Aluminum is an important industrial raw material. However, due to low hardness and a high coefficient of thermal expansion, it is easy to deform when machining thin-walled parts. In the CNC machining process, in addition to improving the performance of the cutting tool in advance and eliminating the internal stress of the material, some measures can also be taken to reduce the deformation of the material as far as possible. This article will introduce the first three methods, and we will continue to update other methods later.
1. Symmetrical machining
For CNC aluminum parts with a large machining allowance, excessive heat concentration should be avoided to produce a better heat dissipation effect and reduce thermal deformation which is called symmetric processing.
Imagine that a 90mm thick aluminum plate needs to be ground to 60mm thick. If the milling side is transferred to the other side immediately because each surface is machined to the final size, the continuous machining allowance is large, which will cause the problem of heat concentration, and the flatness of the alloy plate can only reach 5mm.
However, if the method of symmetrical machining on both sides is repeated, each surface can be machined at least twice until it reaches the final size, which is conducive to heat dissipation, and the flatness can be controlled at 0.3mm.
2. Multi-layer processing
When there are many cavities on the aluminum alloy plate, it is easy to twist the cavity wall due to the uneven force. The best way to solve this problem is to use a multi-layer machining method, that is, machining all cavities at the same time.
Not all CNC aluminum parts are finished at one time, but the parts can be divided into several layers and processed to the required size layer by layer. The force applied to the part will be more uniform and the possibility of deformation will be less.
3. Select suitable cutting parameters
The cutting force and cutting heat can be reduced by selecting appropriate cutting parameters. In the process of machining, if the cutting parameters are greater than the normal value, the cutting force is too large, it is easy to cause deformation of parts and affect the spindle stiffness and tool life.
Among the influencing factors of cutting parameters, the most important one is the depth of back cutting. However, reducing the number of cutting tools is conducive to ensure that the parts do not deform at the same time, the processing efficiency will also be reduced.
Hope the information we provided will be helpful to you, the remaining methods will be listed in the article “How to effectively avoid part deformation in aluminum CNC machining? (2)”.