Cutting slabs is a delicate matter! The process of cutting slab, sheet and roll materials. Selection of cutting patterns and methods


CUTTING PLATE MATERIALS

Goal of the work:

Practical and theoretical study of the technological process of cutting lined and unveneered particle boards.

Job objectives:

By doing laboratory work in a production environment, students must study the process of cutting slabs; operation and arrangement of equipment; principles of organizing workplaces in the cutting area; methods for determining productivity, specifics of developing cutting charts for this type of equipment.

General information about cutting slab materials

Cutting particle boards is one of the most important stages in the production of furniture based on them. How well furniture made from chipboard is made largely depends on how well the slab was cut into blanks.

The efficiency of the slab cutting operation is determined by the productivity and rational use of the material.

The efficiency of cutting based on the rational use of material is determined by the coefficient of useful output P, which is determined by the formula

(1.1)

To organize rational cutting of slab materials, technologists develop cutting maps. Cutting cards are a graphical representation of the arrangement of workpieces on a standard format of the material being cut. To draw up cutting maps, it is necessary to know the dimensions of the workpieces, their quantity within the production program, the formats of the material to be cut, the width of the cuts, the number of saws and the sequence of cuts corresponding to the technical data of the equipment.

If lined or laminated boards, plywood and similar wood materials are cut, then when drawing up cutting maps it is necessary to place the workpieces on the format, taking into account the direction of the fibers on the lined surface. In this case, the workpieces have a definite size along and across the grain, which makes the useful yield less than when cutting uncoated slabs. Covered particle boards are cut to exact size.

Due to its high consumer qualities at affordable price Altendorf format cutting machines and their numerous analogues (FL-3200B, FL-3200B, FL-3200 Light, etc.) have become very popular. Models of such machines differ in the level of control systems and manufacturability. On the global equipment market we offer various models formatting machines with scoring saw: Omnia 3200R (MJ3200D), KS3200 MAKA, WA6, ELMO IV (Germany), SC-32, OPTIMAL-350, TEMA2600, EXPRESS-3200, UNICA-500E (Italy), etc.

The range of equipment has also expanded due to the appearance of vertical machines for cutting slabs from Reich (Holz-Her), Sonnenberger, Striebig (Switzerland), Homad-Espana (Spain). These machines differ in that the cutting of slab materials is carried out in a vertical position. This ensures a reduction in production area necessary for organizing the workplace.

Chipboards are used as a tool for cutting circular saws with a diameter from 320 to 400 mm with plates made of hard alloys. Feed rate per tooth Uz = 0.05-0.12 mm. Deviation from the perpendicularity of the sides of the workpieces is no more than 0.5 mm, from straightness – no more than 0.3 mm. When cutting coated particle boards, to maintain the quality of the cladding, the cuts are made with two saws: the main saw and the scoring saw (Figure 1). A scoring unit is provided on the machines so that when cutting materials with double-sided lining, bottom side There were no tears or chips. The cut line of the scorer exactly coincides with the cut of the main disk, including when sawing at an angle.

Figure 1 – Scheme of piece and batch cutting of lined slabs

The estimated productivity of the machine can be determined by the formula

,

where T cm – duration work shift, min;

K p – coefficient taking into account the loss of working time due to breaks introduced into the work mode;

K m – coefficient taking into account the loss of computer time;

U – feed speed, m/min;

n is the number of simultaneously cut slabs;

m is the number of blanks according to the cutting map for one slab;

∑L pr – length of cuts according to the cutting map;

L gap. - length of inter-end gaps.

The FL-3200B format cutting machine from Filato is used as a basic model of equipment (Figure 2).

Figure 2 – Appearance machine

The machine is designed for longitudinal, transverse and angular piece and batch cutting of panel materials (MDF, fibreboard, chipboard and laminated boards) lined and laminated, as well as blanks made of solid wood, with preliminary trimming of the lower edge of the blank to prevent the formation of chips. When cutting uncoated slabs, a scoring saw is not used. Such equipment is used in enterprises for the production of cabinet furniture, in carpentry workshops for the production of joinery and construction products.

