking into account the normal amount of employment - K yes. When working on CNC machines, taking into account heterogeneous technological operations with a changing range of manufactured parts, K l l - 0.75 ... 0.85. When working on backup machines K A5 = 0.85. D95.
Z42. The calculation of the number of machines serviced by one worker, necessary for servicing the CNC equipment available at the site, and the number of the link is carried out according to the formulas:
a) when working on backup machines
P c \u003d (-bs- + 1) K L1; (21)
b) when working on machines that produce heterogeneous products,
"c \u003d + 1) to, (2-2)
where - the cycle time of the automatic operation of the machine (machine-programmed time for processing the part, the operation of the manipulator or robot, not overlapped by the processing time of the part), min (according to formula 13); 2j - the sum of the processing time
bottling of parts (according to the program and the operation of the manipulator or robot) at the workplace for the period of one cycle, min; T, - time of employment of a worker by performing manual, machine-manual work, active monitoring of the progress of the technological process, etc., min; Jj T a - the sum of the worker's employment time on all serviced machines for the period of one cycle, min; is the normal amount of employment.
The number of the link is calculated by the formula
S - -b "-, (23)
where S is the number of the link required to service the equipment available at the site, people; Pu Ch - the number of CNC machines installed on the site; n s - the number of machines serviced by one worker.
T, - T, y + TYo, + T MM(+ T. + Tn + T^, (2.4)
where T lu - time to install and remove the part manually or with a lift, min; Tio - auxiliary time associated with the operation (not included in the control program), min; T th - time of active monitoring of the progress of the technological process, min; T p - time of transitions of a multi-machine operator from one machine to another (during one cycle), min (given in Table 2.4); T m - auxiliary time for control measurements, min; - time for maintenance of the workplace, min.
2.43. The number of machines at multi-machine workplaces is determined on the basis of a comparative calculation of labor productivity and the cost of processing, especially when installing expensive equipment, such as multi-purpose CNC machines.
The economical number of machines served by a multi-machine can be determined by comparing the costs associated with the operation of a multi-machine and equipment, operating machines and various options for serviced equipment.
When calculating the number of serviced machines corresponding to the lowest total costs of performing operations, the costs of performing operations, the costs of embodied labor required to produce the same volume of products, which include depreciation costs, expenses for current repairs and maintenance, electricity, are taken into account, through from 0
ratio-and employment coefficient K/. 3
1. GENERAL
1.1. The standards for time and cutting conditions are intended for technical regulation of work performed on universal and multi-purpose machines p. numerical control in the conditions of small-scale and medium-scale types of production. One of the main characteristics of the type of production is the coefficient of consolidation of operations (К^), calculated by the formula
where O is the number of different operations; P is the number of jobs that perform various operations.
The coefficient of fixing operations in accordance with GOST 3.1121-84 is taken equal to:
10 < К м £ 20 - для среднесерийного типа производства;
20 < 3 40 - для мелкосерийного типа производства.
The value of the transaction fixing coefficient is taken for a planning period equal to one month.
The collection is based on the medium-scale type of production. For enterprises of a small-scale type of production or for individual sections in a medium-scale type of production, operating in conditions of small-scale production, correction factors for auxiliary time are applied.
1.2. When introducing a brigade (link, group) form of labor organization, the standards can be used to calculate service standards, complex time standards, production and number standards.
13. The use of machine tools with numerical control is one of the main directions of automation of metal cutting, gives a significant economic effect and allows you to free up a large number of versatile equipment, as well as improve product quality and working conditions for machine operators. The greatest economic effect from the introduction of machine tools with numerical control is achieved when processing parts with a complex profile, which is associated with constantly changing cutting parameters (speed, feed direction, etc.).
The use of machine tools with numerical control instead of universal equipment allows:
use multi-machine service and brigade (link, group) form of labor organization;
increase labor productivity by reducing auxiliary and machine processing time on the machine;
exclude marking operations and interoperational control; due to abundant cooling and favorable conditions for the formation of chips, increase the processing speed and eliminate the need for visual tracking of the markup;
automate the methods of auxiliary work (approach and withdrawal of a tool or part, setting a tool to a size, changing a tool), use the optimal tool trajectories;
Expenses * associated with one minute of work of the main multi-machine worker, prn the average percentage of raising the norms, taking into account the accrual of wages, the cost of maintaining auxiliary and maintenance personnel -
Rank of work
w
2.4.4. Employment Rate Calculation
t + t
w - operational time, min.
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Table 2.2 Cost of operating CNC machines for one minute |
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reduce the labor intensity of metalwork refinement due to obtaining high accuracy and less roughness of curved sections of contours and surfaces of parts;
reduce the labor intensity of the assembly of the product, which is due to the stability of the dimensions of the parts (increase in accuracy) and the elimination of fitting operations; reduce the cost of designing and manufacturing tooling.
L4. The collection is developed in two parts. Part I contains the standards for preparatory and final time, time for installing and removing a part, auxiliary time associated with the operation, for servicing the workplace, breaks for rest and personal needs, for control measurements, for tool setting outside the machine; part P contains cutting data standards that allow you to select the tool size, its geometric parameters, the brand of the cutting part of the tool, the required allowance, the number of feed strokes, cutting speeds, and the power required for cutting.
The standards for time and cutting conditions are given both in tabular form and in analytical form, thereby allowing the use of a computer when compiling a program and calculating time standards that correspond to the lowest operating costs and the highest machine productivity while ensuring increased reliability of the tool. The operation of tools in the modes recommended by the standards is possible only if the technological discipline of production is observed (equipment, tools, workpieces, tooling must meet the required standards).
The time standards given in the collection are calculated for the rationing of work when servicing one machine by a worker. When rationing multi-machine work to calculate the norm of time, it is necessary to use the guidelines and time standards for multi-machine work given in cards 17,18,19.
15. When developing standards for time and cutting conditions, the following materials were used as initial data:
primary materials of production observations on the organization of labor, technology, time consumption and cutting modes of engineering enterprises;
industry standards for time and cutting conditions developed by the Orgariminstrument GSPKTB (Moscow), Ryazan, Minsk and Novosibirsk branches of the Orgstankinprom Institute, the Center for the Scientific Organization of Labor of the Min-Tyazhmash (Kramatorsk), etc.;
Determination of time limits for rest and personal needs. Intersectoral guidelines (M.: Research Institute of Labor, 1982);
Development of multi-machine service and expansion of service areas in the industry. Intersectoral guidelines and scientifically based normative materials (M.: Research Institute of Labor, 1983);
General machine-building standards for auxiliary time, for servicing the workplace and preparatory and final time on metal-cutting machines. Small-scale and single production (M.: Research Institute of Labor, 1982);
General machine-building standards for auxiliary time, for servicing the workplace and preparatory and final work for work performed on metal-cutting machines. Medium and large-scale production (M.: Research Institute of Labor, 1984);
passport data of CNC and multi-purpose machine tools; technical literature.
1.6. The norm of time and its components
1.6.1. The norm of time for performing operations on CNC machines when working on one machine (H ^ consists of the norm of preparatory and final time (G in J and the norm of piece time (T ^)
a tta ^ a org a exc \
T D1 = Cr u . + T.-Kj(i +
where T n is the cycle time of automatic operation of the machine according to the program "min;
T.-T. + T., (13)
where T c is the main (technological) time for processing one part, min;
Tn = £ (1.4)
where C - the length of the path traversed by the tool or part in the feed direction when processing the technological section (including infeed and overrun), mm; S* - minute feed in this technological section, mm/min; T m - machine auxiliary time according to the program (for supplying a part or tool from the starting points to the processing zones and retraction; setting the tool to size, changing the tool, changing the magnitude and direction of the feed, the time of technological pauses (stops), etc.), min. ;
m. = Tn + + Tnn, (1.5)
ede T m - time to install and remove the part manually or with a lift, min; T w - auxiliary time associated with the operation (not included in the control program), min; T mai - auxiliary non-overlapping time for measurements, min; K TV - correction factor for the time of performing manual auxiliary work, depending on the batch of workpieces; а^, а^, а ex - time for technical and organizational maintenance of the workplace, for rest and personal needs during single-station service, % of operational time.
1.6.1.1. With a collective form of labor organization, complex norms of labor costs (H wrl, man-hour) are calculated, which can be obtained by applying corrective factors to the sum of operating norms calculated for the conditions of an individual form of labor organization. It is possible to use corrective coefficients to the sum of individual components of the complex norm, reflecting the total value of time spent by categories of these costs.
