Woodworking is one of the rapidly developing areas in the Russian industry. Modern woodworking production makes it possible to obtain lumber, log cabins, furniture and many other products through wood processing.

How to improve efficiency?

Sawmilling is a traditional craft for our country. But, compared to the past, modern equipment allows cutting, drying and processing wood not only better, but also faster. Woodworking production today is aimed at increasing the efficiency of sawmilling through the introduction of new processing technologies and innovative equipment. As a result, many processes become mechanized, old machines are replaced by new models, automatic wood processing lines are introduced with its rejection and sorting.

Sawing features

Wood products are made from wood and processed in different ways, depending on what the woodworking industry is specifically engaged in: logging, furniture and wood pulp production, paper, cardboard and products made from them, and so on. In general, the steps can be described as follows:

1. It is carried out on a specially selected site for logging.
2. Sawing wood and sawing fallen trees into logs.
3. Rejection to sort large and small logs of different diameters.
4. Already at the sawmill, the processing of logs into lumber using circular or band saws. It must be said here that the production of woodworking equipment is being carried out at an active pace today, therefore woodworking is both faster and better.

Consider the above technological stages a little more.

Cutting and drying

These two processes are closely related, and they can follow the enterprise in different sequences. Most often, the wood is dried directly in the boards, and the lumber is cut into blanks already in a dry form. According to experts, if drying is carried out in boards, then the output is 2-3% more lumber. In addition, cutting already dried boards allows you to timely notice defects and defects in wood and reject unsuitable elements.

The technology of woodworking industries involves drying in several ways, but most often - either atmospheric or using special chambers. Atmospheric drying is a lengthy process that involves storing wood for outdoors. Usage drying equipment allows you to speed up the harvesting process. It is worth remembering that the quality of the final construction depends on the degree of drying of the lumber.

What technologies?

Modern woodworking production involves the processing of harvested wood in various ways. Note that any mechanical woodworking processes are complex cutting. But, depending on the technological goals, the woodworking process can be reduced to three actions:

1. Wood and wood-based materials are subject to division.
2. All elements undergo surface treatment, within which technological allowances are removed.
3. Materials are subjected to deep processing, during which finished blanks are turned into finished parts of products.

The division of wood can occur with or without the formation of waste chips. Surface machining involves milling, grinding and turning, while deep machining involves drilling, deep milling and chiselling. Each of these processes has its own characteristics. Sawing, milling, peeling, grinding, turning, drilling - all these are technologies on the basis of which any woodworking production works. By the way, this is the first product that schoolchildren create at a technology lesson in the fourth grade. It is at this age that children get acquainted with the process of woodworking.

Protective measures

Wood is a material that is not resistant to external environmental factors. That is why at any enterprise that works with wood, protective measures are necessarily taken. Their task is to prevent the destruction of wood and protect it from fire, fungus, mold. As part of these activities, not only thorough drying of the material is carried out, but also chemical treatment using antiseptics. In most cases, sawmilling and woodworking industries for this purpose use antiseptics with an oily base, varnishes that do not dissolve in water. Processing is carried out with wood tar, creosote oil, carboleum.

What is produced?

Modern wood processing enterprises strive to optimize their technologies in order to obtain a larger volume of end products using less wood. Woodworking production allows you to get a variety of end products:

• MDF boards. D For their production, production waste is used, which is ground and processed with steam under high pressure- the mass is rubbed, then dried and glued.
• Slatted wood. This semi-finished product is obtained by gluing strips of already dried wood.
• Chipboard boards. They are panels of uniform thickness based on chips mixed with binders.
• Plywood. It consists of sheets of wood of different thicknesses, which are glued together with special adhesives.

What machines?

Woodworking machines for production are presented in a huge variety and can perform the most various works associated with material processing. Popular equipment includes:

• Combined machines is a multi-purpose equipment capable of sawing, planing, drilling, cutting spikes and so on. These machines are used in the complex processing of blanks made of natural wood or its waste.
• Lathes they process the workpiece by cutting and turning, cut out the thread, process the ends, drill holes.
• Band saws make it possible to perform straight or figured sawing of materials. The blade in such equipment is a continuous metal band with teeth.
• Milling machines perform work on guide lines, while the material is brought in manually. The use of such equipment is advisable in the profile, planar and shaped processing of wood blanks.
• Drilling machine allows you to process holes, removing chips;
• Panel saws allow piece-by-piece or batch cutting of slab materials.
• Circular saws are tools that have hard teeth that can process wood.

