Laser based feature detection system including internal thread detection

Looks at how Ariel adapted its laser-based orientation and inspection system to perform the task of automating the inspection of turned parts to check for the presence of threads. Typically, components are presented to the laser inspection system on a moving conveyor belt. As the component passes the laser inspection station, if threads are present, laser light is scattered back from the threads and into a laser detector. If no thread is present, the laser light continues on its path, and will reflect off the component at its normal incident angle. The system would normally be set up to take, say, 1,000 readings from the laser detector, as the component cuts a "part present" photoswitch. A set point is established in the laser system on a scale of 0-100 per cent of laser reflection. If the set point is set at 50 per cent, any laser reflections received by the detector above this 50 per cent reflection set point will be counted as high readings, and anything below the set point will be counted as low readings. A threaded component would normally give 200-300 high readings out of 1,000 laser readings taken, and an unthreaded component would give high readings of zero, or one. This gives a wide differentiating band between good and bad, and the system would be set up to accept components giving anything above 200 high counts