Sensor Color Sensitivity Problem with Edgebander

Infrared lights and sensors in some edgebanders need to be calibrated to the color of the edgebanding, or they won't trigger when they're supposed to. December 8, 2010

I ran into an odd problem on my new Holz Her Sprint. It seems to not like red 1mm PVC tape. There is an infrared light thing that detects when the tape needs to be fed after cutting. If it does not see the tape, it actuates the pneumatic roller that pushes the banding into the banding feed belt. After a second it starts the belt and stops after a predetermined amount of time so the end of the edgeband is ready for the next piece.

I am running a red 1mm edgeband that is the same color as the infrared light. I think the banding is absorbing too much of the light, causing the sensor to think it needs to feed more. The little yellow light on the sensor actually flashes erratically, not blinking. The result is the pneumatic roller is constantly pressed against the tape feed belt and it prevents the tape from feeding onto the panel properly.

When I switch to any other color, it goes away. It is weird. I checked for any loose connections and cleaned the sensor with a soft brush (it wasn't dirty). I am pretty sure it is the color of the banding screwing with the IR receiver. By the way, it is not really IR because the light is visible. It looks like a red laser light, but I am pretty sure it is not a laser. The light does not shine onto a receiver; it reflects off the tape and back to the same little switch.

Forum Responses
(Cabinetmaking Forum)
From contributor J:
I had a similar issue with some dark mahogany PVC a while back. Contact Chris at Lakeside Industrial and speak with her or Lee. They offer a replacement sensor light to work with dark colors, and may be able to help. Very friendly and helpful people.

From contributor R:
We had similar issues with our bander. We switched from the standard eye to a retro-reflective eye. This eye requires a reflective tape which we attached with duct tape to the back of the plate that is behind the edging (by the cutoff knife). This removed all issues we had with colors and was a direct replacement for the existing eye, as it was from the same company. We do still have issues when we run aluminum edging if it has a clear pealcoat on it, but otherwise we never have issues with the eye not seeing the tape.

We purchased the new sensor from Sensors and Safety LLC. I spoke with Peter and he was able to make sure that the new sensor used the same cable as existing so it was a quick and easy fix.

Our part number was:

Sensor # - PRK 3B/66-S8
Reflector # - REFL TAPE NO. 4/100X10

From contributor T:
Same thing on our Sprint. White or almond worked fine, but any dark color and it's a problem. It was within warranty, so Wayne came out and I think he replaced the eye and definitely added the reflective tape.

Cutting has been improved but there are still mysterious issues that occur when nothing but the color changes. Mainly top and bottom trim leaves too much material left over. Try and make an adjustment and now it cuts in too much when you go back to white. Same brand of melamine, same thickness (measured with a caliper), same brand and thickness of banding, same glue and speed. It's a mystery!

From the original questioner:
Wow! I did not expect so many others with this problem. The techs here are not aware of this problem. I thought my diagnosis was a little farfetched. I guess not. I am not too excited about having to change the sensor. Oh well.