The polyamide PA 2210 FR was especially designed to meet the flammability, smoke and toxicity standards for the civil aerospace industry. Aircraft manufacturers like Boeing, Dassault, Embraer and others have successfully tested the new material. To achieve a fire retardant rating of UL94 V-O, a minimum 2 mm wall thickness is required.

In the telecommunications industry, Ogle has for some time been producing a fire retardant, fibre optic tray for communications towers using a combination of stereolithography (SLA) and vacuum casting. The process used to be time-consuming and relatively expensive. The same part is now laser-sintered in one operation using PA 2210 FR in quantities up to 180-off, without the need for tooling, resulting in a 30 per cent cost saving for the customer.

Recent investment at Ogle’s product development service centre in Letchworth has seen a near doubling of floor area, giving more space to develop both the traditional model making and CNC prototyping sides of its business. Clients include many blue chip organisations such as Bentley and GlaxoSmithKline as well as leading design, building and architectural firms including Laing O’Rourke, Arup and KPF.

The first EOS plastic laser-sintering machine, an EOSINT P 385, was installed at Letchworth in 2000, but for the last 18 months it has been working to capacity, 24 hours a day. Ogle’s rapid prototyping director, Steve Willmott, commented that the machine has been upgraded twice by EOS to take advantage of improvements in laser-sintering. The result has been a 30 per cent increase in productivity and a 50 per cent improvement in component quality.

Series production of laser-sintered plastic components is becoming the norm at Ogle, in addition to ones and twos for prototype applications. A good example is the manufacture of parts in batches of several hundred for a thermal imaging camera used in search and rescue work.

From a CAD model supplied by the customer, laser-sintering is used to make the chassis that supports the thermal imaging screen and the electronics. No hard tooling is required, so any alteration in design is easily accommodated without additional expense.

A big advantage of additive layer manufacturing by laser-sintering is that the process is fully self-supporting, allowing parts to be built within other parts and with complex geometries that could not be realised any other way. These attributes lower the cost of production and at the same time offer unfettered freedom of design. Moreover, the resulting components are strong and rigid enough to be used in places where they may be subjected to mechanical and thermal stress.

By way of illustration, Mr Bennion described a project that Ogle carried out for a rally team. Prototype under-bonnet parts previously machined from aluminium and composites, specifically for the air inlet catch tank and head breather, were replaced by laser-sintered, aluminium-filled nylon, reducing both the weight and cost of the new car. The integrity of the parts was maintained during seven days of rigorous endurance and reliability tests in Europe, during which the car clocked up 1,400 km.