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The company is ambitious and competitive. A move to a purpose built freehold facility with a 55 tonne lift capability in 2004 provided the opportunity to expand into 24 hour working, impossible at its previous site. The company’s two old oxy-fuel profile cutting machines could not meet the capacity and quality requirements of the new factory, leading Works Manager, Steve Robinson to look for a replacement. “This is a very competitive industry, and all our plate work goes through the cutting machines. If we get it wrong, the whole process will be compromised.” After evaluating the available machines on the market, Allerton Engineering chose an Air Liquide Welding OXYTOME HPC 35. The machine has a High Precision Plasma Cutting system capable of cutting steel 30mm thick in production, and five oxycutting torches capable of mid plate piercing up to 120mm and cutting up to 200mm. For strip cutting in one pass, which features heavily in Allerton’s beam production, the machine also includes 15 gas heads with automatic ignition. Steve Robinson said, “Reliability of the gas jets is crucial when we are ripping plate into strips. The individual automatic gas controls on each torch ensure that oxygen and fuel gas pressures are optimised for every blowtorch.”

Quality and accuracy have also improved with the introduction of the 27.5m long OXYTOME HPC 35. Steve Robinson explained, “With our old processes, grinding to clean up the plate edges was a major activity. This has now been eliminated, not only are we saving an operation, but our use of grinding consumables has greatly decreased.” Edge quality and accuracy on the machine are ensured by the dual rack and pinion drive, which can achieve a positional accuracy of ± 0.4mm, and the HPC digital process oxycutting control. Steve Robinson continued, “Our customers appreciate the quality and squareness of the cut edge, which is nearly as good as a machined surface. This is especially important for any architectural beams visible in the finished structure. The HPC control also makes the machine much easier to operate as it automatically sets the parameters for optimum cutting performance irrespective of the material, removing our reliance on skilled operators.” Thanks to the ease of use of the HPC control, Allerton Engineering has trained six operators to use OXYTOME HPC 35 since its installation, giving the company the flexibility to run two shifts and provide plenty of cover for absence and holidays. The subsequent assembly of the welded structure also benefits from the increased accuracy. “Because the parts have square edges and are the correct shape we do not have to dress them to make them fit together. This makes assembly simpler and ensures that the finished structure meets the design criteria.” For one customer, Allerton cut components simultaneously on all five torches from 70mm thick plate with a cross section of around 10mm. Steve Robinson was impressed with the performance, “Our customer was delighted with the quality which was both square and precise, straight off the machine.”

With just one OXYTOME HPC 35 machine Allerton Engineering has more capacity than it had with both the old machines. Plasma has provided a large increase in speed, reaching 2 m/minute on 20mm steel and, piercing times have been cut by half. Further savings come from the automatic plasma marking of components, this ensures that they are reliably identified and scribed to provide an indelible location for mating parts. Steve Robinson said, “The OXYTOME cuts four times faster than our old machines. Plasma marking cuts out an additional operation and eliminates possible errors in identification, saving around 50 man hours per week.”

After sales service was a major factor in the decision to purchase the OXYTOME HPC 35. Steve Robinson continued, “Everything goes through the machine, so a breakdown will stop the whole factory. Response from Air Liquide Welding’s Daventry office has been excellent. When we had accidental damage to the machine it was repaired the next day, with spare parts from stock in the UK or directly flown from France.” In the first five months following the machine’s installation the company won ten new jobs which it would previously have been unable to manufacture. He concluded, “The machine has proved to be very cost effective and is of incalculable importance to us, it is the hub of our operation. Currently, we are processing around 200 tonnes of steel per week, achieving scrap rates as low as 10% and delivery times measured in hours, all in a much cleaner environment. This machine is the first step in our aim to become one of the top ten subcontract fabricators.”