General information about cutting board materials. The process of cutting plate, sheet and roll materials

The task of cutting sheet (plate) and molded materials into original parts (blanks) is an important part of the process of designing and manufacturing cabinet furniture products and is of great practical importance. It consists in placing flat geometric objects corresponding to the original blanks on sheets of material. In a linear nesting, objects are placed that are measured in running meters, on strips of material, also measured in running meters.

Cutting materials in automated furniture production

The role and importance of the task of cutting materials in furniture production are determined by three main factors that have a significant impact on the entire production activity of the enterprise:

▼ reduction of material waste is the most important factor improving the efficiency of furniture production;

▼ manufacturability of cutting charts allows to reduce the labor intensity and time of the technological operation of cutting, ensuring the efficient use of equipment;

▼ cutting operation, being the first operation technological process production of cabinet furniture, largely determines the efficiency of production sites that implement subsequent operations.

These factors are relevant for any furniture company, regardless of the volume and range of products, due to the large share of materials in the cost of products.

From the point of view of automation, the nesting optimization problem has two features that explain the existence of a large number cutting programs on the market software:

▼ high labor intensity of manual generation of cutting charts;

▼ the possibility of formalizing the mathematical formulation of the cutting problem and the elaboration of algorithms for its solution.

As a rule, all existing programs are designed to optimize the cutting of sheet materials into parts (blanks) rectangular shape using straight through cuts and taking into account the texture of the materials, if necessary. In a number of programs there is an additional possibility of cutting molded materials.

The main goal of all programs is the automatic generation of material cutting charts, the quality of which is assessed by the following parameters:

▼ material utilization factor;

▼ completeness of parts obtained during cutting in accordance with the volume of production;

▼ the complexity of the technological operation of cutting.

The material utilization factor (KIM) is calculated as the ratio of the sum of the areas of the obtained panels (panel elements of cabinet furniture products) to the sum of the used areas of the original plates. It can be calculated taking into account the fact that the remains of slabs (trimmings) that are not used when cutting parts this product, but having sufficient dimensions, can be used in the manufacture of other products, which contain similar materials. In addition, when calculating it, the operation of trimming the edge of the slab may or may not be taken into account to ensure accurate basing and elimination of defects.

The completeness of the parts necessary to ensure the plan for the release of products, in the case of integration of cutting programs into the CAD structure, is provided automatically when transferring product models from the design module to them. When using offline nesting programs, the list of parts is entered manually, which often leads to picking errors, the correction of which is costly.

The complexity of cutting depends on the number of turns of the workpieces on the machine and their weight, the number of resets of the stops and the cost of moving the operator to working area machine. The most adequate numerical characteristic of labor intensity can be the average time for cutting one slab (a pack of slabs for cutting centers). Creating nesting plans, the implementation of which requires minimal labor, is a mandatory requirement. The labor intensity of cutting and the subsequent organization of the technological process is influenced by many production factors, that is, the task of minimizing labor intensity is a multicriteria one.

The result of the work of the cutting programs are nesting maps - graphic diagrams showing the location of parts on a standard slab format of the material to be cut. Optimization of material cutting is a multi-criteria task, which must be solved using geometric and technological criteria.

The cutting algorithms currently used work mainly with geometric information about the dimensions of the parts to be cut. This does not allow to fully take into account the features of technological processes in a particular production. Based on this, when creating the BAZIS-Nesting module, new cutting optimization algorithms were developed, with the help of which it is possible to achieve a much more complete account of the totality of geometric, technological and organizational features of furniture production technological processes. The practical use of the developed algorithms makes it possible to find the most balanced relationship between the requirements for saving materials, the manufacturability of cutting charts and the efficiency of loading all technological equipment.

The close integration of modules for designing and cutting materials in the CAD structure is of particular importance when working with complex products, the number of which is constantly increasing on the furniture market. In addition to automatically ensuring the completeness of the parts needed to ensure the product release plan, it allows you to implement three important additional features:

▼ the use of not only full-size slabs, but also scraps left from previous cuttings of the same material, which, with proper organization of production, provides tangible savings;

▼ transmission to the cutting module along with the overall dimensions of the contours of curved parts, which is useful in terms of their subsequent routing;

▼ automatic generation of control programs for CNC sawing equipment, including those operating on nesting technology, which has recently become widespread.

When importing information from a product model, automatic two-level sorting is performed:

▼ Depending on the type of material used, two lists of parts are created: from sheet materials and from molded materials;

▼ Within each list, parts are sorted by material type.

Facing materials are also included in the list of molded materials, since they can be cut, for example, when a profile is used, which arrives at the enterprise in the form of strips of a certain length.

When preparing the initial data for cutting, it is necessary to perform a number of additional actions, the set and nature of which is determined by the parameters of the equipment and manufacturing technology. When using nesting modules integrated into CAD, these actions are performed automatically, since the product model contains all the necessary information. For example, in the case of cutting sheet materials, sawing dimensions are read from the model. However, some types of edge banding machines perform a pre-milling of the edges before banding. This is taken into account when generating cutting maps by specifying an allowance when applying the cladding.

An important parameter of parts in terms of the formation of optimal cutting maps is the direction of the material texture. Since one of the material attributes in the model of a furniture item is the type of surface texture, when importing a list of parts, its direction is determined automatically. During the technological control of the model, this parameter can be adjusted by changing or disabling texture directions for an individual part or group of parts.

These are just a few examples showing that the efficiency of using cutting programs is significantly increased if they are combined with programs for designing cabinet furniture and organizing a single information space at the enterprise. BAZIS+Nesting was originally developed as a module integrated into BAZIS CAD, fully using models of furniture products created in the BAZIS+Mebelshchik and BAZIS+Kkaf design modules.

Automation of technological preparation for the production of cabinet furniture

The ultimate goal of complex automation of an enterprise is to optimize two components of its activity: the processes of performing production duties by each specialist and information links between processes, specialists and departments.

Generalized scheme information flows furniture company operating in the order mode industrial production, is shown in fig. 1.1. It shows that the technology department is a source and consumer of a significant amount of information. Therefore, the automation of technological preparation of production (TPP) is an important task in terms of ensuring effective work enterprises in general.

Depending on the specific enterprise, the division of project operations into departments, shown in Fig. 1.1 can be both real and functional in relation to departments or performers. For example, in many furniture enterprises, especially those belonging to the class of medium and small enterprises, there is a combination of a number of functions within the competence of one department or specialist (designer + technologist, designer, etc.).

The execution of any design operation, design or technological, involves the receipt of input information, its processing and transmission of output information for subsequent operations. Such a scheme is universal and is determined by the very fact of the existence of the enterprise. Automation of design operations allows you to increase the speed and quality (error-free) of the implementation of the processing and transmission of information, which predetermines the efficiency indicators for the implementation of CAD. In other words, the work of any specialist participating in the project is evaluated by two key quantitative indicators: the time it takes to complete the project operation and the number of subjective errors introduced into the project. These indicators for the existing structure of the enterprise are mutually exclusive: the acceleration of the execution of tasks leads to an increase in the level of defects and, conversely, the increase in quality requirements leads to a decrease in the speed of execution of tasks, that is, the growth in the efficiency of the enterprise is limited by its existing structure.

