Process measures to reduce machining deformation

1. Reduce the internal stress of the hair culture

Natural or artificial aging and vibration treatment can partially eliminate the internal stress of the blank.Pre-processing is also an effective process.The blank of fat head and big ears, because of the large margin, so the deformation after processing is large.If the pre-processed blank of the excess part, reduce the margin of each part, not only can reduce the processing deformation of the next process, and the pre-processed place for a period of time, but also can release part of the internal stress.

Process measures and operation techniques to reduce deformation of aluminum parts

2, improve the cutting ability of the tool

The material and geometrical parameters of the cutting tool have important influence on the cutting force and cutting heat.

(1) Reasonable selection of tool geometric parameters.

(1) front Angle: under the condition of maintaining the blade strength, the front Angle is appropriately selected larger, on the one hand can be ground out of a sharp edge, and can reduce the cutting deformation, so that chip smooth, and then reduce the cutting force and cutting temperature.Do not use negative rake tool.

(2) Back Angle: The size of the back Angle has a direct impact on the wear of the back knife surface and the quality of the machined surface.The cutting thickness is an important condition for selecting the back Angle.Rough milling, due to the large feed, cutting load, heat, the requirement of good heat dissipation conditions, therefore, after the Angle should be selected smaller.When precision milling, the blade is sharp, reduce the friction between the cutter surface and the machining surface, reduce the elastic deformation, therefore, the back Angle should be selected larger.

(3) spiral Angle :(lift Angle) in order to make milling smooth, reduce the milling force, the spiral lift Angle should be selected as large as possible.

Main Angle of deviation: reduce the main Angle of deviation properly can improve the heat dissipation conditions, so that the average temperature of the processing zone down.

(2) Improve tool structure.

(1) Reduce the number of milling cutter teeth, increase the chip space.Because the aluminum material plasticity is larger, the machining deformation is larger, need a larger chip bearing space, so the chip bearing groove bottom radius should be larger, fewer milling teeth is better.

(2) fine grinding knife teeth.The roughness of the cutting edge of the cutter should be less than Ra=0.4um.Before using a new knife, you should use fine whetstone in the front and back of the knife teeth gently grinding a few times, in order to eliminate the remaining burrs and slight serrate grain.In this way, not only can reduce the cutting heat but also the cutting deformation is relatively small.

(3) strict control of tool wear standards.After tool wear, workpiece surface roughness value increases, cutting temperature rises, workpiece deformation increases.Therefore, in addition to the choice of good wear resistance tool material, the tool wear standard should not be greater than 0.2mm, otherwise easy to produce chip tumor.When cutting, the temperature of the workpiece generally do not exceed 100℃, in order to prevent deformation.