How to Reduce the Deformation of Aluminum Parts During Processing?

There are many reasons for the deformation of aluminum parts, which are related to the material, the shape of the parts, and the production conditions.

There are mainly the following aspects:

  • deformation caused by internal stress of the blank
  • deformation caused by cutting force and cutting heat
  • deformation caused by clamping force

Process measures to reduce processing deformation

  • Reduce the internal stress of the blank

Natural or artificial aging and vibration treatment can partially eliminate the internal stress of the blank. Pre-processing is also an effective process method. For thick blanks, due to the large margin, the deformation after processing is also large. If the excess part of the blank is pre-processed and the margin of each part is reduced, not only can the processing deformation of the subsequent process be reduced, but also a part of the internal stress can be released after pre-processed for a period of time.

  • Improve the cutting ability of the tool

The material and geometric parameters of the tool have an important influence on the cutting force and cutting heat. The correct selection of the tool is very important to reduce the deformation of the parts.

  • Reasonably choose the tool geometry parameters.
    • Rake angle: Under the condition of maintaining the strength of the cutting edge, the rake angle should be appropriately selected to be larger. On the one hand, it can grind a sharp edge, and on the other hand, it can reduce cutting deformation and smooth chip removal, thereby reducing cutting force and cutting temperature. Never use negative rake angle tools.
    • Clear angle: The size of the relief angle has a direct effect on the wear of the flank surface and the quality of the machined surface. Cutting thickness is an important condition for selecting the relief angle. During rough milling, due to the large feed rate, heavy cutting load, and large heat generation, the tool requires good heat dissipation conditions. Therefore, the relief angle should be selected smaller. When finishing milling, the cutting edge is required to be sharp, reduce the friction between the flank face and the machined surface, and reduce the elastic deformation. Therefore, the relief angle should be selected larger.
    • Helix angle: In order to make the milling smooth and reduce the milling force, the helix angle should be selected as large as possible.
    • Entering angle: Appropriately reducing the entering angle can improve the heat dissipation conditions and reduce the average temperature of the processing area.
  • Improve the tool structure.
    • Reduce the number of teeth of the milling cutter and increase the chip space. Due to the large plasticity of the aluminum material, the large cutting deformation during processing requires a large chip space, so the bottom radius of the chip pocket should be larger and the number of milling cutter teeth should be small.
    • Fine grinding of the teeth. The roughness value of the cutting edge of the tooth should be less than Ra=0.4um. Before using a new knife, you should lightly grind the front and back of the teeth with a fine oil stone to eliminate the remaining burrs and slight serrations when sharpening the teeth. In this way, not only can the cutting heat be reduced, but also the cutting deformation is relatively small.
    • Strictly control the wear standard of the tool. After the tool is worn, the surface roughness value of the workpiece increases, the cutting temperature rises, and the deformation of the workpiece increases. Therefore, in addition to selecting tool materials with good wear resistance, the tool wear standard should not be greater than 0.2mm, otherwise it is easy to produce a built-up edge. When cutting, the temperature of the workpiece should generally not exceed 100°C to prevent deformation.

Choosing the right CNC cutting tools for processing aluminum parts is important, do you think so?

Write a Comment