Complex norm Determined by the formula
n,p,= £n.n-k*, (1.6)
where H (- the norm of time for the manufacture of the i-th part of the brigade set, man-hour; i = 1,2,3, ..., l - the number of parts included in the brigade set;
N.R, \u003d S n * (1.7)
shche H Bpj - the norm of time to perform the j-th operation, man-hour; j = 1, 2,3,..., w - the number of operations required to manufacture the j-th part; - coefficient
teamwork effect (K^< 1).
The brigade work effect coefficient (K^) takes into account the average increase in labor productivity expected in the transition from the individual to the brigade form of labor organization, which should be included in the complex norms.
As a result of the redistribution of functions between members of the brigade, the implementation of mutual assistance or interchangeability, the required time to perform the amount of work assigned to the brigade is reduced, therefore, the corresponding time norm should be reduced. This happens due to the reduction
For more complete and detailed data, see Guidelines for the regulation of workers' labor under collective forms of its organization and stimulation. M.: Economics, 1987.
the values of the individual components of the time norm: auxiliary time, workplace maintenance time, regulated breaks, preparatory "Final time", and also due to the overlap of individual components of the time norm by machine time (in the latter case, the value of each component of the time norm may remain unchanged).
In cross-cutting teams, the labor intensity of manufacturing a team kit can be reduced by eliminating individual elements of the preparatory and final time and the time for servicing the workplace when transferring a shift "on the go".
Team work effect coefficients (К^) are established: at the industry level;
at the enterprise level, if there are no sectoral coefficients or they do not fully reflect the specifics of the brigade organization of labor at a particular enterprise.
are introduced as a Standard for the entire industry for a certain period (at least 1 year).
In order to expand the possibility of using the coefficient of the effect of team work, in addition to the total value of the coefficient, the values of each of its components are calculated.
The effect of teamwork can be obtained through the following components:
expansion of the combination of professions (K ^; expansion of multi-machine service (IQ; mutual assistance and interchangeability of team members (K,); shift transfer "on the go" in through teams (K 4); redistribution of functions between team members (K 3) and so on.
The total value is defined as the product of its components (for a given type of brigade), i.e.
K*-K,-K,-K, ...K, (1.8)
At the level of the enterprise, as a rule, the general values \u200b\u200bof K^ are established, taken during the period for which they are calculated, but not less than a year, if the conditions of production do not change.
If the brigade, in addition to workmen-workers, includes time workers in engineering and technical workers, then the complex time rate (man-hours) cl "then from the sum of the time norms of piecework workers, time workers and engineering and technical workers for the manufacture of one brigade set, adjusted for the teamwork effect factor.
L6.2 Auxiliary time limits for installation and removal of a part. The time standards for installing and removing a part are given by type of fixture, depending on the types of machines and provide for the most common methods of installing, aligning and fastening parts in universal and special clamps and fixtures. As the main factors influencing the time of installation and removal of the part, the mass of the part, the method of installation and fastening of the part, the nature and accuracy of alignment are taken. In addition to these factors, the xapierei of the mounting surface, the number of parts installed at the same time, the number of clamps, etc. were taken into account.
Standard time for installation and removal of the part provides for the following work:
when installing and removing manually
take and install the part, align and secure; turn the machine on and off; unfasten, remove the part and put it in a container; clean the device from chips, wipe the base surfaces with a napkin;
when installing and removing the part with an overhead crane
call the crane; sling the detail; transport the part to the machine; install the part, sling the part, align and secure; turn the machine on and off; unfasten the part; call the crane; sling the detail; remove from the machine, transport it to the storage place; unsling the part, clean the fixture or table surface from chips, wipe the base surfaces with a napkin.
When installing and removing a part with a hoist at a machine (or a group of machines), the same work is performed as when installing and removing a part with an overhead crane, except for calling the crane.
When installed in special fixtures, auxiliary time is defined as the sum of the time: for installing and removing one part; for the installation and removal of each subsequent part more than one in multiple fixtures; to fix the part, taking into account the number of clamps; for cleaning the device from chips, for wiping the base surfaces with a napkin.
At enterprises, in addition to universal and special devices on CNC machines, robots, manipulators and satellite tables are also used to install and remove parts.
Due to the wide variety of types and technical characteristics of robots and manipulators, it is not possible to develop time standards for installing and removing parts with their help; each enterprise needs to draw up maps on the use of robots. Appendix 15 is given as an example. For cases of work on multi-purpose machines using satellite tables, it is necessary to use map 20, which shows the scheme of loading satellites and the time of changing satellites.
In some cases, when the program provides for a special technological pause for re-fastening the part, the standard time should be reduced by an amount overlapped by the automatic operation of the machine. The regulations provide for the installation and removal of parts weighing up to 20 kg manually and over 20 kg using lifting mechanisms.
The time for manual installation of a part weighing more than 20 kg is given in the regulations for use in individual cases when processing in areas where there are no lifting and transport vehicles. It is not allowed to manually install parts weighing more than 15 kg for men under 18 years of age and women.
This takes into account that parts installed manually are at a distance of 2 m from the machine, and installed by a crane - up to 5 m.
1.6.3. The norms of the auxiliary epeuienu associated with the operation. Ancillary time associated with the operation is divided into:
auxiliary time associated with the operation, not included during the cycle of automatic operation of the machine according to the program and providing for the execution of the following work:
turn on and off the tape drive mechanism; set the specified relative position of the part and the tool along the X, Y, 2 coordinates and, if necessary, perform fine-tuning; open and close the cover of the tape drive mechanism, rewind, load the tape into the reader; check the arrival of a part or tool at a given point after processing; move the punched tape to its original position; install the emulsion splash guard and remove;
machine auxiliary time associated with the transition, included in the program and related to the automatic auxiliary work of the machine, which includes: supply of a part or tool from the starting point to the processing zone and withdrawal; setting the tool to the processing size; automatic tool change; turning the feed on and off; idle strokes during the transition from processing one surface to another; technological breaks provided
when abruptly changing the direction of feed, checking dimensions, inspecting the tool and reinstalling or re-clamping the part.
The machine auxiliary time associated with the transition, included in the program for the listed techniques, is determined according to the passport data of the machines or other regulatory documents, is included as constituent elements during the automatic operation of the machine and is not taken into account separately (see appendices 27-30, part II ).
1.6.4. Auxiliary time standards for control measurements. The required dimensions of parts processed on machines with numerical control are provided by the design of the machine or cutting tool and the accuracy of their settings.
In this regard, the time for control measurements (after the completion of work according to the program) should be included in the standard piece time only if it is provided for by the technological process and taking into account the necessary frequency of such measurements in the process of work, and only if it cannot be overridden by the cycle time of the automatic operation of the machine according to the program.
1.6.5. Standards of time for maintenance of the workplace. The time for maintenance of the workplace is given by the types and sizes of equipment, taking into account single-machine and multi-machine maintenance as a percentage of the operational time. Maintenance of the workplace includes the following works:
change of the tool (or block with the tool) due to its blunting; adjustment and readjustment of the machine during operation (change of tool offset value);
sweeping and periodic cleaning of chips during operation (except for sweeping chips from the base surfaces of the installation devices, the time for which is taken into account in the auxiliary time for installing and removing the part).
Organizational maintenance of the workplace includes work to care for the workplace (main and auxiliary equipment, technological and organizational equipment, containers) related to the work shift as a whole: inspection and testing of equipment during work;
layout of the tool at the beginning and its cleaning at the end of the shift (except for multi-purpose machines);
lubrication and cleaning of the machine during the shift;
receiving instructions for the foreman, foreman during the shift;
cleaning the machine and workplace at the end of the shift.
1.66. Standards of time for rest and personal needs. Time for rest and personal needs for the conditions of maintenance by one worker of one machine is not separately allocated and is taken into account in the time for maintenance of the workplace.
For cases of multi-station service, a map of the time of breaks for rest and personal needs is provided, depending on the characteristics of the work and with recommendations on the maintenance of rest.
1.6.7. Standards of preparatory and final time. The standards are designed for setting up CNC machines for processing parts according to embedded control programs and do not include additional programming directly at the workplace (except for machines equipped with operational program control systems).