2 hours

Lecture outline

2.1.1 Development of slab cutting charts

2.1. 2 Tools and equipment used

2.3.5 Modes of cladding with synthetic cladding materials

2.36 Defects in facing layers
2.3.1 Types of cladding
Based on the type of surfaces being coated, the cladding process is divided into: technological process veneering of layers and technological process of veneering of edges. Based on the temperature of the process, veneering is divided into cold and hot. According to the method of creating pressure in the lining zone - for lining in presses with flat plates and lining in roller-type presses, in membrane and vacuum presses.
2.3.2 Adhesives used
For cladding in the production of wood products, adhesives based on urea-formaldehyde resins in accordance with GOST 14231-78 grades KF-BZH, KF-Zh (M), KF-B and modified by them are widely used. The following hardeners are used: ammonium chloride for hot gluing and oxalic acid for cold gluing. For filling adhesive solutions They use kaolin, talc and wheat sour cream. Incoming adhesives must be tested to ensure they meet their standards. The standards regulate the proportion of dry residue, mass fraction of free formaldehyde (1%), viscosity, gelatinization time, hydrogen ion concentration and adhesive strength.

The amount of simultaneously prepared glue is determined by calculation based on the need for the period of its viability. For cladding during cold gluing, 4-7% is added to the KF - Zh (M) resin oxalic acid in a 10% solution. coincide with the direction of the warp fibers.

Glue consumption depends on the materials used. It should be enough to form a continuous layer. When lining with films, the glue consumption is from 80 to 100 g/m2, with planed veneer - from 130 to 140 g/m2.
2.3 . 3 Equipment used

Panel and other straight blanks are veneered in multi-storey or single-storey presses with heated plates. The panels' surfaces are faced with synthetic veneer and polymer films using the same equipment as for veneering with sliced ​​veneer.

When veneering in single-deck presses with heated plates, the specific pressure, MPa, for film is 0.4-0.5, for veneer 6.5-0.8; holding time under pressure for KF-Zh (M) resin, not less, s; for film - 40, for veneer with a thickness of 0.6-0.8 mm - 60, for veneer with a thickness of 1.1-1.5 mm - 90; for KF-BZh resin, the exposure time in the press is reduced by approximately half.

After lining in hot presses, the lined blanks must be stored in tight stacks until completely cooled, approximately 24 hours. When lining in multi-deck presses, metal spacers are used to load the bags into the press. The panels are covered with film in multi-story presses at a specific pressure of 0.4-0.5 MPa, when faced with veneer 0.8-1 MPa; temperature of press plates from 110 to 140 °C; holding time 2-4 minutes.

On the basis of single-deck presses AKDA 4938-1, AKDA 4940-1, semi-automatic lines for cladding panel blanks MFP-2, MFP-3 were created. Imported production lines are also used. Thanks to the mechanization of the process, labor costs for cladding panel blanks on single-deck presses are 3 times less than labor costs for cladding in multi-deck presses. The advantage is the higher quality of the lined surface.

1 - feeder; 2 - glue-mowing machine KB 18-1; 3 - packet formation conveyor; 4 - ZhDA press 4938-1; 5 - automatic stacker of panels

Figure 3. 1 – Scheme of the line for lining MFP-2 layers

The methods for loading packages into presses of different lines may be different (Figure 3. 2).


a-steel tape: /-steel tape; 2- packages; 3- press plates; b-with loading carriage: /-carriage; 2-packs; 3 - press plates; 4- unloading conveyor; c-with a loading conveyor made of heat-resistant tape: 1- conveyor; 2-pa chum salmon; 3 - press plates; 4 - heat-resistant tape; 5 - unloading conveyor; g - with a chain loading and unloading conveyor; / - package formation table; 2 - packages 3 - press plates; 4 - receiving conveyor; 5 - emphasis; 6 - chain

