Air motors perform well in start-stop rewind application

Coppice Alupack, a manufacturer of aluminium foil trays, is using Huco Dynatork air motors to systematically replace all of its electric drives on rewind systems that handle the surplus foil after the aluminium coil has been stamped. Inclusion of these piston motors has not only simplified the design but also made it more controllable and safer.

Webbing (or 'lacing') is left after the foil is stamped and blown to form aluminium containers. Much of this is gravity fed out of the press. On certain tools, however, it needs to be rewound and its tension maintained so that containers can be ejected cleanly and new foil fed-in efficiently.

The original system for rewinding this material had its problems. Its electric drive with limit switches and inverter for speed control made for a complicated design, and the high torque presented a degree of risk to the operators when removing the coiled lacing. A redesign was clearly needed and the Huco Dynatork air motor offered many advantages.

Motor characteristics

Engineering Manager, James Lamin explains: "Stall characteristics were the main features we were looking for, as well as compact design and ease of installation. As we obviously work to food standards, the replacement motor needed to be robust and clean."

Trial units were readily available from Huco Dynatork to test the concept before order placement, and technical support helped the engineers to optimise the design.

Initially Huco Dynatork piston air motors were requisitioned to replace the electric drives on the standard rewind system. Several bespoke rewind units have also been subsequently made. These are self-contained and transportable from press to press in accordance with with the tools being employed.

Lamin states: "The piston air motor has allowed us to adjust most of the tension out of the system to eliminate lacing breakage. It has also made the process inherently safer by reducing torque and negating the need for any electrical cables."

A further benefit is that maintenance of the motors can now be carried out by a shop-floor technician instead of a skilled electrician, saving cost and minimising downtime.

The Huco Dynatork motors run from 0–220rpm for 24 hours a day in a cycle that goes from stall to start in the order of sixty times per minute.

Lamin concludes: "They have worked very well. Three units are now running on the shop floor and we have plans for more as the year progresses."