The norm of time for setting up the machine is represented as the time for receiving preparatory and final work for processing a batch of identical parts, regardless of the batch, and is determined by the formula
T p, \u003d T pz1 + T pz2 + T prlbr, (1.9.
where T pz - the norm of time for setting up and setting up the machine, min; T pz (- the norm of time for organizational preparation, min; T pe 2 - the norm of time for setting up sgaik
fixtures, tools, software devices, min; - time limit for trial processing.
The time for preparatory and final work is set depending on the type and size group of equipment, as well as taking into account the features of the program control system, and is divided into time for organizational training; for setting up the machine, fixtures, tools, software devices; for a trial pass through the program or trial machining of the part.
The scope of work for organizational training is common to all CNC machines, regardless of their group and model. Time for organizational preparation includes:
receipt of an order, drawing, technological documentation, software carrier, cutting, auxiliary and measuring tools, fixtures, blanks before the start and handing them over after the processing of a batch of parts at the workplace or in the tool pantry;
familiarization with the work, drawing, technological documentation, inspection of the workpiece;
master's instruction.
In the brigade form of labor organization, when inter-shift transfer of workpieces is carried out, organizational preparation takes into account only the time for familiarization with the work, drawing, technological documentation, inspection of workpieces and instructing the master.
The composition of the work on setting up the machine, tools and fixtures includes methods of work of a setting nature, depending on the purpose of the machine and its design features:
installation and removal of fasteners;
installation and removal of the block or individual cutting tools;
setting the initial modes of operation of the machine;
installing the program carrier in the reader and removing it; zero position adjustment, etc.
Time for trial processing of parts on lathes (up to 630 mm) and turret groups includes the time spent on processing the part according to the program (cycle time) plus auxiliary time for performing additional techniques related to measuring the part, calculating corrections, and entering correction values into the CNC system , and auxiliary time for machine control and CNC control.
The time for trial processing of parts on lathes (630 mm) % of carousel, milling, boring groups, and general purpose machines includes the time spent on processing parts using the test chip method with a cutting tool, end mills, plus auxiliary time for performing additional techniques related to measuring the part, calculation of correction values, introduction of correction values into the CNC system, and auxiliary time for machine control and CNC control.
1.7. Standards of piece time for dimensional setting of the cutting tool outside the machine
1.7.1. Piece time standards are designed to standardize work on setting up a cutting tool for CNC machines, which is carried out by tool mechanics (tool setting) outside the machine in a specially equipped room using special devices.
The norms of piece time are set depending on:
type of devices used;
the type and size of the tool to be adjusted;
the number of customizable coordinates;
the nature of the setting (according to the actual size or to a given coordinate).
The following devices are used to set up tools at enterprises in the mechanical engineering and metalworking industries:
for machines of the drilling-milling-boring group - optical with digital indication type BV-2027, without digital indication type BV-2015 and contact type devices;
for machines of the turning group - optical with digital indication type BV-2026, without digital indication type BV-2010, BV-2012M and contact type devices.
Taking into account the specifics of the tool setting processes, the time standards are developed separately for the machines of the drilling-milling-boring group and the machines of the turning group.
The most advanced devices with digital indication are taken as the basis, but taking into account the correction factors given in the maps for changed operating conditions, these standards are used when rationing work on devices without digital indication (such as BV-2015, BV-2010, BV-2012M, etc.) and contact devices.
When setting up a tool without devices (using universal measuring instruments), the time standards must be calculated according to the standards for contact-type devices.
The unit time standards for assembling and setting up a cutting tool on imported devices with digital indication must be calculated according to the time standards for domestic-made devices such as BV-2027 n BB-2026 with a coefficient of 0.85; for devices without digital indication - but for devices gopa BV-2015 and BV-2010 with a coefficient of 0.9.
The normative materials of this section cover the most typical connection of a typical / cutting and auxiliary tool for the branches of mechanical engineering and metalworking and are presented in the form of enlarged standards for piece time.
When calculating the norms of time for assembly and adjustment of the cutting tool of the snow profile, take a multiplying factor of 1.2.
In addition to the time for the main work, assembling and setting up the tool, the unit time schedule includes additional time costs such as organizational and technical maintenance of the workplace, preparatory and final time and time for rest and personal needs in the amount of 14% of the operational time.
The expediency of including additional costs in the general time rate is due to the difficulty of separating them from the total time associated with preparing the workplace for tuning, and the time of the assembly itself and tool tuning.
To determine the norms of piece time for disassembling a used tool, in the cards for assembling and setting up a tool, correction factors are given, calculated differentially for each type of work.
Piece time standards for individual assembly methods and tool settings that are not included in the complexes are reflected in cards 50 and 51.
1.7.2. The norm of piece time for assembly, adjustment and disassembly of one tool is determined by the formula
T SLR \u003d T wk + m ^, 0.10)
food T - piece time for assembly, adjustment and disassembly of one tool, min; T shi - piece time for assembling and setting up one tool, min; T shr - piece time for disassembling the tool, min.
V * "b * T" p \u003d T - K '0-11)
where K is the correction factor for piece time, depending on the device used.
T SLR \u003d T w. + = t sh + t sh K = T shi (3 + K).
The most important operation is sirlilno-frosrao-restoring.
The main way to automate the processes of machining parts for small-scale and single-piece production is the use of machine tools with numerical control (CNC). CNC machines are semi-automatic or automatic, all moving parts of which perform working and auxiliary movements automatically according to a predetermined program. The structure of such a program includes technological commands and numerical values of the movements of the working bodies of the machine. The changeover of the CNC machine, including the change of the program, requires little time, so these machines are most suitable for automating small-scale production.
A feature of normalizing the operations of machining parts on CNC machines is that the main time (machine) and the time associated with the transition constitute a single value T a - the time of automatic operation of the machine according to the program compiled by the technologist-programmer, which consists of the main time automatic operation of the machine T o.a and auxiliary time of the machine according to the program T v.a t. e,
T a \u003d T o.a + T c.a;
T v.a \u003d T v.h.a + T oc t
where Li is the length of the path traveled by the tool or part in the feed direction during processing of the 1st technological section (taking into account the plunge and overrun); s m - minute feed in this area; i == 1, 2, ..., n - the number of technological processing sections; T v.h.a - time to perform automatic auxiliary moves (supply of a part or tools from the starting points to the processing zones and retraction, setting the tool to a size, changing the numerical value and direction of feed); T ost - time of technological pauses - stops of feed and rotation of the spindle for checking dimensions, inspection or tool change.
Auxiliary manual work time T in not overlapped by the time of automatic operation of the machine,
T in \u003d t set + t v.op + t counter,
where t mouth - auxiliary time for installation and removal of the part; t v.op - auxiliary time associated with the execution of the operation; t counter - auxiliary non-overlapping time for control measurements of the part.
Auxiliary time for installation and removal of parts weighing up to 3 kg on turning and drilling machines in a self-centering chuck or mandrel. is determined by the formula
t mouth \u003d aQ x
to determine the auxiliary time for insertion and removal of parts in centers or on the center arbor of a lathe
t mouth \u003d aQ x
to determine the auxiliary time for insertion and removal of parts in a self-centering or collet chuck on lathes and drilling machines
t mouth \u003d aD in x l y vy l
to determine the auxiliary time for the installation and removal of parts on the table or square of the drilling and milling machine
t mouth \u003d aQ x N y children + 0.4 (n b -2)
Coefficients and exponents for determining the auxiliary time for installing and removing parts in the vise of a drilling and milling machine
t mouth \u003d aQ x
Auxiliary time machine control. (turning, drilling and milling machines)
t v.op \u003d a + bSH o, Y o, Z o + sK + dl pl + aT a
Auxiliary time for control intentions.
t counter \u003d SkD z change L u
The preparatory-final time is determined
T p-z \u003d a + bn n + cP p + dP pp
After calculating T in, it is adjusted depending on the serial production. Correction factor
k c er \u003d 4.17 [(Ta + TV) n p + T p-z] -0.216,
where n p is the number of workpieces in the batch.
The preparatory-final time is defined as the sum of time: for organizational preparation; installation, preparation and removal of fixtures; setting up the machine and tools; trial run of the program. The main characteristics that determine the preparatory and final time are the type and main parameter of the machine, the number of tools used in the program, the correctors used in the operation, the type of fixture, the number of initial modes of operation of the machine.
