Fresh approach

Despite the credit crunch new designs for products – from deodorant caps to mountain boards – still need prototyping, reports Charles Clarke

A good barometer for the state of manufacturing is how busy the design and prototyping houses are. Despite the doom and gloom about the economy Seymourpowell, one of the UK’s leading design and prototyping houses, is reporting lots of activity right across the spectrum from consumer products to new top secret major developments.

Seymourpowell in many ways is a traditional prototyping and model-making business using craft skills, preferring to outsource its rapid prototyping technology needs. The mainstay of its prototyping activity is two large, three-axis CNC machine tools driven by MasterCAM software.

The prototyping process starts with foam models and as the design develops the prototypes become harder and closer to the finished article in terms of shape and material.

In recent months Seymourpowell has developed packaging for Lynx deodorants and personal hygiene products from Unilever, including the new rotary aerosol cap. This work has extended into the Dove range with the development of the ‘soft touch’ aerosol cap for deodorants. This sophisticated capability involves a soft silicon over moulding.

‘The early prototypes for the Lynx line were quite tricky,’ said Jamie Cronk, workshop manager at Seymourpowell. ‘And we found ourselves moving swiftly to SLA because of the thin walls. There is a fairly complex mechanism inside the cap and one of the critical aspects was the break-off button for the first use, which was difficult to trial from solid.’

The Dove aerosol cap has a rubber membrane over the top producing a soft-touch feel.

Although quite an expensive multi-shot moulding, Mike Webster, associate director of packaging pointed out that, ‘Having a flexible top can have beneficial affects on the actuator. And using a dual-shot moulding has the potential to reduce assembly times so it might appear expensive when in actual fact it’s quite cost-effective. The cost of assembly is often more expensive than the cost of a dual-shot.’

Meanwhile, the Expanded Metal Company is doing prototyping work with the new TVR Segaris, including grills for the re-styling of the rear end.

‘The exhausts now come out at the rear of the car rather than side, so we made a grill for the exhausts to pass through,’ explained Bruce Ellison, business development manager for Expanded Metal. ‘These grills are cosmetic and they also help with the cooling of the exhaust.’

The company uses a combination of craft techniques and CAD to get the grill shapes. Design secrecy is big on the agenda in the automotive industry so templates are usually made on site, but on rare occasions the company might be allowed to take parts away to make templates in its own workshops.

In much the same way when an innovative navigational system needed to be tested, Kelvin Hughes, a leading manufacturer of navigational equipment turned to Ogle Models and Prototypes.

Ogle’s brief was to come up with a suitable production method for the casings and tracker balls, which would form the basic interface on the navigational screen.

Once Ogle had received the data from Kelvin Hughes, it decided to use the RIM (Reactive Injection Moulding) process. Mould tools had to be designed and then machined out of PU modelboard BM5460. The separate parts were hand-finished and assembled using clamps to ensure the sides of the tool were stable once the polyurethane had been injected.

Continuing the nautical theme, Martello, a small prototyping business in the south west of England, has recently been involved in the development of StarFish, a revolutionary high definition side scan sonar, which produces photo-quality images of the seabed.

Starfish is designed by Blueprint Design Engineering, and can ‘Plug and Play’ with any PC or laptop via a USB connector. The simple to use software makes it easy to scan the seabed as part of a team or singly.

StarFish is the smallest side scan system on the market and is now an affordable technology across a range of different markets, unlike many larger commercial side scan systems.

Martello used its Thin-Rim polyurethane elastomeric resin to produce a vacuum cast over-moulding for the body of StarFish. The tool for manufacture had to enable the metalwork and electronics to be encapsulated in the resin and still enable the device to operate.

Martello’s engineers designed an SLA master and silicone tool to manufacture the over-mouldings. Initially six StarFish over-mouldings were produced and rigorously tested before the product launch in June 2007. This process proved the versatility and scope of today’s rapid manufacturing processes to deliver functional and commercially robust products.

Protomold, a more ‘traditional’ rapid injection-moulding specialist is helping German ‘mountain board’ manufacturer Flame Offroadboards to design and manufacture a revolutionary range of affordable boards retailing for between £354 and £786. Mountain Boards are similar to snowboards but have big wheels to keep the adrenaline pumping long after the snow has melted. The problem is that because of their specialist nature and the fact that they have to be seriously rugged, the average price for a professionally manufactured board is around £1,573 which is significantly more expensive than a snowboard.

German entrepreneur Albert Müller started Flame Offroadboards to redress this balance. One of his first rationalisation exercises was to concentrate on local suppliers — he picked Protomold because it had the technology he needed and its German office was close by.

The component central to the partnership is the wheel rim which is crucial in determining the ‘ride’ of the board.

‘We have a unique axle design for our boards,’ said Müller. ‘Standard skate axles are fine for straightforward runs, but at higher speeds on more rugged terrain, unsteady riding behaviour [speed wobble] is frequently encountered. The usual solution is to deploy channel axles, which provide greater stiffness and “track stability” to overcome these difficulties.’

Because the axle and wheels are unique none of established manufacturers had tooling to match, which is where Protomold and its innovative rapid injection moulding process come in.

Various materials with long and spherical glass fibres were discussed for the wheel rims.

‘We subsequently chose a new glass fibre reinforced, stabilised material with good elasticity,’ said Müller. ‘This material is used for wheel rims on BMX bikes and new prototypes are currently being tested.’

If everything goes smoothly, Protomold will manufacture 5,000 wheel rim halves from this material – one of many that it holds on its extensive database of plastic materials.