Transition to quality new level work, and this is precisely what the introduction of an integrated CAD system implies, is impossible without a radical reconstruction of the organizational structure of the enterprise. The nature, direction and depth of such a reconstruction are determined by the chosen automation platform.

It is the extent to which CAD allows you to resolve the above contradiction that determines the effectiveness of automation. An analysis of the results of the implementation of the BAZIS system at a number of furniture enterprises showed that its functionality is sufficient to actually reduce the time to complete orders while minimizing the number of errors caused by the human factor. First of all, it concerns the technological preparation of production, as the most important stage of the product life cycle.

The basis of enterprise automation is the formation of a single information space covering all design and production operations. This allows the design process to take into account whole line technological requirements and implement elements of a parallel design strategy. The introduction of CAD BASIS allows you to create several parallel processed information flows, the main of which are aimed at performing the following operations:

▼ design of products and ensembles;

▼ cutting board and molded materials;

▼ development of control programs for CNC machines;

▼ calculation of technical and economic indicators;

▼ formation of documents for the logistics of production;

▼ standardization of material and labor costs;

▼ formation of information arrays for automated systems project management.

CCI automation has three main goals:

▼ reducing the labor intensity of the process, necessary to reduce the number of specialists involved and, accordingly, the cost of products;

▼ reduction of design time, which is the basis for obtaining competitive advantage due to the rapid implementation of projects;

▼ improving the quality of decisions made and technological processes being developed, which is dictated by the technical re-equipment of modern furniture production by replacing universal equipment with equipment with an automatic processing cycle and the widespread introduction of CNC machines and machining centers.

General statement of the cutting problem

Board materials used in the manufacture of furniture, such as chipboard, fiberboard, MDF, plywood, glued panels, must undergo the first technological operation - cutting into blanks. They are cutting circular saws on circular saws and saw centers. The machines differ from each other in a number of technological parameters that affect the methods of performing the technological operation of cutting, and, consequently, the formation of cutting maps:

▼ the number of sawing units of the longitudinal and transverse directions of sawing;

▼ restrictions in cutting schemes by the dimensions of the maximum and minimum width of the cut strip and the presence of mandatory through longitudinal or transverse cuts (cuts);

▼ maximum dimensions of the processed material;

▼ the number of simultaneously cut boards;

▼ cutting accuracy;

▼ cleanliness of the edge obtained during sawing;

▼ the thickness of the saws used.

Modern material cutting lines and semi-automatic circular saws may have a built-in cutting chart module. However, the input of initial data for their operation is carried out manually, which often leads to errors. best solution in this case is the automatic import of data directly from mathematical model products. In addition, built-in nesting modules are usually quite expensive.

If the equipment used cannot perform such a function, as part of the technological preparation of production, it is required to draw up cutting charts for sheet materials. They serve as technological instructions for the operators performing this operation, and also carry the information necessary to perform subsequent calculations, such as:

▼ material consumption of the product;

▼ useful yield of material during cutting;

▼ the required amount of material to ensure production;

▼ labor costs for performing material cutting operations;

▼ normalization of operations.

Distinguish cutting of finishing and rough blanks. If, after cutting, the dimensions of the part do not change during subsequent operations, it is advisable to carry out a finishing cut. For example, cutting laminated chipboard with subsequent edge banding. If subsequent operations will change the size or shape of the part, rough cutting is performed. For example, cutting chipboard with subsequent facing of the plate and filing to size.

The difference in size between the finished size and the size of the rough workpiece is called the allowance. It is determined by the composition of the technological operations that the workpiece must undergo after cutting, the parameters of the equipment for performing these operations and the type of material being cut.

Nesting charts are a graphical representation of the layout of workpieces on a standard format of the material to be cut. Drawing up nesting maps manually is very time-consuming, while their quality largely depends on the experience and qualifications of the developer. There are three cutting patterns: longitudinal, transverse and mixed. Transverse and longitudinal cutting are very rare in an independent form. Usually, the transverse cutting is a continuation of the longitudinal cutting, that is, cutting the longitudinal strips into blanks.

Mixed cutting combines cutting according to the two previous schemes and is performed on the same machine. On fig. 1.2 shown possible schemes cutting.

In the BASIS+Nesting module, you can choose a longitudinal+transverse or mixed cutting pattern. It implements an algorithm for cutting only straight through cuts. This scheme is used on the vast majority of types of equipment in the furniture industry.

All CAD cabinet furniture presented on Russian market, include subsystems for cutting materials, but they do not really take into account the technological optimization criteria. For modern production conditions in the presence of high-performance CNC sawing equipment, this state of affairs is unsatisfactory. It is necessary to take into account the entire set of parameters that characterize the technological and organizational specifics of a particular enterprise. It is these optimization algorithms that are incorporated in the BASIS+Nesting module.

In addition to optimizing the layout of workpieces, cutting programs should have a number of additional features:

▼ filtration of material residues generated during the cutting process into business scraps that are supposed to be used in the future, and waste to be disposed of;

▼ formation and maintenance of a database of materials and scraps;

▼ setting of optimization parameters, the main of which are the cutting width (thickness of the cutting tool), the amount of trimming of the edge of the slab, the limit on the length of the cut, the direction of the initial sawing of the slabs and the number of products to be cut;

▼ manual editing of cutting maps;

▼ setting the parameters for printing nesting charts;

▼ data export to the most common formats;

▼ data import from external files.

The structure of the problem of optimal cutting of materials and its place in the technological preparation of production are shown in fig. 1.3.

Optimization criteria and technological parameters of cutting

The requirements of the modern furniture market require a reduction in the lead time for orders and an increase in product quality at the lowest possible prices. To achieve such a balance, it is necessary to have at least two components of the production process:

▼ use of modern high-performance equipment;

▼ cost minimization when performing technological operations

With regard to the problem of optimizing the cutting of materials, this means that the criterion for minimizing waste no longer has an unconditional priority. Efficient furniture production requires complex optimization criteria that allow you to generate cutting plans that take into account all emerging costs, in which the achievement of the maximum value of CMM is one (albeit very important) constituent element. The new criteria should help to reduce the labor intensity of the technological operation of cutting, increase the efficiency of the use of existing equipment, and ensure the rhythm of the work of subsequent production sites. Their share in the composition of complex optimization criteria increases simultaneously with an increase in the level of production automation.

One of the complex optimization criteria, which takes into account the specifics of modern furniture production with sufficient accuracy, is the generalized cost of the parts obtained as a result of cutting. It includes the cost of materials, the execution of the cutting operation and the additional costs associated with the maintenance of business cuttings resulting from cutting, and the disposal of waste.