The norm of piece time for the operation
T w \u003d (T a + T ser) (1 + (a obs + a ot.l) / 100].
The time for organizational and maintenance of the workplace, rest and personal needs,% of the operational time, is set depending on the main parameters of the machine and the part, the employment of the worker and the intensity of labor. It can be partially overlapped by the time of automatic operation of the machine; piece time in this case should be reduced by 3%.
Automation of the processing and auxiliary work on CNC machines creates the prerequisites for the simultaneous maintenance of several machines by the operator. The performance by the worker-operator of the functions of servicing the workplace on one of the machines usually leads to interruptions in the work of other serviced machines. The time for rest increases due to the higher intensity of labor in the conditions of multi-machine maintenance. The time of operational work in the norm of piece time increases due to the auxiliary time for transitions from machine to machine.
2.2 Rationing of the work of the main personnel of the organization
Consider the rationing of the work of key personnel on specific examples.
1. Organization, regulation and remuneration of machine work.
Multi-station service- this is a type of service in which one worker serves several machines. Multi-station service can be individual and team. The division of labor in multi-machine brigades is either qualification or functional; in some cases, the so-called pair service is used, when, for example, two workers of the same profession and qualifications serve several machines. Multi-station service is most beneficial if the non-overlapping machine time is greater than the time of manual operations, active observation, and transitions. However, it is not uncommon for a multi-machine service to be economically feasible even if this balance of time is violated, in particular, when there is a shortage of labor, when there is free equipment.
To establish time standards for each element of the production operation, regardless of the form of labor organization, analytical and calculation work is carried out separately. At the same time, they are guided by the provision that the norm of time for an operation must satisfy the following basic conditions:
1) the technological process provides for the rational and full use of technical means: equipment, fixtures, tools and mechanisms involved in the work;
2) processing mode is set based on best practices;
3) full loading of the working day with productive work is envisaged.
Consider the order of normalization of the main and auxiliary time.
The processing modes on the machine are selected by the technologist depending on the material, tool and equipment. The main time is determined by the formulas depending on the type of work (turning, milling) for each transition separately.
When working on metalworking machines, the cost rate of the main machine time can be determined by the formula (9):
to = li / n * S, (9)
where to is the norm of the main time, min; l is the estimated length of processing, mm; i is the number of passes; n is the number of revolutions or double moves available on the machine in one minute; S is the amount of feed of the cutting tool per revolution or double move , mm.
Rationing of auxiliary time is carried out using standards that are set depending on the type of production: more differential - in mass production, the most enlarged - in a single one. At the same time, complexes of labor auxiliary methods are first determined. So, in mass production, the auxiliary time for the operation is normalized according to the following sets of techniques:
1) Time to install and remove the part. The time standards for installing and removing a part in the general machine-building standards for auxiliary time are given for typical installation and fastening methods, taking into account their location when manually installed at a distance of 0.5-1 m from the machine.
2) The time associated with the transition consists of the time to approach the tool to the workpiece or surface to be machined, set the tool to a dimension, turn on the feed and rotate the spindle to take a test chip, measure when taking a test chip, turn on the spindle rotation and feed, retract the tool, and etc.
3) The time associated with changing the operating mode of the machine and changing the tool consists of the time of receptions for changing the speed of the spindle or table moves, the amount of feed, changing the tool, moving parts of the machine and fixtures.
4) The time for control operations includes the time spent on control measurements, which are made after the completion of surface treatment.
The features of remuneration for a multi-machine operator are determined, first of all, by the need to take into account the degree of his employment during the work shift and the establishment of appropriate additional payments to tariff rates. They are established depending on the ratio between the standard and project employment of the worker. The maximum level of surcharges, as a rule, should not exceed 30% of the tariff rate. This level corresponds to the equality of the project and standard employment levels, that is, surcharges increase as project employment increases, but only as long as the worker has time to rest during the shift.
2. Organization, standardization of stamping and foundry works.
When standardizing forging and stamping operations, which include hot forging under hammers and presses, landing on horizontal forging machines and free forging, the following features of this type of metal processing should be taken into account:
1) The presence of two parallel processes - heating of blanks, deformation of the metal and the need to separately determine the time for heating blanks, stamping (forging) and trimming parts.
2) The brigade nature of the work and the need to ensure a uniform load of each member of the brigade.
3) Insignificant specific gravity of the metal deformation time in the norm of piece time.
4) The need to determine auxiliary time for individual operations and techniques.
5) The need to use a differentiated rationing method for calculating manual and computer time.
6) Establishing a time limit for forging and stamping work according to the longest operational time of all members of the team, since when the process of heating blanks is carried out in parallel with the process of metal deformation, work is organized in such a way that the heating time of the blanks overlaps with the forging time and partially with the maintenance time of the workplace, therefore, the heating time is usually not included in the norms.
The rate of piece time for forging on hammers and presses, depending on the scale of production of blanks, is calculated by the formula (10):
tsht = (∑(to * Ky+ tv) * (1 + (αobs + αexc) / 100) * Km + tnsht) * Kn, (10)
where to is the main time of one hammer blow; Ky is the number of blows required to deform the metal; Km is the correction factor for forging various steel grades; tnshtv is the auxiliary time for free forging associated with the product; Kn is the correction factor that takes into account the change in the pace of work depending on batch size.
The correction factor values are given in Table 28.
Table 28
Correction factor Kn
In the General Machine Building Standards for Forging Time on Hammers and Presses, auxiliary time is given taking into account the time of breaks for rest and personal needs and the time of breaks associated with the organization of the technological process.
3. Organization, regulation of metalwork and assembly and welding works.
Locksmith work on the processing of blanks is a cold working of metals by cutting, performed by hand or mechanized tools. Such processing aims to give the part the required shape, dimensions and surface roughness by cutting with a hacksaw, chopping, filing, scraping, drilling, threading and chamfering, burrs
and so on.
Technological features of the listed processes are characterized by the tool and equipment used for this work. In assembly work, operations can be carried out directly at assembly sites without placing the product in a vice or on a workbench.
Rationing of metalwork and assembly works is carried out in the following sequence:
1) establishment of the object, purpose and method of normalization;
2) analysis of the actual operations of locksmith processing and assembly, identification of the compliance of the organization of labor at the workplace with the requirements of the NOT, the choice of a rational option for its technological content, which ensures the least expenditure of working time while observing the technical requirements presented for processing;
3) the choice of standards for standardization in accordance with the type of production, the nature of the work;
4) designing the content of the work according to the methods of work and identifying the compliance of the actual working conditions with the normative ones;
5) calculation of operational time for an operation based on determining the duration of individual elements of work on standard materials. Operational time is determined by the formula (11):
Top = ∑topi * k, (11)
where topi is the operational time of the i-th calculation complex of works, min; k is the total correction factor for changes in working conditions when performing the i-th calculation complex.
In the conditions of small-scale and single-piece production, operational time is not allocated when rationing locksmith and assembly work, and the calculation is carried out on an aggregated basis for piece time for each i-th settlement complex.
6) Calculation of time for maintenance of the workplace, rest and personal needs.
Plumbing and assembly work is mostly manual, so it is difficult to allocate auxiliary time. In the collections of standards for metalwork and assembly work (when normalized by operational time) there are two types of tables.
In the first type of tables, the main and auxiliary time is included in the norm of time, except for the preparatory and final time, time for servicing the workplace and time for rest and personal needs. The time norm is set per unit of measure.
In the second type of tables, the operating time is given with the inclusion of auxiliary time related only to the tool or the material being processed, but does not include the time associated with the entire part or assembly.
As for the regulation of welding work, it can be said that electric welding, gas, contact and electron beam welding are used in mechanical engineering.
Here, the main time is the time during which the formation of a weld occurs by melting the base and filler material (electrode, electrode or filler wire).
The main time for welding 1 m of the seam is determined by the formula (12):
to1I = (60 * F * Þ) / (J * αn), (12)
where F is the cross-sectional area of the weld, mm2; Þ - specific weight of deposited metal, g/cm3; J - welding current, a; αn - deposition coefficient, g/a * h.
The most common elements of auxiliary time, depending on the product and type of equipment for all types of arc welding, include the time to install, turn, remove the product, fasten and unfasten parts, and move the welder. For all types of arc welding, it is installed according to the standards.
In automatic and semi-automatic (cassette) welding, the time spent on refilling one cassette is separately allocated. The list of costs is given in table 29.