This is only a small part of the machines that are used in woodworking. With their help, you can create lumber, blanks, semi-finished products, which are further used in construction, furniture and other areas.

conclusions

It should be noted that every year both technologies and equipment used for wood processing are becoming more and more perfect. And this, in turn, makes it possible to create a variety of products from this natural material. Note that even at school, and in elementary school, woodworking is studied. The product "Ladder-support for plants" is the first thing a child can create already in the fourth grade. This makes it possible to teach children to take good care of wood and nature in general even at an early age and to draw attention to logging and woodworking as one of the actively developing areas in Russia.

TO category:

Woodworking machinery

Mechanization and automation of production

Under the mechanization of technological processes understand the partial replacement manual labor machine. Human participation is necessary here to load and unload parts, control their accuracy and quality of processing.

Under the automation of technological processes is understood the control of individual machines or a group of machines and control over them, excluding the direct participation of a person in this. Automatic machine or the line work according to a program that was pre-compiled and debugged by a person. The use of automation in the woodworking industry improves the quality of products and labor productivity, and also significantly improves the working conditions of workers.

IN furniture production, despite the large range of products, mass production of parts from sheet and panel materials is being created with the widespread use of semi-automatic machines, automatic machines and automatic lines.

Semi-automatic machines are machines that operate in an automatic cycle, the repetition of which requires the intervention of a worker. Usually, on semi-automatic machines, the worker manually sets, fixes and detaches the workpiece, turns on the feed to carry out the work cycle.

Automatic machines are machines on which parts are made without the direct participation of the worker. The operator only periodically loads stores or feeders, measures and controls the machined parts, adjusts the machine as it is misaligned.

Automatic line - a set of main, auxiliary, transport equipment and mechanisms that provide automatic basing, fixing, rotation and movement of workpieces in order to perform technological operations in the required sequence and at a given rhythm without the direct participation of a person. The functions of the worker are to control the operation of the equipment and its timely adjustment, as well as to ensure uninterrupted loading of workpieces at the beginning of the line and unloading of finished parts at its end.

At integrated automation in one continuous technological process, various technological operations are combined (for example, cutting, veneering, trimming, grinding).

into a single automatic system several automatic lines of serial or parallel action can be combined. Such systems of automatic lines are called automatic sections. If the main production processes are carried out on automatic lines, then their combination forms an automatic workshop or plant.

Automation of production qualitatively changes the content labor actions worker. These actions consist in setting up and setting up equipment, performing minor repairs and testing equipment, monitoring the progress of the production process, controlling the quality of processing finished products, etc. The degree of efficiency in using expensive equipment depends on the skill and qualifications of the worker performing these functions.

CHAPTER X MECHANIZATION AND AUTOMATION OF WOODWORKING PRODUCTIONS

MACHINE LINES

In the seven year development plan National economy Soviet Union extensive mechanization and automation of woodworking industries is envisaged. Mechanization and automation open up great opportunities for improving the quality and increasing output, reducing its cost, increasing labor productivity, and improving working conditions.
Mechanization and automation of production processes is the basis for creating a continuous mass production in the woodworking industry. Flow methods of organizing the production process contribute to the growth and improvement of production on the basis of higher technology.

Flow semi-automatic and automatic lines are being introduced both at individual technological sites and at plants as a whole. In the latter case we are talking already about the creation of automatic factories.

Automatic lines consist of machine tools or automatic machines that perform processing and control operations; devices used for loading and unloading the line and transporting parts from one machine to another without intervention from the worker; devices that serve to fix (fix) parts during their processing, and a unified control system for lines.

The line is serviced by one operator located at the central control panel. If the loading of blanks and unloading of products, as well as their intermediate control and rejection, are carried out by workers, then in this case the line is called semi-automatic.

Automation of technological processes in woodworking is currently developing in three directions. Automatic lines are created or based on existing universal machines general purpose with their partial reconstruction, or on the basis of new specially designed specialized stacks, or on the basis of universal machines general use and new specialized machines (combined acquisition).

One of the factors that determine the performance of automatic lines is the design feed rate. To maximize the use of lines, it is important to exclude time losses associated with loading the bunker, harvesting products, transporting material, as well as eliminating downtime associated with changing the cutting tool, setting up the line, lubricating, checking the condition of critical components, etc.

The productivity of automatic lines is much higher than conventional production lines. The number of service workers is reduced, the area under the machines is reduced. Working on automatic lines is safer and less tiring, it comes down to watching the machines and operating the line, putting workpieces into loading devices at the beginning of the line and removing finished products at the end of the line. However, the automation of processes in the presence of complex automatic equipment requires a higher qualification of workers for its maintenance and a good knowledge of many designs of woodworking machines.

The basis for further technical progress in sawmilling and woodworking production - mechanization and automation production processes, aimed at solving one of the important tasks - replacing manual labor with the work of mechanisms and machines.

