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Design Tips For CNC Machined Part

Date:2020-06-10 Author: Times:26805

Among the past several years, we meet a lot of problems when doing business with our customers. Some problems come from miscommunications, but some questions occur because the bad initial design from the clients. Here we summarize some common errors the designer may make when designing a CNC machined part.

Sharp Internal Corner

Simply put, the absolute 90 degree pocket corner is impossible to be made by CNC milling, the right technology to make this feature may be Die-Sink EDM. Because the end mill tool is turning rapidly when milling the material, even the tiniest tool will leave the slight radius on the corner. So when you design the pocket corner or internal corner, please set a proper radius for the machinists. This also refer to another question, the cavity depth and the radius, because the end mill tools have a limited cutting length, maybe 4 or 5 times of their diameter. The larger diameter of the tool, the deeper depth of the cavity. If you set the radiu in a smaller number, then adjust the depth of cavity accordingly.

Thin Walls

The wall can not be design too thin, even it looks like beautiful. Think about the viberation of the machining process, which will break the thin wall of the workpiece, we suggest the wall thickness more than 0.5mm for metal and 1mm for plastic. The thin wall thickness will reduce the strength of the metal part and make the plastic part easy to be warped.

Small Features

The hole or other features with less than 2mm size would be different to make, because the size of mill tool is limited. We have to use the special tool to machine this tiny feature. It would be costly and increase the difficulty of machining.


Undercuts for CNC machined part is not impossible, however it is a big challenge for mache programmer and jig designer. Too many undercuts would make the machining process difficult and increase the cost. Some special geometry have to be machined by 5 axis CNC machine, if not necessary, we don't suggest it.

Surface treatment

Good apperance pleases every people. But we have to notice, not all surface treatment can apply on each material, for example, painting is not suitable for PP material, and anodized surface will show good appearance on CNC machined aluminium but not good on die casted aluminium. Please consulant the CNC machining supplier before confirming the surface treatment of the part.

The above are some design tips for metal product designer. If you have requirements of making cnc parts, please contact via Sea@lixin-imachining.com.