When sanding small wooden blanks of small thickness, it is difficult to manually hold them still. In addition, you have to remember to protect your fingers from possible injuries. I made two devices that help me a lot in my work.
For square pieces
To process workpieces with straight parallel sides (from square and rectangular to polyhedral), I made something like a small hand vise. The clamping jaws are two metal plates 3 mm thick. One of them was fixed motionless on a small plate of self-tapping screws (photo 1, item 1), the second - movable (2). which I fix in the desired position with a screw with a clamping wing nut (photo 2, sheet 1). The screw moves freely inside the sawn through groove (2). When working, I insert a wooden blank between the jaws and clamp it with a “lamb” - the part remains motionless (photo 3).
…and round
Due to the fact that the diameter of round blanks varies, the above-described vise (even if equipped with semi-circular jaws) will not work. Therefore, I made a device for fixing round parts. The working part was bent from steel wire d 2 mm in the shape of a hook with two additional loops (photo 4, p. 1), through which the part was screwed to the board with a pair of self-tapping screws (2)
Such a device allows me to grind workpieces d 30-45 mm (3).
Important!I installed the heads of all fixing screws and bolts into metal plates so that they do not interfere with the processing of the part.
On a note
I chose a wire of medium hardness empirically: too soft cannot be used - it will not hold the workpiece under load, and too hard will create difficulties in fixing.
Large workpieces unbend the locking hook a little, but it is easy for him to return the required bend for small parts, which does not affect the clamping force in any way.
Such devices can be used not only for grinding, but also for engraving, fine carving and other types of machining, when it is problematic to hold a small workpiece by hand.
The locking hook must be bent so that its diameter is smaller than that of the workpiece, which is installed with some effort - the spring properties of the wire will do the rest.
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The manufacture of wooden parts, assembly of components and finishing in mass production are woodworking operations. The technological process here is built according to a complete cycle, starting with the drying of lumber or blanks and ending with the finishing of the units.
CHARACTERISTICS OF THE TECHNOLOGICAL PROCESS
The technological process of manufacturing wooden parts of tools is generally homogeneous with the process of manufacturing products of carpentry and mechanical industries and consists of: drying lumber (or blanks); cutting lumber and plywood; processing blanks to obtain parts of exact dimensions and shape; assembling parts into units; subsequent processing of nodes with their preparation for finishing; internal and front finishing of knots.
Each stage is a complex of sequential operations, the implementation of which requires appropriate jobs, equipment, cutting tool, fixtures and skilled workers.
The mechanized process of manufacturing and assembling parts is carried out on the basis of the use of standard and special high-performance equipment, assembly clamps, various devices and high-quality cutting tools.
Mass production requires the interchangeability of parts, without which the mechanization of assembly operations is impossible.
§ 2. MATERIALS FOR MANUFACTURING PARTS OF THE BODY, GROOVE AND INTAKE CHAMBERS The raw material for the manufacture of wooden parts of reed instruments is the products of sawmilling and plywood production in the form of boards, blanks and plywood glued, planed and peeled (veneer). The quality and grade of both lumber and plywood must meet the standards (GOST) and republican standards (RST). List of applicable tree species limited mainly to birch, maple, beech, linden, alder, spruce, fir and cedar. In some cases, as facing material colored plywood is used.
Currently, the enterprises receive both sawn timber (boards) and blanks. The initial moisture content of the boards is 80-100%, the blanks are 40-70%. It is advisable that enterprises receive only cutting blanks with a moisture content of 22 to 25%.
In production conditions, when almost all parts are processed in blanks that are multiples of length and width, the supply of dried blanks is very economically profitable: smaller drying facilities are required and there are no cutting departments. It is also advisable because drying wood at sawmills, which have a large amount of cheap fuel, is cheaper. Transportation costs are also reduced, since the transportation of waste, which makes up at least 40% when cutting boards into blanks, is excluded. That is why the supply of enterprises with dried billets produced by sawmills on special orders should become very widespread in the near future.
Storage of timber. Timber arriving at the enterprise, as a rule, is not immediately sent to production, but is stored in a timber warehouse. lumber conifers usually stored in stacks, lumber hardwood and all types of blanks - under sheds, and plywood - in closed warehouses. The norm of the area for storing lumber here is similar to the norms for furniture factories(for 1 m3 of sawn timber in stacks during mechanized laying, 1 m2 of warehouse area is required, for 1 m3 of sawn timber stored under sheds - 2 m2 of shed floor area).
When storing lumber in a warehouse, measures must be taken to prevent it from spoiling. You should strictly adhere to the rules for atmospheric drying and storage in warehouses of softwood lumber, regulated by GOST 3808-62, and hardwood, regulated by GOST 7319-64.
Standards for the stock of sawn timber. These standards are determined by the volume of production, terms of delivery and the need to dry lumber in a timber warehouse to an air-dry state. Lumber usually arrives at enterprises with a high initial moisture content, reaching up to 80-100%. Drying lumber with a high initial moisture content to a final moisture content in the range of 8 to 10% causes an overload of the drying chambers and practically does not provide a uniform content of the desired moisture content in a batch of dried lumber, especially hardwood. Uneven humidity of individual parts in a batch inevitably leads to marriage. Therefore, it is necessary to keep lumber in the warehouse to an air-dry state, i.e. to a moisture content of 20-22%. Such moisture content is acquired in the warehouse for various periods depending on the breed and thickness, climatic conditions, season.
According to GOST 3808-62 and 7319-64, the territory of the USSR is conditionally divided into four zones according to the conditions for drying lumber, and the active drying period in natural conditions is defined as six months (April - September). Depending on the assortment, lumber entering the warehouse during this period reaches a moisture content of 20-22% in 20-75 days. On average, with a uniform supply of sawn timber throughout the year, the stock standards for their stock in the warehouse can be taken as follows: for sawn softwood - 4 months, hardwood - 6 months, plywood - 2 months.