Consider the nature of the components of the generalized cost of parts. The geometric component is determined by the total cost of the used full-size slabs and commercial trimmings obtained during the previous cutting operations.

The complexity of cutting depends on three main parameters:

▼ number of panel turns,

▼ number of size settings,

▼ number of nesting cards.

Since circular saws and sawing centers realize straight through cuts, before performing the next technological transition, it becomes necessary to rotate the sawn strips. These actions are performed manually and take time, which depends on the number of turns and the size of the swathes to be turned. Minimization of the total number of panel rotations makes it possible to generate nesting maps that provide minimal labor intensity and execution time.

The technological transition in the cutting operation consists of several passes, each of which corresponds to the receipt of the next strip or finished part. When changing the standard size of the part to be sawn off, the operator sets special devices(stops), providing required size. Each new strip size provides for reinstallation of the stops, which takes time and, moreover, is performed with some error due to the presence of play in the stops. The cutting error, without directly affecting the execution time of the operation, can have Negative influence on the quality of the product. Minimizing the number of size settings means arranging strips of the same size in series in order to cut them with one stop setting.

If the two previous parameters refer to the nesting of individual slabs of material, then minimizing the number of nesting charts allows you to reduce the total time to complete all nesting operations associated with a particular order. This is determined by two main factors: a reduction in the number of technological cutting operations and the possibility of simultaneous cutting of several boards, when the equipment used allows it. In addition, the reduction in the number of identical cutting charts leads to a decrease in the likelihood of subjective errors in the case of cutting on circular saws without CNC.

To save materials, the enterprise can operate a warehouse for business scraps - fragments of slabs remaining after cutting, which are rational to use for subsequent cutting of parts from the same material. The use of offcuts significantly increases the utilization rate of the material, but at the same time requires additional costs associated with the transportation of offcuts to the warehouse and production, their storage, identification and additional processing, for example, in the presence of chips. Estimating the costs of these operations is difficult. The same is true for waste disposal costs. Along with the optimization criterion, the formation of cutting charts is greatly influenced by the technological parameters of cutting. Their feature is a significant dependence on many factors of a particular production, which predetermines the need to develop flexible customization tools for the software implementation of the automated cutting module.

The parameter that determines the direction of the first cuts can take one of three values, corresponding to cuts along the slab, across the slab, or arbitrary cuts. Last option is of more theoretical than practical importance, since when choosing it, some of the cutting patterns may have the first cuts across the plate, and the rest along the length, which will lead to additional costs when cutting, and also increase the time for generating cutting patterns.

The kerf width parameter, as a rule, corresponds to the width of the saw, however, there is one significant refinement. If the saw is well sharpened and the machine is correctly adjusted, then the width of the cut is the same as the width of the saw. If the saw is dull, or the saw and undercutter are not in the same plane, then the width of the cut will be slightly larger than the width of the saw. Therefore, to set the value of this parameter, it is necessary to be able to specify the actual kerf width.

The parameter that sets the maximum width of the sawn strips is determined by the design of the machine used. The right stop on the circular saw can be moved to certain limits. As a rule, its position is selected from a range of 800, 1000, 1300, 1600 mm. Any size can be set on the left stop, but the right stop may interfere with the operation. On many machines, it can be folded back or removed altogether, but such manipulations will not only require extra time, but will not always lead to the desired result. The movement of the slab may be hindered, for example, by an aspiration pipe. An illustration of the importance of taking this parameter into account is presented by examples of nesting charts shown in fig. 1.4 and fig. 1.5.

The cutting map shown in fig. 1.4 cannot be performed from the right stop, and when basing from the left stop, problems may arise in moving the plate. The formation of such maps should be avoided. In this case, it is more expedient to obtain the map shown in Fig. 1.5, where the plate can be based both from the right and from the left stop, so there will be no difficulties with its execution.

The parameter of the maximum length of cut is, in fact, the amount of stroke of the machine carriage. It affects the possibility of making longitudinal first cuts.

Modern trends in the development of the furniture market lead to an increase in the proportion of curvilinear parts in the composition of products, the manufacturing technology of which has certain features. In particular, in the presence of convex edges, as a rule, it is necessary when process design cutting cards to make an allowance in the appropriate direction for further processing. Areas with edge mating are considered special cases: depending on the manufacturing technology, they may or may not be taken into account when adding an allowance, and in the first case, the allowance is added to both mating edges. This means that appropriate capabilities must be available in the nesting module.

Another method of technological correction of the dimensions of parts is the simulation of the rough cutting mode. By default, finishing cutting is modeled, and sawing dimensions are calculated according to the design dimensions from the product model, taking into account allowances. However, in some cases, the processing technology involves the operation of milling the contour of the part after cutting. In such cases, a rough cutting should be simulated, before which the specified allowance values ​​for each side of the part are added to the dimensions of the corresponding sides.

As follows from the foregoing, the technological parameters of cutting are an important addition to the optimization criteria, which allow taking into account the peculiarities of the work of a particular furniture production.

Material cutting automation technique

In the BAZIS system, the task of optimizing the cutting of materials is solved in the context of automating the entire design + production section of the life cycle of cabinet furniture. The material cutting operation actually determines the initial conditions for most production operations. It is this provision that underlies the proposed method for optimizing the cutting of materials.

The joint use of the module for automated cutting of materials and modules for designing products allows you to automatically generate information arrays based on a model of a product or a furniture ensemble that ensure error-free completion of tasks for cutting, while performing the necessary preliminary processing.

First of all, when importing information from a model, an automatic two-level sorting of parts is performed:

▼ depending on the type of material used, two lists of parts are created: from sheet materials and from molded materials;

▼ Within each list, parts are sorted by material type.

Naturally, cutting operations are performed separately for each material. Facing materials can also be included in the list of molded materials, since it is necessary to cut them, for example, when a profile is used that comes to the enterprise in the form of strips.

An important part of the pre-processing of parts is the formation of sawing dimensions according to the design dimensions, that is, their correction depending on the conditions for performing the technological operation of edge facing and other subsequent operations. The first version of the correction is to take into account the method of cladding: with trimming the contour of the part or without trimming. The second version of the correction is associated with modeling the features of the operation of some edge banding machines, which, before edge banding, perform the operation of their preliminary milling. When using such machines, it is necessary to take into account the amount of preliminary milling, that is, automatically simulate the rough cutting mode.

An important detail parameter from the point of view of designing optimal nesting patterns is the direction of the material texture or its absence. This parameter is determined automatically in accordance with the assignments made in the product design process. During the preliminary processing of information, it is allowed to manually correct it by one of the the following ways:

▼ changing the texture direction for a separate part;

▼ refusal to take into account the texture direction for individual parts for aesthetic or other reasons, which can lead to an increase in CIM (for example, the part is an element of a basement box and is located under the bottom of the product);

▼ refusal to take into account the direction of the texture for all details, if the corresponding material has no texture (for example, painted fiberboard), or its texture has no direction (marble chips).

