SwePart Transmission AB (Liatorp, Sweden), which manufactures more than 100 different types of gear parts for heavy trucks, was looking for a way to improve its manufacturing process by reducing the need for manual parts measurement.

The company had a number of different turning centers, with one operator per machine loading and unloading parts. After a prescribed number of parts, the operator would manually measure the work dimensions of the part.

To improve upon this process, SwePart turned to CE Johansson's (Irvine, CA) Swedish subsidiary to install a system that would eliminate the need for manual measurement. The system installed relies on a Saphir CMM that works with a conveyor system linking four turning centers. The result is a system that now produces more accurate measurements, reducing scrap, and also reduces from four to two the number of operators required for four turning centers.

SwePart chose CE Johansson because the company has a lot of experience with building this type of system that integrates turning centers developed by different manufacturers. The system is capable of knowing where parts are loaded and unloaded, as well as having a measuring control that compensates for the next part.

Operators load a part on a plate on the conveyor belt, which is about 100 feet long. The part goes around the main loop of the conveyor system until it passes one of the four turning centers. Each turning center manufactures a different type of part, so several parts can be on the conveyor at one time. The part is taken from the plate in the handling system and placed into the turning center. After the part is machined, it is placed back on the plate. Operators can then unload the turned parts.

"Between every third and fifth part, it goes to the CMM to measure inside specifications," says Thomas Pettersson, application engineer for CE Johansson. "The CMM then sends the measurement value back to the turning center, so that the machine can compensate for the next part it is machining."

The system has allowed SwePart to produce parts more frequently with tighter tolerances. "The whole process have improved, and of course there are fewer scrap parts," says Per-Ake Ohlsson at SwePart.

Beside scrap rates being reduced, measurement time and machine downtime have also been reduced. An average workpiece has about four dimensions, and the measuring cycle using the previous manual system typically took two to three minutes, which included loading and unloading the part from the pallet. The new system has reduced that time to about 60 seconds, and even with the machine working 24 hours per day, downtime is almost nothing, Ohlsson says.

This system is extremely flexible and can be built to work with whatever type of machines that are on the shop floor. "I think this is a very good concept if you have a lot of parts and room on the shop floor," says Ohlsson. "This type of system can be used for other types of production as well."

--Kimberly Schmidt

CE Johansson
(877) 764-6397