Melamine Chipping

Is it the bits, the feed rate, the material? Pros troubleshoot a case of melamine chipping on a new CNC unit. June 30, 2005

Our company just purchased a Mulitcam 3000 (our first cnc) and is very pleased, however when we are cutting through 3/4" 2 sided melamine we are getting small chips along edge with a brand new 1/2" compression bit. My thinking is to slow the feed speed or rotation speed? Does anyone have any input?

Forum Responses
(CNC Forum)
From contributor D:
We are now cutting melamine with a 3/8" up and down at 650ipm with a 16000 rpm. With an 1/2" I think you could go at least at 700 ipm with at least 16000-17000 rpm

From contributor T:
To contributor D: Are you getting chips or dust with the tool? Remember, you want chips, not dust.

From contributor A:
I use a 3/8" compression at 18,000 rpm, 750 inches per minute with no problem. Couple of questions: Are you getting chipping along the entire edge or just the entry? Make sure the tool is entering the material at some sort of an angle or radius, also are you over cutting the depth? Make sure you are cutting into the spoil board by a few thousands so the up-cut on the bottom of the bit has a chance to work.

From contributor D:
Contributor A, do you go in 1 or 2 passes?

From contributor A:
To contributor D: One pass, unless the part size is below a certain size, then I onion skin. This is just for the hold down, not for the quality of edge.

From contributor P:
We have had our CNC for 2 1/2 years. At first we started using carbide cutters, then after ten sheets we had chipping problems too. We started using 1/2 diamond tooling and love it. The bits may be more expensive, but well worth it it. They last much longer than carbide.

From contributor G:
Contributor A, you never said where you are getting chips. Is it the top or bottom of the board? You have to take into consideration the material. Has this been an ongoing problem with all melamine?

From contributor M:
It may not be your cutters or feed rate. We had chipping problems all of a sudden about 2 months ago with our melamine. Tried everything with tooling. Turns out to be the melamine and core is inferior to the prior shipments we received. This might be a temporary problem, but the new melamine product we are using now gives us 3 times more life out of our carbide cutters.

With the melamine that was chipping, we noticed the melamine layer was thinner and the core material was coarser than our new stuff. Note: Chipping was worse when the board was not clamped or directly supported under the routs, probably due to extra vibration.