Drying lumber. In industries engaged in wood processing, lumber is dried to a moisture content at which the parts. can no longer change their shape in the assembled product. Lumber can be dried both in boards and in blanks. The advantages of one or another type of drying must be carefully analyzed for each specific case. Drying lumber in boards allows more economical use of wood, as well as wood waste. Drying in blanks allows more economical use of drying chambers. Considering that, on a national scale, the economical use of wood is more important than the best use of kilns, drying in boards should be preferred. In our case, we should recommend drying in boards at sawmills to a moisture content of 20-25%, cutting dried boards into blanks, supplying blanks to enterprises and drying the blanks to a predetermined final moisture content. The type of drying chambers depends on the volume of production and the range of lumber used. For the production of accordions, button accordions and accordions, which uses a large assortment of lumber in small batches, the most effective drying chambers periodic action of small capacity, with high-speed reverse air circulation of the TsNIIMOD type.
Drying modes are set depending on the range of dried wood from among the normative recommended by the All-Union Conference on Wood Drying.
Cutting lumber. When lumber enters the enterprises in the form of boards, after drying, they must be cut into blanks of the required length, width, and sometimes thickness. Usually, one or two of four cutting methods are used: transverse-longitudinal (first, the boards are cut across into cuts equal to or multiples of the length of the workpiece, and then sawn along the width of the workpiece); longitudinal-transverse (first, the boards are sawn along the width of the workpiece, and then the sawn long segments are cut into workpieces of the required length); cut according to the markup (the boards are first drawn into blanks, and then sawn according to the first or second method); cut according to the marking with preliminary planing of the board (before marking, the boards are planed on one side, and then they are marked and sawn into blanks).
According to research, for furniture enterprises, if the useful yield of the workpiece by the first method is taken as 1, then the yield for the rest will be 1.03, 1.08 and 1.12, respectively. Therefore, according to the fourth method, the useful yield of blanks is 12% higher than according to the first one. In the production of harmonicas, button accordions and accordions, where blanks are intended for the manufacture of small parts (neck and bars of inlet chambers, linings, thrust bars, valves, etc.), i.e. with a large multiplicity in length and width, cutting is usually done according to the first way. For more critical and large parts (body walls, walls of fur frames, neck parts, wedges of inlet chambers, etc.), boards are cut into blanks according to the fourth method.
For transverse sawing of boards, they are usually used round- sawing machines two types. In machines of the first type (pendulum), the saw, mounted on a swinging frame above the work table, is pulled over the material being cut by hand. Machines of the second type (with rectilinear motion) are the most convenient, since the saw moves on the material parallel to the surface of the desktop. In machines of this type, automatic feeding Saw advance and retraction are carried out automatically at the push of a button. The productivity of these machines is high and amounts to 10,000 cuts per shift. For longitudinal sawing of boards, circular saws are used with both manual and mechanical feed. The productivity of machine tools with mechanical feed is on average 10,000-12,000 running meters. m per shift. When reconstructing existing or designing new workshops for cutting boards into blanks, as well as with a significant amount of production, a semi-automatic line should be recommended.
A semi-automatic cutting line, especially for hardwood lumber, should include pre-gouging and marking boards. Such a line usually consists of a hydraulic lift, which receives boards from the cooling room of the drying department, roller tires, roller conveyors with pusher rollers, a thicknessing machine, trimming and cutting machines (for transverse and longitudinal sawing) and a belt conveyor.
Cutting of plywood is carried out on a circular saw with manual feed, and peeled and planed plywood is made on guillotine shears.
The output of blanks when cutting boards is determined technical requirements and therefore depends on the grade of lumber. Most rational use lumber of I, II and partially III grades in the following ratio: I grade - 40%, II grade - 40%, III grade - 20%. With the indicated ratio of lumber grades and cutting of blanks for the largest and most important parts according to the fourth method, the output of blanks from lumber is 50-60% on average.
Workpiece sizes. With regard to production conditions, where small wooden parts predominate with a multiplicity of blanks from 2 to 100, the dimensions of the blanks are set mainly based on the convenience of their further processing. However, in each individual case, the dimensions of the workpieces should be selected so that, with the minimum laboriousness of their processing, the maximum yield of suitable parts is obtained.
The thickness of the workpiece (board) is determined from the conditions of the current assortment of lumber, the thickness of the part in cleanliness, the allowance associated with the drying of wood, allowances for primary and subsequent processing, and more efficient use of raw materials with the intended technology. The length and width of the workpiece are set depending on the dimensions of the machined parts, the more appropriate multiplicity of parts, the above allowances and the accepted processing method, taking into account maximum output details. Usually the length of the blanks is in the range from 700 to 1000 mm, and the width is from 40 to 50 and from 80 to 110 mm.
The allowances associated with the drying of wood should take into account the change in the size of sawn timber and blanks due to the drying of wood from initial to final moisture content. At the same time, the shrinkage value for sawn timber up to 15% moisture content is given in GOST, and the allowance for this shrinkage is given for boards for sawmills.
Shrinkage of lumber from 15 to 8% moisture is very insignificant and is usually not taken into account, as it is covered by the processing allowance. If it becomes necessary to dry the workpieces with a moisture content of more than 15%, then allowance for shrinkage should be taken into account (for coniferous species in accordance with GOST 6782-67, for hardwood - with GOST 4369-72). When drying blanks of hardwood with a high initial moisture content, especially from beech, the appearance of end cracks is inevitable, which must be taken into account in the length reserve. For workpiece lengths from 700 to 1000 mm, the length allowance for end cracks is taken into account in the range from 15 to 20 mm (for two ends).
Allowance for primary processing. The processing of the workpiece to give it the correct geometric shape begins with leveling by planing one wide face and one edge with the formation right angle between adjacent edges. Two faces adjusted to a plane and a right angle are basic for processing the remaining faces of the part. The third face of the workpiece is usually processed by planing along the thickness of the part, and the fourth by sawing along the thickness. In addition, the workpiece is trimmed along the length of the part. The size of the allowance for the thickness and width of the workpiece depends on the transverse and longitudinal warping, on the deviation in nominal dimensions, on the dimensions of the workpiece and the multiplicity of its width and length.
All of these factors are found in production in various combinations, so the allowance cannot be a simple algebraic sum of all the deviations encountered. Rational allowance for this production usually established by experimental work. The observations carried out at the time by the laboratory of the Krasny Partisan factory over experimental batches of blanks made it possible to establish the following allowances.
The length allowance depends on the defects of the ends of the workpiece, i.e., on the perpendicularity of the ends to the longitudinal edges of the workpiece, as well as on the size of the end cracks and the multiplicity of the workpiece along the length.
