Elscint recently completed an order which required two collets to come out side by side in the opposite orientation. The Engine Valve Collets are used as a pair to hold the inlet and exhaust valves in the engine. These are used widely in all four-stroke internal combustion engines. Collets are very small parts (5 to 10 mm in length) with one side slightly tapered at just 5 degrees and half cut. Feeding and orienting them is always a challenge. However, Elscint has designed a bowl which not only orients and feeds the collets but also a very high speed of almost 80 to 100 collets per minute is achieved per bowl feeder. This is more than sufficient for the automatic assembly of the engine valves. In this case, two Model 250 vibratory bowl feeders were used, one clockwise and one anti-clockwise.
The orientation tooling for both the bowl feeders was the same. After the bowl feeders, the collets were passed through a gravity chute and a singulator / escapement was provided which held back the collets while a single one was released on receipt of a signal from the customer. Further, Elscint also provided feeding of the rest of the parts, namely, the spring valve and the retainer valve spring. The collets being very small, all the parts had to be machined with high accuracy and tooling too had to be very accurate.