Application of the most popular five axis five lin

2022-08-05
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The application of five axis five linkage machining center in the clock industry

the output of watches and clocks in Guangzhou in the Pearl River Delta of Guangdong Province accounts for 1/4 of the world. In order to improve the grade and quality of products, it is necessary to import high-grade 3D cad/cam technology, refer to the process of producing high-grade clocks in Switzerland, adapt to the market demand of many varieties and small batches, and directly adopt (multi axis or even five axis) machining centers to manufacture high-grade clocks, so as to ensure their unique style and shape of clear edges and sharp corners

cad software is a sharp tool in the cam field. It is one of the best software packages suitable for 2 ~ 5 axes. It is especially famous for its powerful functions such as NURBS surface design and modeling and NC machining programming

willmin-408 machining center in Switzerland has the processing capacity of five axes and five linkage. This kind of five axis machine tool is representative in programming and post-processing. Through the machining practice of several parts, the method of compiling five axis machining program with CAD is explored

1 basic principle and idea

as shown in Figure 1, the CAD module of I-DEAS master series or camamd software is used for part modeling, and then the cam module is used for programming to obtain the tool position file (CL file) of NC machining, and then the NC machining program can be obtained through the post-processing program (the post-processing program is compiled for the machine tool structure and NC system)

figure 1

willmin-408 machining center is equipped with a swing disk and a rotating workbench in addition to the three linear movements of X, y and Z. As shown in Figure 2, the center of the rotary table coincides with the rotary axis C of the table, and the rotary axis B of the swing disk intersects the rotary axis C of the table vertically. The machine tool is specially used for clock production. A special fixture is installed at the center of the rotating worktable to fix the workpiece, which ensures that the center of the workpiece is the rotating axis C. The X and Y values of the center and the Z value on the fixture positioning surface are input into the workpiece coordinate system for the use of the processing program

figure 2

the machining center is equipped with French num-1060 numerical control system. For the five axis plane, the weight reduction and thinning of polyethylene foam are raised to a new height tilt, and a G150 code is defined. The coordinate changes after the plane tilt can be calculated by the system itself. As shown in Figure 3, the coordinates of the processing point before the plane inclines and rotates are x-10.0 y-0.0 z-5.0. In order to process to the point after the plane inclines by 30 ° and the c axis rotates, the G150 code can be used to calculate the position of the point after the plane inclines. In practical machining, this function is often used for simple plane inclination. In fact, programming in cam also needs to establish the distance between the workpiece and the oscillating axis to generate the correct NC program. When writing a five axis machining program with cam, it is necessary to determine the machining coordinate system. The origin of the coordinate system is the position of swing axis B. the machining coordinate system of the five axis NC program and the three axis NC program should be consistent. If the three-axis NC program takes the workpiece bottom as Z0, the distance from the oscillating axis B to the workpiece bottom must be subtracted from the Z value of the five axis NC program

figure 3

to verify whether the configuration in G150 or cam is correct, the simple part processing shown in Figure 4 can be used to verify. The blank is a 26mm cylinder, the upper surface is polished with an 8mm end milling cutter, and the rectangle is milled for 20mm × 15mm × 10mm (three-axis machining), and then mill four slots with 8mm cutter (five axis machining). The theoretical value of the boss width after machining shall be 5mm, and the error of the actual value shall be measured. After the trial machining of this simple part proves that the machine tool configuration is correct, the more complex five axis machining or three axis Five Axis Hybrid machining can be carried out

figure 4

2 processing example

the part shown in Figure 5 is a high-end watch case made of stainless steel with a blank of 40mm × 2. Gradually transfer the thermal insulation materials to the suburbs and other cities for 8M × 8mm, 8mm hole is pre drilled in the middle to facilitate cutting. 24mm below × 21mm × The 3mm slot has two functions: clamping position It is also a movement position

figure 5

willmin-408 machine tool has a maximum rotation speed of 18000r/min, using imported 13mm corn milling cutter (cemented carbide material), so that during rough machining, the rotation speed can reach 4000r/min, and the feed speed can reach 500mm/min. Taking full advantage of the five axis processing capacity, the side edge of the cylindrical end mill is used to process the meter case R. the demand for plastics in the fields of packaging, automobile, agriculture and construction is increasing day by day, The bottom edge is used to process the materials around the blank and the open ear 13mm (with the watch band), the inclined planes 76 ° and 20 °, the circular arc planes r1.5m and inclined planes 45 ° on both sides of the watch case, the side edges of cylindrical end mills for rough machining, and the forming cutters for finish machining, which not only improve the efficiency but also ensure the surface quality. G150 can be directly used for programming, which is convenient and intuitive. Cam can also be used for programming. At the glass position, it is necessary to ensure the accuracy. In this way, after the glass is assembled, it has good sealing performance and water resistance, up to 5atm or even 1oatm. To ensure that it is perpendicular to r60mm, it must be programmed with cam in five axis linkage. The round corner of the glass position is r1.5mm. Therefore, the vector control mode of the cutter axis of 3mm end milling cutter can be used to use the normal of the surface, and the function of projection curve can be used to establish the curve in the cutter, so that the processing quality of the bottom surface is better. The tangential tanto () method can also be used for tool axis vector control to establish ruled surface and set the tool diameter to 0.001mm, so that the machining quality of the side is better. In five axis linkage machining, the control of feed speed is different from three-axis linear motion, which is represented by G94 code; The five axis linkage has the rotation movement of the axis. In order to make the rotation uniform and the machined surface smooth, the inverse speed must be used. In the num-1060 CNC system, the G93 code is used to indicate how many seconds it takes for every 1mm or 1 °, and there is a feed speed at each coordinate position, so as to ensure the uniform operation. The feed speed is generated by CAM software. The whole case is clamped once, and the processing takes about 1min

through the processing of dozens of tables, some five axis processing experiences are summarized:

the fixed axis (fix) vector method can be used to process curved surfaces, which is similar to three-axis processing, but the axis vector is inclined at an angle and is not parallel to any machine tool axis. In this way, when machining with a ball head cutter, the end cutting of the ball head cutter is avoided. Because the linear speed at this point is zero, the processing efficiency and surface quality can be improved

when using the normal vector method, the tangent point can be set at any position in the tool plane. The tangent point can be specified as required to obtain the desired surface. The surface quality cut with the tool bottom is good, so it should be used as far as possible

when using tangent vector method, it is better to use ruled surface. The direction of ruled surface determines the direction of cutter axis, so the surface should be smooth without wrinkles and distortion

when machining a surface, its normal surface or normal can be established to control the direction of the cutter axis and generate a machining program

in order to prevent overcutting, when generating the five axis machining program, the interference inspection surface shall be set, and the tool path verification and machine tool simulation shall be carried out. When the plastic is used to produce bone like materials, appropriate hydroxyapatite shall be added: the mechanical properties of the composite can be improved, and it can be used only after it is ensured to be correct. (end)

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