Figure 3.2 - Press loading diagrams

Cold cladding is used when gluing thick layers of cladding made of decorative laminated paper, fiber, artificial leather, etc. onto the surface of workpieces. Cold-curing adhesive is applied to the base. The package is completed in the following sequence: gasket - facing material- base - facing material - gasket. The packages are placed in a stack on the underplate and the edges are aligned. The foot is covered with a second shield and beams are laid, which are connected to each other with ties. The foot is placed in a long-span press, pressure is created and the foot is tightened with ties, after which the pressure is removed and the foot is rolled out along a roller conveyor from the press to soak until the glue is completely cured in the workshop. The use of combined adhesives based on urea-formaldehyde resins with polyvinyl acetate emulsion speeds up the cold gluing process several times. The use of rubber-based adhesives requires two-time application and drying. When gluing plastic to panel blanks on one side, a compensating layer is glued to the second side to prevent warping of the panels.
2.3. 4 Modes for veneering with sliced ​​veneer
In the furniture industry, sliced ​​veneer is one of the main facings; adhesives based on filled urea resins are used with the following composition (parts by weight):

Resin MF-17, KF-Zh(M) ........ 85...88

Technical kaolin (filler) .. . . . 12...15

Ammonium chloride (hardener) .... 1

An important factor determining the veneering mode is the amount of glue applied per 1 m 2 of the surface to be veneered. Optimal thickness the adhesive layer should be 0.08...0.15 mm. The amount of pressure during cladding depends on the area of ​​the surfaces to be veneered and the materials used.

The duration of exposure in presses under pressure depends on the temperature and type of glue used.

Technological regime for veneering board faces on automatic lines with quick-curing adhesives
Room air temperature, °C, not lower...... 18

Relative humidity

in room, %, not higher. . 65

Adhesive viscosity according to B3-4 viscometer, s......... 125...180

Time from glue application to loading

bags per press, min, no more.................... 20

Time from the start of downloading packages

until full pressure is established, s, no more........... 30

Pressing time, s, at plate heating temperature, °C:

130...150 .................. 30.,.35

145...150 ................... 25...30

Specific pressing pressure, MPa......... 0.4.,.1

Process holding time, h, not less....... 2
The parts to be coated in adjacent spaces of the press must be located one below the other and centered with respect to the axes of the press plates. The deviation in the thickness of parts placed in one press space should not exceed ±0.3 mm.

Veneer facings must be firmly glued to the base. The tensile strength when chipping along the adhesive layer in a dry state must be at least 1 MPa. There should be no air bubbles, ruptures, divergence of fugues or darkening of them from glue, seepage of glue, shift of the finishing cladding, overlaps, dirt, flakes, or dents on the lined surface. The quality of the lined parts is checked visually. All details are subject to verification. Temperature, viscosity and glue consumption are checked at least 2 times per shift, other mode parameters are monitored constantly during operation.
2.3. 5 Modes of cladding with synthetic cladding materials
For the hot veneering method, the following adhesive formulations are recommended.

Adhesive based on filled urea resins, mass. h.:

resin (MF-17, KF-Zh(M)). . ..; . . . . ... 85...88

technical kaolin (filler) ......... 12...15

ammonium chloride (hardener) .......... 1

Adhesive based on urea resin combined with polyvinyl acetate dispersion, wt. h.:

resin (MF-17, KF-Zh(M)) ............ 70

polyvinyl acetate dispersion........... 30

ammonium chloride............... 0.5

Adhesive based on urea resin combined with rubber latex, wt. h.:

resin (MF-17, KF-Zh(M)). .......... 70

latex (DMMA, MH-ZO, LNT, L-4, L-7) ........ 30

ammonium chloride............... 1

After veneering, the coating should be even, smooth, without air bubbles, tears, glue leakage, dirt, or dents. The quality of the coating is checked visually.

* To avoid warping, the same materials as for the front layer can be used as a compensating layer, or selected experimentally.