Mechanization is the replacement of manual labor by machines. In this case, the machine performs the work that was previously performed by a person with the help of muscle power.

However, during the operation of this machine, a person cannot move away from it, since he must perform a number of auxiliary operations, without which the machine ceases to perform its functions. Sometimes the performance of such a machine is limited by the physical capabilities of a person and it is not fully used.

The working machine (non-automated) has, as a rule, the mechanisms of working moves and performs mainly the main working movements. Auxiliary operations, such as loading blanks, clamping, etc., are performed by a person. In this case, the entire production process is based on the interaction of man and machine. The sequence, (program) of performing operations is chosen by the person himself.

Automation is a higher stage in the development of machine production, in which a person is freed not only from physical labor but also from the duties of operational management of the mechanisms that carry out the production process. There is no need for continuous maintenance of the automatic machine, and a person can move away from it, since it itself performs all the main and auxiliary operations of the production process. The performance of such a machine is not related to the physical capabilities of a person, so it can reach a high level.

An automatic machine (machine) is a self-controlled working machine that performs the entire range of assigned operations. All the functions of managing the production process, i.e. turning on and off individual mechanisms, changing the order of operation of the working bodies, are performed by special devices. These devices without human intervention can maintain technological processing modes within the specified limits.

At the first stage of development of automation, the task was to automate the execution of individual operations. Interoperational transportation of blanks and parts, as well as other auxiliary operations, were performed manually.

IN modern conditions automation tasks have expanded significantly. Now automation covers all parts of the production process, including transport, loading and unloading operations and control of finished parts. In some cases, pipelines with automatic addressing are used.

With the introduction of automated lines, it became necessary to develop fundamentally new designs of products, which would make it possible to radically improve the technological methods of their manufacture. The design of manufactured products must meet the requirements of highly mechanized production.

Thus, the concept of production automation covers a wide range of measures for the development of technological processes for the manufacture of products and the creation of high-performance automatically operating means of production.

The automation process affects not only technical, but also social aspects production, determines fundamental shifts in the economy and organization of production. In our country, in recent years, large-scale automated production has been organized for the production of window and door blocks, board materials and parquet.

The complex mechanization of sawmilling and woodworking processes is associated with the creation of machine systems that combine the performance of various operations of processing, assembly, transportation, and sometimes control of products. Such machine systems include equipment arranged in the order of the sequence of operations of the technological process and are called lines.

Lines of sawmills and woodworking machines are divided into flow, semi-automatic and automatic according to the degree of automation.

A line is called a line of working machines arranged in the order of the sequence of technological operations and requiring individual maintenance. The machines that are part of the production line may or may not be connected by transport devices.

An automatic line is a system of interconnected working machines (machines, auxiliary equipment etc.), located along the technological process and automatically carrying out the assigned sequence of technological operations without the intervention of the worker. Such a system needs only periodic monitoring, adjustment and technical maintenance by the operating personnel. Loading the head machine of the automatic line and receiving finished products are also carried out automatically with the help of special loading and unloading devices.

If some operations of the technological process are not automated and require individual maintenance, the line is called semi-automatic.

Lines can include universal, specialized and special machines. Experience has shown that automatic lines, composed of the simplest universal equipment with a low concentration of operations, are cumbersome, require a large production area and do not provide the necessary reliability.

Composed of automated universal and specialized machines, the lines are more compact and reliable.

When using normalized units and mechanisms (power heads, feeders, unloaders, etc.), the time for designing and creating lines is reduced, and costs are reduced.

Lines of sawmill and woodworking equipment can be with rigid, flexible and mixed connection of aggregates. If the machines of the line are interlocked with each other and form a continuous chain with the direct transfer of the workpiece from one position to another, the connection is called rigid. Such a connection is very common in lines, but in this case, when any of the units stops, the entire line is idle.

Published: March 22, 2012

Chapter II

TECHNOLOGICAL PROCESS OF WOODWORKING AND METHODS OF ITS AUTOMATION

Process structure

The technological process of manufacturing wood parts and assembling them into finished goods is divided into several parts:

processing of parts and assemblies;

gluing wood;

assembly of components and products;

hydrothermal treatment.

The processing of parts and assemblies is almost always performed by machine tools, and the assembly of assemblies and products is mainly carried out manually. Gluing wood in the manufacture of panels or veneering must be accompanied by a certain exposure in time, necessary for the adhesive to set. Finishing also requires additional time for the applied coatings to dry. At present, mainly the processes of mechanical processing of parts and assemblies made of wood are automated.

In the machine process, work processes are distinguished, as well as management and control processes.

Work processes include actions aimed directly at the implementation of a given technological task. Management and control processes include actions that ensure the correct flow of work processes.

