Troubleshooting Edgebander Cutting Issues

Keeping the knife well sharpened and lubricated helps. So does keeping the air lines and filters clear. September 16, 2013

(WOODWEB Member) :
Our smaller Holz-Her 1310 has been having trouble cutting 3mm PVC tape lately. We have sharpened the knives and that did not help. I have checked the guillotine - it is free and working well. We keep the tape at about 65-70 degrees, turn the air pressure up to about 6.5-7 bar on the guillotine, and still it won't cut through the 3mm PVC tape. Has anyone else had trouble? Right now we are cutting pieces to length and that is a pain. I will call Holz-Her and our supplier to see if I can find anything out.

Forum Responses
(Cabinetmaking Forum)
From contributor L:
Is your oiler working? Did you open up the cylinder to see if the seal has gone bad?

From contributor F:
We had a similar problem with our SCM bander some time ago. I checked everything and it would not cut tape. After many calls, the SCM tech walked in and fixed it in under 30 seconds. On the SCM bander (not sure Holz-Her), there is an air filter on the back side of the guillotine piston that was clogged with dust. He blew it out and we now keep it clean and never have problems. Basically the piston was getting full pressure, but not able to exhaust fast enough, so the cutter never operated at full capacity.

From contributor H:
Sounds like you may have an air exhausting issue, or possibly the guillotine knife cannot slide freely.

1) Disconnect air pressure from the machine and see if you can slide the guillotine knife back and forth freely. If not you may have some burrs on the back of the guillotine that you'll need to knock down with a knife sharpening stone.

2) You likely have a problem with the fast exhaust valve at the front of the guillotine cylinder. It could be full of debris, or like a previous poster mentioned, the port filter could be clogged.

From the original questioner:
I found the problem this time around - I missed it the first time. When I had the knife sharpened I did not put enough lube on it when I reassembled it.

About a month it galled up and would not slide easily, so I cleaned it up and then when I assembled it I lubed it with grease (too much, as I was afraid it would repeat again). The other day when I checked to see if it slid freely with the air off the machine had been running for some time and everything was warm/hot and it slid freely. Today when I checked again, it was cold and sure enough it was a gummy mess and would not slide.

I cleaned everything up and wiped a light coat of 3n1 oil as I was told to use. When I tightened the screw up on the bronze piece that the knife slides on I noticed I could tighten it down enough and it would cause the knife to bind up when reaching the end of its cut. So I backed it off just a bit and used the nut on the other side to lock it down and hold it in place. Now it moves free and there is a very slight movement in the knife. Now it cuts the 3mm at 4 bar just fine. I also checked the bumper inside the air cylinder (cushions the end of the stroke) and it looked like new. I was told this was another area to look as these will break up and cause problems with air exhaust and delivery.

Missing things like this is caused by me being in a hurry and not thinking things through. I should have checked it for sliding freely more than once!

From contributor H:
Glad to hear you've got it worked out. Usually 4 bar is more than adequate to cut 3mm PVC with a good sharp knife and a mechanically sound system.

As a side note - regarding the lube for the guillotine knife, I would suggest a light film of fresh Gleitmo 805 (Holz-Her track grease) on the back side of the knife. Fresh Gleitmo 805 is the right consistency to hang in place and provide excellent lubrication for the life of the guillotine knife edge.

From the original questioner:
I kind of wondered that. I will put a light coat of that on next time I am working on it. Thank you.