Performance improvement for sliding contacts utilizing tip polishing

The potentiometer uses a sliding contact over a resistive track to transfer a mechanical position to an electrical resistance or voltage potential. The sliding stamped contact is subject to a die break condition on the contacting surface. Important to the performance of the device is contact resistance variation, which can be directly affected by the die break condition. A new process called tip polishing has been developed to selectively polish the contact tip. Samples of tip polished and unfinished parts were subjected to a 10 million-cycle dither test and the results compared. It was concluded that tip polishing has a major effect on controlling the contact resistance variation.