Question
We have a Komo CNC router and I understand that the melamine paper is more scratch resistant now and they are adding abrasives similar to what is sand paper to create the scratch resistance. The melamine is cutting a groove in router bits similar to cutting laminate lay-ups. I have used every brand of tooling and carbide cobalt mix and I’m still having the same issue. I understand from tooling suppliers that we are not the only ones having this issue. Is anyone having this problem?
Forum Responses
(CNC Forum)
From contributor S:
What brand material are you using? What tooling and rates?
Courmatt, Vortex, and Onsrud are all industry standards and excellent tools. For my money I get the best life from Onsrud MW tools, short from Maximum Wear. I believe they do the carbide differently with MW, it is not a coating, although that is available too. Coatings are usually gone after your first sharpening, but they help when a tool is new.
I have found the grooving issue is worst with laminates, way worse with Wilsonart products, and probably least bad in Abet with Formica and Nevamar somewhere in between.
The melamines have not been much trouble for me. I use more Tafisa than anything else, but other brands work into the mix too, especially with all of the LEEDS work being done now. Measuring in number of sheets is difficult since people cut different numbers of parts and have different part densities and sizes, but I cut more than 50 sheets of typical cabinet parts densely nested with one tool if it is all melamine. Mixing up materials is always going to make your tool life less since it is harder to optimize feed rates in multiple materials.
To sum it up, yes I find that the surfaces are indeed harder in the recent past and it does seem to affect tool life. Diamond is usually the suggested solution but I resist diamond for a few reasons. It isn't on cost either but instead on the reality that I will never be able to optimize feeds and speeds for the dozens of materials I cut on a weekly basis so I will never get the tool life I really should. I would also have to sacrifice material yield (diamond is larger in diameter so you have more kerf) and also does not have really good tool geometry (it is hard to make a really slick three flute compression cutter you can sharpen in diamond). If I cut only melamine and p-lam, I might sacrifice some speed and material yield and go for diamond. For now I will keep using the Onsrud MW and hope something even better comes along in high-grade carbide. I am always willing to try a new suggestion.
Issue # 1: Heat is the enemy. All tools get dull eventually and dull tools heat up fast.
Issue # 2: The faster your top speed, the more flutes you can use. My particular machine is good for about 1200 to 1600 IPM and that is reasonably fast. I use a three flute tool at these speeds. If your top speed is 800 or 900 you should be in the two flute range, and 300 to 600 likely down toward one flute tools, all assuming roughly 18000 RPM (chip loading permitting) which varies from tool to tool.
The problem is that most of the time machines with a top speed of 1600 IPM are traveling more slowly than top speed since they have to accelerate. Low mass machines that have lower head mass (often bridge gantry) are apt to accelerate more quickly. Heavy mass machines (big iron or overarm) are generally slower. My machine is overarm and heavy. It is solid as a rock, but it takes a long time to accelerate to top speed. All the while it is accelerating the bit is spinning at constant RPLM because the controller (and to a certain extent the spindle) though very reliable is not sophisticated enough to slow down the RPMs into the corners or have the capability of adjusting the RPMs for feed speed. This creates poor feed/speed balancing and therefore faster machines that accelerate slowly generate more heat.
Nearly all machines suffer from this malady to one extent or another. Some machine manufacturers are beginning to address this problem now that machines are getting faster and the heads are heavier with drill banks and aggregates and other options. Controller/spindle combinations that allow for ramping speeds into and out of corners would solve this problem very well. In the end, I slow my spindle down to help alleviate some of these effects but rather than drop speeds and go with 800 IPM and two flutes I live with this imperfect balance.
It is a nesting router and one thing I notice right away is that it is always slowing down (feed) to turn a corner. I nest out of cabinet vision and it eliminates plunge cuts to one at the start. I was told plunging was hard on bits as well. Might I be better to slow my feed and RPM down in the nest so on the corners it is not so fast? I cannot change the feed/rpm within the nest to compensate for corners. My ramp up speed is fast (the installer actually slowed it down) so most of the time it is up to full speed quickly.
The original poster has a perfectly legitimate comment. He may very well benefit by dropping his RPMs some or increasing his feed rate a little according to chipload tables. That being said, I have never changed a bit on account of the core area wearing more than the melamine contact area. Look closely at any of your bits that are nearly used up, pull out a microscope (if you can't see it with your naked eye) and tell us all here where the tool is failing.
Oscillating Z can help but depending on what you're cutting, chipping can be an issue. As has been pointed out, the router guys definitely have issues with oscillating. I have found that I start a new bit at a certain distance below the material, and with each cabinet I lower it .01mm to be helpful.
There are a myriad of other factors that play into this equation. Southern board, western board, Canadian board, paper weight, laminate brands, different finishes. I know I saw dramatically different results with tool life within one brand of melamine when I used to use Panolam, depending on whether it came out of Norcross or Huntsville. At the time Norcross being southern board and Huntsville being Canadian board. I would also be willing to be bet there were differences in the melamine composition as well. The long and the short of it, are there some guidelines you can start with, absolutely, are there hard and fast rules, in my opinion, no, you need to figure out what works best for you.
