Inline final surface inspection of panels and doors
As the painted panel passes under a fringe light screen, cameras watch the fringe reflection on the glossy surface. Dents, scratches and paint defects show up as local fringe distortion and are recorded with their position on the panel.
The defect list and the positions on the panel are sent to the rework station; a panel with a defect above the limit is flagged on the stack light and the operator display, and the result is stored with the panel ID.
- 01 Infeed
- 02 Fringe pattern
- 03 Analysis
- 04 Decide
The entry photo-sensor detects the carrier and the panel enters the station at constant speed.
- Scanned length
- —
- Defects
- —
- Local deviation
- —
Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
On a glossy painted surface a small dent or a light scratch gives almost no contrast under flat lighting; the reflection of the surroundings, carrier vibration and the crown that varies from panel to panel hide the defect.
Solution approach
A fringe light screen tilted over the panel reflects in the glossy surface and two area-scan cameras watch the reflected pattern. A dent or scratch bends the fringes locally; the distortion is converted into a curvature map and located in the panel's own surface coordinates. An entry photo-sensor detects the carrier and the panel length is scanned step by step at constant speed.
Process steps
- 01
Infeed
The entry photo-sensor detects the carrier and the panel enters the station at constant speed.
- 02
Fringe pattern
The screen fringes reflect in the glossy surface while the cameras watch the reflection.
- 03
Analysis
Local fringe distortion is converted into a curvature map and defects are marked.
- 04
Decide
The defects found are compared with the limits.
Related applications
Let us assess your application together
We test your sample in our laboratory and report on resolution, optics and lighting selection.