Table 29
Time for one cassette refill
Filling method |
Cassette characteristic |
Time for one |
|
weight, kg |
|||
Closed |
|||
Mechanized |
Open |
||
Closed |
|||
4. Features of the regulation of automated production operations.
The automated production process shows that in the organization of labor, its forms are influenced by the presence of automatic systems and apparatus.
The main way to automate the processes of machining parts for small-scale and single-piece production is the use of machine tools with numerical control (CNC). CNC machines are semi-automatic or automatic, all moving parts of which perform working and auxiliary movements automatically according to a predetermined program. The structure of such a program includes technological commands and numerical values of the movements of the working bodies of the machine. The changeover of the CNC machine, including the change of the program, requires little time, so these machines are most suitable for automating small-scale production.
A feature of normalizing the operations of mechanical processing of parts on CNC machines is that the main time (machine) and the time associated with the transition constitute a single value Ta - the time of automatic operation of the machine according to a program compiled by a technologist-programmer, which consists of the main time of automatic operation of the machine Toa and the auxiliary time of the machine according to the program Tva, that is, (13), (14), (15):
Ta = Toa + Tva, (13)
Toa = ∑ (Li / smi), (14)
Tva = Tvha + Toast, (15)
where Li is the length of the path traversed by the tool or part in the feed direction when processing the i-th technological section (taking into account the plunge and overrun); smi - minute feed in this section; i = 1, 2, ..., n - number of technological processing sections; Tvha -
time to perform automatic auxiliary moves (applying a part or tools from the starting points to the processing zones and retracting, setting the tool to a size, changing the numerical value and feed direction); Toast is the time of technological pauses-stops of feed and spindle rotation to check dimensions, inspect or change tools.
Flexible automated system(GPS)- this is a system of machine tools and mechanisms designed to process various structurally and technologically similar parts in small batches one by one without direct human participation. The constituent parts of the GPS are subsystems: technological, transport, storage, instrumental maintenance and automated control with the help of a computer.
The central element of the FMS is a flexible technological system (FTS), which is a set of multi-operation CNC machines (such as a machining center) that directly process objects.
Depending on the number of machines in the FMS, there are: flexible production module (FPM); flexible production line (GPL); flexible production site (GPU); flexible production shop (GPC) and plant (GPZ).
A flexible production module is a technological unit of equipment (CNC machine) equipped with manipulators or robots for loading and unloading parts and a tool magazine. The main feature of the GPM is the ability to work without human intervention and the ability to integrate into a system of a higher rank. The flexible line consists of several modules equipped with transport and tool systems and controlled by a microcomputer. Flexible section - a type of GPL; it differs in the composition and interchangeability of technological equipment and mode of transport.
Transport and accumulation subsystem represents a set of automated warehouses for blanks and parts, drives for machines with automatic loading and unloading and automatic vehicles that serve to move processed items from the warehouse to the machines and back (robot carts, conveyors, roller tables, etc. ).
The tool service subsystem includes warehouses for tools and fixtures, a department for preparing tools for work (sharpening, assembling, picking magazines, etc.) and a flexible automated system for installing, removing and moving tools from warehouses and back.
The automated control subsystem is a complex of technological tools with a computer capable of receiving information from the automated systems of an enterprise: automated control system (schedules), CAD (part drawing), ASTPP (technological process for processing and controlling a part), converting it from using control programs, transmit commands directly to the executive bodies of the equipment of all subsystems of the GPS.
Thus, two streams of resources function in the GPS: material and informational. The material flow ensures the performance of all the main and auxiliary operations of the processing of objects: the supply of workpieces, tools and their installation on machines; mechanical processing of parts; removing finished parts and moving them to the warehouse; tool replacement and relocation; control of processing and condition of the tool; chip cleaning and supply of coolant. The information flow provides: sequence, timing and number of processed items, provided for by the work plans of the State Border Service; transfer of processing programs directly to the executive bodies of machine tools, programs for the operation of robots, installation and transfer mechanisms, programs for providing blanks, tools, auxiliary materials, programs for managing the entire complex and accounting for its work, as well as group control of machines, transport and storage mechanisms, tool service system.
The main features of flexible manufacturing systems are as follows:
1) Employees of the State Fire Service are not directly involved in the impact on the object of labor. Their main task is to ensure the efficient operation of the equipment. With the change in the functions of workers, the cost structure of their working time changes. Most of it is spent on adjustment, preventive maintenance and repair of equipment.
2) The number of units of technological equipment of the State Fire Service exceeds the number of employees of each group: adjusters, repairmen, electronic engineers, etc. Therefore, it is necessary to establish optimal ratios between the number of units of equipment and the number of employees of each group, normalize the time spent in two sections : in relation to the equipment and to the workers.
3) In order to increase the level of reliability of the functioning of the State Fire Service, it is necessary to create integrated end-to-end teams with remuneration for labor according to the final product. At the same time, it should be taken into account that equipment downtime during and in anticipation of maintenance is the less, the wider the profile of each employee in relation to the functions performed and equipment service areas.
The theory and experience of operating the existing GPS show that at present the norms of the duration of operations in relation to equipment (norms of machine-tool intensity of operations), norms of labor intensity, norms of number and service have the greatest practical significance.
For practical calculations of the norms of duration, it is necessary to proceed from the division of the normalized time costs into direct and indirect. The former can be quite accurately calculated directly for a unit of production of a given type. The latter relate to all products manufactured at a given workplace or site, and therefore are included in the normalized duration of the operation in proportion to the amount of direct costs.
The procedure for calculating labor standards in the State Fire Service is as follows:
1) the coefficient of equipment utilization is determined by the time of automatic operation, necessary for the implementation of the production program;
2) the standards for the employment rate of employees of each group are determined;
3) based on the relevant standards, a preliminary version of the labor intensity of each type of work and the number of norms for each group of workers is calculated;
4) the load factors of employees of each group are determined, corresponding to the accepted version of the number norms;
5) the coefficient of automatic operation time is established, corresponding to the accepted version of the population standards;
6) the load factors of workers of each group and the time of automatic work are compared with their specified values;
7) the amount of costs for employees of all groups is determined;
8) for the variant of the norms of the number, recognized as optimal, the values of the norms for the duration of the execution of technological operations for each part are found;
9) based on the norms of number and duration, norms of labor intensity (time) are established for each detail, each group of workers and for the team as a whole.
In the conditions of automated production, including flexible production systems, direct, as a rule, include only the time spent on automatic operation of equipment. It is advisable to include indirect time costs in the norm of the duration of operations, based on the following formula (16):
Nd \u003d ta * (Tm / (Tm - Tnp)), (16)
where ta is the operating time of the machine in automatic mode during the manufacture of a unit of production in a given operation; Tm is the planned daily fund of the time of operation of the HPS; Tnp is the duration of normalized breaks in the operation of technological equipment associated with servicing and waiting for service by workers of all groups during Tm.
The value of Tnp should include only those real interruptions in the operation of the equipment that are objectively inevitable under the conditions of a particular FMS, based on the optimal equipment maintenance schedule, the established work regime and rest of workers. The composition of the TNP is determined by the design features of the analyzed system and operating conditions. As a rule, the value of Tnp includes the duration of adjustment, adjustment, and verification work that is not overlapped by machine time, downtime of equipment associated with regulated maintenance of mechanical, electrical, electronic and other subsystems, time for manufacturing and testing test parts, etc. e. When establishing the composition of the Type, one should strive to ensure that as much as possible overlap one work with another, perform them in parallel, combine the functions of employees of the State Fire Service, use the advantages of a brigade organization of labor, collective contracting.
In all SFSs, the equipment is not turned off during the rest of the workers, which should be installed according to a rolling schedule. Therefore, time for rest and personal needs is not included in the TNP. It is taken into account when calculating the optimal standards of service and number, which are set at a level that allows you to realize the standard time for rest due to the mutual substitution of workers.
The second multiplier can be expressed in terms of the utilization rate of the equipment in terms of the time of automatic operation (17):
Tmelt / (Tmelt - Tnp) = Tmelt / Ta = 1 / Ka, (17)
where Ta is the time of automatic operation of the equipment for the planned period of its operation Tm.
The average normalized production time (standard duration) is determined by the formula (18):
Nd \u003d ta / Cap, (18)
where Cap is the planned coefficient of equipment utilization by the time of automatic operation.