The main defects when veneering with films arise for the same reasons as when veneering with sliced ​​veneer. Glue seepage when veneering with synthetic veneer can be avoided if you use a film with a water-soluble resin content of no more than 14%; glue consumption should be 90...110 g/m2 and specific pressure in the press 0.5...0.6 MPa.
2.3. 6 Cladding defects
During cladding, the following defects may occur: leakage of glue onto the front surface, unevenness on the veneered surface, cracks in the cladding, local or complete separation of the cladding from the base, warping of the veneered parts. Each of the defects can be caused by one or more reasons. As a rule, the main cause of defects is non-compliance with technological operations.
2.4 FORMAT PROCESSING OF BOARDS. EDGING OF FURNITURE BOARDS

In the production of wood products, slabs, sheets and roll semi-finished products from wood materials, manufactured in accordance with the requirements of the standards for them. The standard formats of these materials received by enterprises are cut into blanks of the required sizes. The main limitations when cutting slabs and sheet materials are the number and dimensions of the workpieces. The number of standard sizes of blanks must correspond to their completeness for the production of products provided for by the program. Cutting slab and sheet materials in relation to the organization of the intended purpose of the resulting blanks is usually divided into three types: individual, combined and mixed. With individual cutting, each semi-finished product format is cut into one standard size of the workpiece. At combined form When cutting from one format, you can cut out several different standard sizes of workpieces. When mixed cutting, it is possible to use individual and combined cutting options for various cases. The efficiency of cutting based on the rational use of materials is assessed by the yield coefficient of blanks.

Particle boards and fibreboards are widely used in the production of wood products. Organizing their rational cutting is the most important task modern production. An increase in the yield rate of particle board blanks by 1% in the overall result of their consumption is expressed by saving millions of cubic meters of boards, the efficiency in monetary terms will amount to millions of rubles.

The efficiency of cutting depends on the equipment used and the organization of the process of cutting slabs and sheet materials. Based on the technological features, the equipment used for cutting slabs can be divided into three groups.

The first group includes machines with several supports rip sawing and one - transverse. The material to be cut is placed on a carriage table. When the table moves in a straight direction, the rip sawing supports cut the material into longitudinal strips. The carriage has adjustable stops, the action of which on the limit switch causes the carriage to automatically stop and drive the transverse sawing support into motion.

The second group includes machines that also have several longitudinal sawing supports and one transverse sawing, but the carriage table consists of two parts. When cutting longitudinally, both parts of the table form one whole, and when moving backwards, each part moves separately until the stop position determines the position of the cross cut. In this way, the alignment of the transverse cuts of the individual strips is achieved.

The third group includes machines that have one longitudinal sawing support and several transverse sawing supports. After each stroke of the longitudinal sawing support, the strip on the movable carriage is fed for cross cutting. In this case, those calipers that are configured to cut a given strip are activated. The rip sawing support can perform a non-through cut (trimming). In addition, there are single-saw format-cutting machines.

1. The first group of equipment is focused on performing the simplest individual cuttings. This gives a low material utilization rate. When implementing more complex circuits After longitudinal cutting, it becomes necessary to remove individual strips from the table with their further accumulation for subsequent individual cutting. At the same time, labor costs increase sharply and productivity decreases.

2. The second group allows you to perform cutting patterns with a variety of stripes equal to two. With a large variety of types, the same difficulties arise as in the first case.

3. The third group allows you to cut more complex patterns with up to five different types of strips. This group of equipment has high performance and is the most promising.

The MRP cutting line for sheet and slab materials is designed for cutting wood sheet and slab materials into blanks in furniture and other industries.

Cutting is performed with one longitudinal and ten cross-cut saws. The original feeding device allows you to remove a stack of several sheets of material from the stack and simultaneously feed it to the cutting tool. During the feeding and processing process, the bundle being cut is in a clamped state. The packs are fed at an increased speed, which decreases sharply when approaching the working position. All this ensures high productivity and increased accuracy of material cutting. Special electrical interlocks make work on the line safe and protect the line mechanisms from damage. When the line is disconnected, electrothermodynamic braking of the spindles occurs cutting tool. Furniture factories use automatic feed machines with one longitudinal and ten cross-cut saws. This machine can be used for cutting according to five programs. Crosscut saws are set to the program manually. The minimum distance between the first and second cross-cut saws (left in the feed direction) is 240 mm. The minimum distance between other saws is 220 mm. The machine can simultaneously cut two slabs in height with a thickness of 19 mm or three slabs with a thickness of 16 mm each. The rip saw cuts according to the programs should be made with a consistent reduction in the optimal strips. For example, the first cut is 800 mm, the second is 600, the third is 350, etc.

