Troubleshooting Melamine Chipping on CNC Equipment

Maintenance steps, different bit choice, or RPM and feed speed modifications should correct a chipping problem. September 7, 2006

Question
I need to cut melamine chip free for a customer. We are making a desk system for her to sell to the public. She sees the melamine stuff in stores and wants that chip free manufacturing. We are using a CNC. I have tried compression bits, but they leave a line that is noticeable after edgebanding. Currently, we are cutting with a downshear leaving .05 and through cutting with an upshear to get as good a finish as we can. However, we still get chips. Sometimes they are minimal, but sometimes quite noticeable. Today I'm increasing the final pass to .1 inch. I have a new spoilboard, new cutters and Im resurfacing the spoilboard after each cut. I need help. I'm about to halt production. What is acceptable chip rate in other shops? How do you repair your little chips?

Forum Responses
(Cabinetmaking Forum)
From contributor A:
I'm going to say its all in the feed and rotation speeds. Generally, you should increase your feed speed or slow the rpms down, or a combination of both just the opposite of what you'd think. Without knowing any more I'd tell you to increase feed to about 7-8k mm and back the rpms off to about 12-13k and use a compression bit.



From contributor B:
As far as acceptable chips, the answer is very simple in my shop - zero. The previous gent is exactly right. Feed and speed. You should not have to make an onion cut then finish with an upshear tool when using a compression bit. There are a million combinations from a million folks to get a clean cut. Run some tests to get dialed in.


From contributor C:
You should not have lines in the material. Several things could be going wrong:

1. the collet is old replace it


2. dirt in the collet - clean
3. toolholder is worn
4. you got a defective tool

Also, you should not have any chipping with an up/down spiral. The downshear you are using will give you a great edge finish at the top, but when you use the upshear fore (I'm thinking golf) the final cut you will get chipping on the top side. I'll put my money were my mouth is - we will send you a tool, and if it works, buy it - if not send it back, no questions asked.