Formula (18) is most convenient for the practical regulation of the duration of operations, since it includes two parameters used in all the main technological and organizational-planning calculations of the GPS.
For practical calculations, the following formula for the complexity of operations (19) is convenient:
Ht \u003d (Nh / N * C * Ki) * Nd, (19)
where N is the total number of GPS modules; C is the number of equipment shifts; Ki is the planned equipment utilization factor.
When calculating the total employment of employees of the State Fire Service, it is advisable to separately take into account their employment with the main functions - the performance of production work and additional - the performance of supporting work (20):
Kz (X) \u003d Kp (X) + Ko (X), (20)
where Кп(Х) and Кo(Х) - the coefficient of employment of workers in this group by performing the relevant production and support work.
The optimal number of personnel of the State Fire Service is established on the basis of relations (21), (22):
Kz (X) ≤ Kzn, (21)
Ka (X) ≥ Kan, (22)
The coefficient Ka(X) is determined for each variant of the norms of the number of employees according to the formula (23):
Ka (Nch) \u003d Tpl - Tnp (Nch), (23)
where Тнп (Нч) - the duration of normalized breaks in the operation of the equipment, depending on the accepted option for the number of employees, the form of division and cooperation of labor, the equipment maintenance regulations, the mode of work and rest.
In the conditions of automatic lines (including rotary and rotary-conveyor) for labor rationing, the following are used: norms for the number of personnel; norms for the duration of the performance of production operations; norms of time (labor intensity of operations) for individual groups of workers and in general for the brigade serving the line; production standards; standardized tasks.
The main role is played by the norms of the number of personnel (adjusters, repairmen, electricians, electronic engineers) serving the line in accordance with the established regulations and ensuring the implementation of the production program.
The basis for calculating the norm of time and output in the conditions of automatic lines is the technical (passport) productivity of the line rm, which determines the number of units of production that can be obtained from this equipment per hour or in another unit of time when operating in automatic mode.
The production rate is set based on the technical performance of the unit and the line utilization rate according to the time of automatic operation (24):
Hb \u003d rm * Kan, (24)
After determining the production rate, the rate of labor intensity (time) is found for the i-th group (profession) of workers (25):
Hti \u003d Tm * (Nchi / Hv), (25)
On the basis of the norm of numbers, time and output, a normalized task is set. It indicates the scope of work for the regulated maintenance of the line in the planned period, the time to perform these works, the standard number of workers, the planned output of the line.
If products of several names are manufactured on an automatic line, then calculations of time standards and production can be carried out for sets of products. Along with this, for multi-subject lines, it may be more expedient to calculate the norms of duration Hd and labor intensity Ht according to the method for HPS. In this case, calculations are performed according to formulas (26), (27):
Ndk = tak / Kan, (26)
Htk \u003d Nh * (Ndk / But), (27)
where tak is the time of automatic operation of the equipment in the manufacture of parts of the kth type.
When developing a technological process for processing parts and control programs for CNC machines, one of the main criteria for assessing the perfection of the selected process or optimizing it is the rate of time spent on processing a part or a batch of parts. It is also the basis for determining the salary of a machine operator, calculating the load factor of equipment and determining its productivity.
The estimated rate of time (min) for processing one part (labor input) is determined from the well-known formulas:
piece time T pcs \u003d T o + T m.v + T v. u + T obs,
piece-calculation time
The total value of the operation time with all movements can be conditionally called the time of the tape T l \u003d T o + T m.v,
where T about - the total technological time for the entire operation of the transitions, min; T m.v - element-by-element sum of machine auxiliary time for processing a given surface (approaches, retractions, switching, turns, tool changes, etc.), taken from the machine's passport, depending on its technical data and dimensions, min.
The values of these two components of the norm of processing time are determined by the technologist-programmer when developing a control program that is recorded on punched tape.
The value of T l is practically easily checked when the machine is running using a stopwatch as the time from the start of processing in the automatic mode of starting the tape until the end of the processing of the part according to the program.
Thus, we obtain: operational time T op =T l + T v.y;
piece time T pcs \u003d T l + T v.y + T obs,
where T v.y - the time of installing the part on the machine and removing it from the machine, taken depending on the mass of the workpiece, min;
T obs \u003d T op * a% / 100 - time for maintenance of the workplace, personal needs and rest of the operator (accepted as a percentage of the operational time), min. For single-column lathes take a = 13%, i.e. T obs = = 0.13 T op, and for two-column T obs = 0.15 T op; then T pcs \u003d T op X (1 + a% / 100) min.
Scope of work for the maintenance of the workplace.
1. Organizational maintenance - inspection, warming up and running-in of the CNC device and the hydraulic system of the machine, equipment testing; receiving a tool from a master or adjuster; lubrication and cleaning of the machine during the shift, as well as cleaning the machine and workplace at the end of work; presentation of a test part to the Quality Control Department.
2. Maintenance - change of dull tool; input of tool length compensation; regulation and adjustment of the machine during the shift; removal of chips from the cutting zone during operation.
If the number of parts obtained from one workpiece on a lathe exceeds one and is equal to q, then when determining T pcs, it is necessary to divide T by the number of parts received q.
T p.z - preparatory and final time (determined for the entire batch of parts launched into processing P z). It consists of two parts.
1. The cost of a set of organizational work that is carried out constantly: the machine operator receiving a job assignment (order, drawing, software carrier) at the beginning of work and handing them over at the end of work; instructing the master or adjuster; installation of the working bodies of the machine and the clamping device in the initial (zero) position; installation of the program carrier - punched tape in the reader.
For all these works, the standards for lathes and vertical lathes allocate 12 minutes. If the design features of the machine tool or CNC system require, in addition to those listed, additional work, then their duration is determined experimentally and statistically and an appropriate correction is introduced.
2. The time spent on the performance of adjustment work, depending on the design features of the CNC machine. For example, for single-column lathes with CNC, the following time standards are accepted: to install four cams on the faceplate of the machine or remove them - 6 minutes; to install the fixture on the faceplate of the machine manually - 7 minutes, with a lift - 10 minutes; for installation of one cutting tool in the tool holder 1.5 min, its removal - 0.5 min; to install one tool holder in the turret head 4 min, removing it - 1.5 min; for installation at the beginning of work in the zero position of the crossbar and calipers - 9 min.
If the position of the tools is adjusted during the processing of a test part, then the time for processing the test part is also included in the preparatory and final part.
METHODOLOGICAL DEVELOPMENT ON THE DISCIPLINE
"TECHNOLOGY OF ENGINEERING"
Compiled teacher: Fazlova Z.M.
Introduction
The intensification of production, the successful introduction of the latest equipment and technology require the improvement of the organization of labor, production and management, which is possible only on the basis of technical regulation.
Labor rationing is the establishment of a measure of labor costs, ts of the total socially necessary costs of working time for the production of products of a certain consumer value for a given period of production and technical conditions. The most important tasks of labor rationing are the consistent improvement of the organization of labor and production, the reduction of the labor intensity of products, the maintenance of economically justified relationships between the growth of labor productivity and wages. Labor rationing should contribute to the active introduction of best practices, achievements of science and technology.
The methodological development “Rationing of work performed on machines with NC U” allows you to acquire the necessary skills to establish a reasonable time limit for performing a technological operation. It outlines the theoretical foundations for establishing time standards for a technological operation with CNC. The appendix contains the main machine-building labor standards.
REGULATION OF WORK, PERFORMED ON CNC MACHINES
The main way to automate the processes of machining parts for small-scale and single-piece production is the use of machine tools with numerical control (CNC). CNC machines are semi-automatic or automatic, all moving parts of which perform both working and auxiliary movements automatically according to a predetermined program. It includes technological commands and numerical values of movements of the working bodies of the machine.
The changeover of the CNC machine, including the change of the program, requires little time, so these machines are most suitable for automating small-scale production.
Time limit for performing operations on CNC machines Nvr consists of the norm of the preparatory and final time T pz and the norm of piece time T pcs:
(1)
T pcs \u003d (T c.a + T in K TV) 
(2)
Where n - the number of parts in the manufactured batch;
T c.a - cycle time of automatic operation of the machine according to the program, min;
T in - auxiliary time, min;
K TV - correction factor for the time of performing manual auxiliary work, depending on the batch of workpieces;
and those, a org, a ex - time for technological and organizational maintenance of the workplace, for rest and personal needs during one-stop service,% of the operational time.