Allowances for further processing. These allowances take into account the formation of parts during their processing before and after assembly into units, as well as specific features of the technological process. The establishment of rational allowances for subsequent processing is carried out on the basis of a thorough analysis of all factors affecting their value (process flow diagram, processing requirements, equipment used, cutting tools, fixtures).
Allowances for subsequent processing should take into account: subsequent processing of parts on milling and other machines before giving them the final shape; sawing parts with multiple dimensions of the workpiece; dimensional milling of cases and fur frames to remove sagging and give an accurate shape.
TECHNOLOGICAL PROCESS DIAGRAM
To consider the technological process of manufacturing wooden parts and assembling the body, neck and entrance chambers, the button accordion was mainly chosen as the most common and characteristic appearance instrument in the entire subgroup.
According to the nature of the technological steps and their sequence, woodworking operations are divided into: drying-cutting - for drying and cutting plywood and lumber into blanks; machine tools - for the production of parts of exact sizes and shapes from blanks; assembly - for assembling bodies, necks and entrance chambers and finishing - for internal and front finishing of instruments.
Usually all these operations are combined in the woodworking shop of the enterprise.
In addition, this workshop also includes auxiliary departments: a tool room with the functions of caring for a cutting tool (point, editing, installation, operation); gluing - for centralized preparation of glue and varnish-preparatory - for preparing working solutions of primers, varnishes and polishes.
We have already considered the features of drying and cutting operations.
Both universal and special woodworking equipment are used to process bar body parts, neck and other components. Universal equipment and methods of working on it, as well as the used fixtures and cutting tools, do not differ from those used in carpentry and mechanical production. These issues are very widely covered in the literature on woodworking and therefore it is inappropriate to repeat them. To show the features of the technological process, examples are given that characterize the use of special equipment, special types of equipment and specific working methods.
The walls of the floor of the buildings. The workpieces are fed to the jointer to align one face and one edge, then to thicknesser for planing the second layer, i.e. for gouging to size in thickness. Then they are transferred to a circular saw for longitudinal sawing along the width of the part, then pa? circular saw for cross cutting along the length of the part.
The next operation is cutting the spikes. This operation must be carried out with great precision, as it affects the interchangeability of parts. Therefore, it is advisable to cut the spikes simultaneously from both sides of the housing wall. Since there is no universal equipment for performing such an operation, a special two-sided tenoning machine with mechanical feed is used.
In the absence of the specified machine, one-sided cutting of spikes is usually carried out on a milling machine with a bracket adapted for heavy work. A pack of walls is placed in a husk and is fed manually along the guides to rotating slotted cutters, reinforced with spacer rings on the machine spindle. The selection of the fold and the profiling of the edge of the wall are performed on a conventional milling machine.
To eliminate the wavy surface formed during the processing of parts with rotating cutters, as well as to remove burrs and scuffs, the body walls are ground. Internal surfaces parts are ground before assembly, external - after assembling the nodes. Belt sanders are usually used for grinding. grinding machines with the bottom location of the sanding belt.
Accompaniment overlay. Sheets of plywood are cut on circular saws, first into strips along the width of the lining, and then into strips along its length. Given that mechanical properties of wood are dependent on the direction of the growth layers, the accompaniment overlays must be cut in such a way that the long side of the overlay is in a plane perpendicular to the direction of the annual layers of plywood shirts. According to the specifications, this overlay should be glued on both sides with celluloid. Details about the mode of gluing wood with celluloid and the adhesives used will be discussed below. The accompaniment overlay, pasted over with celluloid, after an appropriate exposure, is sent to a drilling machine for drilling holes. As already mentioned, in the overlays of full bayans and accordions, 100 or 120 holes are drilled, placing them in five to six rows, 20 in each, on a special 20-spindle drilling machine with constant pitch between drills.
From the electric motor 1, through a belt drive 2, a worm gear 3, twenty spindles 4 with drills 5 are driven into rotation. detail 11. At the same time, the rocker arm 12 presses the button of the magnetic starter 13, which turns on the electric motor 1. Such machines are introduced at the Leningrad factory "Red Partizan", the Rostov button accordion factory, etc.
Decks. Sheets of plywood are cut into circular saws in width and length of decks with an allowance for further processing. Here it is also necessary that the long side of the deck is in a plane perpendicular to the direction of the annual layers in the plywood shirts. It is advisable to drill cylindrical holes on multi-spindle drilling machines of the type used for processing the lining, and oblong holes on copy-milling machines. In the absence of such special machines, holes in the deck are drilled on a conventional single-spindle drilling machine with the help of a plume. A pack of 6-8 dec is placed in the sous lag, which are processed simultaneously. They drill along the lower conductor, which fixes the location of the holes on the deck, and the catcher, mounted on the machine table.
The next operation is planing the deck along the contour (along the perimeter) until its exact width and length are obtained. The operation is performed on a milling machine using a device (sulagi) with upper cylindrical catchers. A pack of 8-10 decks is put on with extreme holes on catchers, which are basic, that is, they determine the specified distances between the axes of symmetry of the holes and the edges of the deck. Sulagu lead, pressing against the thrust ring. Multi-knife is used as a cutting tool milling head or smooth bore cutter. The next operation is the grinding of two deck planes on a belt sander.
The grooves are sawn on a special horizontal multi-saw machine. A set of saws with spacer rings are fixed on the shaft, which determine the pitch of the cuts in the bar.
The workpiece is fixed in the carriage 3, which moves along the guides in the direction perpendicular to the plane of rotation of the saws, as well as in the vertical plane.
entrance chambers. Wedge. As already mentioned above, it is possible to mill a wedge to form cells (nests) for each vocal plank separately both along and across the direction of the annual layers of wedge wood. Although the technology for making a wedge when milling cells along the annual layers is longer, it is preferred, since when milling across the annual layers, a significant percentage of rejects is obtained during the production process. As an example, the following is a technological process for manufacturing a wedge of the melody inlet chamber when milling cells along the annual layers.
