Melamine Chipping on a Sliding Table Saw
A cabinet shop goes through the learning curve cutting melamine on an entry-level slider. The discussion covers blade choices, sharpening, setup, adjustments, and technique. August 8, 2008
Question
I recently purchased a mid-90's Robland sliding table saw. We have cut a lot of 3/4" melamine panels on it with decent success. I say decent because it will be cutting just fine, and then I will get some chipping on the bottom side. I have adjusted and readjusted, and then re-checked what I have readjusted and cannot find my problem. So that I don't leave the rock unturned, what type of tooth cut do you use on the main blade? How about the score blade? At what height do you keep the main blade and score blade? My guys are pissed at me for buying this machine and making them use it, but I did enough research to know that after you get through the learning curve, most folks would not want to work in a shop without a slider. Anybody have suggestions?
Forum Responses
(Cabinetmaking Forum)
From contributor M:
I get chipping some when cutting full sheets. The board will come up off the table a little and not hit the scoring blade. When cutting, listen to the blades. You can tell by the sound if the scoring blade is cutting or not. Other than that, I don't really know except keep the scoring blade sharp because it dulls quickly, and get your scoring blade alignment right. To answer your blade question, the main blade is a 72 tooth atb and the scoring is a 24 tooth flat top.
From contributor K:
With a good TCG blade with 80 teeth, you should be able to cut melamine without a scoring blade and get chip free cuts. The blade should be just high enough to fully expose the gullets in the saw body. If you're still getting chip out, then there is runout in the arbor or you don't have a good blade. Feed at a reasonable pace and you shouldn't have any problems. The other alternative is to go with a Hi ATB blade, but you won't get as many sheets out of it as you will with a TCG blade.
From contributor S:
What kind of scoring blade do you have, split or conical? Conical is not really meant for sliders, and when your material comes off the table (warped sheet), you are prone to chipping.
You also need to make sure that your blades are sharp. Expect to cut about 20 sheets of melamine before it is resharpened. Have both blades sharpened at the same time.
As far as blade height, I have mine set at 1.7". Put a scrap piece that you are cutting behind the blade. You need to have 2-3 teeth in the material at once.
Some guys swear by not using the scoring, but I have not been able to make it work consistently.
And I am not talking trash, but Robland is not one of the more robust saws. It is considered by many to be an enthusiast's machine. It could be that the tolerances are not tight enough to cut melamine. You don't have much room for error when cutting this material. I would call them and see what adjustments you can make to tighten the play. Look and see if there are areas that are consistently chipping after proper adjustment and freshly sharpened blades. And talk to your tooling supplier to see what blades they recommend. A good manufacturer will be able to support their blades.
From contributor A:
What does TCG mean?
From contributor K:
Triple chip grind.
I should also qualify what I mean by a chip free cut with a TCG blade. It is within acceptable limits. You have to look pretty close to see it. Even with scoring I've had as much chip out, at times as much as I get without it, which isn't very much.
The other thing I might suggest, and I don't mean to imply you aren't doing this already, is spend a few more dollars per sheet and get a better grade. That also makes a big difference.
From contributor R:
Could also be stress in the material. Does it chip on both sides of the blade, or just one?
From contributor J:
I get 3 units out of my main blade and 1 1/2 -2 out of my scoring set. I use the Amana shimless split set and a FS tool main blade or the Amana 80 tooth 12" blade. Both blades are TCG. If I was only getting 20 sheets I would find a new blade shop.
From contributor R:
I had a Robland slider and have upgraded to a Felder. That made all the difference.
It is critical that all adjustments be right on sliders. Check the height of the table relative to that of the sliding table. They should be the same and flat. Could be a little wear with the slider that may be causing some vibration. I also suspect that the learning curve may have a little to do with it. When you are feeding a sheet lengthwise, clamp it down to the slider at the slider fence and hold it down at the rear. If you don't like clamping, then lift the left rear corner to bring the right front corner down tight to the table while holding the right rear corner down to the table.
I have found that the grind of the main blade is not that critical when both the scoring and the main blades are sharp. I never ever had a melamine blade not chip out the bottom without the scoring blade. Even brand new, they still chip. I guess it depends on how much chipping you think is acceptable.
From the original questioner:
Since writing this, we have cut about a unit of cabinet parts, and it seems to be going pretty good. A few chips here and there, but overall pretty good. I agree about the new Roblands not being very robust, but this is an older model and I feel pretty good about it. It is just taking us some time to get used to it. This forum has helped out a ton!
From contributor M:
Something else is, if this saw is fairly new to you, you could need a little more time to get familiar with using it. It took me a little while before I could rip a sheet without putting sideways pressure on the sheet and shifting it while cutting. You can also try splitting the sheet in half first, then re-straightening. A lot of melamine these days has a lot of pressure in it that can cause it to shift and bind on the blade when cutting. I am by no means an expert, just throwing out a few ideas not mentioned.
From the original questioner:
I just went into the shop and checked again, and the cuts are now going very well. I think that much of it was in the learning curve.
From contributor O:
Many people bash the Robland. I bought mine new in 1999 and it has cut consistently well all this time. It has required very little maintenance. It was our main saw most of this time and all we have done is replaced a locally sourced bearing on the scoring unit. We do get at least 3 units of melamine from the blades. Since you seem to have worked out the problems, set your sights on a Tigerstop unit for the saw. I ordered my Robland with one and it made a huge difference. By the way, if in doubt, ask the Laguna Tool people for the blade type and configuration. I have bought replacement blades from them with success.
From the original questioner:
Thanks. I just came in from the shop and the operator said that he could not have imagined cutting that much on a regular table saw, and the cuts are very good. He finally agreed that it was a good thing (we still have a couple of table saws). I know that cost is irrelevant (it is how much you make on a machine that counts), but I only have $2200 in this machine, so it will be easy to pull the trigger on an upgrade when the time comes, as it should be an easy sell. The only thing that I have found to be less than stellar is the adjustment of the scoring blade, but once adjusted, it stays in place.
We have been in the countertop business forever and we are in the process of going deeper into the commercial casework business, and utility storage cabinets (72" X 30" units that hang on the wall). I don't post much on this forum, but over the past year or so, I have learned a ton!
From contributor S:
You probably use a negative hook blade and spend half of your time fighting it through the cut. A negative hook will last longer, but your feed rates are increased. An aggressive hook and Hi ATB will cut faster, give crisper edges, but dull quicker.