The technological process usually consists of a number of separate operations.

It is customary to call an operation a part of the technological process performed at a specific workplace, machine or machine unit before moving on to the processing of the next part. Usually technological process is divided into operations in such a way that the execution of each of them would solve a certain technological problem, for example, the separation of the material along the length into a number of blanks, the formation of an Oa (ipmn) surface, planing to size, the development of spikes, etc.

Operations that are repeated during the processing of each part, i.e., at each cycle of equipment operation, are called cyclic.

Operations are divided into main and auxiliary.

The main ones include operations that directly give technological results, such as cutting, bending or gluing wood, and the auxiliary ones include all other operations necessary to complete this process, such as loading and unloading, transport, control and management operations.

The time required to perform the basic operations on the machines is called the main technological or machine time. For machines in which the cutting tool or part moves intermittently, the machine time is the sum of the duration of the working stroke of the processing working body or part and the idle time.

Workflows include:

actual working operations, in which the tool directly affects the workpiece;

loading and unloading operations, i.e. loading, installing, guiding and securing the workpiece before processing and unloading, unfastening and removing the workpiece after processing;

transport operations, also called transfer operations, in which workpieces or working bodies are moved from one technological operation to another;

workplace maintenance operations that are not part of each cycle of equipment operation and are called off-cycle.

Management and control processes include:

working control operations performed to comply with a certain sequence of movement of the workpiece or working bodies, as well as to automatically maintain established modes(automatic regulation);

adjustment and adjustment (adjustment) control operations performed in advance to set up the process in accordance with the specified requirements for processing sizes, tolerances, product quality, productivity, etc.;

control operations performed to check the quality, sorting and counting of products, as well as to check the condition and position of the processed workpieces or working bodies.

Workflow operations are usually divided into transitions, passes, settings and positions.

A transition is a part of an operation performed by the same cutting tool when processing the same surface of the object being machined and with the same mode. If on the machine the same surface of an object is simultaneously processed by several cutting tools, for example, on four-sided planers or tenoning-frame machines, this means that several transitions of this operation are performed simultaneously.

A passage is a part of the operation, limited by the removal of one layer of material from the same surface of the object and carried out without changing the installation of the working bodies of the machine, for example, when jointing, grinding material, planing on a thicknessing machine, etc.

Installation is the part of the operation that is performed without releasing and re-securing the workpiece. For example, with a single fixing, two sockets are drilled on a drilling and grooving machine in one setting, and with a double fixing, in two settings.

The position is the part of the operation performed without changing the position of the part relative to the machine, that is, without releasing it from the clamp.

Features of the technology of mechanical processing of wood

Easy workability of wood. Insignificant (compared to metal) resistance of wood to cutting makes it possible to process it with a significant length of contact between the cutting tool and the material and to apply high cutting and feed speeds. In this regard, woodworking machines, compared with metalworking machines, are characterized by relatively simple kinematics and very high productivity.

The relatively small forces required for cutting wood also lead to a simplification of the design of machine tools, including locating and holding bodies.

Simplicity of forms and low weight of parts. The prevailing part of the parts made of wood is characterized by simplicity of form and low weight. This facilitates the installation, basing, fixing and feeding of workpieces in the machine and their movement from one machine to another. Since the automation of machine technological processes often depends on the degree of mechanization of transport operations, this feature of the mechanical processing of wood is of particular importance.

Reduced requirements for processing accuracy.

Due to the ability to change its shape and elasticity, the requirements for the accuracy of mechanical processing of wood are much lower than those of metal. "This facilitates the stabilization of the technological process and simplifies control and measuring devices.

The predominant distribution of pass-through processing.

In the mechanical processing of wood, the through movement of the part past the rotating cutting tool is mainly practiced. Such a processing scheme is called a pass-through. It makes it possible to use the simplest design of transport devices and process simultaneously with several tools, which increases the productivity of the machine.

Thus, the principle of threading is laid down in the methods of processing wood parts, which makes it possible to automate the process by the simplest means.

Big specific gravity ancillary operations. High wood processing speeds significantly reduce the duration of the main operations. When auxiliary operations, such as loading and unloading parts on the machine, are not combined with the main ones, their share increases. This prevents a reduction in the overall cycle time, i.e., an increase in machine productivity, and thus negates economic effect, achieved as a result of reducing the duration of the main operations. Therefore, it is most expedient to combine the main and auxiliary operations in time.

