In addition to improving tool performance and pre-use of aging treatment to eliminate the internal stress of the material, in practice, the use of appropriate operating methods can effectively avoid the material processing deformation.

1, symmetrical processing method

For the machining of large parts, in order to make it in the process of machining have better heat dissipation conditions, to avoid heat concentration, processing, it is appropriate to use symmetrical processing. If there is a 90mm thick plate needs to be processed to 60mm, if milling a good side immediately after milling the other side, a machining to the final size, then the flatness of 5mm; if the use of repeated feed symmetric machining, each side of the two times to the final size of the machining, can ensure that the flatness of 0.3mm.

2, layered multiple processing method

If there are multiple cavities on the plate parts, as shown in the figure below. Processing, it is not appropriate to use a cavity of a cavity order processing method, which is likely to cause uneven force and deformation of the parts. The use of layered multiple processing, each layer as far as possible at the same time processing to all the cavities, and then process the next level, so that the parts are uniformly stressed, reducing deformation.

3, the appropriate choice of cutting amount

Reduce the cutting force and cutting heat by changing the cutting amount. In the three elements of the cutting amount, the back draft has a great influence on the cutting force. If the machining allowance is too large, the cutting force is too large, not only will make the parts deformed, but also affect the rigidity of the machine tool spindle, reduce the durability of the tool. If you reduce the amount of back draft, and will make a big difference in productivity. However, in CNC machining are high-speed milling, can overcome this challenge. While reducing the amount of back draft, as long as the corresponding increase in feed, increase the speed of the machine tool, you can reduce the cutting force, while ensuring that the machining efficiency.

4, the order of the tool should be careful

Roughing and finishing should be used in a different order. Roughing emphasises the improvement of machining efficiency, the pursuit of the removal rate per unit of time, generally can be used in reverse milling. That is, the fastest speed, the shortest time to remove the excess material on the surface of the blank, the basic formation of the geometric contour required for finishing. The finishing process emphasises high precision and quality, and it is appropriate to use downstream milling. Because of the smooth milling when the cutting thickness of the teeth from the largest gradually decreasing to zero, the degree of work hardening greatly reduced, while reducing the degree of deformation of the parts.

5, thin-walled parts of the second compression

Thin-walled workpieces in the machining of deformation due to clamping, even if the finishing process is also difficult to avoid. In order to minimise the deformation of the workpiece, you can reach the final size in the finishing is about to be, the pressure of the pieces of loose, so that the workpiece is free to return to its original state, and then a slight pressure to just clamp the workpiece shall prevail, so that you can get the desired processing results. In short, the action point of the clamping force is best in the bearing surface, the clamping force should act in the direction of good rigidity of the workpiece, in order to ensure that the workpiece does not loosen the premise, the smaller the clamping force the better.

6、Drilling and then milling processing method

In the processing of parts with a cavity, try not to let the milling cutter like a drill directly down into the parts, resulting in the milling cutter chip space is not enough, the chip is not smooth, resulting in parts overheating, expansion, and chipping, tool breakage and other unfavourable phenomena. To use the same size as the milling cutter or a larger drill bit to drill down the hole, and then use the milling cutter milling. Alternatively, CAM software can be used to produce a spiral undercutting programme.