Factors causing ridge formation during wide-belt sanding and corrective actions

Ridges are a costly defect that occur during the finish sanding of hardwood cabinet doors and other items. Current methods of dealing with the problem include changing abrasive belts to eliminate the formation of ridges and resanding products to remove ridges. This research was conducted to determine the cause of the ridges in an effort to eliminate the problem. It was determined that ridges form as a result of damaged abrasive belts, with the major source of damage resulting from mineral particles that are deposited on the surface of the workpiece by prior sanding operations. A mineral particle embedded in the product surface scratches the abrasive belt in a continuous line as the workpiece is sanded by that belt. Ridges then result on products that are subsequently sanded by the damaged area of the abrasive belt. The optimum solution to preventing this defect involves eliminating the mineral particles on the product surface to prevent damage of abrasive belts. A secondary solution involves optimizing abrasive belt oscillation.