After cutting, the workpieces are fed to a jointer to align one face and two edges. The sequence of further manufacturing operations is shown in fig. 128: 1 - blanks are fed to the thicknessing machine for planing the second layer in thickness; 2 - gluing boards (700X700 mm) from the resulting plots; 3 - after planing two layers, the shields are cut into planks; 4 - trimming the strips along the length into two parts; 5 - sawing each plank into two wedges; 6 and 7 - milling a wedge into a cone in height and thickness. The next operations 8 and 9 are milling of cells and air channels.
These operations are performed on a special horizontal milling machine. circuit diagram such a machine does not differ from that shown in Fig. 122. Instead of saws, a set of smooth-running cutters with spacer rings is fixed on the shaft, which determine the pitch of the cells (nests), i.e. their location on the wedge. This machine is also used for milling nests in the bodies (combs) of harmonicas.
In addition to the schemes recommended above technological processes production of bar parts, when they are transferred from one machine to another during processing by conventional means of transport (trolley, forklift), for Lately automatic lines are widely introduced in the woodworking industry. Such a line usually consists of universal equipment general purpose and special Vehicle and loading devices that allow you to automate the process of loading parts into a line, feeding from machine to machine and transferring parts from longitudinal to transverse movement; line capacity is about 4000 linear meters. m parts per shift.
In industries where lumber is used in small quantities, and the range of parts is very large, the introduction of an automatic line for processing bar parts is economically feasible for a production volume of at least 50,000 button accordions per year in the manufacture of case walls from lumber.
The line for processing bar parts (body walls, neck bars, details of inlet chambers, etc.) is shown in fig. 129.
GLUE AND ASSEMBLY OPERATIONS
All wooden parts of the body, neck and entrance chambers are interconnected with glue, and some of them, for greater strength, are also fastened into a tongue, into a spike or screwed on with screws.
If there is a metal deck in the semi-hull, it is connected to other wooden parts with screws.
The parts are glued together with collagen and synthetic adhesives, including polyvinyl acetate emulsion.
Since the characteristics of these adhesives, methods of their preparation and modes of application are well known in the literature on woodworking, and the presentation of these issues is also provided for in the material science course, only the main mode of gluing wooden parts with synthetic glue with heating of adhesive joints to 110-120°C.
Bonding parts consists of the following elements: preparing the surfaces to be bonded, applying an adhesive layer on them, connecting the parts to be bonded and pressing. The surfaces to be bonded must be clean and dry, free of grease and other contaminants, well adjusted to each other and slightly rough. The quality of the preparation of the surfaces to be bonded has a great influence on the strength of the bond. Glue is applied to both surfaces to be glued in an even layer with bristle or bast brushes. After joining the surface, the parts are lightly wiped to distribute the adhesive more evenly and to expel air bubbles from it, and then hydraulic, pneumatic, eccentric or screw clamps are applied.
Heating of the adhesive layer. Gluing wood at a normal temperature of 16-25 ° C continues quite long time, the production cycle of adhesive units is stretched and requires large production areas, as well as a lot of gluing equipment and fixtures. When gluing knots without heating, more than 85% of the cycle time is occupied by exposure. It is known that the rate of curing or polymerization of the adhesive depends on its temperature. Heating the wood being glued to 110-120°C significantly reduces the holding time of the parts in the pressed and free state.
To heat the parts to be glued, high-frequency and low-voltage electro-contact heating is most often used.
High-frequency heating should be used when gluing parts of considerable thickness (more than 6 mm) with multi-layer gluing, as well as in all other cases when adhesive joints are in places that are hard to reach for contact heating ( spike connections body walls). It should be borne in mind that during high-frequency heating, the adhesive seam, due to its increased dielectric constant, absorbs more electrical energy and therefore heats up much faster than wood. This position contributes to a noticeable acceleration of the gluing process and a decrease in the specific power consumption. Electro-contact heating gives good results when gluing the soundboard to the body plates, the back of the neck to the end bars, the top of the neck to the main bar, rosettes to the wedges of the inlet chambers, etc. The introduction of high-frequency and contact heating of the glued parts opens the way to the organization of the flow method on conveyor lines.
For high-frequency heating of the adhesive layer, it is recommended to use lamp generators. At present, there is still no high-frequency lamp generator specially designed and manufactured for heating wood. Therefore, relatively easily adapted universal generators are used in the woodworking industry.
In the production of accordions, button accordions and accordions, good results were obtained using a high-frequency tube generator of the LGE-3b brand. Such a generator usually serves two glue clamps. While the parts are glued and held in one haym, the parts for gluing are laid in the other. Depending on the type of parts to be glued, three or more clamps can also work from one generator. You can also use the LGD-10 generator.
For electric contact heating of wood, heating elements (copper, steel and aluminum tapes) are used, powered by step-down transformers. Such transformers are connected to a common power network with a voltage of 220/380 V. The output side of a step-down low-voltage transformer is in the range of 2-3 V. It is advisable to centrally supply electricity to glue clamps located in a certain area. Depending on the bonding area and the thickness of the bonded parts, from four to eight bonding clamps can operate from one 3 kW transformer.
Assembling the body and fur frame. The assembly of the walls of the right or left semi-body of the button accordion, as well as the fur frame into the box, consists in dipping the straight, flat and through spikes and lugs with glue, connecting the vertical and horizontal walls at a right angle and compressing them. For the flow organization of assembly work, as well as gluing, it is necessary to introduce a system of tolerances and fits, and to intensify gluing, use synthetic quick-hardening adhesives, and in this case the adhesive layer is heated in a high-frequency current field. Clamps with pneumatic clamps are also required. The walls of the semi-body and the fur frame are assembled in an assembly clamp.
In a two-position hayme, nests L and B are located in the same way and are designed so that if gluing is performed in nest A, then the glued knot is removed in nest B and the details of the next one are laid. The frame 15 of the clamp is equipped with rigidly installed base beams 12 and 13 and adjustable power crossbars 2, 9 and 16.
