Rotary table replaces inaccurate linear moving table

“As well as less to no missed connections, we now have virtually zero production downtime, no waste and no tool damage,” confirmed Pete McNally, Whitecroft Lighting’s production engineer responsible for factory automation.

Based in Ashton-under-Lyne, Whitecroft Lighting Ltd is a UK-focused company whose products illuminate a wide spectrum of applications from healthcare to education, work to recreation. It attributes much of its success to its continued investment in manufacturing technology that gives the company the capacity to respond to any customer requirement.

Its new HepcoMotion rotary table replaced an inaccurate linear moving table. In addition to boosting accuracy the upgrade has also saved operating costs as only one operator is now required to run the process.

The robot itself is a 6-axis arm housing a wiring tool that strips the insulation off the wire for connection into either a control gear or lamp holder. It then runs the appropriate length of wire along pre-programmed path positions to an end connection, where the tooling cuts off the wire and strips the end ready for final connection.

The operator’s role is to load onto the table the jigs that house the control ballasts and the correct number of lamp holders per control gear according to the product type. The bed then rotates by 180° to present the new jigs to the robot and to return the freshly wired looms to the operator for unloading.

The basis of the table is a HepcoMotion® Heavy Duty ring system that carries two aluminium plates weighing in the region of 15 kg each. The ring is a one piece gear whose vee profile accommodates concentric and eccentric bearings and is driven by a servo motor with encoder. The table turns at a speed of about 0.5m/sec and is able to move from zero to 180° and back with a positioning accuracy of ±0.25mm.

The connection accuracy achieved by the new table is a pronounced improvement to the 70 – 80% provided its predecessor. “It means the operator is no longer wasting a production cycle rectifying connection misses or even shutting the machine down and hand wiring,” Pete McNally continues. “In the event of a fault we would previously lose five looms every 10 minutes. And if the machine had to be shut down we would lose three looms for every one made manually.”

The greater accuracy also allows Whitecroft Lighting Ltd to use the machine’s software to its full potential as programmes can now be created without having to teach the machine manually.

Aesthetically the new set-up is more professional and in addition to boosting productivity, it is also saving on waste. Previously wire had to be scrapped when a missed connection caused it to be caught and damaged by the robot.

The HepcoMotion® rotary table proved to be by far the most cost effective upgrade option. Supplied as a complete system with MCS frame, its cost was 50% less than the quote by a system builder to repair the old bed. It also brought an important space-saving benefit too. Thanks to the compact nature of the new set-up the footprint of the robot area has been reduced. This in turn has led to the creation of new production lines to boost the Whitecroft Lighting Ltd productivity even more.