Aluminium/Nylon engine parts laser sintered

For prototype under-bonnet parts, Ogle Models replaced machined aluminium and composites parts with EOS laser-sintered, aluminium-filled nylon, reducing car weight and cost.

Rapid manufacturing and prototyping (RM, RP) specialist, Ogle Models, has introduced EOS PA 2210 FR flame retardant plastics to the range of materials it uses to produce components The powder is used in Ogle’s three laser-sintering machines, two of which were bought in June 2008 as part of a GBP 1 million investment .

The UK company believed it is one of the first RM/RP bureaus in Europe to run the fire resistant material in its machines.

Already it has produced two sets of parts for the cabin and fuel tank of an aircraft in quantities ranging from 50- to 200-off, said sales and marketing director, David Bennion.

* Automotive – Bennion described a project that Ogle carried out for a rally team.

Prototype under-bonnet (hood) 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.

The laser-sintered RP parts reduced the weight and cost of the new car.

Bennion said that the integrity of the parts was maintained during seven days of rigorous endurance and reliability tests in Europe, during which the car ran 1,400km.

* Aerospace – the EOS polyamide PA 2210 FR meets the flammability, smoke and toxicity standards for the civil aerospace industry.

Airplane manufacturers like Boeing, Dassault, Embraer and others have successfully tested the new material, said EOS.

PA 2210 FR typically qualifies for ‘flying hardware’ with wall thicknesses down to 2mm.

* Telecommunications – 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.

The benefit is a 30% cost saving.

Recent investment at Ogle’s product development service centre in Letchworth has nearly doubled floor area, giving more space to develop 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, 24h/day.

Ogle’s rapid prototyping director, Steve Willmott, said that the machine has been upgraded twice by EOS to take advantage of improvements in laser-sintering.

The result has been a 30% increase in productivity and a 50% improvement in component quality.

A step-change in performance came with the installation of the two latest machines, a larger EOSINT P 730 with 700 x 380 x 580mm build volume and a smaller 200 x 250 x 330mm capacity FORMIGA P 100.

Willmott explained: "New control software makes these machines much easier to operate, as no guesswork or experience is needed to set the scaling factor that allows for shrinkage of the part".

He continued: "There is less of a problem in X and Y as shrinkage is linear, but it is non-linear in Z.

The latest EOS software applies compensation in all three axes automatically, making it quicker to set up a new job".

He reported that the EOS twin-laser P 730 is 40% faster than earlier laser-sintering machines.

It produces components that look as though they have been moulded.

They also have better dimensional accuracy and surface finish.

Willmott believed that the key to the improvement is the 0.12mm standard layer thickness, down from 0.15mm on the P 385.

Similarly the FORMIGA P 100 does everything that the large machine is able to, but within a smaller work volume, yet to even higher accuracy thanks to the 0.1mm layer thickness.

An early contract fulfilled by Ogle using this machine was for a customer in the medical sector, whose fine tolerance, nylon parts were previously made by SLA and vacuum casting in a longer lead time and at higher cost.

* Series production – series production of laser-sintered plastics components is becoming routine 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.

EOS told manufa cturingtalk that a big advantage of additive layer manufacturing by laser-sintering is that the process is fully self-supporting.

It allows parts to be built within other parts and with complex geometries that could not be done in 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.

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