Positioning systems help trunking assembly

With demand for electrical trunking booming, Legrand has used a Toshiba robot and a parts indexing system based on Hoerbiger-Origa pneumatics to automate its production line

As offices and other buildings increase their cabling capacity to cope with the increasing need for telecoms, computers and electronic equipment, Legrand has developed several ranges of trunking systems to meet the different needs of commercial, industrial and domestic users.

Production of these was originally largely manual, but recently the need to automate has become imperative, so specialists Automation and Machine Tools were called in to advise.

Managing Director Bob Busby explains his approach: "We couldn't stop production, so had to approach one section at a time, minimising disruption and making sure the line could still reach its daily targets".

One task to be automated involved inserting turnbuckles into 3m lengths of trunking lids.

Previously this was very labour intensive and was a potential bottleneck that could bring the whole production line to a standstill.

"We studied this carefully and realised that absolutely constant throughput was the vital requirement.

There were also requirements for a compact solution and one that had the flexibility to cope with the different ranges and future developments.

This pointed us towards a robot: it could run all day without a break, and easily be re-programmed for different tasks".

Busby opted for a SCARA robot from Toshiba that could insert the turnbuckles in pairs.

Before insertion, it runs the buckles over a sensor to check for the presence of a critical spring; if a spring is missing the robot rejects the buckle and collects a replacement.

After insertion the robot presses home each buckle, ensuring it is properly secured.

"The critical point of the design was being able to consistently supply buckles to the robot and synchronise the passage of the trunking lid through the workstation with this," recalls Busby.

The developed indexing system, based on Origa rodless pneumatic cylinders that moves each lid sideways into the workstation, indexes it lengthways as three pairs of buckles are inserted, then exits it sideways at the far end of the work station.

"The Origas are brilliantly compact, so were a natural choice for this job.

Because of the length of the lids we also needed a guidance system to ensure that they moved smoothly through the system.

We were delighted to discover that the Proline guides integrate with the Origa units without increasing their space envelope at all.

For the air valves, filters, regulators etc, it was natural to specify Hoerbiger-Origa".

The bespoke system has been installed in Legrand and has already proved its worth, with increased throughput, reduced reworking and the capacity to increase production beyond current levels.

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