Thus, with automated cutting of materials in the complex CAD system BAZIS, the main array of initial information is formed accurately and automatically, of course, with the correct setting of pre-processing parameters.

To maximize the combination of the initially conflicting requirements of manufacturability and cost-effectiveness of the designed cutting charts, an algorithm has been developed for constructing a plan for the optimal cutting of areal materials, based on bringing it to the cutting of molded materials (linear cutting).

It is known that the problem of constructing an optimal plan for the linear cutting of linear materials has an exact mathematical solution, and it is very easy to achieve the manufacturability of cutting. The task of areal cutting can be reduced to the task of linear cutting if strips are formed, including blanks in them, the dimensions of which differ slightly. The size deviation value was chosen based on the analysis of the results of cutting at a number of enterprises. This is due to the fact that there is a certain boundary value, after which a further change in the deviation has practically no effect on the cutting results.

Thus, the sheet is first cut into strips of the first order, then each strip is cut into strips of the second order, and so on. Since the only criterion for optimizing linear nesting is to achieve the maximum value of the CMM, the strip nesting performed gives optimal nesting maps that are a priori technological at each level.

We note an important feature of the considered approach. Manufacturability serves as the initial postulate for optimizing cutting maps, since linear cutting is a priori technological. The solution to the problem of achieving the maximum value of KIM is already found for technological nesting charts. This allows you to optimally resolve the contradiction between the economy and manufacturability of the designed cutting patterns.

At practical implementation The proposed methodology uses an approach based on setting priorities for the action of optimization criteria. For this, a list of criteria is compiled, which includes seven positions that determine the material consumption and labor intensity of manufacturing products:

▼ maximization of the KIM value;

▼ minimization of the total number of cuts;

▼ minimization of the number of size settings;

▼ minimizing the number of panel turns;

▼ minimizing the length of cuts;

▼ minimization of the number of cutting patterns;

▼ optimization of business trim sizes.

The material utilization factor can be calculated in two ways: with and without taking into account the subsequent use of commercial offcuts. Its value largely depends on the set of standard sizes of blanks. In accordance with the All-Russian design + design and Institute of Technology furniture with recommendations when forming cutting maps, the useful yield of the material should be:

▼ not less than 92% when cutting chipboard;

▼ 88...90% when cutting hard fiberboard with paintwork;

▼ 85% when cutting plywood.

In the conditions of custom-made industrial production, the set of standard sizes of blanks used is quite wide. Sizes of full size slabs may vary depending on the material and lot used. These factors lead to a decrease in the potentially achievable IMT values, but these recommendations are relevant as indicative indicators.

Minimizing the total number of cuts, the number of size settings and the number of panel rotations determines certain aspects of the manufacturability of cutting charts and is of particular relevance when designing the cutting of a large number of full-size sheets.

Minimizing the total length of cuts characterizes the wear of the cutting tool and prevails when working with especially hard or brittle materials that require expensive tools.

Minimizing the number of cutting charts allows you to reduce the number of different actions of the operator of the circular saw, reducing the likelihood of errors of a subjective nature.

Optimization of the size of business scraps involves the formation of nesting maps in such a way that the sizes of scraps are maximum and their number is minimal. The use of this criterion is justified in the presence and good organization of the scrap warehouse. As a rule, the criterion for optimizing the size of trimmings is of an auxiliary nature and is used in the design as a clarifying indicator in the presence of several almost identical options for optimal cutting. The complexity of cutting and the subsequent process of organizing the technological flow is affected by the composition of parts in the cutting chart. When designing the cutting of materials, one should strive to ensure that when cutting one plate or sheet, the minimum number of standard sizes of parts comes out, and the repetition of the same parts in different cutting maps is minimal or completely excluded.

The set of these criteria is a contradictory set of requirements, therefore, depending on the task, the technologist must determine the priority of their action. The use of such a technique allows you to obtain cutting maps that are maximally adapted to a specific production.

To further increase the manufacturability of cutting charts, at each level, the operation of sorting workpieces in the strip is performed. When choosing a sorting method, the technologist needs to evaluate the properties of the material and the geometric dimensions of the workpieces, and then choose one of the options:

▼ to decrease the value of the CMM in the band;

▼ to reduce or increase the width of the lanes;

▼ by increasing the width of the stripes, starting from the center of the sheet;

▼ to reduce the size of the strips with the placement of the widest strip of the last one;

▼ to decrease the value of the CIM in the strip with the placement of the widest strip of the last one.

The latter sorting method is due to the fact that internal stresses in chipboard sheets are distributed unevenly across the width of the sheet (Fig. 1.6).

This can lead to the fact that when sufficiently narrow and long workpieces hit the edge of the sheet, they will bend under the action of the difference in shear stresses (Fig. 1.7).

Let's consider the examples of the influence of sorting methods on the designed nesting charts. Figures 1.8, 1.9 and 1.10 show cutting charts that have the same KIM value. However, the following differences can be noted.

The map in fig. 1.8 is designed using the method of sorting by decreasing the value of the KIM in the strip: the area of ​​​​cuts decreases from the top strip to the bottom. Visually, it seems to be the most rational, but when it is implemented, the operator will be forced to move the machine stops in different directions.

Map in Figure 1.9. has the same performance in terms of number of panel turns, sizing, cut lengths, etc. However, unlike the map in Fig. 1.8, the width of the stripes increases from the top stripe to the bottom. This allows the stops to move in only one direction, which leads to the elimination of backlash when setting new dimensions.

The map in fig. 1.10 has more size settings, but the narrow stripes are clustered in the middle of the sheet.

It is impossible to say unequivocally which of the above cutting maps is better. The right of choice remains with the technologist, since everything depends on the specific production situation and the properties of the material used. Note that sorting methods do not affect the CMM value, they only make an additional contribution to obtaining technological nesting charts.

The proposed approach to the design of material cutting charts separates the optimization of the distribution of workpieces and their sorting. This makes it possible to implement flexible adjustment of algorithms to the technological conditions of a particular enterprise.

Organizational aspects of the cutting section

As noted above, cutting materials is an operation that combines design and production stages work on the order. This means that the rhythmic work of many production sites of a furniture enterprise largely depends on the high-quality design of cutting, that is, in the algorithms for generating cutting maps, in addition to geometric and technological parameters, production aspects determined by the technological processes used should be taken into account. Let's consider them.

With any cutting of materials, trimmings are inevitably formed, some of which can be used in further work and the other part is to be recycled. By business trimming we mean a fragment of a sheet of material that is rational to use for subsequent cutting of parts from the same material, in contrast to waste, which is irrational to use. Since there is often no clear boundary between cutting and waste, it is up to the technologist to determine it. For automatic crop sorting, you must set the minimum length and width values. All offcuts that exceed both values ​​at the same time are business offcuts and will be taken into account in subsequent nesting design operations.