Structure heterogeneity (anisotropy) of wood. Processing wood against the direction of the fibers often causes chipping, especially when the cutting tool exits the material being processed, when the natural support of the fibers is less than the cutting force. The heterogeneity of the wood structure is also reflected in the cutting force. This feature of the mechanical processing of wood in some cases necessitates the appropriate regulation of processing modes, for example, during milling. The increase in cutting speeds and the improvement of the cutting tool, as well as the guides, clamps, feeders and other devices of modern machine tools make it possible to reduce or completely eliminate chips along the wood fibers.

High processing speed. This feature causes increased requirements for the movable working bodies of the machine, especially for intermittently moving bodies. In a number of cases, in connection with this, it is necessary to use special equipment that would make it possible to increase the number of inclusions per unit time.

The main advantages of automated production

Automation of production increases the productivity of workers and facilitates their work. In addition, it makes it possible to improve working conditions, reduce the duration of the production cycle and the required production space, ensure the rhythm of processes, improve quality and reduce the cost of production.

Increasing labor productivity. Labor productivity of workers on automated production increases as a result of automation of loading blanks and unloading of machined parts, connection into a single complex of a number of basic technological operations, automation of control, regulation, material transportation, etc.

Due to the concentration of processing characteristic of automation, the number of working bodies of machines serviced by one worker increases significantly, and the productivity of his labor increases. Modern automatic machines or machine systems perform a complex set of technological process operations without direct human intervention. Thus, automation frees up a significant number of workers. Under capitalism, this leads to an increase in unemployment and a deterioration in financial situation workers. Under the conditions of a planned socialist economy, an increase in labor productivity as a result of automation is a source of growth in the material well-being of the people and a reduction in the length of the working day. The released workers are used in other enterprises.

In different processes, labor productivity increases differently and depends on the degree of concentration of processing and the continuity of the process. The higher the concentration of processing and the greater the degree of continuity of the process, the higher the productivity. The highest labor productivity of workers is achieved with complex automation of production.

Facilitate the work of workers. In automated production, a person only adjusts the automatic system of machines to the desired processing mode, monitors the condition of the mechanisms and working parts of the machine, ensures its loading with blanks and monitors the correct operation of all mechanisms using instruments. Thanks to the automation of production, the labor of a worker approaches the labor of engineering and technical personnel.

Improving labor safety. The replacement of manual labor by automatically operating machines contributes to a significant increase in labor safety, since the worker who monitors the progress of the process is at a distance from the working bodies of automatic machines that directly process workpieces. In automated production, the protection of the working organs of machines is improved, the noise during their operation is muffled, the trapping of wood dust is improved, and the harmful effects of heat, humidity, solvents, varnishes, paints, etc. are eliminated. Improving the working conditions of a worker in automated production reduces his fatigue.

Reducing the duration of the production cycle. In serial non-automated production, batches of blanks are periodically launched. The duration of the production cycle in this case is determined mainly by the period of time during which the workpiece lies without movement in anticipation of processing.

Automated production is based on flow methods, in which the workpiece at the end of one technological operation is directly transferred to the next. As a result of this organization of production, all or most parts of the product are processed simultaneously, and the production cycle is drastically reduced.

Reducing the duration of the production cycle is accompanied by a significant decrease in the volume of work in progress, which increases the turnover working capital and therefore improves economic indicators enterprise activities.

Reducing production space. In well-organized automated production, the reduction in production space is a consequence of a reduction in the duration of the production cycle and a decrease in the volume of work in progress. Eliminates the need to allocate a large area near the process equipment to accommodate work-in-progress parts, so machines can be located closer to each other. Assigning strictly defined operations to each technological section promotes the use of multi-operational machines with a high concentration of processing, which also makes it possible to limit oneself to the smallest production area.

rhythm of production. The time interval between the exit from the workplace of two workpieces following one after the other is called the rhythm or work cycle. In non-automated production, the rhythm in various operations is usually not the same, which makes it difficult to plan and organize such production. In automated manufacturing, workflow operations are usually performed on several machines, which must be performed synchronously. Synchronicity is most often ensured by the equality or multiplicity of the rhythms of the machines involved in the process. The multiplicity of the rhythm greatly facilitates production planning. Rhythmic production requires a particularly clear organization, since any change in the established rhythm disrupts work and can lead to downtime in certain areas.

Improving product quality. Strict observance of the rhythm and mode of operation of machines, reduction of the production cycle, mechanization and automation of control, automatic regulation of the modes of machining parts and units of products, automation of assembly and finishing operations ensure a higher quality of products.

Reducing the cost of production. Automation of technological processes usually leads to a reduction in the cost of manufactured products. This is achieved as a result of increasing the productivity of workers, reducing the duration of the production cycle and production: areas, more rational organization of production.

Conditions for the introduction of integrated automation in woodworking

The most important conditions for the introduction of integrated automation in woodworking are: specialization of production, manufacturability of product design, normalization and unification of the dimensions of parts, normalization of allowances, the introduction of a unified system of tolerances and fits.

