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New control system boosts cable production by 29%

Manchester-based British Cables Company has improved productivity on two insulated cable-making lines by 29% after replacing the control system. Waste and energy costs have also been reduced.

The new system controls the wire tension and maintains the correct drawing diameter as the wire is pulled through an extruder, while running at an increased speed of 1,800m/minute. There has been an increase of 29% in the number of reels produced during an eight-hour shift.

The company had been unable to source spare parts for the original control system. This resulted in frequent breakdowns, costing over £60,000 annually in lost production. Restarting the system added a further £38,000 annually in engineering costs.

The original system was slow to respond, and setting up the machine to produce a new colour of cable often resulted in several false starts, resulting in wire snapping and up to 10,000m of cable being scrapped.

It has been replaced by a new ABB Compact HMI SCADA system, supplied, installed and commissioned by ABB’s engineering centre in Coalville, controlling two ABB AC500 programmable logic controllers on each line. The PLCs are linked by ProfiNET to five ABB variable speed drives, rated between 4kW and 60kW, each of which control the speed of ABB AC motors. A smaller ABB drive is used to control the positioning of the water trough that cools the extruded wire. Upgrading the motors and drives has reduced energy costs for the two lines by £16,000 a year.

The control system allows cable colour changes on the fly by reducing the machine speed to 200m/minute during the changeover. This has resulted in an 80% reduction in waste. Safety of the production line is improved because guards are electrically controlled and rotating equipment is electrically interlocked. This prevents the safety guards from being opened while the line is running.

“We have exceeded our goal of running the lines at 1,600m/minute,” said James Glenn, business improvement team leader for BCC. “The engineering detail we can get from the system shows exactly what state each machine is in – and the speed of everything on the lines. Installing the two systems has achieved over £60,000 in extra production due to the higher line speed.”