Rapid benefits

As consumer taste and industrial demand change ever faster, rapid prototyping is at the forefront of the technology helping manufacturers to develop new products. Colin Carter reports.

Modern manufacturing has to meet the consumer’s demand for ever-improving, evolving, and developing products. Most consumers want a new model of phone or mp3 player every couple of years, and the same applies to industrial products.

New product developments in all areas need new designs to highlight the technological advances inside — would we be have been flocking in our millions to buy iPods if they looked like the old Sony Walkman?

At the forefront of technology in the drive to develop new products faster is rapid prototyping, in which solid prototype objects or design models are formed direct from CAD drawings by solid freeform processes such as stereolithography (SLA) and selective laser sintering (SLS). These processes can build a model in three dimensions by analysing slices of the item, then building them slice by slice. Typically, these slices are about a tenth of a millimetre thick.

Advances in rapid prototyping and its associated technologies have opened up exciting possibilities for businesses that need to test and evaluate new products quickly.

Protomold, based in Telford, Shropshire, highlights rapid injection moulding as an example of how advanced technology is giving significant first-mover advantage to those canny enough to use it.

Rapid injection moulding allows companies to create fully-functioning prototypes with high-quality materials, enabling designers to evaluate first-run parts at an economic cost.

The process can deliver precision moulded prototypes in volumes as low as 25 or as high as 10,000 in three to 15 days, says Protomold.

The CNC-machined aluminium mould delivers the same geometry as subsequent steel production tooling, allowing designers to easily replicate the planned shape and functionality of the finished product.

An unusual illustration of the use of rapid prototyping techniques comes from Ogle Models and Prototypes, known for designing the Reliant Scimitar car and the Raleigh Chopper bicycle. Product Partners had a complex design problem with an industrial fire detector the company was working on: how to keep a laser beam in precise alignment between the source and detector when a building expands or contracts due to environmental changes?

In some buildings this misalignment could be up to five degrees, which could severely affect the efficacy of the device. Developing an automatic gimbal mechanism would have been costly but, luckily, one of the team realised exactly that kind of mechanism was used in car wing-mirror adjustment, and could be adapted.

Ogle Models and Prototypes was brought in at this point to develop a practical manufacturing method for the parts. From SolidWorks files Ogle constructed the prototype parts from nylon 12 using an argon laser in an SLS process, which was capable of producing parts with the required accuracy to make the detector work.

Rapid prototyping also plays a significant role in new product development at Triumph, the re-born company famous for its motorcycles for many decades. Since restarting production in 1991 Triumph has sold more than 300,000 bikes and now sells more than 40,000 bikes worldwide per year.

Part of the reason for Triumph’s huge success has been its eagerness to embrace new technologies, in both fast tracking new designs and reducing overall manufacturing costs, which has helped establish a foot-hold in the market that is dominated by the far east.

For example, the company employed High Wycombe-based CRDM to produce an SLS Duraform PA model of the engine from Triumph’s flagship motorcycle, the 2300cc Rocket III which, since launch in 2004, has sold about 9,000 units. The company has helped Triumph with rapid prototyping as well as pre-production metal castings in steel and aluminium, production blow mould and injection mould tooling.

Another technique becoming more common is 3D printing, whereby materials are deposited via a nozzle similar to those used in inkjet printers to form a 3D model, either by depositing on a frame or on its own by curing polymers as they are deposited.

Evidence of the rapid uptake of these technologies is not hard to find — a global study of the 3D printing, additive fabrication and rapid manufacturing industries published by Wohlers Associates last year noted that the lower-cost options offered by 3D printers were driving growth by about 37 per cent per year since the market appeared, with about two thirds of the units installed being 3D printers over the three years to 1996. As costs fall, this proportion is expected to rise even more in future.

New prototyping applications for 3D printers are found in a number of diverse fields such as the use of complex, functional prototypes of Reebok footwear, sandals and athletic equipment using DuraForm Flex Plastic in 3D Systems’ Selective Laser Sintering System.

Another modelling application of 3D printers can be seen in the US Army Corps of Engineers’ use of a Z Corporation Z810 3D printer to create colour models of cities, mountainous areas and other complex terrain around the world in support of military operations and related applications.

The printer transforms digital geospatial files into detailed 3D colour models in two hours, compared with weeks using traditional methods. The end result could be topographical models of areas under attack downloadable as CAD files eventually — the military value is obvious.

The development process can be speeded up considerably if old designs are re-purposed (the various generations of iPods are a good example of this).

This was highlighted in a recent design re-use study by the Aberdeen Group within which Chad Jackson, Aberdeen’s research director and analyst, noted that ‘best-in-class companies are… more likely to be procedurally focused on making sure that designs are ready for re-use’.

This philosophy has been exploited by product design and development specialists such as Minima which, as an example, has produced a set of design concepts for gasGenie, producers of gas turbines and associated power generation equipment, for the next generation of hydrogen fuel cell systems.

Minima supplied industrial designs, visually accurate rendered images and computer simulations of the product, which were flexible so as to allow the product to be branded for launching into two separate markets — the marine industry and the workplace.

All these examples are glimpses of an exciting future. Imagine the situation where offices are equipped with rapid manufacturing facilities (which is likely to happen once prices of 3D printers come down further) as a matter of course. No more ordering everyday plastic items such as pen holders, and an end to the purchasing trail many large organisations insist on, which can lead to weeks before delivery. It would be possible to select a design from an archive of CAD files and produce it in situ to save time and money.