I visited a hardwood finishing components manufacturer today because they were going through a lot of 80 grit belts on their 3 head planer sander (planer, drum, combi running 80,120).
The customer was extremely confused because the belts were leaving polished shiny marks tracking with the belt.
This is the first thing they showed me upon arrival.
The belt is embossed by massive pressure.
I did my due diligence and checked for issues with the machine. The table was still square and the final product was acceptably accurate. The stock removal only required slight adjustment. There were no missing planer knives. There was no significant damage to either drum. We even checked the new belts. The machine is fine.
The customer (lead machine operator) believed that it had to be something out of calibration.
Looking at the lines again I realized that they were not continuous…they end and start again.
A couple minutes later it hit me. They must have had a machine stoppage and the operator ran the parts out without lowering the bed. Remember, this is a planer sander. The material that rolled through could be up to 1/8″ thicker than what would be sanded by the second head.
The damage was not the raised 1″ wide spots but the 4″ wide spots in between. The parts rolled through and put massive pressure on the drum, crushing the paper and embossing the 4″ wide dents in the paper.
If the drum had been running the belt would have cut through and destroyed the drum. This mistake must have been repeated several times.
If you see crushed paper you can be sure there was a lot of pressure involved.
Adam West
SurfPrep Abrasives Specialist
440 855 2453