The cycle time of the automatic operation of the machine according to the program is calculated by the formula
T c.a \u003d T o + T mv (3)
where T o - the main (technological) time for processing one part, min:
T o = 
(4)
L i - the length of the path traversed by the tool or part in the feed direction during the processing of the technological section (including infeed and overrun);
s m - minute feed in this technological area, mm/min;
T mv - machine auxiliary time according to the program (for approaching and retracting a part or tool from the starting points to the processing zones, setting the tool to a size, changing tools, changing the magnitude and direction of feed, the time of technological pauses (stops), etc.) , min.
Auxiliary time is defined as follows:
T in \u003d T v.y + T v.op + T v.meas (5)
where T v.y - time to install and remove the part, min;
T v.op - auxiliary time associated with the operation (not included in the control program), min;
T in. ism - auxiliary non-overlapping time for measurement, min.
Time limits for installing and removing a part are determined by types of fixtures depending on the types of machines and provide for the most common methods of installation, alignment and fastening of parts in universal and special clamps and fixtures.
Ancillary time associated with the operation, subdivided:
a) for auxiliary time associated with the operation, not included during the cycle of automatic operation of the machine according to the program;
b) machine-assisted time associated with the transition, included in the program, related to the automatic auxiliary operation of the machine.
The required dimensions of parts processed on CNC machines are provided by the design of the machine or cutting tool and the accuracy of their settings. Due to this time for control measurements should be included in the standard piece time only if it is provided for by the technological process, and it cannot be blocked by the cycle time of the automatic operation of the machine according to the program.
Workplace maintenance time is determined according to the standards and standard sizes of equipment, taking into account single-station and multi-station service as a percentage of the operational time.
Rest time and personal needs when servicing one machine by one worker, it is not allocated separately and is taken into account in the time for servicing the workplace.
Norms of preparatory and final time are designed for setting up CNC machines for processing parts according to embedded control programs and do not include additional programming directly at the workplace (except for machines equipped with operational program control systems).
Standards of piece time for dimensional setting of the cutting tool outside the machine are designed to standardize work on setting up a cutting tool for CNC machines, which is carried out by toolmakers outside the machine in a specially equipped room using special devices.
TYPICAL PROBLEM WITH SOLUTION
Initial data: detail - shaft (Fig. 1); material - steel 30G; surface precision 1,2,3 - IT10; surface roughness 1, 2 Ra5; 3 - Ra10.
Workpiece: production method - stamping (normal precision IT 16); surface condition - with a crust; weight 4.5 kg; surface treatment allowance: 1 - 6 mm; 2 - 4 mm; 3 - 5 mm.
Machine: model 16K20FZ. Passport data:
spindle speed P(rpm): 10; 18; 25; 35.5; 50; 71; 100; 140; 180; 200; 250; 280; 355; 500; 560; 630; 710; 800; 1000; 1400; 2000;
feed range s m (mm/min)
along the coordinate axis X- 0,05...2800;
along the coordinate axis z - 0,1...5600;
the greatest force allowed by the longitudinal feed mechanism is 8000 N, by the transverse feed mechanism - 3600 N;
main drive power - 11 kW;
regulation range of constant power electric motor speed - 1500...4500 rpm.
Operation: basing in the centers, with the leash on the surface.
1. Choice of stages of processing.
The necessary stages of processing are determined. To obtain the dimensions of a part corresponding to grade 10, it is necessary to process it from a workpiece of grade 16 in three stages: roughing, semi-finishing and finishing.
2. Choice of cutting depth.
The minimum required depth of cut for the semi-finishing and finishing stages of processing is determined (Appendix 5).
In the finishing stage for the surface 1, whose diameter corresponds to the size range 8...30 mm, recommended depth of cut t = 0.6 mm; surface 2, the diameter of which corresponds to the range of sizes 30...50 mm, t= 0.7mm; for surface 3, the diameter of which corresponds to the size interval 50...80 mm, t = 0.8 mm.
Similarly, in the semi-finishing stage for surface / it is recommended t = 1.0 mm; surface 2 - t - 1.3mm; for surface 3 - t = 1.5 mm.
Figure 1 - Shaft sketch and tool path
The depth of cut for the roughing stage of processing is determined based on the total allowance for machining and the sum of the depths of cut of the finishing and semi-finishing stages of processing: for surface 1 - t = 4.4mm; for surface 2 - t = 2.0mm; for surface 3 - t = 2.7 mm. The selected values are entered in table 1.
Table 1 - Definition of cutting mode
|
Cutting mode value |
Surface treatment stage |
||||||||
|
Draft |
semi-finishing |
Finishing |
|||||||
|
Depth of cut t, mm | |||||||||
|
Tabular feed s from, mm / rev | |||||||||
|
Accepted feed s pr, mm / rev | |||||||||
|
Tabular cutting speed V t, m/min | |||||||||
|
Corrected cutting speed V, m/min | |||||||||
|
Actual spindle speed n f, m/min | |||||||||
|
Actual cutting speed V f, m/min | |||||||||
|
Tabular cutting power N t, kW | |||||||||
|
Actual cutting power N, kW | |||||||||
|
Minute feed s m, mm/min | |||||||||
3. Tool selection.
On the machine 16K20FZ, cutters with a holder section of 25 x 25 mm are used, the plate thickness is 6.4 mm.
Based on the processing conditions, a trihedral shape of the plate with an angle at the top is taken 
° hard alloy T15K6 for roughing and semi-finishing stages of processing and T30K4 - for the finishing stage (Appendix 3).
Standard durability period: T = 30 min.
4. Feed selection.
4.1. For the roughing stage of processing, the feed is selected according to adj. 3.
For surface 1 when turning parts with a diameter of up to 50 mm and a depth of cut t = 4.4 mm recommended feed s =0.35 mm/rev. For surfaces 2 and 3, respectively, the feed s from =0.45 mm/rev. is recommended. and s from =0.73 mm/rev.
App. 3 Feed correction factors are determined depending on the tool material TO s and = 1.1 and plate mounting method K sp = 1,0.
4.2. For the semi-finishing stage of processing, the feed values are determined by adj. 3 in the same way: for surfaces 1 And 2 s from =0.27 mm/rev., surfaces 3 s from =0.49 mm/rev.
Feed correction factors depending on tool material K s and = 1.1, method of fixing platinum K sp = 1.0.
App. 3 we determine the correction factors for the feed of the roughing and semi-finishing stages of processing for the changed processing conditions: depending on the section of the cutter holder TO s d = 1.0; cutting edge strength K s l = 1.05; mechanical properties of the processed material TO s and = 1.0; workpiece installation schemes TO at =0.90; workpiece surface conditions K s p =0.85; geometric parameters of the cutter K sp =0.95; machine stiffness K sj = 1,0.
The final feed of the roughing stage is determined by:
For surface 1
s pr1 \u003d 0.35 1.1 1.0 1.0 1.05 1.0 0.9 0.85 0.95 1.0 \u003d 0.29 mm / rev. ;
For surface 2
s pr2 \u003d 0.45 1.1 1.0 1.0 1.05 1.0 0.9 0.85 0.95 1.0 \u003d 0.38 mm / rev. ;
For surface 3
s pr3 \u003d 0.73 1.1 1.0 1.0 1.05 1.0 0.9 0.85 0.95 1.0 \u003d 0.61 mm / rev.
Similarly, the feed rate of the semi-finishing stage of processing is calculated:
for surfaces 1 And 2 s pr1.2 = 0.23 mm / rev.;
for surface 3 s pr3 = 0.41 mm/rev.
surface 1 s from1 \u003d 0.14 mm / rev.,
surface 2 s from2 \u003d 0.12 mm / rev.,
for surface 3 s from3 =0.22 mm/rev.
App. 3 correction factors are determined for the feed of the finishing stage of processing for changed conditions: depending on the mechanical properties of the material being processed TO s = 1.0; workpiece installation schemes TO at=0.9; tool nose radius K st = 1.0; workpiece accuracy quality l 4 = 1.0. The final feed of the finishing stage of processing is determined by:
surface 1 s pr \u003d 0.14 1.0 0.9 1.0 1.0 \u003d 0.13 mm / rev.,
surface 2 s p p \u003d 0.12 1.0 0.9 1.0 1.0 \u003d 0.11 mm / rev.,
For surface 3 s p p = 0.22 1.0 0.9 1.0 1.0 = 0.20 mm/rev
The calculated feed rates for the finishing stage of surface treatment are entered in Table. 1.
