Additive manufacturing finds increasing applications

While additive manufacturing continues to be used to produce mould tooling, research is pushing towards production volumes of metal parts, while quirky low volume consumer design applications continue to surface. Andrew Allcock explains.

The additive manufacture of metal mould tools has been a well trodden path over several years, and that will continue, although in this first example the mould tool is a ceramic-filled plastic used in place of a machined metal one.

Swindon based Toolcraft Plastics – a long established plastic product mould toolmaking, injection moulding and vacuum forming firm – was looking for a quick turnaround injection moulding tool.

It sought a cost-effective and fast way to produce a very small number of mouldings. The company wanted to mount the tool in its standard machines, which normally use a steel or aluminium tool, to handle short runs of plastic injection mouldings and produce good results in a wide range of materials: ABS, polypropylene, TPE (thermoplastic elastomer) and PA (polyamide).

3D printing and rapid prototyping specialist firm Graphite Additive Manufacturing was approached to help deliver the solution.

A mould tool for Toolcraft's supermarket trolley coin (right) was 3D printed by Graphite, using a ceramic-filled plastic. The two-part mould was built by streolithography (SLA) at Graphite's base in Aylesbury, Buckinghamshire, within one day. By comparison, complicated metal tooling can take weeks to produce, while the cost would be much greater.

Toolcraft mounted the new 3D printed tool in a standard tool bolster and ran it in one of its automatic injection moulding machines. The results for the short production runs in each of the chosen materials were excellent.
The ceramic-filled plastic tool does not have such a long life as a steel or aluminium one, but as a cost- and time-effective technique the process is ideal.

The 3D printed tool option is now offered by Toolcraft to customers having either very short run projects or those demanding an urgent turnaround.

Now, these plastic injection moulded parts could not themselves sensibly be created directly by additive manufacturing, of course. But looking to move direct metal additive manufacturing of components into the higher volume arena, and so avoid tooling production, is a new UK project, however.

High Wycombe-based CRDM, now owned by US-headquartered 3D Systems, is to lead a 30-month £1.25 million program to develop additive layer manufacturing (ALM) for production applications. The project consortium includes McLaren Automotive, Ultra Electronics, Delcam, Selex-ES and Flitetec, and is part funded through Innovate UK, previously called the Technology Strategy Board.

Known as Automotive and Aerospace Part Production by Additive Layer Manufacture, or AA-PALM, the effort has three distinct goals: the automatic application of CAD correction techniques to ensure that ALM parts are manufactured with tolerance levels similar to traditional processes; the application of automatic finishing techniques to ALM components to provide aesthetic and mechanical properties that mimic traditional manufacturing and at costs that leverage the benefits of ALM; and to help OEM users develop Production Part Acceptance Procedures (PPAP), so that ALM parts can be directly accepted onto production lines. PPAP was pioneered in the automotive industry to establish confidence in component suppliers and their production processes.

The project includes ALM components manufactured in metals, polyamides and stereolithography resins. A key element is to deliver acceptable ALM parts at costs that are attractive, when compared to those manufactured traditionally.

"The economics of ALM have historically required that we consider parts that would be manufactured in low volumes and normally require tooling," explains Graham Bennett, AA-PALM project leader. "However, even though this market is still quite considerable, recent developments suggest we may have an opportunity to expand our focus to higher volumes.

"Once we are able to use parts manufactured by ALM for production applications, we eliminate the requirement to produce costly tooling. Frequently, the large capital requirement of tooling costs acts as a barrier to new product introduction. We hope to address this problem, which, in turn, will make new product introduction a less costly affair."

The project started producing deliverables late in 2014 and, by the end of the programme, the consortium is hoping to see ALM components regularly used in a variety of production devices.

Another UK additive manufacturing project was announced earlier last year at the Farnborough International Airshow. CADCAM specialist Delcam is to be part of a consortium of UK companies, lead by GKN Aerospace, which is undertaking a 3½ year, £13.4 million research and development programme called Horizon (AM).

The Horizon (AM) team includes GKN Aerospace, Renishaw, Delcam, and the Universities of Sheffield and Warwick. The programme is backed by the UK's Aerospace Technology Institute (ATI) and funded jointly by industry and the UK Government's Innovate UK.

With its aerospace focus, Horizon (AM) will take a number of promising additive manufacturing techniques from research and development through to viable production processes, able to create components that could be as much as 50% lighter than their conventional counterparts, and which have complex geometries that cannot be manufactured cost effectively today.