The slabs are laid transversely on the loading table and aligned along a movable stop ruler. By pressing the handle located under the work table, the longitudinal saw is brought into working position, and it cuts the first strip of the slab package. During the working stroke, the cut strip is placed on the lever and clamped with pneumatic clamps, which makes it impossible to shift the cut. After making a longitudinal cut, the saw goes under the table and returns to its original position. When the rip saw is lowered, the movable table located behind it rises above the level of the lever and receives the cut strips. The table then moves in a transverse direction. The leftmost saw, installed permanently, cuts the edge of the slab (10 mm) to create the base. The remaining cross cuts are performed according to the selected program. The cut blanks are brought to the table on an inclined plane and placed in piles. Then the cutting cycle is repeated according to the selected programs. On automatic machine It is possible to perform transverse and longitudinal sawing of particle boards in a stack up to 80 mm high according to a pre-set program. The machine is equipped with separate support tables. Each part of the table can be separately driven, which is necessary for mixed cutting. Cross cuts are made after the table parts are aligned along the cross cuts. Cross cut through the entire width of the slab. When cutting slabs with through cross cuts, all parts of the table are connected and work synchronously. The table is loaded using a loading device. The packages placed by the loader are aligned in length and. width automatically. The aligned package is clamped onto the table trolley by automatically closing clamping cylinders and fed to the rip saws or crosscut saw depending on the installed program. The saws rotate in opposite directions in such a way that the scoring saw works with a downstream feed, and the main saw with a counter feed. The scoring saw has adjustable movement in the axial direction for precise installation relative to the main saw blade. When cutting slabs on this machine, an accurate cut is obtained without chipping even very sensitive material on the edges. There are semi-automatic machines that also use scoring saws, but the translational movement during cutting is performed by the saw unit while the plate is stationary. The workpieces are moved either manually until they stop against the limiting ruler, or by a carriage, the positions of which are set using adjustable stops (in accordance with the width of the longitudinal grooves) and limit switches. This machine is used for format cutting of laminated panel materials and those lined with plastic. The cutting accuracy is up to 0.1 mm. The productivity of the machine when cutting particle boards to the required format is 5.85 m3/h. On the machine instead of organs manual control feeding material during longitudinal cutting, you can install an automatic pusher, which is controlled electronic device. The latter is programmed to perform certain cuts using saw blade required thickness. When cutting particle boards, circular saws with a diameter of 350-400 mm with hard alloy plates are used. The cutting speed is 50-80 m/s, the feed per saw tooth depends on the material being processed, mm: particle boards 0.05-0.12, fiberboards 0.08-0.12, plywood for longitudinal cuts 0.04 -0.08, plywood for cross cutting up to 0.06. Cutting cards. To organize rational cutting of slabs, sheets and roll materials Technologists develop cutting maps. Cutting cards are a graphical representation of the location of workpieces on a standard format of the material being cut. To draw up cutting maps, you need to know the dimensions of the workpieces, the formats of the material to be cut, the width of the cuts and the capabilities of the equipment. Particle boards arriving at the plant usually have damaged edges. Therefore, when developing cutting maps, it is necessary to provide for preliminary filing of the slabs to obtain a base surface along the edge. If the workpieces are cut out with an allowance that provides for their filing around the perimeter in further operations, then such filing of the edges of the slabs can be eliminated. When developing cutting maps, it is necessary to specifically take into account all the features of the supplied materials. All blanks cut from it are placed on a scale on the format of the material to be cut. If veneered material, laminated boards, plywood and similar wood materials are cut, then when drawing up cutting maps it is necessary to place the workpieces on the format, taking into account the direction of the fibers on the cladding. In this case, the workpieces have a definite size along and across the fibers. Drawing up cutting plans for a large enterprise is an important, complex and time-consuming task. Currently, methods have been developed for drawing up cutting maps for slab, sheet and roll materials with simultaneous optimization of the cutting plan. The optimal cutting plan is a combination various schemes cutting and the intensity of their use, ensuring completeness and a minimum of losses for a certain period of operation of the enterprise. When drawing up cutting maps, only those acceptable options are left that ensure the yield of workpieces is not less than the established limit (for wood boards 92%). The procedure for optimizing the cutting process is complex and is solved using a computer Rykunin S. N., Tyukina Yu. P., Shalaev V. S. Technology of sawmill and woodworking industries: Tutorial. - M.: MGUL (Moscow State University forests) - 2005 - p. 198.

