Perfect Bore uses EdgeCAM’s adaptive feed rate capability to maximise potential

A piston is a piston is a piston

I expect you thought as I did: a piston is a piston is a piston. Well, it isn’t. There is much more to it than meets the eye, especially if you are at the leading edge of motorsport. To design lightweight pistons that can withstand and transmit the immense forces generated within competition internal combustion engines is one thing. To manufacture them in the short timescales demanded by customers is another. To do so, profitably, that really is something very special. That is why Perfect Bore is now using EdgeCAM from Pathtrace Engineering Systems to maximise the potential of its considerable investment in high-speed machine tools.

Perfect Bore Limited

Based in Andover, Hampshire, Perfect Bore Limited is one of seven independently managed companies in the Performance Motorsports Inc. division of the Dover Corporation, a multi-billion dollar, NYSE-traded, diversified manufacturer of products and components for industrial and commercial use. Perfect Bore has strong connections to the whole of the motorsport community and has specialist capabilities in the manufacture and coating of thin walled cylinder liners and high performance pistons. Alan Baynes is Manufacturing Manager in the pistons division at Perfect Bore. He says, “We manufacture in single units up to batches of several hundred, for a wide range of top level series throughout Europe, Japan and the USA.”

Forged or solid? - that is the question

Perfect Bore manufacture both forged pistons and pistons machined from solid billets. What are the advantages of the different processes? Alan says, “There is a volume break point at which it becomes more economical to forge pistons than to machine them from solid. However, it can take three to four months to deliver forged pistons, taking into account the design and manufacture of the forge tool. You have to be absolutely certain of your design if you take that route.” He continues, “However, solid machined pistons can be made much more quickly when the volumes are modest. We can draw up a piston in Pro/ENGINEER®, analyse it in Pro/MECHANICA®, have it approved by the customer and get it into manufacturing within two to three weeks of order. Then we can quickly and easily embody any changes required by the customer after the piston has been raced.” He adds, “Once a customer has run them in his car or race series and is satisfied with the design, he can switch over to forged pistons if the volume warrants it.”

EdgeCAM: the system that works so well

Perfect Bore has been using EdgeCAM for a number of years for the finish machining of the forged pistons that account for around 70% of piston output. However, the ability to produce low volumes at short notice is an important part of Perfect Bore’s strategy for growth. Alan Baynes takes up the story, “To do this, we knew we needed a much more sophisticated level of software so we enhanced our EdgeCAM software to the level of functionality we needed.” He continues, “We were aware that there were competitors but to be honest, the service that Pathtrace provided has always been very good and we opted to stay with them.” Alan adds, “I’ve had people in here trying to sell other systems but I am not changing from the system that is so easy to use and that works so well for us.”

Progressive productivity improvement

Paul Daley is Perfect Bore’s CNC programmer and has been with the company almost three years. He says, “EdgeCAM can machine directly from the Pro/ENGINEER model, although we actually modify the model to suit the sequence of machining processes. Because the programme for a typical piston undercrown is very complex, especially in the gudgeon pin boss area, it can take up to two days to create a programme. Consequently, because we make a large number of different pistons, programming time is one of the most critical items for us. We have to reduce the time it takes to write programmes and we have to write programmes that reduce machining time.” Paul continues, “However, that is where EdgeCAM is so powerful. Each successive upgrade is progressively improving our productivity. Even so, I’m fully occupied writing programmes and all our CNC machines have had memory upgrades to handle the sheer complexity of our work.”

Saving the cost of downtime

It does not stop there. As Paul says, “Machining high performance pistons from solid is very challenging, and it can take over an hour to machine the more complex ones.” That is where EdgeCAM’s adaptive feed rate capability comes in. Paul says, “This does exactly what is says. It adapts the cutter feed rate to suit the circumstances within the parameters you set. It reads the surface geometry to determine the optimum feed rate, slowing down in tight areas, speeding up in more open areas. This means that we get a more even cut with reduced risk of cutter damage.” He continues, “This would normally involve a lot of extra programming time but with EdgeCAM you don’t have to bother. It’s just a click of the button to set it up, turn it on, and enter the parameters.” Paul adds, “That’s it basically. You use it as part of your machining strategy. You’d usually do your roughing without it, and then choose the zones where you want it to operate.” He continues, “The real benefit is that it saves on cutters. More importantly, it saves the cost of the resultant downtime. If the cutter breaks we’d normally have to scrap the piston and start again, losing machining time and putting delivery times under pressure.”

A third more productive

To machine the pistons, the company uses 20,000 rpm Matsuura V-Plus 800 high-speed machining centres each with Nikken 4 and 5 axis units and each with a capacity of 30 tools. Paul says, “Because we run at such high speeds, the operators can't read the programs. They have to rely on them to be correct. However, with EdgeCAM, things just don’t go wrong, full stop.” He adds, “Thanks to EdgeCAM, typical machining times have come down from 45 minutes to 30 minutes, a productivity improvement of 33%, with the machines running five days and four nights a week. In fact, we are currently running a Friday night shift because we are so busy.”

With us all the way

Alan says, “Since 1999 we have made a significant investment in CNC lathes and machining centres, with EdgeCAM as an enabler.” He adds, “We are now looking to bring all our manufacturing processes within the four walls of the machine shop and we are continuing to invest in processes and equipment in order to reduce turn-round times for our customers. We fully expect that EdgeCAM will be with us all the way.”