Optical Inspection System with Hardware from mk | NewsLIGHT #13 | mk-technology

A vision system inspects small lacquered parts in a cycle and learns to detect and rate optical defects. Essential are precise, but flexible adjustment options of the cameras.

The Fraunhofer IWU in Chemnitz has developed a system to detect optical defects on small parts for the automotive industry. The software independently learns to detect and rate optical defects. For a perfect interplay of software and hardware, Fraunhofer IWU relies on the profile and conveyor technology of Maschinenbau Kitz.

The software

One example of what the software can do is combine the data from different or redundant sensor systems and give the opportunity to increase their range of identifiable defects and the rating reliability associated with that. With the aid of structure-detection techniques, the software can find complex interrelationships in data pools and identify patterns.

The system

19 cameras, with 35 fps in full HD resolution, check up to 250 small parts for visually identifiable faults during the cycle. The workpiece carrier conveys the small parts below the cameras at 18 m/min. The cameras take 360 images in 3 to 4 seconds, which are then evaluated within a cycle time of 30 seconds.

The hardware

The system still needs the conveyor technology and all the casings, camera and lighting holders, computer housing and a workstation. Fraunhofer IWU had positive experiences in earlier projects working with the profile and conveyor technology specialist Maschinenbau Kitz. To ensure the parts could be thoroughly inspected, the cameras had to be precise to within 1/10 mm and adjustable on three axes. Also the used materials had to be free from substances that interfere with the lacquering process and the design also had to be antistatic. A ZRF-P 2010 timing belt conveyor, conveying the workpiece carrier through the entire plant, was also included in the scope of the project. Moreover the whole camera area had to be provided with a non-transparent casing and the plant had to be easy and quick to open for maintenance purposes. Thanks to the extensive modular mk construction kit of profile and conveyor technology, no great difficulties in integrating the hardware are expected.

Machine housing protects against extraneous light in the system and acts as a glare shield

The workpiece carrier containing the parts to be in-spected is transported through the inspection system by a ZRF-P 2010 timing belt conveyor.