I have an SCMI bander that applies glue on just half of the 3/4" edge of the panel once in a while, leaving the entire length loose. Since it's intermittent, it's hard to spot what's happening. Glue quantity is good and panels don't seem to be going into the machine at an angle. What else could be causing this?
From contributor M:
Check your temperatures in the pot and on the roller. Make sure they are within range. You could have a heater going out. Also clean your glue pot. You could have old glue caked on, keeping the new glue from getting to the roller effectively.
When we turn the glue up, we end up with glue slung everywhere inside the machine and much glue clean-up on the panel. We are using good glue with a high solids ratio. The boards are cut on a vertical panel saw and the edges are square. Is it normal to have to apply so much glue to the edge that there is a lot of glue to clean up in the machine and on the panel? When you turn the glue rate down, do you get skips and one side of the edges without glue? Any help would be greatly appreciated.
You might want to check your temp as well. I think that the heaters are only made to last 3-4 years. The 56 should have 4 heaters - 3 in the base, and 1 in the tower. Get a cooking thermometer and test the temp on the roller.
Another thing that might be happening is your sheet stock could be bad. You could be cutting straight, but your stock bending. We have had melamine and plywood curve. It is much like cutting a piece of lumber that has been case-hardened. Watch the edge when you feed it. Does it stay against the fence?
You might not have enough clamping pressure. Try cranking down a little more on the pressure beam. Some of my pieces act like this when I do not have the height set correctly. It will start to glue, but the pressure roller pushes it out away from the glue because the clamping rollers will not hold it.
The next step may be a rebuilt glue pot. I know they are expensive, but there is only so much they can do in the field. The tolerances on those Brandt glue pots are in the .001's. That roller can be pushed out of alignment if it has not been well maintained.
Comment from contributor R:
The first generation of uneven roller coater glue application on Edge Banders was a disaster. Some companies have proven the system out now and they are switching in Europe. To understand how the system works you could check out Robatech. They are expensive retrofits but they can reduce glue consumption by 40% alone. So if you produce enough, and with improved quality and reduced maintenance, the payback can be quick.