Wane measurement on board edges
As the board travels on the rollers, a top and a diagonally mounted laser profile sensor measure the cross-section of the edge. The measured profile is compared with the nominal rectangle; the barky, missing part of the edge is computed as wane and the usable-section map goes to the cut control.
The section map and wane ratio are sent to the cut control; a board over the limit is diverted by the flap to the edging lane and the usable width is written to the board record.
- 01 Infeed
- 02 Scan
- 03 Section
- 04 Decide
The board advances on the roller conveyor with its edge facing the sensors.
- Wane
- —
- Usable width
- —
Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
Wane starts on the underside and the side face of the board; a single sensor looking from above cannot see the loss under the edge. Bark is dark and matte with varying contrast to the wood, and the measurement must be made in the section reference even if the board arrives skewed or shifted.
Solution approach
The top sensor scans the upper face and the upper corner of the edge, the diagonal sensor the side face and the lower corner; both profiles are merged in a common coordinate frame. The nominal rectangle is fitted to the merged section, and the area outside it and the loss ratio along the edge are computed. Encoder steps build the section map along the board.
Process steps
- 01
Infeed
The board advances on the roller conveyor with its edge facing the sensors.
- 02
Scan
The top and diagonal laser lines measure the edge section at every encoder step.
- 03
Section
The two profiles are merged; the nominal rectangle is fitted and the area outside it is computed.
- 04
Decide
The wane ratio is compared with the limit; a board over it is diverted to the edging lane.
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