The crossbars 9 and 16 are equipped with pneumatic cylinders 10 and /7, to the rods of which pressure shoes 8 and 14 are pivotally attached. The crossbar 2 is equipped with two pneumatic cylinders 4 and 16 with pressure shoes 3 and 7. clamping shoe tips. In addition, the regulation of the position of both pneumatic cylinders in the crossbars and the crossbars themselves is provided using screw mechanisms 11, 18. The clamp is adjusted so that when the pressure shoes are in their original position, the distance between them and the fixed bases opposite to them more sizes of the body to be assembled by an amount sufficient for the free laying of parts. For more convenient insertion of parts and removal of the assembled housing, each of the clamp positions is equipped with a lifting pallet (from a separately located pneumatic cylinder) with spring part holders (pallets with pneumatic cylinders are not shown in the diagram). Vaima has a device for high-frequency heating of glue joints, consisting of a set of electrodes 5, attached to a lamp generator of the LGE-3b brand.
To protect the worker from burns and injuries, the wyma is equipped with an automatic protective device connected to the starting device for turning on the lamp generator. Pneumatic cylinders are controlled by an air distributor, which ensures their subsequent switching on and automatic switching off at the command of a time relay, which operates according to a regulated regime. Vaima can also work with an unregulated rhythm. To do this, the following conditions must be met: during crimping and drying of the semi-body in socket B, the electrodes are connected to a lamp generator; at this time, the finished half-body is taken out of slot A and the details of the next half-body are placed in it. When loading parts, the electrodes are disconnected from socket A from the lamp generator, the pallet is in the upper loading and unloading position; they are installed in the pallet holders along the edges of the body walls, the spikes and lugs of which are lubricated with glue (the spikes must match the lugs).
At the end of the laying of parts and the expiration of the holding time of the semi-body in the nest, usually determined by a light or sound signal, the air distributor pedal is pressed, and therefore the following cycle operations are automatically performed sequentially: the tray of nest A with the stacked parts lowers to its lowest position; Pneumatic cylinders 4 and 17 are switched on, compressing the semi-body on socket A; the socket electrodes are disconnected from the lamp generator at the same time raise the fence of this socket and lower the fence of socket A; the electrodes of socket A are turned on and at the same time the pneumatic cylinder for lifting the pallet of sockets B is turned on. At the end of these operations, the semi-body is removed from socket B and the details of the next product are placed here, after which the cycle is repeated.
The productivity of such a clamp is determined by the duration of the cycle of gluing the floor of the hulls. Typically, the hourly output of a vayma is 40 semi-corps. With two-shift operation, the productivity of the wyma, taking into account the gluing of fur frames, will also be 70-75 thousand sets per year. After gluing and appropriate curing, the semi-body is transferred for further processing to a milling machine. Here, he is given dimensions in height and at the same time eliminates the sagging of the edges that have arisen during gluing. To do this, on the spindle milling machine strengthen two saws, between which there are gasket rings. The distance between the saws corresponds to the height of the semi-body; the latter is put on the template and sawn off along the thrust ring.
Gluing parts into a semi-body. Details such as lining, deck, neck bars, thrust bars, etc., are glued using templates that exclude marking of gluing points. To clamp the parts to be glued, various devices are used, which are quite well known in woodworking. It is expedient to glue the soundboard to the facings by the electrocontact method in a pneumatic clamp.
After gluing all the parts, the semi-body enters the area for subsequent machining. Depending on the required shape of the semi-hull and the method of its manufacture, the nature of the subsequent machining is different and may include such operations as removing sagging in the corners of the walls by grinding, planing or milling, rounding corners, shaping milling of corners and ribs, selecting cutouts for meshes, finishing surface grinding, etc. To perform all these operations, standard woodworking equipment, conventional cutting tools, and fixtures adopted in wood processing are used. If necessary, local puttying and surface grinding are carried out, after which the semi-hulls are transferred to the finishing (lining) department. The cleanliness of the wood surface is characterized by dimensional indicators of irregularities, as well as the presence or absence of hairiness or moss on the treated surfaces. In accordance with GOST 7016-54, 10 cleanliness classes are established depending on the magnitude of surface irregularities. Hairiness and mossiness on the surface of wood of the 6th, 7th, 8th, 9th and 10th classes are not allowed. The cleanliness of the wood surface in the drawings is indicated by the class number, preceded by the letter d (wood) and an equilateral triangle with its apex facing the surface to be treated (for example, dd7).
Bonding of entrance chambers. Gluing the parts of the inlet chamber in the manufacture of a wedge by milling is reduced to gluing the top plate and rosette to the wedge, the thrust bars to the rosette, and cleaning the assembly from dust. When constructing an inlet chamber with a composite wedge, it is necessary to additionally glue partitions to the wedge and saw them in length and width. Finished inlet chambers are sent to the area for mounting voice strips.
Gluing the fur frame. The fur frame is usually glued into a blank 4 times in width, similar to a semi-hull, which is then sawn in width into four fur frames. This is followed by operations: rounding the corners and profiling the walls, after which the frames are sent to the fur manufacturing area.
The use of synthetic adhesives in combination with heating the glued wood to a temperature of 100-120 ° reduces the duration of holding the parts in the pressed state to 1-2 minutes, which creates conditions for organizing a flow process.
Selection and calculation of pneumatic clamping devices. Recently, various pneumatic clamping devices have been widely used in industry. They are used for clamping parts during their processing on woodworking and metalworking machines, as well as for clamping parts in the process of gluing them in clamps. Since these questions are not sufficiently systematized in the specialized literature, it is necessary to dwell on them in some detail. The advantages of pneumatic clamping devices in comparison with others, characterized by the time factor, can be seen from the following data from TsNIIMOD and NIIDREVMASH.
Pneumatic clamping devices compare favorably with others by their high efficiency, simplicity of the device, reliability in operation and ease of use. The use of high-speed pneumatic clamping devices eliminates the disadvantages inherent in manual operations (incomplete clamping, the application of significant efforts by workers, long clamping times) and creates opportunities for regulation, control, automatic control, and also along with characteristic feature pneumatic drive- constancy of the value of the clamping force - allows you to work with increased modes and increased accuracy.
There are three types of pneumatic clamping devices - piston, hose and membrane.
Piston clamps are used in cases where a significant clamping force is required with a relatively large piston stroke, when gluing the walls of the case, the walls of the fur frame, etc., when the distance between clamping bar and glued parts is more than 30 mm.
Hose clamps are usually used with a small clamping force and when the distance between the clamping bar and the parts to be glued is less than 30 mm, for example, when gluing plates or thrust bars with a deck, rosettes with wedges, etc.