The problem of rational use of scraps at the enterprise has informational and technological aspects. Informational aspects are connected with the maintenance of the database, in which the necessary information is automatically entered after the cutting is completed. From it, data on the available trimmings are also retrieved before starting the cutting. It should be noted that the use of scraps requires additional costs for their storage and transportation, which must also be taken into account.

The technological aspect of the use of scraps is determined by the possibility of various damages during storage, which, as a rule, are formed along the edge of the trim. Therefore, before the formation of cutting maps for each material, the value of preliminary filing of scraps is set, which leads to additional costs.

If there is a database of scraps, the enterprise provides two modes of cutting materials:

▼ cut only full-size slabs of materials without taking into account scraps of the same material formed during previous cuttings;

▼ cutting taking into account the available scraps.

In the second case, cuttings are cut first, and then, if the cuts are over, or it is impossible to place the parts remaining in the list on them, the plates are cut.

In the process of trim cutting, a situation may arise when the number of trims at the beginning of cutting, that is, those that are used as source sheets, turns out to be less than the number of trims resulting from the cutting. This is due to the fact that when cutting scraps, new trims may appear. The occurrence of such a situation in most cases is extremely irrational. To eliminate this, it is necessary to automatically analyze each cutting map and exclude from the set of acceptable options those cut cutting maps that give at least one new cut. However, such automatic analysis is not always required, so this mode is optional. In addition, in some cases there is a need to directively classify newly appeared scraps for certain materials as waste, without changing the general sorting criteria.

Thus, three conditions for the rational use of information about trimmings in the design of nesting are determined:

▼ CIM of scraps exceeds some predetermined value;

▼ The KIM for cutting offcuts from the database exceeds the KIM for the current cuttings by an amount not less than the specified value;

▼ information about cuttings must be removed from the database.

To radically increase the material utilization factor, a cascade cutting technology has been developed and implemented in software, which is a method for generating nesting maps that allows you to automatically “redraw” individual maps that have unsatisfactory characteristics, in accordance with the local scale of optimization criteria.

Since the criteria scale has an end-to-end effect, separate cutting plans can be formed, the quality of which can be improved. To do this, a new local scale of criteria is determined, which applies only to the cards specified by the technologist, and the operation of cutting parts placed on these cards is performed without changing all the others. The number of repetitions of cascade cutting is not limited. An additional option for nesting design is manual editing of nesting maps, taking into account the texture direction and completeness.

Based on this, the resulting optimal cutting plan includes three components:

▼ many cutting patterns accepted by the technologist without modifications;

▼ many maps designed using cascade cutting technology;

▼ many manually edited nesting plans.

Since the use of scraps in the design of material cutting leads to additional costs, a new methodology for organizing design has been developed, which can significantly reduce their number. To do this, the list of parts to be cut is divided into two lists:

▼ the main list containing information about the blanks of the current designed product or ensemble;

▼ an additional list that includes information about blanks for the manufacture of future products, small-form products (flower shelves, small bedside tables, etc.) or elements that will be used in many products (drawers, shelves for a computer keyboard, etc.). d.).

The additional list includes blanks that will be cut out on scraps obtained when cutting the main list. Information about them, as well as information about cuts, is entered into the database. However, their average residence time is much less than the information about prunings. This is due to the fact that before starting the cutting of materials for the next job, two operations are performed:

▼ information about all available blanks is retrieved from the database;

▼ all blanks that were previously cut through the additional list are excluded from the main list.

The fundamental difference between the algorithms for cutting blanks from the additional list and the regular cutting of scraps is that in the first case, both lists are cut together. In this case, blanks from the additional list are placed only on the trimmings formed when cutting blanks from the main list. Cutting blanks of the additional list is performed according to the same algorithms and with the same technological settings as the blanks of the main list.

When using an additional list, you must select one of the three possible modes of using data from it:

▼ use only current cuts;

▼ use current cuts and cuts, information about which is available in the database, without additional conditions;

▼ use trimmings from the database only if at least one blank from the main list is placed on them.

The principles for the formation of an additional list are determined when preparing the initial data for cutting, based on the current and future needs of the enterprise. The concept of material utilization factor when working with it expands to four possible options, depending on what is considered a useful output of the cutting operation:

▼ area of ​​blanks of the main list;

▼ area of ​​blanks of the main list and business scraps;

▼ area of ​​blanks of the main and additional lists;

▼ area of ​​blanks of the main list, additional list, as well as business scraps.

Integration of cutting into the production environment of the enterprise

The technological operation of cutting materials is the beginning of the manufacture of cabinet furniture products. This means that cutting charts are the source of initial data for the implementation of subsequent technological operations: edge cladding, hole fillers, assembly, packaging. How the initial conditions for their implementation will be formed depends both on the execution time of this order and the execution time of the following orders.

This requires inclusion software module cutting in production environment enterprises for the purpose of algorithmic solution in the process of forming maps for cutting a number of organizational and production problems. Modern sawing centers can simultaneously cut packages of full-length sheets, and their number in a package depends on the type of machine and has a certain multiplicity. If the center cuts n sheets at a time, and for cutting the product blanks k sheets are required (k is not a multiple of n), it becomes possible to form two cutting options:

▼ cutting with a backlog in which all cards are optimized for execution on the saw center, that is, cutting is planned in them additional sheets and obtaining an excess number of blanks, information about which will be entered into the database;

▼ accurate cutting, which contains two types of cards, for example, for a saw center and for a circular saw, which allows cutting one plate of material at a time.

The presence of such a possibility in the BAZIS+Nesting module allows the use of the so-called technology of a fixed level of cutting. Above it was said about bringing the areal cutting to the linear cutting. This means that such an optimization algorithm actually splits each full-length sheet into strips of a certain level, while the original sheet is a zero-level strip. Each new level in terms of cutting performance is a turn of the package being cut. By specifying the number of the maximum level as an input parameter, it is possible to design cutting plans of two types - with a limit on the number of turns and without a limit.

Proper use of this technology makes it possible to generate nesting maps that ensure optimal loading of the entire fleet of cutting equipment.

Another production aspect that must be taken into account in the automated cutting of materials is ensuring the planned exit of parts from the cutting area. This is achieved by using the stacking technique. It is known that in order to optimize the operation of milling, filler and edge banding equipment, it is necessary to minimize the number of changeovers, that is, to maximize the number of identical parts coming from the cutting section in different batches. The BAZIS+Nesting module implements the ability to control the maximum number of different standard sizes of parts that are located on one sheet - the stacking level.

