How to process wooden parts?

The process of making pre-dried boards, squares or artificial boards into parts with certain size and shape by machinery. Generally, sawing, planing, drilling, engraving, milling, tenoning, drilling and other equipment are used, which are completed through batching, planing, tenoning, slotting, drilling, milling contour, surface finishing and other processes.

condiments

According to the size, shape and material requirements of parts, and leaving appropriate processing allowance, the processing process of sawing plates, squares or artificial boards into certain specifications of wool. When batching, it is necessary to determine the reasonable processing allowance, master the requirements for the moisture content of finished products, and correctly choose the batching method and processing method. The common batching methods are as follows: ① First, cross-cut the board with a circular saw according to the length of wool, and then disassemble it longitudinally with a circular saw or a small band saw according to the width of wool. This method is convenient for transportation between processes and can make full use of the conical part of the burr plate. However, when defects are removed horizontally, some useful wood is often sawed off. (2) First, use a single-blade or multi-blade circular saw machine to solve the problem longitudinally according to the width of wool, then cross it according to the length of wool, and remove the defective parts at the same time. This method has a slightly higher utilization rate of wood, but the workshop occupies a large area and is inconvenient to transport. (3) Before sawing, mark the board surface according to the size of wool in advance, and then carry out sawing. If you can cut and then cut, the output can be increased by 9%. This method is suitable for batch processing of curved parts. (4) Before sawing, the ingredients are prepared by rough planing, which can improve the quality of ingredients. But the workshop covers a large area and is inconvenient to transport. The composition of man-made board is slightly different from that of wood board. Before cutting particleboard and MDF, the thickness should be fixed with a broadband sander to ensure that the thickness tolerance reaches 0.2 mm. When cutting plywood and cardboard, a dozen pieces should be sawed in piles. Because the man-made board is large in format and inconvenient to move, it is usually fixed on a machine tool, and the saw blade automatically cuts vertically or horizontally. If the incoming material is a veneer-based panel (veneer or impregnated paper veneer), a sawing machine with a notch saw must be selected for cutting.

Planing plane

Plane the wool into a clean material that meets the size requirements. The method includes planing the datum plane and the datum edge, and planing the opposite surface and edge of the datum plane. The machining of datum plane and datum edge is usually carried out on planer; The machining of the reference opposite surface and edge can be completed on a planer or milling machine with specified thickness and width. If the reverse side is not parallel to the datum plane, it should be machined at the required angle with a fixture. For planes with low quality requirements, such as doors and windows, it can be done directly by three-sided planing or four-sided planing.

Tenon joint

The process of machining tenons with tenoning machine or milling machine. According to the shape, quantity, length and position of tenon on the part, the processing equipment and tools are selected and the reasonable processing method is determined. Tenoning machine can process right-angle single tenon, double tenon and oblique tenon. For single dovetail joints, conical milling cutter can be used instead. Milling machine can process single tenon and multi-tenon, toothed tenon and so on. Dovetail tenons can also be machined with a tapered end milling cutter on a special dovetail joint machine tool, and the cutter shaft moves along the comb guide plate (Figure 1). Rectangular tenon is completed in a special rectangular tenon and groove machine, and the milling cutter rotates once along the end of the part. The size of tenon can be adjusted as required, and the machined surface is smooth.

Figure 1 tenon

The process of machining tenons and tenons along the fiber direction by using rotating tools. Tenon and groove machining can be carried out on planer, milling machine or universal circular saw. Using the guide ruler and corresponding tools on planer and press planer, tenons and grooves with larger width can be machined (1, 2, 3 and 4 in Figure 2). The tenon and groove with smaller width can be machined by using the vertical cutter head on the four-sided planer (5 and 6 in Figure 2). To cut the transverse incision, a cantilever universal circular saw can be used, and the milling cutter head or multiple saw blades are stacked together with a hook milling cutter in the middle for machining. For dovetail-shaped notches, circular saw blades with different diameters must be stacked together or cone-shaped combined cutters must be used, and the cutter shaft must be inclined at a certain angle during machining, or the dovetail-shaped end milling cutter must be used for machining on the vertical upper shaft milling machine. Hinge groove can be completed on a special groove elevator.

