How to Reduce the Deformation of the CNC Turned Aluminum Parts?

Aluminum is one of the most easily available materials on earth and aluminum alloys are mostly used in aeronautical and automotive applications because of their machinability and malleability. In aerospace industries, aluminum parts are required to be made with higher quality to avoid any unpleasant failure of the part during the operation. Aluminum CNC machining is one of the best ways to produce high-quality CNC turned parts.

cnc turned machining parts

As compared to other materials, Aluminum has a low hardness and higher value of thermal expansion which makes aluminum vulnerable to deformation of the final product after the machining processes. The deformation of the part means that the size of the final product is different from the expected size. This deformation of the CNC turned parts is desired to be avoided for the proper functioning of the final product. The machinists should be careful while machining aluminum parts.

Several factors cause the deformation of the aluminum e.g material used, the desired shape of the part, the performance of the cutting fluid, and the manufacturing conditions of the part. The more the part is complex, the more will be the deformation of the final part. Also, in the case of small aluminum parts and when aluminum parts are thin-walled then it may cause the part deformation

To reduce the deformation, there are different possible ways which help to reduce the deformation of the machined parts e.g by reducing the internal stress of the aluminum material, enhancing the tool’s cutting efficiency, improving workpiece clamping techniques, improving the design of cutting tools, organizing machining processes precisely, selecting suitable cutting parameters, and symmetrical machining. Following are some methods to be used to avoid the deformation of aluminum parts:

Reduce the internal stress of the blank

The different types of stresses may be present in the machined parts like internal stresses, residual stresses, thermal stresses, etc. The internal or external forces induced the strain in the material which is the measure of deformation in that material due to stresses. By reducing the internal stress of the blank, the manufacturer can avoid the deformation of the final part. Using the manufacturing process like Aging and vibration treatment can help the manufacturer to reduce the deformation of the aluminum parts. Vibrational Stress Release (VSR) is a common way to reduce stress. Cryogenics and other heat treatment processes like annealing and solution heat treatment processes are also used to reduce the stresses.

Improve the cutting ability of the CNC machining turning tool

cnc turning

To reduce the deformation in the CNC machined aluminum parts, it is imperative to improve the cutting ability of the CNC machining turning tools. The material and geometric parameters of the tools greatly influence the cutting force and cutting heat which may result in the deformation of the CNC turned parts. So, to reduce the deformation, it is imperative to choose the correct material and parameters of the tools to be used for machining aluminum parts. The geometric factors that can affect the performance of the tool are front, back, helix, and entering angles. In order to maintain the strength of the blades, the correct front angle is required to be chosen to reduce the deformation, cutting force, and cutting temperature. The use of an appropriate rake angle also makes the chip removal smooth. Depending upon the requirements, a suitable rear angle should be used to avoid deformation in the aluminum parts. A smaller rear angle is used in case of large feed rate, rough milling, larger heat dissipation, and larger cutting loads. A larder rear angle is used in case of precision where sharp edges are needed. The larger helix angles are used to reduce the milling force and make the milling process smooth. The smaller entering angles are used to improve heat dissipation.

Improve the clamping method of aluminum CNC machining turning parts

Clamping is used in almost all machining processes to hold the workpiece during the machining processes. It helps to minimize the vibrations during the machining process and produce the product with accurate dimensions. In the case of thin-walled parts, a suitable clamping method should be used to avoid any kind of failure because the clamping deforms the thin parts after loosening.

If a 3-jaw self-centering chuck is used for radial clamping of the thin-walled aluminum parts, then the part will deform after the removal of the part from the jaws. To avoid deformation, the method of pressing the axial end face with better rigidity should be used.

In the case of thin-walled and thin-plates workpieces, to evenly distribute the clamping force vacuum suction cups are used. With the use of vacuum suction cups, CNC machining is done with a small amount of cutting to avoid deformation in the aluminum parts.

The packing method is used to increase the rigidity of the thin-walled workpieces. To reduce the deformation during cutting or clamping, a medium can be filled in the workpiece and removed after the final product is formed.

Reasonable arrangement of machining procedures

In high-speed cutting, the wide machining allowances and intermittent cutting allows significant vibrations during the manufacturing process which results in a compromise of quality and poor surface roughness. In this case, it is better to split the complete cutting process into multiple processes to get the final product. For this purpose, in high-speed machining of aluminum, the cutting process is categorized as rough machining, semi-finish machining, clear corner machining, and finishing. After rough machining, the workpieces are allowed to cool down naturally which results in a reduction of internal tension and deformation. In case of the high level of quality requirements, the semi-finishing machining is performed before the final finishing of the CNC machined aluminum parts. During the machining operations, the tool should be kept steady to minimize deformation and produce a high-quality product.

low volume cnc turning parts


To summarize, in the aeronautical and automotive industries, most of the components of the machinery are required to be made from aluminum. It is desired that the machined aluminum parts meet all the quality standards for their proper functioning. Usually, aluminum machined parts get deform because of their low hardness and higher thermal expansion. This deformation is not favorable in the final products for proper functioning and may result in failure of the part during the operation. The different factors that caused the deformation are discussed in this article along with the possible solution to avoid the deformation in the final product made from aluminum. The deformation can be avoided by reducing the internal stresses, improving the cutting ability of the tool being used, improving clamping methods, and using an appropriate arrangement of the procedures for the CNC machining of aluminum parts.

Post a Comment