The Effect of Nose Radius on the Surface Finish during CNC Turning

by Norm Grimberg CNC Machining and Machine Shop

Surface finish undoubtedly is a very important feature in the manufacturing of Custom CNC Machined Parts.

There are a lot of factors, which when ignored, can pave way for a poor surface finish- something that can create an issue in assembly and that is not aesthetically pleasing. These factors include cutting tool placement, tool wear, chipping, incorrect feeds and speeds, rake angle, tool holding and work holding and incorrect nose radius selection.

In this blog post, we would be talking about the effect tool nose radius has on the surface finish during CNC turning.

According to several types of research done on the topic, one should opt for a larger tool nose radius to get a finer surface finish. But the chances of tool wear are particularly higher in such cases when compared with the small nose radius. This is due to the fact that specific cutting energy increases with an increase in the nose radius.

Large nose radius helps reduce part bending and vibrations during the CNC turning process. It aids to a larger depth of the cut, thereby increasing the axial forces on the part reducing the chances of a poor surface finish.

Chipping is another major factor handled by the nose radius. Chip breaking is highly dependent on the feed rate and the cutting pressure, but nose radius also plays a major part in it. At the same feed and speed, a smaller tool nose radius aids to a better chip breaking. Thus, increasing the nose radius along with an increased feed rate can help tackle the chipping problem, if you don’t have a chip breaker that is.

All in all, one is advised to use a small nose radius for a small depth of cut and for the parts that demand reduced vibrations. On the other hand, the large nose radius is used for the sturdy CNC machined parts that need higher feed rates and a large depth of cut.

For more related blogs: 360° CNC Machine Solutions

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