Membrane clamps are very compact, consume little air, but have a limited clamping force, usually not exceeding 600 kg, and a stroke of no more than 15-20 mm; they are used mainly for clamping parts when processing them on machine tools.
The piston clamp is a metal case, consisting of a cylinder 1 and two covers - front 3 and rear 14. The cylinder is made of steel, and the covers are made of cast iron. The cylinder and covers, connected by a tight fit, are equipped with lead sealing gaskets 15 and are additionally tightened with studs 7 with nuts 5 and lock nuts 6. Both covers have channels 2 through which compressed air is supplied to the cylinder. Fittings 4 cylinders are connected to the air line using a flexible hose. A cast iron piston 20 is placed in the cylinder, moving as compressed air is supplied. The piston has two sealing leather cuffs 18, pressed against the piston by rings 17 and 19, which are fixed with screws 16. The piston rod 10 passes through the sleeve 13, pressed into the opening of the front cover and having a seal in the form of a leather ring 11, pressed by the flange 12. At the end of the rod an eye 8 is screwed on, which, together with the pin 9, forms a swivel clamp of the clamp.
By turning the handle of the air valve, air is opened into one of the fittings and at the same time air is released through the other fitting. From the above, it can be seen that the clamping force depends on the air pressure in the network and the piston diameter. The air pressure in the network should be 5 kgf / cm2, but for calculations they take p \u003d 4 kgf / cm2. Usually used pneumatic cylinders with an internal diameter of 30, 40, 50, 75, 100, 150, 200 and 300 mm. The rod diameter is usually 0.2 piston diameter.
The basis of the hose clamp is a rubberized hose 1 (Fig. 134). The ends of the hose are connected using fittings 2 with flexible air ducts through which compressed air enters. Hose 1 and spring 5 are placed between a fixed bar 3 and a movable bar 4, connected by a spring 5. The parts to be glued are placed on the base 6 of the clamp and rest on a fixed bar 7. Until the press is applied, i.e., before the compressed air enters the hose, it occupies the position shown in Fig. 134, a, where the letter x denotes the distance that the hose occupies between the fixed and movable bars. The hose diameter commonly used in these clamps is 75mm and the hose thickness is 3mm. In position a, the distance d: \u003d 3-2 + b where X is the gap between the walls of the hose, which is assumed to be 2 mm, i.e. l: \u003d 3-2 + 2 \u003d 8 mm. After the moment of applying the press, the hose takes the position indicated in fig. 134b.
On the basis of experimental work, it was found that the largest value of the clamping force is achieved at a value of x equal to 0.4 of the hose diameter, i.e. in our case, l: = 0.4-75 = = 30 mm. With a further increase in the x value (from 30 to 75 mm), the clamping force will decrease accordingly, and with x equal to the diameter of the hose, i.e. 75 mm, the clamping force will become equal to 0. Thus, the hose clamping force turned out to be somewhat greater required effort, which indicates its compliance with this type of work.
The membrane clamp has a rubber membrane sandwiched between two cast iron hemispherical covers 4 and 9. In the center of the membrane there is a hole into which the stem shank 12 enters, connected to the membrane by two steel washers 2 and 14 and a nut 5. Cover 9 has a tide, in the hole of which is pressed cast-iron bushing 13, which is a guide for the rod. Two through holes 8 in cover 9 serve for free passage of air inside the hemisphere formed by this cover. The other hemisphere formed by cover 4 is hermetically sealed and can change its volume under the pressure of compressed air supplied from the network through fitting 5 screwed into the opening of cover 4. When the valve is opened, the compressed air squeezes out the rubber membrane and it transmits movement to the stem 12, which has a swivel joint 10 with a clamping bar 11. The rod is returned to its original position by a rubber membrane 7, which contracts when air is removed from the hemisphere formed by cover 4. The membrane clamp is attached to the machine using bracket 6 and bolts 7. With a membrane diameter (along the contour of the clamp) D equal to 230, 200, 75 mm and a design pressure in the network p = 4 kgf / cm2, the membrane clamp accordingly develops forces Рg equal to 450 -500 kg, 350-400 kg and 50-60 kg; at the same time, large forces correspond to smaller ones, and smaller ones correspond to a longer stroke length of the rod.
A summer cottage is a place where you can relax in the shade of trees, grow your favorite vegetables and herbs, admire flowers and harvest every year. And the summer cottage is a great opportunity to realize your creative abilities and work in the fresh air. More on initial stage– landscape development garden plot, you can add zest and decorate the site garden figures. You can make a sculpture out of wood yourself if you arm yourself essential tool, material and get acquainted with the recommendations for creating sculptures from wood.
Before you start work, you should familiarize yourself with the rules for choosing figures for a garden plot.
What you need to know:
- The figurine (one or more) should "fit" into the design of the garden. If it causes controversy, then harmony should not be expected, even if the sculptures look very pretty.
- If you doubt whether the sculptures will look harmonious, then make a layout of your suburban area from paper and cut out figures from cardboard. Place them in a place that suits you. If you don't like how the sculpture looks, you can move it or swap the shapes. This visualization will help you decide on the choice of location.
- No need to pile up several massive figures in a small area. This will only complicate perception. It is better to install 1-2 figures to decorate the site and achieve harmony with nature.
- It is not at all necessary that the sculpture occupies a central position. It is better to arrange several small wooden sculptures that will be in harmony with the plants. The location of one wooden sculpture in the garden is not excluded, but then it is desirable to decorate it with others. decorative elements- climbing plants, wattle or arch.
Wood sculpture photo:
Sculpture material
To create garden sculptures with your own hands, you can use different material: stone, gypsum, cement, mounting foam. But the most suitable and plastic material for garden sculptures is wood. Because this natural material you can take it anywhere, but it’s better to go into the forest and find a suitable tree there. For large sculptures, it is better to take a massive log. Large branches or small logs are suitable for small figures.
Before taking natural material with you, carefully inspect the wood - it should not have traces of mold, decay and insect "moves". Such natural material is best left in the forest, as a sculpture made of wood will not last long.
If you are planning to make a small wooden figurine, then first you need to prepare the material - rinse with water and separate the bark. Do not rush to send fragments, bark and even chips to a landfill - this material can be used to decorate decorative compositions or will be needed when finalizing a wooden sculpture.