These new processes are expected to unlock innovations in low-drag, high performance wing designs and in lighter, even more efficient, engine systems – and lead to dramatic reductions in aircraft fuel consumption and emissions.

Quirky examples abound
Aerospace is already fruitful ground for the application of additive manufacturing, of course, but there is also no shortage of 'quirky' applications for metal additive manufacturing, a process that clearly bridges the industrial and consumer worlds, offering designers a tool to produce their creations at, literally, the touch of a button.

For example, Renishaw's technology has been put to use by those involved with the at the Triennial arts festival in Folkstone in 2013. Collaborating with Strange Cargo, the technology firm has produced 'the world's first recycling point for luck and wishes'.

For the installation entitled The Luckiest Place on Earth, Renishaw produced an intricately designed and sculpted luck and wish recycling point from titanium, using one of its AM250 additive manufacturing systems. The elaborately crafted titanium plaque incorporates a variety of lucky symbols into its design, including wish bones, horse shoes, clovers, shooting stars, black cats and more.

"We're incredibly pleased with how accurately our additive manufacturing machine has been able to reproduce Strange Cargo's unusual and alluring design for the luck and wish recycling point," enthuses Chris Pockett, head of communications at Renishaw. "The piece is yet another example of the potential of 3D printing when it comes to design freedom. 3D printing is no longer just a prototyping method; it's a practical solution for producing highly complex one-off and small batch builds."

Elsewhere, Jewellery designer Jenny Wu has launched her first 3D printed jewellery collection, Lace, in collaboration with 3D printing technology developer Stratasys. The designer's latest collection is, 'inspired by line-based geometry and organic movement'.

A key piece from the collection is the Tangens necklace, which features interlocking elements created by fused deposition modelling technology on the Stratasys Fortus 400mc Production System.

Wu also worked with Stratasys subsidiary Solidscape to produce the Papilio ring, a piece that reflects the movement of a butterfly wing.

Printed using Solidscape's MAX2 3D Printer, the ring was then cast in sterling silver and hand finished.
And staying with the jewellery theme, additive manufacturing technology firm EOS has launched Precious M 080 machine in collaboration with Cooksongold, part of the Heimerle + Meule Group, unveiling the new machine at the Hong Kong Jewellery and Gem Fair 2014.

Dr Keppler, chief marketing officer at EOS says: "This Additive Manufacturing process introduces an innovative and paradigm shifting technology to the luxury goods industry... Additive Manufacturing paves the way for a completely new approach towards design and manufacturing, enabling the design-driven manufacturing that the industry has long been searching for."

Using additive manufacturing, Cooksongold says it will support the most demanding jewellery brands in the creation of entirely new product lines that meet their high quality standards.

Additive manufacturing's strengths are exploited across both industrial and consumer markets, with its use in end product production set to grow.

Manufacturing End Products

An article in Siemens' Pictures of the Future publication last year drew on research to give an overview of additive manufacturing (AM) and its future.

The article cited the latest research from world AM authority Wohlers Associates on market size and future growth, with comment from Bernhard Langefeld, a machine construction expert at Roland Berger Strategy Consultants.

Wohlers Associates says that the AM market had a size of €2 billion in 2012. And while it took the sector 20 years to reach a market value of €1 billion, the second billion was reached in only a further five years. Analysts now believe that it could grow at least fourfold over the next 10 years.

And while its roots are in the rapid prototyping of product designs, not direct manufacturing of products, it is direct manufacturing that is set to take off.

"Money will be made with manufacturing, not with prototypes," forecasts Tim Caffrey, a consultant at Wohlers.
Langefeld agrees, saying that industry is already close to the large-scale production stage in the use of AM to create metallic structures for selected products in medicine and aviation.

It goes on to say that AM is already a reality for making artificial hip joints and crowns for teeth, for example. And in another sector, Siemens is now printing burner tips from powdered steel for use as replacement parts for gas turbines.

The slow speed and expense of the process does, however, remains an issue, but, says Berger: "Manufacturers are now greatly increasing the machinery's efficiency. The latest generation of machines uses multiple lasers, larger build chambers, automatic changing systems and improved online monitoring features. Performance can be substantially increased as a result."

And faster processes mean lower unit cost of production. The manufacturing costs of printed metallic products will probably be cut in half over the next five years, adds Berger, and decline by another 30% in the five years after that. This assumes, however, that the current average build rate will increase eight-fold over the next 10 years – from 10 to 80cm3/h.

Andrew Allcock

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