Ta-ta to tooling

For tomorrow’s maintenance engineers there’ll be no such thing as stock. Instead, with just a pile of powder and a clever little machine they’ll be able to conjure up just about any functional component you require.

Improved materials and processes are narrowing the gap between between Rapid Prototyping (RP) and manufacturing. And, although on-the-spot production of functional components is still largely restricted to niche applications, many believe that it’s only a matter of time before the whole manufacturing industry embraces Rapid Manufacture (RM).

Neil Calder, a specialist engineer from BAE Systems, believes that the main advances required to make RM a reality are in the area of materials – specifically making them both ‘transportable and transformable’.

Indeed, materials manufacturers seem to be aware of this challenge. ‘The concept of RM is gaining momentum all the time’, says Darrell Cross, Vantico’s global marketing manager for RP. ‘We are introducing materials with ABS like properties and materials suitable for both functional prototypes and production applications.’

From the machine perspective, Calder says that the area that needs to be developed is process control. ‘If you’re creating a material on the spot, you need to know that the material you put down is as good as the stuff that came from your material supplier.’

However, Calder claims that that the main hurdle to RM’s acceptance is the traditional resistance to change.

‘It takes a paradigm shift in thinking’ he says. ‘Just imagine it in a car dealership. You pay your money, they squirt the electronic signals down a data line and print out the part rather then holding loads of stock.’ ‘Indeed,’ he adds, ‘this approach is consistent with globalisation. Using local resources to get a product across the world.’

Calder suspects that RM will first appear in niche applications, and indeed there are already a number of examples of this.

Stratasys, for instance, is working with NASA on using FDM (Fused Deposition Modelling) machines to build functional parts on board the space shuttle or the international space station.

In another project, the US army has developed a prototype trailer – dubbed the Mobile Parts Hospital – that could allow army maintenance engineers to manufacture small parts on the spot. The trailer is equipped with a vertical milling machine, an SLS (selective laser sintering) machine, which converts powdered rubber, metal, plastics and ceramics into actual parts and a laser-point scanner which can be used for reverse engineering parts when no engineering data is available. It’s also rigged with an array of communication technology for receiving engineering data.

In terms of existing RP technologies, Calder believes that LENS (Laser Engineered Net Shaping) is the one most likely to make the initial impact in RM.

Developed at Sandia National Laboratories in the US, LENS uses lasers to quickly weld air-blown streams of metallic powders into custom parts and manufacturing moulds. The technique is said to produce shapes close enough to the final product to eliminate the need for rough machining.

Nozzles each direct a stream of metal powder at a central point beneath them. Simultaneously, that point is heated by a high-powered laser beam. The laser and jets remain stationary while the model and its substrate are moved to provide continually new targets on which to deposit metal.

LENS is produced as a commercial product by Optomec, a small Albuquerque company. A machine costs between $350,00 and $500,000.

A renowned authority on RP technology, Professor Phill Dickens of Loughborough University, believes that the use of layer manufacturing techniques to produce large quantities (up to millions of parts) of products will be an important manufacturing technique within the next ten years.

Dickens says that promising processes for manufacturing include powder sintering, 3D printing, screen printing and jetting. He adds that materials are currently limited but that there’s a major opportunity for new materials (especially composites), controlled porosity and graded materials.

RM will create major changes in the way designers work, adds Dickens, because they will have very few geometry restrictions. Indeed, random changes of product geometry would be possible without affecting efficiency. He says that this new way of producing parts ‘could revolutionise the way the manufacturing industry is organised’. In the marketplace, the rise of RM is perhaps best indicated by the fact that 3D systems has set up a company specifically to concentrate on this technology.

However, the RP behemoth prefers to refer to use the term Advanced Digital Manufacturing, so get ready to tie your tongue around a plethora of acronyms over the coming years.

3D says that its new company – OptoForm, is focussing on technology that enables parts to be manufactured without tooling.

Mike Kelly, 3D’s UK manager, says that not only will this reduce the time and cost of production, but most importantly, will enable previously impossible manufacturing feats.

‘Via ADM you can manufacture parts that via traditional methods were not possible,’ he says. ‘For example, to produce a car door probably comprises up to 11 individual parts from brackets, handle to washers and screws. Using a Solid Imagining system you can build a car door in one single part, cutting out the pressed tools, jigs, fixtures and assembly operation. A car comprises 18,000 parts, with solid imaging we can reduce that to 1800 parts. Parts can be any size, thickness, complexity now we can go beyond only what is manufacturable. Typically it takes 2 years to bring a car to production, that process can be shortened to just months.’

The key to ADM growth, concludes Kelly, is to develop materials that designers want to use, and to make designers realise the freedom they can have.

Echoing Neil Calder’s vision that initial applications will be in the medical world, one of ADM’s first appearances is in a new hearing aid manufacturing process that uses SLS for US company Widex.

The Perfect Employee

Brainstorming meetings and working lunches can be a crucial part of the product design process but a fresh employee at design consultancy PDD shuns this sociable approach, preferring to work through lunch and never leaving the office.

The ‘new boy’ clearly isn’t human. It is, in fact, an FDM (Fused Deposition Modelling) rapid prototyping machine, and it’s allowing PDD’s design team to take a step closer to having a 3D printer on their desk.

While many companies use FDM to produce finished prototypes in the workshop, PDD is putting the technology’s considerable advantages to use in its design studio. PDD’s development director Tim Court says that his company’s purchase of a Stratasys Prodigy FDM machine has led to a ‘big reduction in risk during the speedy development programmes that categorise the world of product innovation’.

Court adds that the machine is an integral part of ‘PDD’s approach to physically touch and feel concepts, to provoke clearer communication with team members and network partners at the earliest stage.’

Traditionally, companies in PDD’s position have turned to stereolithography (SLA) models produced by external bureaux. However, while these models are highly accurate and finely detailed, sourcing and supply is at best 24 hours, and the cost is considerable. For example, while an SLA model of a body-worn industrial computer housing would cost £280, Court says that the cost on the FDM machine was only £14. The low cost of FDM thus allows the product’s designers to print off a model whenever they want and appreciate design details in a much more direct manner.

Court adds that this approach also stimulates collaboration across the whole of the product development team. For example, early models can be used to help the customers’ electronics team fully understand the PCB requirements. The models can also be used to verify that assembly issues have been considered early in the programme, while critical details such as battery insertion and position of connectors can be checked without losing time or incurring additional costs.

What’s more, says Court, the machine is simple to use, and extremely unobstrusive. Build material is automatically loaded from cassettes – the operator doesn’t even touch it, and programming is quick – the machine has only 4 control buttons and an on off switch. Indeed, within two hours of it arriving in a carton, the team had been trained and models were being built.

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