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a machine for working wood to impart to it the required dimension and shape. Woodworking machines are used to fashion raw wood materials into various materials and semifinished products (beams, boards, plywood, shavings, and slabs), parts of articles and structural members (for furniture, agricultural machinery, railroad cars, and ships), and finished products (furniture, windows, doors, parquet, building floors, containers, skis, musical instruments, and office supplies).
Woodworking machines are classified according to the type of work performed as woodcutting, bending, assembly, cementing, and finishing machines. Woodcutting machines are the most widespread in the woodworking industry. Using different woodcutting tools, a certain part is separated from the wood on these machines in order to produce blanks, parts, or products of predetermined size and shape, with the required surface quality. Wood is cut by sawing, milling, planing, drilling, grooving, grinding, peeling, and polishing. The shavings may be either the waste material or the product (for example, veneer from the paring process of thin slabs from dustless cutting). Cutting without shavings occurs during cleaving (wood-splitting machines), veneer cutting (shears), die cutting (plywood-mending machines), and crushing (crushing and chopping machines).
Sawing is performed with saws whose motion is reciprocating, rotary, or rectilinear. Milling is done with rotary cutters (rectilinear blades or profile cutters), and planing is performed on planers with fixed cutting blades (in which case the blank moves) or reciprocating blades, which shear away a thin surface layer of wood. Drilling and grooving (mortising) are performed with special drills on drilling, drilling-slotting, and mortising machines. Grooving is usually done with a mortising tool for making holes in wood, primarily for tenon joints. During the turning process, shavings of an even thickness are removed from the surface of a rotating body. Peeling is the spiral reaming of a cylinder into a thin strip (veneer sheet). It is analogous to the radial feeding phase of the turning process but is accompanied by pressing of the shavings (veneer) and takes place after the preliminary steaming of the wood being worked. In wood polishing, granules of abrasive materials serve as cutters. Crushing is done in rotary and disk crushing or chopping machines to produce industrial chips for paper mills from waste materials of the woodworking industry (edgings and slabs). Such machines pulverize the waste pieces by means of blades mounted on a shaft or by metal plates attached to the machine’s rotor.
According to the woodworking method (which is characterized by the type of cutting process used, the cutting-tool design, and the nature of the starting material), a distinction is made among woodworking machines that operate by sawing, milling, planing, drilling, lathing, peeling, turning, polishing, and crushing. According to specialization, woodworking machines are classified as general-purpose machines, which are widely used in various branches of the national economy, and special-purpose machines, for work performed only in certain industries. Multipurpose machines (multiple-unit and all-purpose lathes) are usually used in small shops. Multiple-unit machines have several independently operating spindles mounted on a common stand, and universal machines are equipped with one spindle, to which various tools may be attached. Multispindle automatic and semiautomatic machines, multiunit machines, transfer lines, and lathe-combines, which simultaneously or consecutively perform several operations on the piece being worked, constitute a separate group. Transfer lines are commonly used in large specialized enterprises. Woodcutting machines, particularly rotary saws, band saws, milling machines, and grinders) have high cutting speeds (20-60 m/sec; sometimes 100 m/sec and higher). Because of the great cutting speeds, the operating shafts of many types of machines have rotation speeds of 3,000-6,000 rpm, and copying (profile) milling machines have speeds of up to 30,000 rpm.
Machines with reciprocating tools (gang mills and veneer slicers) have lower cutting speeds (usually not more than 7-8 m/sec). Woodcutting machines usually have mechanical feeds (up to 100 m/min). Most machines are equipped with individual electric drives with a power of 0.5-200 kilowatts. Hydraulic and pneumatic drives, photorelays, high-frequency currents (100-400 hertz), and remote controls are widely used on modern lathes and automatic transfer lines.
Bending machines give the wood the required shape by bending without disrupting the bonds between the wood particles. The work of joining separate pieces into units and products is performed on assembly benches. Different assembly benches exist for assembling pieces for cementing, and for making tenon, wood-screw, dowel, nail, and clasp joints. Cementing benches are equipped with rubber-covered rollers or brush, disk, rolling, or spraying devices. Finishing benches are designed for painting the products and applying decorative and protective coatings to their surfaces, as well as for processing the coatings (polishing and buffing). Colors are applied on machines with rollers; decorative, lacquer, and protective coatings are applied on special lacquer-pouring machines or on lines with the use of spray pouring. Grinding machines, usually of the band (multiband pass-through) type, are used to grind and polish the surfaces of the articles just before the lacquer coat is applied; the surfaces of the article are buffed on roller machines, and sometimes by means of pads. The most efficient and commonly used roller machines have rollers that are assembled from special cotton disks.
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N. K. IAKUNIN