In almost every area of our daily life, they ensure the right movement of mechanical parts: springs. We encounter them, for instance, as an extension spring in a drawer or as a compression spring in the switch used for stairwell lighting. In a car alone there are some 8,000 springs. Quality and accuracy are therefore considered an integral element of the production process.
WAFIOS AG in Reutlingen is a world leader in machinery for wire and tube processing, which also includes spring coiling machines. In collaboration with the Steinbeis Transfer Center Quality Assurance and Image Processing in Ilmenau, engineers from both companies developed an innovative, userfriendly image processing system for full quality control in spring production. The system tests each of up to 600 springs per minute for dimensional features such as length and diameter. For this purpose, an image of the spring is taken directly prior to cutting. While the spring falls, the special analysis software has approx. 50 ms time to measure these features in the image and compare them with the control and tolerance limits.
If, for example, the spring is longer, the software intervenes in the process and corrects the spring length automatically so that the next spring is of the right length again. On reaching the tolerance limit, this spring is rejected via a special ejector unit.
This highly specialized system is also easy to use for the machine operator. He can create a new quality control test automatically each time a spring has new dimensional features using an analysis button and requires no special background knowledge of the image processing system.
Integrating the hard- and software completely into the existing environment represented a considerable challenge. However, this was achieved with a short time frame by the staff of both companies.
Prof. Dr.-Ing. habil. Gerhard Linß
Steinbeis Transfer Center Quality Assurance and Image Processing (Ilmenau)