Fig. 2 Drilling

The process of machining mortises with drilling machine or drilling machine. There are several types of mortises, such as rectangle, rectangle and circle. Rectangular mortises are usually drilled with hollow drill sleeves, and their machining accuracy is very high. Chain drilling machine can drill rectangular mortise at one time, but the inner wall of mortise is rough and the bottom of incomplete mortise is arc, which needs supplementary processing. This method has high productivity and is often used to drill holes in building wooden components. Long round mortise, processed by drilling machine or upper axis milling machine. Round holes (holes) can be machined by standard drills and vertical single-axis or multi-axis drilling machines. Most of the punching at the end of parts is done by horizontal drilling machine; For round holes with larger diameter, two cutters or cylindrical saw blades should be installed on the beam of the drill shaft for processing; Punching holes can be made in thin plywood or fiberboard. Screw holes need to be completed with a small drill with steps.

Milling surface

The process of machining various surfaces and curved surfaces with the help of forming tools or plane tools and fixtures. Due to different configuration files, the processing methods are different. (1) Machining a straight profile requires a corresponding forming milling cutter, which is used to mill parts along the guide rail of the machine tool. When the width of the part is large, the corresponding forming milling cutter can be installed on the horizontal cutter head of the planer and the four-sided planer for processing, but when the planer is used for processing, a guide device needs to be added to the workbench. (2) When machining curved surfaces, such as the back legs of chairs and the handrails of sofas, fixtures (templates) must be used, and the edges of the fixtures are made into parts with required shapes. When the edge of the fixture moves along the retaining ring, the tool can machine the required curved surface on the surface of the workpiece (Figure 3). If it is processed by a milling machine fed by a rotary table, several fixtures are fixed on the table at the same time, and the parts are milled according to the fixture shape with the rotation of the table. The flat carving and through carving on the surface of parts should be processed by upper axis milling machine. A profiling positioning pin is installed on the workbench, and the positioning pin is on the same vertical line with the rotation center of the cutter shaft. When the inner edge of the fixture is close to the profiling locating pin, the cutter can gouge out the required pattern or pattern on the surface of the workpiece (Figure 4). Cylindrical surfaces can be machined on a woodworking lathe (rotary bed) or a round bar machine. Complex surfaces, such as shoe last, gun stock, bent feet, etc. , should be completed by copying (copying) milling machine. Make metal fixture (template) according to the shape and size of parts. The fixture and the workpiece rotate synchronously, the copying roller is close to the fixture, and the copying milling cutter processes the workpiece into the same shape as the fixture. Its machining accuracy depends on the manufacturing accuracy of the template and the trimming of the tool. Carving patterns are processed by CNC engraving machine. According to the designed program, more than a dozen parts with the same shape can be processed at a time. High machining accuracy and production efficiency, and wide application range.

Figure 3

Figure 4 Surface dressing

The process of planing or polishing a pre-decorated surface with a net planer or grinder. Its purpose is to eliminate the tiny ripples left on the surface when the rotary blade cuts wood and the defects such as tearing, burr and indentation produced during processing, and to make the decorative surface have a specified roughness. (1) planing: planing the surface of the part with a polishing machine. There are two kinds of polishing machines: one is that the workpiece is fed horizontally and the planer moves back and forth; The other is that the planer is fixed, and the rotating rubber crawler drives the workpiece to plane through the blade continuously. It should be pointed out that the large plane of veneer should not be planed. ② Polishing: Use various types of sandpaper and abrasive belt to polish the wood surface. Polishing quality depends on abrasive particle size, grinding direction, pressure and material characteristics. The larger the abrasive particle size, the higher the production efficiency, but the machined surface is rough, so the number of sandpaper should be selected according to the surface quality requirements of parts. Sanding should be done along the fiber direction, and the unit pressure should not be too high. For the grinding of large flat parts, upper belt grinder and wide belt grinder should be used; For narrow plane or component sideline, vertical belt sander can be used; For concave surfaces or inner surfaces of components, a single drum grinder should be used; For parts with small concave-convex curvature radius and complex contour, brush sander can be used, and if the trajectory of curve contour moves linearly, contour belt sander can be used; For the grinding of rotating surface, it is best to use the workpiece to do rotating motion and cooperate with the grinding brush with corresponding shape; For chamfering and rounding the end face of parts, a disc grinder or a vertical belt grinder can be used.