Changing the bundling level changes the number of groups of current parts that must be stored near the cutting machine before they are transferred to subsequent technological areas. Reducing the number of such groups, achieved in the process of generating nesting charts, allows you to get a number of significant advantages: the use of a smaller production area for storing parts; minimization possible errors the operator due to the need to sort a smaller number of standard sizes of parts; uniform loading of equipment of other sections.

Naturally, the inclusion of additional conditions in the nesting parameters is the reason for the decrease in the value of CMM and/or the manufacturability of nesting charts. The task of the technologist is to use the capabilities of the BAZIS+Nesting module to form cutting plans that meet the requirements of the current production situation to the maximum extent. The developed algorithms and cutting techniques provide all the necessary conditions for solving this problem.

In addition to the considered settings for optimizing production, the following additional features are implemented in the BAZIS+Nesting module:

▼ selection of the optimal batch of cut products in a given range, which is relevant when combining custom and serial types of production;

▼ high-quality design of cutting charts, which is of great importance for reducing the time of its implementation;

▼ automatic generation of custom labels containing a given set of parameters, presented both explicitly and as a barcode in one of the coding systems, which makes it possible to implement elements of paperless technology in production.

Technological operations for cutting sheet and plate materials include sawing them along and across to obtain blanks or parts of the required dimensions. At the same time, it is necessary to fulfill the main requirements for cutting - ensuring the maximum cutting ratio, completeness of blanks in accordance with the volume of production and the corresponding quality. The maximum percentage of useful yield of parts in cleanliness can be ensured if the allowances are minimal, organizational and technological losses are reduced to zero, and the cutting of plate and sheet materials into blanks is based on strict mathematical calculations.

In production, blanks from plate and sheet materials are cut according to cutting charts. When developing cutting charts, strict adherence to the maximum output of parts, completeness of parts is required different sizes and assignments in accordance with the volume of production, the maximum number of standard sizes of parts when cutting one plate and the minimum repetition of the same parts in different cutting charts. Cutting charts are made taking into account allowances for subsequent machining. For furniture blanks made of board materials, processing allowances are set along the length and width. When compiling cutting maps lined with chipboard, the direction of the pattern in the blanks is taken into account.

The equipment for cutting boards used at furniture and woodworking enterprises implements a step-by-step cutting scheme, in which at the first stage the chipboard is cut along the length into strips, then, at the second stage, the strips are cut into blanks. Depending on the number of standard sizes of workpieces included in the cutting chart, and compliance or non-compliance with the completeness of the workpieces in one cutting chart, there are individual, combined and joint methods of cutting.

In case of individual cutting, materials (boards) of the same type are cut into blanks of one type or materials of the same type are cut into blanks of several types (several sizes) and, finally, materials of several types are cut into blanks of the same type. An individual cutting method is accompanied by a large amount of waste.

Combined cutting provides for the inclusion in each cutting chart of several standard sizes of workpieces or parts with the obligatory observance of the completeness of the workpieces to be cut out. This cutting method is usually more efficient than individual cutting, but it is more complex.

Joint cutting may include individual and combined cutting methods and is the most effective in comparison with those considered.

The greatest application for cutting uncoated chipboard was found by such machines as TsTMF-1, TsTZF-1 (Russia) (Fig. 67); for cutting laminated chipboard - panel saws ITALMAC Omnia-3200R (Fig. 68), CASOLIN Astra SE400 (Italy), ROBLAND (Belgium), PANHANS (Germany) and CNC cutting centers SELCO EB 120 (Fig. 69) ), Biesse SELCO WNAR600 (Italy), HVP 120 (Fig. 70), etc.

Rice. 67. Cutter machine TsT3F-1: 1-bed; 2-guide; 3-control panel; 4-hydro station; 5-hydraulic drive of the transverse caliper; 6-traverse; 7, 12-calipers; 8, 11 flywheels; 9-saw for ripping; 10-saw for cross cutting; 13-cable; 14-sawn material; 15 carriage

Rice. 68. Panel saw ITALMAC Omnia-3200R

Rice. 69. CNC panel saw SELCO EB 120

Rice. 70. CNC vertical panel saw HVP 120

Let's open called the division of materials by a cutting tool into parts or blanks of the required size and shape. The raw materials for cutting are sheet materials (boards, plywood) and boards made of hardwood and coniferous wood. Parts or blanks are obtained from sheet materials, bar blanks are obtained from boards.

Details made from sheet materials include, for example, the back walls of cabinets, drawer bottoms. Such details receive at once the set size, without an allowance for the subsequent processing.

Blanks from sheet materials and boards are segments of certain sizes and shapes with allowances for further processing. Blanks from sheet materials have allowances in length and width, from boards - in length, width and thickness.

When cutting raw materials, both allowances for subsequent machining and allowances for shrinkage are taken into account.

When cutting, it is necessary to ensure the maximum yield of blanks from the materials being cut, which is understood as the percentage ratio of the volume of the obtained blanks to the volume of the cut material, expressed as a percentage. The norms of the useful yield of blanks in furniture production are at least: from joinery boards - 85%, particle boards - 92, fibreboards - 90, plywood - 85%. The rates of useful output of bar blanks when cutting boards are given in Table. 3.

Cutting sheet materials. When cutting, sheet materials are sawn lengthwise and across into blanks. the right sizes and forms. To ensure maximum yield of workpieces from the slabs standard sizes, make up a cutting map. This method of cutting materials without taking into account their quality in advance established scheme called a group.

The cutting map is a scale drawing of the sheet material to be cut in plan. Several options for cutting sheet material are applied to the plan, indicating the dimensions of the resulting blanks and the number of parts of each size. The optimal options for cutting a sheet are evaluated taking into account the maximum yield of blanks from the sheet, the completeness of the output of blanks of different sizes and their assignment in accordance with the plan for the production of furniture products, the minimum number of standard sizes of blanks in one cutting chart, the minimum repetition of the same blanks in different cutting charts.

To solve the problems of optimal cutting of sheet materials with large numbers standard sizes of the received preparations at the enterprises use electronic computers.

For cutting sheet materials in conditions of mass production, two-, three- and multi-saw format machines TsF-2, TsTZF, TsTMF are used.

Double-saw format machines allow cutting the workpiece immediately in length or width when cutting in one pass. When working on two paired two-saw machines, it is possible to obtain a workpiece cut in length and width (Fig. 53, a). When working on three- and multi-saw machines, workpieces are cut from four sides at once (Fig. 53, b, c). At the same time, several sheets stacked in a stack on carriage 4 are cut out, Conveyors 1 feed the carriage to saws 2 and 3. The thickness of the foot is set by the passport data on the machine. The process of loading sheet materials into the machine is mechanized. A device for loading sheet materials into the machine is installed near the sizing machine, and at the exit of the cut blanks from the machine, an underfoot place is provided for their stacking. The machine is operated by two or three workers.

In the conditions of individual production, circular saws with manual feed Ts-6 or hand-held electric saws are used for cutting.

