Pressing Subcontractor Brings Toolmaking In-House

PAB Coventry (www.pabgroup.co.uk), which produces sheet metal components, pressings and fabrications in quantities from prototypes up to 10,000 per year, has since early 2016 invested £1.5 million in new machine tools. They include a Hurco vertical machining centre (www.hurco.co.uk), another hydraulic press, and a 4 kW flat-bed fibre laser cutting machine, a 4 kW 5-axis laser cutting machine and a 2-metre press brake, all from Prima Power. The company also bought a second and third industrial unit in Falkland Close, Canley, increasing floor area by two-thirds.

Underpinning this expansion is strong growth in sales to the automotive sector, which accounts for 90 per cent of turnover. TS16949-accredited PAB specialises in fabricating sub-frame pressings, bracketry and grilles as well as assemblies such as windscreen surrounds for Aston Martin, Lotus and other top-end car manufacturers as well as Triumph Motorcycles.

The company, which operates 24/7 with close to 100 employees, is moving strongly into the rail industry and has recently used its AS9100 quality accreditation, gained through earlier military work, to win contracts in the aerospace sector.

Overall, turnover has doubled in the last three years. It is partly due to an association with Imperial College London spin-off firm, Impression Technologies, whereby PAB was the first company licensed to manufacture using the patented HFQ (heat treatment forming and in-die quench) technology. It is a method for deep-drawing thinner and hence lighter weight aluminium components for the automotive industry. Aston Martin is supporting the project by designing components, particularly A-pillars, for manufacture using the process.

In 2015 alone, PAB spent over £1 million buying in press tools to produce its vast range of components from aluminium, mild steel and stainless steel, mainly up to 3 mm thick. Around 700 line items are handled per month in typical batch sizes of 300 to 350. The expenditure on tooling was becoming so high that Mark Brazier, second-generation director at the family-owned pressings subcontractor, decided to bring some of the manufacture in-house.

He said, “We already had a smaller Hurco machining centre and one of their CNC lathes which we bought about six years ago to help fulfil a defence contract involving manufacturing blast seats for military vehicles.

“Various metalcutting subcontractors were letting us down, so my father asked one of his friends in manufacturing which machine tools he would recommend.

“He was unequivocal in his advice to purchase Hurco machines, so they were installed and have indeed proved reliable over the years. We had no hesitation in returning to the same supplier for a bigger machining centre to address our toolmaking needs.”

The 3-axis Hurco VMX60Ti, with its 40-taper, 10,000 rpm spindle and 1,524 x 660 x 610 mm work envelope, weighs nearly nine tonnes. It machines PAB’s press tools comfortably to accuracies within ± 0.015 mm. During 2016, it produced 20 per cent of the subcontractor’s tools, helping to manufacture more than one million components shipped that year. In the first half of 2017, the proportion of tools made in the Coventry facility rose to around 35 per cent and Mr Brazier predicts that it will eventually increase to more than half.

Additional duties of the latest machine are the manufacture of inspection fixtures and composite tryout tools, milling and drilling of large parts such as door sills, and production of smaller components such as bosses and machine pins if the other machining centre is occupied.

As far as programming is concerned, the complex surface profiles of most press tools require off-line preparation and downloading of machining cycles, in PAB’s case using a seat of OneCNC software. However, for simpler jobs like milling of inspection fixtures and tooling plates, maximum advantage is taken of Hurco’s WinMAX conversational programming software resident in the proprietary twin-screen control. The second screen allows a graphic of the component to be viewed and checked as it is programmed on the shop floor.

The latest project, PHFHE, will for the first time involve the company in plastic component manufacture. In association with the University of Nottingham, it is helping to develop, optimise and manufacture lightweight polymer micro-hollow fibre heat exchangers that are half the weight of traditional metal heat exchangers, and 50 per cent less expensive. PAB will also develop the heat exchangers for electric vehicles.