To test for a variety of surface defects such as small porosity, cracks, lapping and scratches on rod surfaces of shock and strut components. These surface discontinuities can cause issues with the seals that ride on the surface, potentially leading to leaks of oil or gases within the cylinder of the completed component. This not only increases warranty costs for the customer but also compromises the safety-critical functions of automotive suspension and rear hatch/trunk opening mechanisms.
The FOERSTER Solution
FOERSTER implemented a fully automated in-line solution for the rigorous testing of the steel bar segments used in automotive shock and strut absorber components. This system accommodates lengths ranging from 60 to 600mm and achieves defect detection at speeds up to 200 mm per second, identifying imperfections as small as 20 microns or less. Utilizing the STATOGRAPH DS with Ro20p-35p, the solution is capable of testing diameters from 6 to 25mm. Additionally, the system includes a small demagnetizer to eliminate residual magnetic fields prior to rotary testing and can evaluate sections with as little as 2 mm of untested ends, depending on line speed.
Specalties worth mentioning
The FOERSTER system offers advanced clearance compensation to ensure highly accurate repeatability, effectively countering any nozzle wear. It features an "automatic mastering" function, allowing the reference defect part to be run automatically to verify the test equipment setup. The system is also compatible with easy demagnetization and MAGNATEST additions if required. It supports multiple sorting options, categorizing parts into up to three groups: "OK," "NOK," and "Suspect/Rework." The specially designed hardened rotary nozzles (~65HRC) ensure precise centering into the test head and can be manufactured to any diameter within the rotary range. The solution provides both in-line and off-line sorting capabilities. In-line sorting directs defective parts into a reject bin while allowing compliant parts to proceed to the next stage of the customer’s process. Off-line sorting utilizes a separate table where "OK" and "NOK" parts are segregated accordingly.
Results
FOERSTER's systems operate at a line speed of 200 mm per second, with parts moving seamlessly through the sensor system in a continuous, uninterrupted flow. Even with very minimal untested ends, the system consistently identifies defects as small as 20 microns on high-quality material finishes at maximum line speed. The integrated STATOGRAPH CM/TCL (single channel) and STATOGRAPH DS (up to four channels) ensure precise and sensitive detection, utilizing test heads equipped with 0.8 mm elements for optimal performance.