Production specialization. Under specialization, such an organization of production decreases, which ensures the stable production of homogeneous products for a long time.

More than favorable conditions for the introduction of progressive technology "and technology, since the production of homogeneous products makes it possible to normalize technological processes, enlarge the size of batches of products launched into production, apply flow production methods, etc.

The rational degree of specialization of production is determined by technical and economic calculations and does not remain constant. In most cases, the specialization of each woodworking enterprise is determined by the volume of production, which depends on the availability of raw materials and marketing conditions. The development of transport, the improvement of product designs and the introduction of in-line production methods create conditions for a gradual increase in the degree of specialization in the woodworking industry. In this regard, in the furniture industry, for example, there are specialized enterprises that produce upholstered furniture, carpentry and curved chairs, cabinet furniture. In large economic regions, it is advisable to specialize the production of cabinet furniture, creating, for example, enterprises of furniture, small-sized, kitchen furniture, etc.

Automation of technological processes is easier to carry out at enterprises with a high degree of specialization, producing, for example, any one product: a carpentry or bent chair, parquet, skis, tables, etc.

Manufacturability of the product design. The concept of "manufacturability" establishes a relationship between product design, technology, organization and economics of production. A technological design is a design that satisfies technical requirements and for a given scale of production and the adopted technology provides the lowest cost of funds for the manufacture of products.

With a change in production conditions, the assessment of the manufacturability of the same design also changes. For example, the manufacturability of the same design may change as a result of the introduction of new materials, changes in scale, improvements in equipment and organization of production.

The currently existing designs of the vast majority of products made from wood were created under conditions of poorly mechanized production and remained basically unchanged for a long time. Therefore, in conditions of automated production, the manufacturability of the design of these products requires revision.

For example, panel doors with bars connected on dowels are more technologically advanced than doors with bars connected with spikes, since in the manufacture of the former, wood consumption is 8-10% less. improve the useful use of wood and simplify the technological process.

In the production of cabinet furniture, panel furniture is considered more technologically advanced, the design of which is based on the progressive principle mass production shields and rational methods of their connection.

Often, even small changes in the design of products that do not impair their quality make it possible to significantly simplify the manufacture of such products or use more productive multi-operational equipment. The manufacturability of the product can be significantly improved by expedient replacement of the starting material. Thus, many wooden products of complex shape, but relatively small in size, including turned ones, are already expedient to be replaced by plastic ones. This completely eliminates the complex operations of milling, turning, grinding and finishing, and, in addition, significantly reduces the consumption of wood. With the improvement of press equipment for the manufacture of parts from plastic materials, the dimensions of parts made of plastic will continuously increase.

Normalization and unification of the dimensions of parts. When processing parts on universal single-operation machines in non-automated production, the variety of sizes of parts is not of particular importance, since the readjustment of such machines is very simple and does not require much time. On the contrary, in automated production, the changeover of interconnected machines, often a relatively complex device, takes a lot of time and is therefore highly undesirable. Therefore, the number of sizes of machined parts must, if possible, be minimized by their normalization and unification.

Normalization is the development of a normal range of preferred sizes, which makes it possible to significantly reduce the number of part sizes. When normalizing parts, reducing their number is achieved by combining several parts with the same dimensions into one group, i.e., unifying the dimensions.

Unification is the reduction of several parts to the same dimensions.

Normalization and unification can be carried out in one, two or three sizes of parts, for example, in thickness, length and section. For automated production, it is most important that the workpieces have uniform sections.

Allowance normalization. The amount of machining allowance, i.e., the difference between the dimensions of the workpiece and the machined part, usually depends on the size of the parts and must be justified by technical and economic considerations. For some types of products, for example, for lumber, processing allowances are regulated by GOST. At woodworking enterprises, processing allowances are usually not regulated by anything and are set arbitrarily. A variety of allowances makes it difficult to process parts in automated production, since workpieces with different allowances have to be processed in different modes.

Normalization of processing allowances means the development of a strictly justified range of allowances to save wood and ensure the stability of processing modes.

Implementation of a system of tolerances and landings. Modern techniques for assembling products in assembly devices, on a conveyor, or in special assembly machines, determine increased requirements for the accuracy of manufacturing parts.

The accuracy of parts should ensure their assembly into units and products without individual fitting. To do this, the mating dimensions of the parts must be maintained within the established deviations, regulated by tolerances. When machining according to tolerances, which are assigned according to the required fit of mating parts, full or partial interchangeability of parts is ensured, and consequently, extensive mechanization and automation of technological processes and high quality products.

