BESPOKE ULTRASONIC WELDING FROM CONTAX HELPS INCREASE OEE FOR SAFT

Contax Ltd - UK

29 March 2005

SAFT Ltd, the world leader in the design and manufacture of high-tech batteries has purchased a new bespoke ultrasonic welding system from UK leading independent automation equipment supplier, Contax Ltd. This forms part of a production upgrade that will serve to expand their manufacturing capacity and increase Overall Equipment Effectiveness (OEE).

SAFT manufactures lithium cells for high powered batteries used in industrial and defence applications. It cannot use solder in its production, so relies on ultrasonic welding to connect the aluminium cathode contact tag to the end mesh of the cathode.

SAFT has used Amtech ultrasonic welding equipment since the early 1990s, and had started working with Contax when the original system was moved from the US to the UK.

However, for the new welding system, SAFT required two specific enhancements. "The aluminium tag used is just 1/5000 inch thick, and so it is made of very weak material," explained Brian Gibson, Equipment Improvement Engineer, SAFT Ltd. "The feeder of the tag machine on our old system used to keep jamming and put the tag in the wrong position. We needed Contax to design and build a bespoke feeder.

"Secondly, with our old machine there was no way of accurately positioning the cathode mesh relative to the aluminium tag. We were happy to make this a manual process as the machine is partly automated and requires a full-time operator. So as well as looking at the feed on the tag, we wanted Contax to develop a system to ensure that the cathode mesh is in the correct position."

As a result, Contax developed two bespoke systems: a feeder for the aluminium tag, and a backstop mechanism for the cathode mesh. The operator can now feed the mesh against the backstop to ensure that the positioning is completely accurate.

This has the added advantage of decreasing production time and saving materials costs. Previously, the operator had to remove the leading edge of the mesh following production. This was a wasteful procedure and added significant time to production. As the backstop mechanism ensures that the mesh is correctly aligned each time, there is no need to remove any extraneous pieces.

Not only has the new system improved production efficiency but its results can be measured. Continued Brian Gibson, "We evaluate production by OEE and are working towards world class manufacturing standards. As part of this, we review the results regularly and the improvements are well on track. Our production has improved significantly, and there is no doubt that the new Amtech equipment and enhancements from Contax have contributed to this increase."

He continued, "Contax has done an excellent job - as always. They really understood our production problems and came up with workable and effective solutions. They then worked with us to make sure that the system is functioning perfectly. We are very happy with the Amtech equipment, they are extremely good welders, and Contax added the all-important consultancy and bespoke elements. We would definitely use them again in future."