Bit Life in Melamine

Bits wearing out too fast? Consider the tips in this thread from the CNC forum. November 12, 2005

We are running nested on Komo. Works great, but seems like life on our 3/8" compression spirals cutting mostly 3/4" melamine aren't what they should be. By the end of 40 or so sheets, the bits are leaving a fuzzy core. The melamine edge is still okay, but the core has lots of loose particles sticking out. They cause some problems in banding. We are also tending to tear a chunk out of the center of the core near the corners. 800"/min single line cutting of the nest. Is diamond the answer or are we expecting too much from carbide? What diamond bits are you running good cuts in melamine? Melamine is Roseburg. What bit do you use to run the groove for the 1/4 back panels?

Forum Responses
(CNC Forum)
From contributor S:
How many flutes do your compressions have? I run my 2 flute compression at 800"/min and 3 flute at 1000-1200" and don't usually have a problem... but I am new to this.

From contributor J:
Contact Greg Bialy at Courmatt. He has always helped us and our customers with any questions. I don't work there, so you can take my word as a satisfied customer.

From contributor S:
I usually contact Onsrud directly, or Reliable Tooling, Inc. for my tooling questions.

From contributor M:
I've had similar issues with Roseburg melamine. I'm using Panolam now with better success. I run 2 flute comp 850imp and considering maybe trying a little faster. I've had good luck with Integra bits, but have heard good things about Courmatt and also Onsrud cutters.

From contributor I:
Stick to the carbide for melamine. You can get great cuts in any board if you feed it the right tooling. I think your tooling diameter is too small. I don't ever use tools less than 1/2" in 3/4" thick industrial melamine. Carbide should be fine with the larger tool. I prefer 3/4" shank and flutes. I have bought Amana Tool's carbide router bits for many years and you can get them at a great price, too. Best bang for the buck for carbide and available everywhere. For melamine, diamond is too much of a risk. It's way too brittle when it hits something in the board. For my MDF, I only feed diamond.

From contributor C:
I don't know what software you are using, but we had a similar problem with 3/8 compressions from Onsrud. All we did to fix the problem is set the tools to ramp into the material. If you are doing this already, try setting the ramp length longer.

From contributor G:
I suggest a solid carbide vs. PCD. First, we (Courmatt) would not sell you a PCD at this diameter. We tried this years ago at our customer's request (demand) and it broke within a few feet. Too small of a diameter. Even with a .500 PCD tool, you can only achieve 200IPM. If you are running small parts, this may work, but if you require production, stay with solid carbide. A .375 tool should provide you with 60-70 sheets on a 2+2 tool and 120-140 on a 3+3 tool. On the 1/4 backer tool, use a 7mm down shear. Based on what we have seen, a 1/4 is on the + side. You can use a .250 tool but will need to do two passes. On the 7mm, one pass is all you need. Have the end cut and re-gashed vs. sharpening, so the diameter is the same.

From the original questioner:
We are running nested with single line cutting. That means that on one side of the cut, the bit is climb cutting. I ran a few tests and found that when the bit is brand new, the tear out (fuzzing) is minimal. But as the bit begins to wear, the fuzz increases very quickly. If I switch to conventional cutting, having the bit go all the way around each part, I get a good cut even with the same bit that was fuzzing. It adds a few seconds to the cycle time but not a big deal. MDF core would probably work fine for single line cuts. Haven't tried it yet.

From contributor I:
That's not the only reason it is a bad idea to cut two parts with one pass. You can't use resharpened bits very effectively using that method of cutting. Let the machine do the math using cutter compensation for resharps so that you don't have to write programs based on bit diameter. Rule of thumb with very few exceptions: If it is a panel product, you want to conventional cut. If it is a solid piece of wood, you generally want to climb cut.