Since 1954, uniform standards for tolerances and landings have been established (GOST 6449 - 53). The introduction of this GOST in the woodworking industry is one of the most important conditions for the introduction of integrated automation.

Accuracy classes and type of interchangeability must be selected for each specific case on the basis of technical and economic calculations.

Selection of objects and degree of automation

Automation object. In modern conditions, it is necessary to take into account not only the possibility of implementing automation, but also its economic efficiency, which primarily depends on right choice automation object.

The most effective is the integrated automation of structurally stable products manufactured in mass quantities. When the share of wages in the cost of a product is small, the efficiency achieved as a result of automation is negligible. Efficiency increases with the automation of the production of labor-intensive products, in the cost of which the production wage has a large proportion.

Matches, pencils, reels, spools, shuttles, chairs, skis, as well as ready-made cases can be considered the most suitable automation objects. sewing machines, watches, etc., i.e., products of a sufficiently stable design, produced in mass quantities.

degree of automation. The degree or level of process automation is an indicator that characterizes the degree of release of the worker from direct participation in the implementation of this process. Quantitatively, the indicator of the level of automation can be expressed as a quotient of dividing the number of automated operations (or their labor intensity) by their total number (or total labor intensity):

One of the disadvantages of assessing the level of automation through labor intensity is the lack of consideration for the intensity of the process. The main criteria for the expediency of the degree of automation of production are the improvement of working conditions, economic efficiency and reliability automatic equipment.

The expediency of the degree of automation of production primarily depends on its scale. On large enterprises, producing products in mass quantities, where continuous winding methods and jxxt.trw> .; i. Indeed, there are the most favorable conditions for effective integrated automation of technological processes.

If the scale of production limits the possibility of manufacturing all parts of the product by continuous-flow methods, complex automation can be carried out in conditions of variable-flow production. However, automated variable-flow production is less efficient, since the transition from one stream to another usually requires a long changeover of equipment. Therefore, in variable-flow production, it is necessary to use equipment that does not require significant time for adjustment.

In small enterprises producing several types of products, such as furniture sets, sets of building parts, etc., complex automation of technological processes is associated with significant difficulties and is ineffective. At such enterprises, most often they strive to implement complex mechanization and partial automation, extending to individual sections of the technological process or only to its individual operations.

The automation of a single operation is reduced to the automation of the cycle of the machine and is called low automation. It can be carried out at any scale of production.

Classification of automation systems

Automation of technological processes is carried out with the help of automatic devices, i.e., mechanisms and apparatus that free a person from managing the processes being performed. Depending on the purpose, automatic devices are classified as various systems automation.

The following systems are used to automate technological processes (Fig. 1): automatic control technological process operations necessary to obtain end result; automatic control of the course of the technological process when external or other conditions change; automatic control over the course of the technological process.

Automatic control systems. These systems carry out the change of technological operations or their constituent parts according to a predetermined plan, regardless of changes in external or other conditions and on the course of the technological process.

characteristic feature systems of automatic control is the presence of a stable program of changing operations, as well as the lack of means for measuring process parameters, since the latter do not affect the operation of the systems.

The operation of the elements of automatic control systems is reliable. When any element fails, the process is usually interrupted.

Depending on the nature of the process, automatic control is divided into simple (cyclic) and software.

Simple is called automatic control of machines that repeat the same operations with the object being processed, that is, such machines, the work of which consists of the same cycles following one after another. This group includes most of the cycle woodworking machines.

Software is called automatic control, which provides for a predetermined change in individual operations of the technological process, which cannot be divided into identical cycles.

Previously, program control included control systems for machines, the movement of the working bodies of which could change from cycle to cycle, for example, printing machines, looms, etc. Recently, systems that provide a quick change in the program of work of machines during the transition processing from one part to another.

Automatic control systems. These systems qualitatively change the course of the technological process according to a strictly defined law or maintain a certain process parameter constant.

Automatic control systems measure the value of the controlled parameter and automatically influence the technological process in such a way as to maintain the required value of this parameter.

The failure of any control element usually does not interrupt the process, but affects its result.

Automatic regulation can be continuous, program and tracking.

The regulation of a constant parameter (stabilization) is the automatic maintenance of the constancy of any one technological parameter, for example, temperature, "voltage, power, speed, pressure, speed, etc. The regulation of a constant parameter is, in particular, the automatic maintenance set temperature in drying chamber.

The software includes the regulation of any parameter in time according to a certain law, for example, a predetermined change in temperature in a drying chamber.

Follow-up regulation of a parameter is similar to software regulation, but it is performed not according to a program predetermined in time, but depending on the value of another parameter, i.e., according to a program in time, unknown in advance. The follower can include, in particular, automatic temperature control in the drying chamber depending on the moisture content of the wood.