5. Choice of cutting speed.
At the roughing stage of processing of alloy steel with a crust with a depth of cut t = 4.4 mm and feed s pr \u003d 0.29 mm / rev. cutting speed for surface 1 V t = 149 m/min; with depth of cut t = 2.0 mm and feed s p p =0.38 mm/rev. surface cutting speed 2 V t \u003d 159 m / min; with depth of cut t \u003d 2.7 mm and feed s pr \u003d 0.61 mm / rev. cutting speed for surface 3 V t = 136 m/min.
App. 8, 9 correction factors are selected for the roughing stage of processing depending on the tool material: for the surface 1 TO in = 1.0, for surfaces 2 and 3 TO in =0,95.
The final cutting speed for the roughing stage will be:
surface 1 V 1 = 149 0.85 = 127 m/min;
surface 2 V 2 = 159 0.81 = 129 m/min;
surface 3 V 3 = 136 0.98 = 133 m/min.
5.2. At the semi-finishing stage of processing alloyed steel without skin with a depth of cut t up to 3.0 mm and feed s p p = 0.23 mm / rev. cutting speed for surfaces 1 And 2 - V T = 228m/min; with depth of cut t = 1.5 mm and feed s pr \u003d 0.41 mm / rev. cutting speed for surface 3 - V t = 185 m/min.
Correction factor for semi-finishing depending on tool material K v = 0,95.
App. 8, 9, the remaining correction factors for the cutting speed are selected during the roughing and semi-finishing stages of processing for the changed conditions:
depending on the material machinability group TO v With = 0,9;
type of processing K vo = 1,0;
machine stiffness K vo = 1,0;
mechanical properties of the processed material TO v m = 1.0; geometric parameters of the cutter:
for surfaces 1 And 2 K v f =0.95, for surface 3 K v f = 1.15; tool life TO v T = 1,0;
availability of cooling TO v and = 1,0.
Finally, the cutting speed at the roughing stage is determined by:
surface 1 And 2 V 1,2 = 228 0.81 = 185 m/min;
surface 3 V 3 = 185 0.98 = 181 m/min.
5.3. The cutting speed for the finishing stage of processing is determined by adj. 8, 9:
at t \u003d 0.6 mm and s p p \u003d 0.13 mm / rev. surface 1 V T =380 m/min;
at t \u003d 0.7 mm and s p p \u003d 0.11 mm / rev. surface 2 V T =327 m/min;
at t \u003d 0.8 mm and s p p \u003d 0.2 mm / rev. V T =300 m/min.
App. 8, 9, the correction factor for the cutting speed for the finishing stage of processing is determined depending on the tool material; K V n =0.8. Correction factors for the finishing stage numerically coincide with the coefficients for the roughing and semi-finishing stages.
General correction factor for cutting speed at the finishing stage of processing: K v = 0.68 - for surfaces 1 And 2; K v = 0.80 - for the surface 3.
Final cutting speed at the finishing stage:
surface 1 V 1 = 380 0.68 = 258 m/min;
surface 2 V 2 = 327 0.68 = 222 m/min;
surface 3 V 3 = 300 0.80 = 240 m/min.
Tabular and corrected cutting speed values are entered in table. 1.
5.4. Spindle speed by formula
At the rough stage of surface treatment 1
n = =1263 rpm
The rotational speed available on the machine is taken, n f = = 1000 rpm. Then the actual cutting speed is determined by the formula:
V f = = 97.4 m/min.
The calculation of the spindle speed, its adjustment according to the machine passport and the calculation of the actual cutting speed for other surfaces and processing stages are carried out similarly. The calculation results are summarized in Table. 1.
Since the 16K20FZ machine is equipped with an automatic gearbox, the accepted values of the spindle speeds are set directly in the control program. If the machine used has manual switching of the spindle speed, it is necessary to provide technological stops for switching in the control program or to set the smallest of the calculated speeds for all surfaces and processing stages.
5.5. After calculating the actual cutting speed for the finishing stage of machining, the feed is adjusted depending on the roughness of the machined surface.
App. 8, 9 for roughness no more Ra5 when processing structural steel with a cutting speed V f = 100 m/min with a cutter with a radius at the top r in = 1.0 mm, it is recommended to feed s from = 0.47 mm/rev.
App. 8, 9 correction factors for the feed, the roughness of the machined surface for the changed conditions are determined: depending on:
mechanical properties of the processed material To s =1,0;
tool material K s and = 1.0;
type of processing K s about =1,0;
the presence of cooling K s W =1.0.
The final maximum allowable roughness feed for the finishing stage of surface treatment 1 and 2 is determined by the formula
s o \u003d 0.47 1.0 1.0 1.0 1.0 \u003d 0.47 mm / rev.
Feeds for the finishing stage of surfaces 1 and 2, calculated above, do not exceed this value.
None of the calculated values exceeds the drive power of the main movement of the machine. Therefore, the established cutting mode in terms of power is feasible (the calculation is not given).
6. Definition of minute feed.
Minute feed formula
s m \u003d n f s o
At the roughing stage for surface 1
s m \u003d 1000 0.28 \u003d 280 mm / min.
The values of the minute feed for the remaining surfaces and processing stages are calculated similarly and are plotted in Table. 1.
7. Determining the time of automatic operation of the machine program.
The time of automatic operation of the machine according to the program for the general part.
For the I6VT2OFZ machine tool, the turret locking time Tif = 2 s and the time for turning the turret by one position Tip = 1.
The results of the calculation are given in table. 2.
8. Determination of the norm of piece time.
8.1. The norm of piece time is determined by the formula (2)
8.2. Auxiliary time consists of components, the choice of which is carried out according to the 1st part of the standards (formula (5)). Auxiliary time for installation and removal of the part T v.y = 0.37 min (app.12).
The auxiliary time associated with the operation, T v.op, includes the time to turn the machine on and off, to check the return of the tool to a given point after processing, to install and remove the shield that protects against splashing with emulsion (Appendix 12, 13):
T v.op \u003d 0.15 + 0.03 \u003d 0.15 min.
Auxiliary time and control measurements contains the time for two measurements with a one-sided limit bracket, four measurements with a caliper and one measurement with a simple shaped template (app. 18):
T in.out =(0.045+0.05)+(0.11+0.13+0.18+0.21)+0.13=0.855 min.
8.3. The time of automatic operation of the machine according to the program is calculated for each section of the tool trajectory and is summarized in Table. 2.
Table 2 - The time of automatic operation of the machine according to the program
Continuation of table 2
|
Section of the trajectory (position numbers of the tools of the previous and working positions) |
Movement along the Z axis, mm |
Travel along the X axis, mm |
Length of the i-th section of the tool path |
Minute supply on the i-th section |
The main time of automatic operation of the machine according to the program |
Machine-assisted time |
|
Tool #2 - tool number 3 | ||||||
|
Tool #3 - tool no. 4 | ||||||
8.4. The final cycle time of the automatic operation of the machine according to the program
T c.a \u003d 2.743 + 0.645 \u003d 3.39 min.
8.5. Total auxiliary time
B \u003d 0.37 + 0.18 + 0.855 \u003d 1.405 min.
8.6. Time for organizational and maintenance of the workplace, rest and personal needs is 8% of the operational time (Appendix 16).
8.7. Finally, the norm of piece time:
T PC = (3.39+ 1.405) (1+0.08) = 5.18 min.
9. Preparatory and final time.
The preparatory-final time is determined by the formula
T pz \u003d T pz1 + T pz2 + T pz3 + T p. arr.
Time for organizational preparation: T pz1 = 13 min,
time to set up a machine, fixture, numerical control device
T pz2 = 4.0 + 1.2 + 0.4 + 0.8 + 0.8 + 1.0 + 1.2 + 1.2 + 2.5 + 0.3 = 13.4 min;
time for trial processing
T ex. arr \u003d 2.2 + 0.945 \u003d 3.145 min.
Total preparatory-final time
T pz = 13 + 13.4 + 3.145 = 29.545 min.
10. Part lot size
n= N/S,
where S is the number of launches per year.
For medium series production S = 12, therefore,
n = 5000/12=417.
11. Piece-calculation time
T pcs. to = T PC + T pz / n= 5.18 + 29.545/417 = 5.25 min.
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