During the course of work, you will have a large number of fine chips and sawdust - this auxiliary material is useful for repair work and restoration of wooden sculptures as a natural putty for cracks and holes. It is necessary to mix sawdust with varnish until the mass becomes viscous and immediately fill the holes. It is not necessary to make too thick or vice versa, a rare putty, since it will be inconvenient to work with such material.
It is better to dry the prepared material in a dry, warm place (you can bring it into the house) and wrap it with polyethylene. So you can protect the wood from deformation and cracking.
In the process of work, it is advisable to immediately collect the waste in a separate container and also store it in a dry place.
- apple tree
- cypress;
- birch;
- hazel (hazelnut);
Woods such as boxwood and rosewood (especially black) are difficult to work, so it is best for a beginner to work with soft woods. On rare occasions, wood carvers will recommend that beginners work with hardwoods, as inaccurate movements on the surface will not be as noticeable. But if "spoil" soft material, then all inaccurate movements will be visible at a glance.
Required tool:
Where to start
You have prepared the material, the sharpened tool also lies nearby, you can proceed. But first you need to start with a pencil and a sheet of paper. Don't be lazy, sketch your sculpture.
It is not necessary to have the talent of an artist to transfer the layout of the future figurine to paper. Draw the outlines and main details of the sculpture. And now you can transfer the contours to the workpiece itself. This is what all wood carvers do. In some cases, you can change a simple pencil to a marker to draw a clear contour line. And that's not all - in preparation, after creating a sketch, make a plasticine copy of your garden sculpture from wood. Then you need to build a diagram in several projections. If you find this difficult, skip this step. Wood carvers often do without even a sketch, since it is easier for them to immediately cut a figure out of wood than to draw its exact copy on paper.
DIY wood sculpture
1st stage
We proceed to rough processing and “drawing” the main shape of the figure. First you need to define the "legs" and the base. Use a saw with medium teeth to file the workpiece. Hold the tool perpendicular to the center of the workpiece.
If you get an uneven saw cut, then you can carefully trim it. Treat this stage very responsibly, as the result will depend on it.
Now mark the center of the workpiece and draw auxiliary lines. With a square, check the correct markup. In the process of work, these lines will not be visible, as they will gradually be cut off.
This part of the work is best done with this set of tools:
- tape measure;
- ruler;
- square;
- caliper.
If you are making a large wood sculpture, it is better to use a bright marker instead of a pencil, as it does not wear off as quickly as a pencil.
2nd stage
At this stage, it is necessary to perform a rough processing of the workpiece with an ax, and small parts can be cut down with an adze. During work, it is better not to go deep, but to leave a supply of material so that later it can be finalized and amended. Use measuring tools while working.
First, the part that requires the most attention is cut down, and then the lines are restored and strokes are drawn. For example, if your sculpture will be made in the form of a bear or other large animal, then start working from the head, gradually carving the wood from top to bottom.
Look at this photo to understand how it works:
To complete this part of the job, you will need the following tools:
- hand saw (with fine or medium teeth);
- half hatchet for carpentry;
- semicircular and straight adze.
3rd stage
Cutting out the four faces of the figure. At first glance, this will seem like a difficult task to you, but everything is extremely simple - you need to “draw” and separate the arrays with the help of a carpentry tool - the torso, arms and legs. At this stage, it is not necessary to round the workpiece yet. This part of the work can be done with large chisels.
4th stage
You will get an angular blank - now you need to trim and make a relief without small details. It is important to "revive" the future figure and not to miss the main points. It is too early to detail and round the wood sculpture. For work it is necessary to use a set of small chisels and knives-jambs.
5th stage
Finally, we can proceed to the most interesting part - detailing and rounding the sculpture. You can remove the edges and work out small details - drapery, facial features, animal fur. Try to draw less with a pencil on the figure, as it will remain and it will be possible to remove it only with fine-grained sandpaper. Entrust this crucial part of the work to such tools: joint knives, scalpels and Caesars.
When the work is completed, it is necessary to sand the figurine with an emery cloth and apply a thin layer of sunflower oil. In some cases, wood sculptors are advised to weld the carved figurine in oil. When heated, the vegetable oil will begin to polymerize and wooden surface will be resistant to moisture and dirt. This advice applies only to small wooden sculptures.
By the same principle, you can carve animal sculptures from wood:
Wood sculpture processing
Depending on the coating material, there are several ways to finish the sculpture.
Let's take a closer look at each method:
- Use of stain. Light wood species: linden, birch and maple need toning. Can be reached certain color different ways, including natural ones. For example, use aniline dyes, or you can prepare the stain yourself.
How to prepare a stain:
- iodine. Take a small plastic cup and fill halfway with water. Add 3-5 drops of iodine, stir. Try on white paper, what shade turned out - if it is too saturated, you can dilute it with water, if it is weak, add iodine. If you cover the product with one layer, you get a beautiful “honey” shade, and if you apply 3-4 layers, then the color is ocher;
- brown stain is prepared from water and potassium permanganate crystals according to the same principle;
- to prepare a stain for alcohol, prepare coffee (instant), you can take the cheapest one. Pour 1 tbsp into a plastic cup. coffee and add the same amount of boiling water. Pour alcohol (half a glass) and mix. Such a stain is useful for covering volumetric threads; it is not suitable for embossed surfaces.
- Varnish coating. There are several types of varnishes for wood: on oil based, nitro and pentaphthalic varnishes. The main condition when buying varnish - take only colorless. Store varnishes are very thick, so they need to be diluted with solvents to a consistency like water. You can dilute oil varnish only with turpentine, and nitro varnish with acetone. To find out what solvent you need to dilute your varnish, look at the label - manufacturers give detailed recommendations. A small wooden figurine can be completely “bathed” in varnish, and a large wooden sculpture can be covered with a brush.
- Viscous and hard woods, such as pear, apple and birch, are subject to oil treatment. Cooking figurines is very simple: pour oil into the pan, put on fire and after 5 minutes, when it heats up, lower the craft. She will float in oil. If you have a lot of small figures, then it is better to cook them separately. Every time the oil must be changed to fresh, otherwise it may catch fire. The duration of processing the product depends on the desired shade, when the figurine begins to darken, it can be removed. The figurines treated with oil are sanded and polished.
