29 September 2015

Automated fibre laser cell triples cutting speed and slashes idle times

Welsh firm Groundhog (UK) manufactures Health and Safety Executive-compliant welfare units in which staff working on construction projects, railways and other sites can wash, change their clothes and eat. The company was one of the first to introduce mobile facilities so that contractors can avoid the costs of transporting and installing static welfare units.

The idea proved highly successful and today, 30 years since Groundhog was formed, business is booming. The size of the factory in Neath was increased from 20,000 to 50,000 sq ft in 2007 and an adjacent machine shop double that size is currently being built.

Production of mobile welfare units has doubled over the past few years to 20 per week, while static units have risen from 2 to 5 per week. Highly productive machine tools are needed to support such rapid increases in throughput, together with the use of automation where appropriate.

The latest example of investment in new production plant was the installation in June 2015 of a 3 kW BySprint 3015 fibre laser cutting machine equipped with a ByTrans 3015 Extended 12-shelf system for automated handling and storage of sheet metal. It joined an automated turret punch press installed in 2010 and took over from a Bystronic CO2 laser cutting machine with manual sheet loading and unloading that had been in use since 2006.

Matthew Stevenson, Design Manager at Groundhog said, “The combination of the manually loaded CO2 laser cutter and our automated punch press, even with the latter running lights-out, could not cope with the doubling of production volumes. The benefit of around-the-clock operation was apparent, however.

“There is not enough space in our current factory for two laser machines, so we decided to replace the CO2 model with the Bystronic fibre laser. Its chiller and other peripherals are compact and the machine is equipped with the manufacturer’s ByTrans automation system, which actually takes up less space than the previous laser machine’s manual loading area.

“Not only does the cell operate 24 hours a day, unmanned after our 8.00 am to 4.30 pm day shift, but it also laser-cuts 1.5 mm thick mild steel sheet three times faster and with greater consistency than our old CO2 laser, which was of the same power.

“We are now cutting at 18 rather than 6 metres per minute, profiling the sides, roof, doors and other parts of our products. Combining high processing speed with low idle times for sheet exchange has dramatically raised the throughput of our welfare unit components.”

A feature of Bystronic’s control software, Bysoft 7, is its ability to tag components automatically during overnight running of the fibre laser so that they remain joined to the skeleton by thin strips of material. During the day shift, when an operator is in attendance to keep an eye on production, tagging is unnecessary as slippage of a component through an aperture to the underside of the sheet can be detected visually.

During unmanned production, however, the addition of small tags ensures that unscheduled stoppages and lost production are avoided. It is an easy job to remove the tags when shaking parts from the machined sheets in the morning.

David Larcombe, Managing Director of Bystronic UK pointed out, “Customers see a real benefit in being able to add or remove tags on the machine at the press of a single button. Typically it can be quickly done when an operator leaves the machine for unattended running.

“The operator only has to set the minimum size of component to which tags should be applied to stop them tipping and it is carried out by the control, while larger parts are left untagged for easy removal.”

Mr Stevenson cited other advantages of fibre laser cutting over CO2 technology. Significantly lower power consumption saves running costs, no expensive consumable gases are needed and maintenance is simpler, providing further economies.

Quality of cut is also better. Dimensional accuracy is within ± 0.05 mm, ensuring trouble-free bending and assembly of products. Additionally, no burrs are left on the material surface, eliminating the need to fettle components by hand, which can spoil the appearance of components.

While there is a three-fold speed advantage when cutting thinner materials, which is important as 1.5 mm gauge accounts for 60 per cent of the 100 tons of steel processed per month, thicker metals can be cut efficiently as well. For example, steel up to 15 mm thick has been through the BySprint Fiber, as have 8 mm 310 stainless steel and 10 mm aluminium.

Mr Stevenson explained that this thickness of aluminium is five times greater than a CO2 laser is able cut and the quality of the fibre-lasered edge is markedly superior. Previously, thicker reflective materials were guillotined on site if straight edges were needed or sent out to a water jet cutting specialist for profiling, at extra expense.

Groundhog also takes advantage of the accuracy of Bystronic press brakes to bend the laser-cut sheets. Two early models of three metres and four metres capacity date back to the period before Bystronic bought Edwards Pearson. Latest machines are a 2.5 metre capacity Xpert press brake and an order has been placed for an Xpert 40, the supplier’s latest model launched at Blech 2014.

Image: Matthew Stevenson (left), Design Manager at Groundhog (UK) and David Larcombe, Managing Director of Bystronic UK in front of the automated BySprint 3015 fibre laser cutting cell at Neath.

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