Synchronizer ring inspection system (SRI)

Synchronizer rings are the core elements of syncromeshs and level gear and shift collar on equal rotation speed avoiding a gear shifting without double clutching at a far smoother shifting. Manufacturers of forged synchronizer rings for the automotive industry usually face the challenge to guarantee high quality at ever greater quantities.

Over the course of several years PENTACON developed and manufactured various modular testing systems for 100% optical control of synchronizer rings for the automotive industry. Here we cover optical and acoustic test methods. Apart from that PENTACON currently develops a new and patented solution to test cracks magnetically for e.g.  micro crazes that can not be detected optically or acoustically.




The surface of the synchronizer ring is being tested on cracks, blowholes, damaged edges and completeness. To do so, the synchronizer ring is rotated around its own axis by a handling and captured by four staggered industrial cameras with high precision lenses made by Jos. Schneider he captured image is then unwound into a two-dimensional shell surface to be tested and evaluated by a software algorithm. Depending on the customer requirements the position and the size of the defect can be adapted individually.

Aside from deviations of form and position the positioning of the cameras also allows a testing of the surface unevenness of the synchronizer ring.

The cycle time for all four cameras is 2.5 seconds. The software algorithm used is based on the MATROX Library.

Similar to the optical surface testing of the outer contour the inner contour of a synchronizer ring may be tested automatically as well. Using a turning station in the course of the testing sequence the synchronizer ring is flipped and tested optically. An image of ring is captured by an industrial matrix camera equipped with a lens made by Jos. Schneider and illuminated by transmitted light. In particular protrusions, cavities or other damages from the forging process can be detected quickly and cost efficient. The evaluation is done by a software double checking the captured images with a template.

The cycles time (without the handling) is 1 second.

The advantages of the acoustic crack detection come into effect when the geometry of the workpiece is complicated. Conventional testing methods (eddy current testing) are usually useless for complex geometries since the testing results are very often too inaccurate. The acoustic audio testing is able to detect hairline cracks or demolished rings way better than an optical surface testing.

At the audio testing the synchronizer ring is placed on an acoustically decoupled tray and put into vibration by a hammer. The resultion tone can be matched with a reference tone and evaluated. The geometry of the part is irrelevant.

The cycle time is 2 seconds per part.

Robot Handling

For the feeding and discharging we use robots from STÄUBLI, Universal Robots, KAWASAKI or Mitsubishi. The system can be designed that the robot either picks a pre-sorted and oriented workpiece ("pick and place") and feeds it to the modular testing sequence. Or at 2D picking the workpiece is taken from an Anyfeeder and oriented by the robot.

Additionally we use spiral conveyors, step feeder, revolving tables or linear feeder.