Consequently, the process of cutting slab sheet and roll materials is simpler than boards, since when cutting them there are no restrictions on quality, color, defects, etc., they are stable in quality and format.

1. Cutting diagram

2. Cutting techniques

2.1. Cross cutting techniques

2.2. Techniques for longitudinal cutting on circular saws

2.3. Techniques for cutting curved workpieces

1. Cutting diagram.

The cutting of wood materials into blanks is carried out mainly on circular saws. The starting materials used are edged and unedged lumber (boards), plywood, chipboard, fiberboard, etc. Blanks are pieces of wood materials cut with the expectation of obtaining well-defined parts from them. Depending on the size of the part, one or more parts can be obtained from the workpiece.

In most cases, blanks are cut out several times large sizes than the clean dimensions of the part, taking into account allowances for processing the workpiece. When cutting lumber p-m, not passed chamber drying, allowances are taken into account not only for machining, but also for shrinkage. When cutting dried p-m, allowance only for machining is taken into account. Blanks of parts made of p-m (boards) must have allowances in length, width and thickness. When cutting standard products (chipboard, plywood), allowances are usually given only in length and width.

Operations cutting p-m consist of sawing them lengthwise and crosswise. It is always necessary to cut the material so that the yield of workpieces is greatest and the quality meets technical requirements. The yield of blanks is understood as the ratio of the volume of blanks to the volume of cut boards, expressed as a percentage. When cutting, it is necessary to take into account the presence of defects that are removed.

The board can be cut into blanks by sawing it first crosswise and then lengthwise (Fig. 1a), but these operations can be performed in reverse order(Fig. 1b). In both cases, cuts should be made so that defective areas of the board do not fall into the workpieces,



Rice. 1 a - cutting the board crosswise and sawing the sections lengthwise; b – sawing the board lengthwise and cutting the slats across.

and the healthy part of the board corresponding technical specifications on the product, was used to the fullest. The useful yield of blanks when cutting according to scheme b is approximately 3% higher than according to scheme a. It is more rational to cut the board into several sizes of blanks - in this case the yield will be greater. To increase the yield of workpieces, the cutting boards are marked in advance. To better identify defects, the board is first pierced on one side.

2. Cutting techniques

To cut boards into straight pieces, circular saws are used, and for cutting into curved pieces, band saws are used.

2.1. Cross cutting techniques.

The operation of transverse cutting (trimming) of boards is performed on caliper, hinged or pendulum cross-cutting machines. The productivity of automatic calipers is almost 2 times higher than that of pendulum and hinged ones with manual feed. On pendulum machines it is necessary to apply significant forces, in addition, when cutting wide boards it is necessary to use saw blades of large diameter.

A necessary accessory for cross-cutting machines is long table, equipped with a ruler and rollers. The machine is serviced by one main worker and one or two auxiliary workers.

The productivity of a cross-cutting machine is determined by the number of cuts per minute. The number of cuts depends on the type of wood, the width and thickness of the boards being cut, the length of the workpieces, the cutting method, and the organization of the workplace.

480 ( , pcs/cm (1)

Working time utilization factor, 0.93 (with manual feed);

n– number of cuts per minute (5 – 8 for coniferous species, 4 – 6 – for deciduous);

m– additional cuts for trimming and cutting out defects (1 – 2);

a– multiplicity of parts in the workpiece along the length;

b– multiplicity of parts in the workpiece in width.