Wood blanks used in constructions from joinery and furniture products (bars, boards) can be either solid or glued, have various forms, sections and lengths. Solid wood blanks are more prone to cracking and warping. Therefore, the proportional ratio of the width and thickness of the bar should not be more than 3:1. Billets of large sections should not be made from one piece of wood. It is desirable to glue them from several plots (parts), tightly fitted one to the other. Glued blanks have increased strength and dimensional stability, and in addition, a more rational use of wood is achieved.
When designing blanks glued along the width, the use of narrow plots allows to obtain blanks that are less subject to warping than blanks glued from wide plots. However, the use of very narrow plots leads to an increased consumption of materials. Therefore, a plot with a ratio of thickness to width of no more than 2:3 is considered optimal. When gluing blanks along the thickness and length, the plots are glued "on a mustache" or at a right angle with the joints arranged apart (by analogy with brickwork, where the seams almost never, with the exception of figured masonry, do not coincide with each other). To obtain a strong connection, it is desirable that the distance between the joints in adjacent plots be at least 300 mm. In all cases, strength adhesive bond blanks should not be lower than the strength of solid wood.
Curvilinear outline elements
Curvilinear parts and assemblies used in furniture, depending on the method of manufacture, are divided into a) solid-bent, 6) glue-bent, ") sawn-bent, d) cut according to a template.
Boxes, half boxes
Supports of furniture products, their parts
Supports in furniture products that carry significant loads, especially when transporting and moving furniture along the floor, depending on the design, are divided into a) support boxes; b) benches; c) decoy and non decoy legs. This takes into account a significant margin of safety in their design.
At present, with the high development of industry, it is almost impossible to find an object or product that could not be bought. Of course, the received thing will fully meet the highest requirements, but it will lose its special individuality and originality, which can be presented wooden crafts made by hand.
Stages and tools for work
Decide what you may need to make wooden products self made. The most important thing is the material from which the craft will be made. All logs are prepared by a special method, for this they are dried to 15% moisture, but experts say that the most the best option is 8-9%. It is important not to forget that wood differs in its strength and structure depending on the type.
To process the product, you will need a mounting table or workbench. Next, be sure to purchase an electric tool - a milling cutter, a circular saw and a grinder, as well as grooving and jointer.
A hand tool will also come in handy, which includes all kinds of planers, chisels, award hacksaws. In order to apply a pattern to a product, you can get drills and engravers.
Drawings of wooden products are also needed in order to understand what the finished object will be. It is advisable to independently develop sketches or borrow them from more experienced craftsmen.
Connection of products on sliding grooves
This is one of the simplest and most common types of bonding, so it is recommended for beginners. You will need to cut the same and straight strips, the width of which will be the same as the thickness of the workpiece, then insert these parts into each other.
Prepare two pieces of plywood or wood in the shape of a rectangle. In the middle, cut the grooves, the length of which is equal to half the workpiece. The width of such a fastener should be the same as the width of the part. The result is a strong and stable cross. If the grooves are cut in the corners, then it will be possible to create an angular solid figure. You can assemble four blanks in this way and get an excellent frame for a box or a rectangular shape for crafts. Such a connection is also perfect for creating round things, for example, a mill or a turbine wheel; production of souvenirs and children's toys; furniture production.
Stages of wood polishing
Primer. It is performed using a swab wrapped in a thin cloth and impregnated with varnish, which is applied to the product in different directions and soaks it. This procedure is done in order to fill the smallest pores and cracks in the base of the tree. After drying, the surface is treated with fine-grained sandpaper, and then the coating is again applied in two layers one after the other. After drying, the product should be treated with the composition for the last time, diluting it one to one with polish. The prepared thing is kept in a closed cabinet for two days.
Polishing. To do this, polish is used, before working with which the swab is wetted with a small amount of vegetable oil. It is brought from the side, and the composition is distributed in smooth circular motions. All processes are carried out in three stages, and after each application, the surface is polished with fine sandpaper, then cleaned of dust. If everything is done correctly, then after the last layer has dried, a slight gloss will be obtained.
Polishing. It is carried out so that the surface acquires a mirror shine. After all layers have dried well after polishing, the base is slightly treated with the finest sandpaper, which is pre-wetted in oil. Then a small amount of varnish is applied to the swab, and the surface is rubbed with the composition until a shine appears. In order to improve the strength characteristics of wood products, this procedure is repeated several times. At the last stage, the surface is wiped with a soft cloth soaked in water.
aged wood effect
In order for handmade wooden products to become exclusive, the effect of aging is used, which can be obtained in three ways.
The chemical method is only suitable for hardwoods, as they contain tannins in their composition. To do this, the surface must be covered ammonia, after which it will darken and acquire a characteristic gray tint.
Using thermal method, you can age any breed. Initially, the surface is treated with a stain, and then it is singed with a soldering iron until a natural texture pattern appears on it. Then the soot is removed with a brush. Everything is varnished.
The mechanical method (often referred to as branching) is best for softwoods. For this method you will need metal brush, which needs to cut through the fibers of the tree - remove the soft layers, after which hard fibers will appear, which will give the material an aged look. Using this procedure, you can hide small defects that appear in the process. At the last stage, everything is varnished or painted.
Finishing Technology
Created with your own hands, after manufacturing they are covered with paint. Thanks to this, they will be especially beautiful and practical. This is done with a swab or a soft brush. Small surfaces, as well as wooden carvings, are best painted with watercolor thin brushes.
Before use, the stain is slightly diluted, after which it is easily applied in several layers, the amount of which will depend on the desired color. Since all parts of wood absorb paint in different ways, it is impossible to cover the product in one go. After each stage, the parts must be completely dried without fail, then you need to walk a little on the surface with sandpaper, remove dust and apply the next layer.
Care
In order for wooden products created with your own hands to look beautiful, they need special care. Steam and moisture easily penetrate inside, but just as easily evaporate. To protect the coating, it is best to use decorative wax. Humidity will not be able to harm products that are coated with such a composition. It is applied with a brush in several stages. This layer will be an excellent protection against minor mechanical damage. For application, you will need a tissue swab, with which the wax is rubbed with wide movements in the direction of the wood texture. For drying, it is necessary to withstand the product for one night at a temperature of +20°C.
