Reaping benefits of radial chip thinning

The well-established concept of radial chip thinning (RCT) provides compelling productivity-enhancing benefits, but is still not widely applied. RCT occurs when the DOC is less than the radius of a round milling insert and chip thickness is less than the programmed feed per tooth. This means a higher programmed feed rate is needed to achieve a particular chip thickness, measured in ipt. In other words, the programmed feed rate can be higher because of chip thinning.

Many programmers and machinists are afraid to increase the feed, a fear usually based on an unfortunate previous experience. However, the industry trend is to step-down significantly deeper during machining, greatly reducing step-over. Step-overs have been typically much more than 50 percent of a tool’s width because end users tend to take shallow step-downs, whereas deep step-downs require reduced step-overs. It’s important to note RCT doesn’t comes into play when applying less than half the tool’s width.

Images courtesy of CNC Software

Calculate Chip Thinning for different cases

Toolpaths programmed with Mastercam’s Dynamic Machining suite produce radial chip thinning (top), whereas a traditional toolpath (above) doesn’t enable the productivity-enhancing benefits RCT provides.

New CAM toolpaths and cutting tool designs, such as those used in Mastercam’s Dynamic Machining suite and Iscar’s High-Efficiency Machining tools, push the advantages of RCT to its practical limit. None of this was possible until all the elements—including cutting tools, machine tools and CAM toolpaths—caught up to each other a few years ago. Therefore, now is the time to consider RCT for your operations.