The layout of the cross-cutting machine workplace is shown in Fig. 2.

Rice. 2. Workplace at the machine for cutting boards.

1 – machine; 2 – roller table; 3 - lift platform; 4 - stack of boards; 5, 6 – stacks of blanks; 7 - box for scraps; 8 – machine operator’s place; 9 – place for auxiliary workers

2.2. Techniques for longitudinal cutting on circular saws.

Longitudinal cutting is carried out on circular sawing machines with mechanical and manual feed. The most advanced are cutting machines with mechanical crawler feed (CDK 4-3). In most cases, sawing is carried out along a guide ruler, which is installed parallel saw blade at a distance equal to the width of the workpiece. If there is a wane, the first cut is made by eye without using a ruler.

Manual feed machines are less productive.

The machine is serviced by two workers - a machine operator and a helper.

The cutting of segments lengthwise is often done in one size. When sawing hardwood for massive unveneered parts, in order to increase yield, it is rational to cut 2 - 3 sizes half width. In this case, the ruler is set to the largest width of the workpiece. To cut into narrower pieces without rearranging the ruler, wooden bookmarks are used, which are precisely planed bars with shoulders at one end (Fig. 3)

To cut 2 - 3 sizes, a worker must have one or two bookmarks. As practice shows, simultaneous work with a large number of sizes is not rational.

Machine performance is determined by the formula

Piece/cm (2)

where U is the feed speed, m/min (10 - 15);

φ d – working time utilization factor (0.93);

φ с – coefficient of computer time use (0.95);

l h – length of the workpiece, m;

m – average number of cuts per workpiece.
The layout of the work place of the cutting machine is shown in Fig. 4.

Technological operations for cutting sheet and slab materials include sawing them lengthwise and crosswise to obtain blanks or parts of the required sizes. In this case, it is necessary to fulfill the main requirements for cutting - ensuring the maximum cutting ratio, completeness of workpieces in accordance with the volume of production and the corresponding quality. The maximum percentage of useful yield of clean parts can be ensured if the allowances are minimal, organizational and technological losses are reduced to zero, and the cutting of slab and sheet materials into blanks is based on strict mathematical calculations.

In production, blanks from slab and sheet materials are cut according to cutting cards. When developing cutting maps, strict adherence to the maximum yield of parts and completeness of parts is required different sizes and purpose in accordance with the volume of production, the maximum number of standard sizes of parts when cutting one slab and the minimum repetition of the same parts in different maps cutting Cutting maps are drawn up taking into account allowances for subsequent machining. For furniture blanks made of slab materials, processing allowances are set along the length and width. When drawing up cutting plans lined with chipboard, take into account the direction of the pattern in the workpieces.

The equipment used in furniture and woodworking enterprises for cutting slabs implements a step-by-step cutting scheme, in which, at the first stage, chipboard is cut lengthwise 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 card, and whether or not the completeness of the workpieces in one cutting card is complied with, individual, combined and joint cutting methods are distinguished.

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

Combined cutting involves the inclusion in each cutting card of several standard sizes of blanks or parts with mandatory compliance with the completeness of the cut blanks. This cutting method is, as a rule, more effective than individual cutting, but it is more complex.

Joint cutting may include individual and combined methods cutting and is the most effective compared to those considered.

The most widely used machines for cutting unlined chipboard are such machines as TsTMF-1, TsTZF-1 (Russia) (Fig. 67); for cutting laminated chipboard - format-cutting machines ITALMAC Omnia-3200R (Fig. 68), CASOLIN Astra SE400 (Italy), ROBLAND (Belgium), PANHANS (Germany) and cutting centers with numerical control SELCO EB 120 (Fig. 69 ), Biesse SELCO WNAR600 (Italy), HVP 120 (Fig. 70), etc.

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

Rice. 68. Format cutting machine ITALMAC Omnia-3200R

Rice. 69. CNC cutting machine SELCO EB 120

Rice. 70. CNC vertical cutting center HVP 120