Based in Ashton-under-Lyne, Whitecroft Lighting is a UK-focused company whose products illuminate a wide spectrum of applications from healthcare to education, work to recreation. The company attributes much of its success to continued investment in manufacturing technology, which has given it the capacity to respond to any customer requirement.
In the continuous flow manufacture of its lighting products, Whitecroft Lighting employs many automated systems, one of which is a robot for automatic direct wiring of standard components. Installed twelve years ago, this installation received a new wiring head and software in 2006, and last year it was fitted with a new rotary table, supplied by HepcoMotion, the benefit of which has been a significant boost in connection accuracy to 99%. In addition to this, the upgrade has also saved operating costs, as only one operator is now required to run the process.
The robot itself is a six-axis arm housing a wiring tool that strips the insulation off the wire for connection either into 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 on 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 degrees 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 15kg each. The ring is a one-piece gear whose’V’ profile accommodates concentric and eccentric bearings and is driven by a servomotor with encoder. The table turns at a speed of about 0.5m/sec and is able to move from zero to 180 degrees and back with a positioning accuracy of ±0.25mm. The connection accuracy achieved by the new table is a pronounced improvement on the 70 – 80% available from its predecessor, as Pete McNally, Whitecroft Lighting’s production engineer responsible for factory automation, explains.
“As well as less to no missed connections, we now have virtually zero production downtime, no waste and no tool damage. It means the operator is no longer wasting a production cycle rectifying connection misses, shutting the machine down and resorting to hand wiring. In the event of a fault we would previously lose five looms every ten 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 to use the machine’s software to its full potential as programs 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 rotary table proved to be by far the most cost-effective upgrade option. Supplied as a complete system with MCS frame, its cost was actually 50% less than a system builder’s quote 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, which, in turn has led to the creation of new production lines at the Ashton-under-Lyne factory.