Surface defect inspection on MDF and particleboard

Need

The panel is wide and moves fast; the height of a blister or dent is small and invisible under steep light, while a stain disappears under low-angle light. The natural pattern of the melamine film and the chip texture of a raw board blend with the defects.

Solution approach

Two line-scan cameras side by side cover the full panel width; encoder-triggered scanning gives constant sampling regardless of speed. The bright-field image under a steep bar light shows dark stains and paper tears; the image under a second, very low-angle bar light shows the shadow-highlight pair of blisters and dents. Both images are merged in panel coordinates and graded by defect size.

Process steps

1. 01

   Infeed

   The panel from the press arrives at the gantry on the roller conveyor.

2. 02

   Scan

   Two line-scan cameras read the surface line by line under bright-field and low-angle light.

3. 03

   Map

   Stains, blisters and scratches are logged on the panel map with their position.

4. 04

   Decide

   Defect size and count are applied to the grade rule; the panel is routed to the corresponding stack.