Pinpoint accuracy

A UK-developed production technology claims to drastically improve tooling time and cost, with applications in areas such as aerospace, motor sport and medical devices.

Employing a patented process called subtractive pin tooling (SPT), Surface Generation has developed a system in which a row of pins are raised and machined to create the face of the tool, as opposed to the entire solid mould insert.

The advantage of this, according to the company, is that the tool can be re-used, thereby saving time in manufacturing and ultimately offering a reduced time to market for new products.

SPT uses a hybrid subtractive and additive build strategy to create the front face of the tool, which is achieved by assembling a bed of disposable square pins, approximately 50mm square.

Following information provided by the CAD file, the pins can be moved into a near-net position and then machined. After use the bed can be reformatted for the next job, allowing companies to build customised products economically.

In addition, if a tool needs to be modified or the surface is damaged, the affected region can selectively be re-formed.

Surface Generation’s chief executive Ben Halford said that SPT is designed to deal with areas of manufacturing for which a 3D part printer will not be suitable.

For example, according to Halford automotive panels do not lend themselves to 3D printing and are not likely to do so in the future. He claimed SPT could eliminate the conventional tool set required for a new automotive interior — which may take months to produce and cost hundreds of thousands of pounds — and achieve the same results in a matter of weeks.

Halford claimed his company’s approach addresses the concerns and key material issues at the heart of both high and low-volume manufacturing. He said the results of using the technology have seen a material saving of 60 per cent, while the best tooling time has seen a reduction of 90 per cent.

But Halford admitted he will have to convince the numerous companies that are currently looking to 3D printing as the answer to their prayers. ‘Yes, companies are coping at the moment,’ he said. ‘We agree it is important to make the first tool quickly and cheaply but we also understand that a tool is only an asset while you use it. There are warehouses full of tools that companies are never going to use again after spending a lot of time and money on them.’

This is the intrinsic difference between conventional rapid tooling and the subtractive pin tooling technology. The pin heads can be replaced cheaply and easily and the time to manufacture them is fast, consequently the time for manufacturing the final product is significantly reduced.

Surface Generation has developed its new, re-configurable, Subtractive Pin Tooling process to reduce lead times and costs for large moulds by 90%. The technology uses a hybrid additive and subtractive manufacturing strategy to selectively create only the front face of the tool against which the moulding is formed.

The only two areas of manufacturing where the new technology is not applicable are injection moulding and stamping of heavy gauge steel. ‘Everything else we can handle in terms of pressure, temperature and impact,’ said Halford.

‘No-one wants tooling, just the end product,’ said Halford. ‘The panacea is 3D printing, which does not require tooling of any kind and that is why it will be so effective. But if we can get close to that, we will be effective too. While it is   important getting the first tool made, it is what you do with it afterwards that is most significant.’

The combination of reduced lead times and costs is a strong proposition, Halford claimed. He hopes the possibility of stealing a march on the competition will be a key factor in driving up interest in the technology.

‘Say you went to a mobile phone manufacturer and told them, “I can save you money or you can get to market three months before your competitor. Which one are you going to choose?”’ asked Halford. ‘You would take the second one every time.’  

Ultimately, the potential for applications is almost unlimited, according to Halford.

Surface Generation is currently in discussion with UK and US companies across a range of industries from aerospace to motorsport. The medical sector has shown a surprising amount of interest regarding possible advances in prosthetics said Halford.

Surface Generation was formed in 2002 and has since won first prize at Oxford University’s Venture Fest business plan competition and been awarded DTI and European grants to develop its technology.