Automatic control systems. For automatic control of process parameters, safety automatic devices and devices are used to record the value of the controlled parameter. In many cases, the functions of automatic control of process parameters and their regulation are combined in one device - an automatic regulator. In this case, the control device is part of the regulator.

Product quality control is carried out using various means, which, if necessary, also allow you to sort products into ready-made(passive control) or in the process of its manufacture (active control). Accounting for manufactured products is carried out using various counters, often attached directly to the machine.

Control over the operation of the equipment is usually carried out using control and measuring devices attached directly to the equipment or installed on special control panels.

Basic methods of process automation

As already noted, there are two main methods of automation: the first is automation existing processes based on the use of existing equipment through its modernization and the second - the creation of new automatic equipment based on a radical improvement of technological processes.

Modernization of equipment. Such automation does not change the technological process and is reduced to the modernization of non-automatic machines and their integration into a single automatic system. Automation tools in this case complement the existing basic equipment and cannot be used most rationally.

In woodworking, the first automatic and semi-automatic lines based on the use of conventional universal equipment were organized in Vitebsk and Kyiv furniture factories, Kiev Woodworking Plant, Moscow Furniture Assembly Plant No. 2 and other enterprises.

Important advantages of this automation are significant cost savings and the availability of implementation in almost any enterprise. In most cases, the cost of automation by upgrading existing equipment is 4-5 times less than the cost of replacing existing equipment with new, automatic.

Since the modernization retains versatile equipment with a relatively low concentration of operations, production space is used less than in the case of the use of special multi-operation equipment.

When automating individual operations on modernized machines, the loading and unloading of the machine is automated. When automating a site or complex automation of the entire production, inter-operational transport, management, control and regulation are also automated.

On many universal woodworking machines: with a mechanized supply of material, the work cycle is automated. Such machines include: autoplaning, thicknessing, four-sided planing, some circular saws, double-sided tenoning, three-cylinder grinding, etc. Automation of these machines is reduced to equipping them with automatic loading and unloading devices. When such machines are included in an automatic line, it is necessary that their productivity is the same and that the interoperational transport devices operate synchronously with the loading and unloading devices.

Introduction of new automatic equipment. Technological processes change according to the level of development - science and technology. At present, two principles for constructing a technological process are most characteristic - differentiation and concentration of processing.

Differentiation is the division of the process of processing parts into a number of simple operations to perform each of them with one tool sequentially on one or on different machines.

Differentiation makes it possible to use separate, simple, narrow-operation machines for each operation, and, consequently, quickly create and master new equipment, which is especially important in the mechanization of technological processes. However, the dismemberment of the processing process leads to an increase in production space and maintenance personnel. In addition, the processing of parts on many machines reduces the accuracy of their manufacture and increases labor intensity.

The period of automation of technological processes is characterized by the principle of concentration of processing, corresponding to more high level development of science and technology.

Concentration is understood as the simultaneous (parallel) processing of one or more parts with many tools.

The widespread introduction of concentration into processing became possible as a result of the appearance of an individual electric drive, the improvement of pneumatic and hydraulic drives, and the development of reliable means of automatic control of machine tools.

The concentration of processing makes it possible to significantly reduce the production area, increase the productivity of the worker and increase the removal of products from one square meter of production area.

The introduction of new automatic, predominantly multi-operational equipment is possible on the basis of a fundamental improvement in technological processes. In turn, automation stimulates further improvement of production technology and the most effective use modern means automation.

A characteristic feature of the development of modern industrial production with the mass production of homogeneous products is the widespread introduction of multi-operational (aggregate) specialized machines instead of universal single-operation general-purpose machines. The former are characterized by significantly higher productivity and occupy less production space.

The need for modular machines for series production is still relatively small, and consequently, the cost of manufacturing such machines is tens of times higher than the cost of serial ones. Therefore, the use of specialized machines should be justified in each individual case by technical and economic calculations. Reducing the cost of specialized machines can be achieved by introducing normalized aggregate units. However, at present, rational forms of aggregation of woodworking machines have not yet been found.

In preparation for the automation of production processes based on the introduction of new equipment, two main tasks are solved: the design of automatic machines and the design of automatic lines.

When designing new automatic machines, it is usually sought to automate the entire cycle of work, including loading workpieces and unloading parts. These machines are suitable for individual work, and for embedding in automatic lines.

When designing automatic lines from specialized automatic equipment, options for choosing the best option much more than with the layout of lines from universal equipment.

excerpts from the book Automation of technological processes in woodworking, N. V. MAKOVSKY (attention! recognition errors are possible)

From: LidiaZaiceva,  58588 views