Sheet materials are cut on machines in the following modes: cutting speed 50-60 m/s, feed per saw tooth 0.04-0.06 mm.

Open the boards. The boards to be cut may have unacceptable wood defects. When cutting, these defects must be removed. Therefore, when cutting boards, an individual cutting method is used, taking into account the size and quality of the boards according to the most rational scheme.

When cutting according to scheme I, the board is first sawn across, then the resulting segments are sawn lengthwise. When cutting according to scheme II, the operations are performed in the reverse order. In both cases, unacceptable wood defects are removed during cutting. The useful yield of blanks when cutting according to scheme II is approximately 3% higher than according to scheme I.

You can increase the useful yield of blanks by using the marking of segments (Scheme III) or boards (Scheme IV). Pre-planing of the board (Scheme V) allows you to better see the defects of the wood and choose the best option cutting.

The use of markings when cutting boards increases the cost of cutting by about 12-15% compared to the cost of cutting where markings are not provided. Therefore, the introduction of markup in each case is decided separately, taking into account all economic

factors. Marking must be performed when cutting boards made of precious wood (walnut, mahogany, etc.) and cutting boards into curved blanks.

The useful yield of curved workpieces can be increased by pre-gluing the segments. On fig. 54a shows three pieces of board, from which four blanks for the back leg of the chair can be cut. If these segments are pre-glued, then five of the same blanks can be obtained (Fig. 54, b). An indispensable condition for cutting glued blanks is the high strength of the adhesive bond.

For transverse cutting of boards, circular saws Ts-6, TsME-3, TsPA-2 with manual or mechanical feed of the cutting tool are used, for longitudinal cutting - circular saws with mechanical feed CA-2A, TsDK4-2, TsDK-5 and machine with manual feed Ts-6. In the conditions of individual production, hand-held electric saws are also used.

Transverse and longitudinal cutting of boards on machines is carried out under the following modes: cutting speed for transverse cutting 50-60 m/s, feed per saw tooth 0.04-0.1 mm; cutting speed for longitudinal cutting 45-50 m/s, feed per saw tooth 0.06-0.12 mm.

For cutting curved blanks, band saw machines LS80-1, LS40-1 are used. Blanks for band saw machines they are sawn out at a cutting speed of 30-35 m/s and at a saw tooth feed of 0.08-0.15 mm.

The cutting of boards is rationally organized at furniture enterprises with direct-line production and mechanization of intrashop movement of blanks. On fig. 55 shows a diagram of the flow of cutting boards into straight bar blanks based on a single-blade and multi-blade trimming machine with mechanical feed.

The boards are transported by narrow gauge railway 1 from the drying shop to the lifting elevator 2. The elevator platform can be lowered below the floor level so that the boards in the stack 3 can be located at any level convenient for the worker. The boards from the stack are fed to the driven roller conveyor 13 and trimmed on the trimming machine 12. The pieces of boards from the non-driven roller conveyor 6 are fed through the chain conveyor 11 to the non-driven roller conveyor 4, from where they are fed to the multi-saw machine 10 for longitudinal cutting and from the roller conveyor 6 are stacked on sections of 7 floor non-driven roller conveyors. If it is necessary to recut longitudinally, the segments are fed to the multi-saw machine by a return belt conveyor 5.

Cut blanks for further processing are transported by a narrow-gauge trolley 8. Waste is removed through hatches 9.

In the diagram, the locations of the workers are shown as half-filled circles, the stack of raw material is indicated by a rectangle with one diagonal, the processed one is indicated by a rectangle with two diagonals. These symbols we will use it in the future, when describing the organization of jobs and production flows.

Cutting accuracy. Permissible deviations in the shape and location of surfaces when cutting on machines when receiving blanks from sheet materials and boards that cannot be re-processed are given in Table. 4.

When cutting, deviations from the nominal dimensions of the blanks to be re-processed are established taking into account the type of subsequent processing. In all cases, these deviations should be as small as possible.

The calculation of the required amount of materials is a necessary part of the technological preparation of furniture production. The calculation of the amount of wood materials is carried out in order to establish consumption rates per unit of production, per thousand products and per annual program. In this case, all losses of materials at various stages of the technological process should be taken into account: when cutting materials into blanks; when processing rough and finishing blanks, as well as technological losses.

The initial data for the calculation are taken in the design documentation for the product. When calculating, one should be guided by the approved reference data on the consumption rates of raw materials and materials given in Appendix D to these guidelines. In addition, it is necessary to take into account the planned scheme of the technological process and the operations included in it. The total amount of wood materials per product is made up of their need for the manufacture of parts included in this product. Therefore, the calculation of materials is carried out in detail, that is, they determine the type and amount of material necessary for the manufacture of parts of each type and size, taking into account their quantity in the product.

The quantity and consumption rates of wood materials are set in m 3 and m 2. Lumber and particle boards are calculated in m 3, and fibreboards and plywood, synthetic facing material, edge plastic, sliced ​​and peeled veneer, as well as roll films - in m 2. The calculation is carried out sequentially for all assembly units and parts of the product. The assembly units include a chipboard base, seam cladding, and edge cladding. The type of facing materials is assigned by the student in accordance with his creative plan or (for part-time students) in accordance with the option of the task according to the Study Guide. The calculation of the required amount of materials is carried out for 1000 products and is drawn up in the form of a statement of the calculation of wood materials.

The columns of table 1 from the first to the ninth are filled in on the basis of assembly and working drawings and specifications for the product and assembly units. The volume of parts made from chipboard or lumber is determined by multiplying the number of parts per product by the length, width and thickness. The amount of sheet materials is determined by area - by multiplying the data in columns 6, 7, 8. The results of calculations in m 3 or in m 2 are recorded in column 10.

After determining the volume or area of ​​parts per product according to tables 1-3 of Appendix D, allowances for machining are found in length and width and recorded in columns 11 and 12 of the material calculation sheet. The allowance value must take into account all operations that determine the overall dimensions of the workpiece in the process of turning it into a part. Without processing allowances, parts are cut out of fibreboard and plywood that are not subject to gluing and veneering, as well as boards made of chipboard and joinery boards that are not subject to veneering and are framed with layouts and bars. Then, by summing up the dimensions of the base in cleanliness with the allowances for mechanical work, taking into account the accepted multiplicity, the dimensions of the base blanks are calculated in length, width and thickness and recorded in columns 14, 15 and 16. The dimensions of the blanks for facing seams and longitudinal edges are determined based on the dimensions of the blanks base and established allowances for sliced ​​veneer or other facing material, that is, to determine the dimensions of the facing workpiece, the allowance for facing material is added to the dimensions of the base workpiece. The volume (m 3) or area (m 2) of a set of blanks per product is determined by multiplying the numbers given in columns 6, 14, 15, and (if the volume is determined) 16 and recorded in column 17. In column 18, the volume or area of ​​\u200b\u200bthe set is recorded blanks for 1000 products.

Next, it is necessary to determine the excess of the amount of material in the blanks against the actual need, taking into account the fact that some of the blanks will be rejected during the production process due to possible material defects, when setting up machines, etc. In this regard, a standard percentage of the margin for technological losses is established and the volume or area of ​​blanks is determined, taking into account technological losses. In column 19, the percentage of production and technological losses is put down, which is determined according to table 4 of Appendix D. In column 20, the volume or area of ​​blanks is indicated, taking into account production and technological losses (K t), that is, these columns 18 are multiplied by (100 + K t) and divide by 100.

The total volume or area of ​​wood materials consumed per 1000 products (column 22) is determined by dividing the volume or area of ​​blanks (column 20) by the percentage of output of blanks when cutting (column 21) and multiplying the result by 100. The coefficient of useful yield when cutting for each type material is determined by drawing up cutting maps (for particle boards) or according to table 5 of Appendix D.

The rational consumption of plate and sheet materials is a mathematical problem that is solved graphically, compiling cutting maps. The map is a sketch of a plan for cutting particle board in a standard format (for example, the most widely used formats: 3500 × 1750 mm; 3660 × 1830 mm) into blanks of the required dimensions. When drawing up maps, it is necessary to find such a cutting option that can be performed on the equipment (technically feasible) and that would ensure the most rational use of the material. Cutting can be individual (one size) or mixed (several sizes). In this course project, it is proposed to draw up possible options for individual cutting maps to obtain one large-sized workpiece (side wall). In this case, the workpiece of the side wall part made of chipboard has overall dimensions of 1728 × 580 mm, and, therefore, it is rational to cut the boards of the largest overall dimensions, namely 3660 H 1830 mm. When drawing up cutting maps, it is necessary to take into account the width of the cut, which is equal to 4 mm.

In accordance with the data of the cutting maps, the useful yield of workpieces P,%, is determined by the formula:

where S zag - the area of ​​the workpiece, m 2 ;

S pl - particle board area, m 2;

n is the number of blanks obtained from one plate.

In the considered example, the useful yield of workpieces for both cutting patterns is 90%. Therefore, it is necessary to optimize cutting maps to increase the rational cutting of particle boards into blanks. An indicator of the efficiency of the use of wood materials is the percentage of net yield, which is determined for each type of material by the ratio of the volume or area of ​​parts per 1000 products to the volume or area of ​​the required wood materials and multiplied by 100. As a result, the total consumption of materials by type (chipboard, veneer, edging) is calculated. material, fiberboard) for columns 10, 20, 22 and determine the average percentage of net output (column 23). The total values ​​are put down in the last lines of the statement. When making parts small size multiple blanks should be used, which allow more economical use of materials, improve conditions machining, loading and unloading operations and transport operations. In multiple blanks, details are calculated, at least one of the dimensions of which is less than 245 mm (in accordance with the technical characteristics of the equipment for cutting chipboard).

The consumption of materials for such blanks is given in the general statement. First, the dimensions of the part and their number in one product are given. Below are the dimensions of the base with an increase (usually one of the dimensions) by an integer number of times, taking into account the width of the cuts (at least 4 mm per cut for subsequent cutting to size). The multiplicity is indicated in the denominator of the number of parts in the product. By analogy with the base material, the lining of the face is calculated. Edge trims are calculated as for independent parts. For example, the design of the product includes a box, the front wall of which has dimensions of 440x150 mm. The size of the double base in cleanliness, taking into account the width of the cut, will be equal to 440×304 mm. These dimensions determine the size of the allowance. The number of such bases per product is 1/2. Further, all calculations are carried out according to the considered method and are entered in the statement.

In the manufacture of wood products, chipboard and fibreboard are widely used, manufactured in accordance with the requirements of the standards for them.

Technological operations for cutting sheet and plate materials include sawing them along and across to obtain blanks of the required dimensions.

Advantages of cutting board, sheet and roll materials over solid wood:

l standard formats;

l when cutting them, there are no restrictions on quality, color, defects;

l they are stable in quality and format.

The main limitations in cutting plate and sheet materials are the number and dimensions of blanks.

The number of standard sizes of blanks must correspond to their completeness for the production of products provided for by the program.

Currently, programs have been developed for compiling cutting charts for plate, sheet and roll materials with simultaneous optimization of the cutting plan.

Optimal cutting plan - this is a combination of various cutting schemes and the intensity of their use with the provision of completeness and a minimum of losses for a certain period of operation of the enterprise.

Cutting charts are a graphical representation of the location of workpieces on a standard format of the material to be cut.

For cutting layouts need to know:

l blank sizes;

l formats of the material to be cut;

l cut width;

l equipment capabilities;

l damage to the material being cut.

Plates are cut

according to three cutting patterns

a) longitudinal

B) transverse

V) mixed

Depending on the number of standard sizes of blanks included in the cutting chart, and compliance or non-compliance with the completeness of blanks in one card, there are
3 ways of cutting:

1. Individual;

2. Combined;

3. Joint.

With individual cutting

cut out:

Plates of the same type for blanks of the same type;

Plates of the same type for blanks of several standard sizes;

Plates of several types for blanks of the same type.

At combined method cutting from one format, you can cut out several different standard sizes of blanks. More effective method in terms of economical consumption, but more complex. With a large number of standard sizes, it is difficult to ensure the condition of completeness in each cutting chart.

With joint cutting for various cases, individual and combined cutting options are used.

This cutting method is the most effective in comparison with the considered ones.

The efficiency of cutting according to the rational use of materials is evaluated yield factor.

The blank yield coefficient is determined from the ratio of the total areas of the obtained blanks to the total area of ​​cut plate or sheet materials.

Cutting efficiency depends on:

Applied equipment;

Organization of the process of cutting plates and sheet materials.

By technological features The equipment used for cutting slabs is divided into 3 groups.

The first group includes machines with:

l several supports for longitudinal sawing;

l one - transverse (TsTZF-1).

The second group includes machines with:

Several supports for longitudinal sawing;

One transverse;

The carriage table consists of two parts (SpK-401).

The third group includes machines with:

one longitudinal sawing support;

several calipers - transverse (MRP lines based on the TsTMF machine).

Panel saws

When cutting sheet materials, single-saw format-cutting machines are used.

All cuts are made with one saw in mutually perpendicular directions. To do this, there are mechanisms for longitudinal and transverse movement, lifting and fixed angles of rotation of the saw head.

Cutting sliced ​​veneer

Before cutting, sliced ​​veneer must be sorted into bundles depending on the purpose of the veneer.

Cut veneer in bundles on guillotine shears or paper-cutting machines. These machines provide a clean cut that does not require subsequent jointing of the edges.

Cutting of rolled materials

To obtain the desired formats, rolled materials are cut on special cutting devices with longitudinal disc knives and transverse ones - rotary or guillotine.