BotMill's Blog

At Euromold 2011, 3D Systems (11.0, F110/FN01) is continuing the race to bring 3D stereolithography (SLA) part-printing to a wider customer base, launching its new ProJet 1500 high-resolution 6-colour colour printer with a €12,300 price tag. The printer is designed to appeal to industrial designers, engineers, architects, marketing staff, teachers, students and even school children.

The ProJet 1500 prints functional testing parts strong enough for fine detailed snap-fit designs with a relatively smooth surface finish. It “brings designs to life at print speeds up to five times faster than any other 3D printer in its class”, the company claims.

Buddy Byrum, senior director 3D Printing, says: “Aside from combining colour printing with high resolution models, we also had the target to make the ProJet 1500 up to 50% less expensive in both acquisition and running costs than comparable products.”

Cathy Lewis, vice president of global marketing at 3D Systems, says the company is underscoring its “commitment to democratise access to affordable 3D content-to-print for the benefit of professionals and consumers alike”.

The ProJet 1500 has network, web and email capability, enabling simultaneous access by a number of users. 3D Systems says the printer can be used in normal office environments as it does not emit heat, odours or dust.

The Germany-based Fraunhofer ILT laser technology institute (11.0, C66) is presenting a new laser process to polish complex three-dimensional moulds. It polishes to a high-gloss finish and is up to ten times faster than laborious 10min/cm2 hand polishing with grinding stones and pastes, says the institute.

A laser beam melts a 20-100µm surface layer, unlike other systems, which remove the material from the surface with conventional tools. This results in typical surface roughness (Ra) of 0.1-0.4µm. Dr Edgar Willenborg of ILT admits hand polishing achieves lower surface roughness but says that Ra as high as 0.5µm is sufficient for standard plastic parts.

The first stage of melting is applied to a 100µm depth of material, and then thinner layers are melted in stages. Depth is determined by laser power level, pulse length and speed of up to 1m/s.

“Surface tension, a property that applies to all liquids, ensures that the layer of liquid metal solidifies evenly,” says Willenborg. “Unlike conventional polishing techniques, laser polishing does not primarily rely on the rigidity of the machine to achieve high component quality, but rather on the physics of surface tension.”

ILT developed the process with laser production cell producer Maschinenfabrik Arnold and production automation specialist S&F Systemtechnik. A 5-axis gantry and a 3-axis laser scanner enable all-round workpiece access and the process is controlled by conventional computer-aided manufacturing (CAM) programs.

Working within the Innosurface project funded by the German BMBF education and research ministry, Fraunhofer ILT (11.0, C66) has also developed a selective laser melting (SLM) process. The process produces close contour mould inserts out of highly conductive copper alloy by building up layers in an additive manufacturing process.

This process was previously not possible, as copper alloy powders have lower laser light absorption and higher heat dissipation than steel based powders because of the higher thermal conductivity. This interrupts the melt track and small molten metal balls form, which, in turn, create pores, leading to low-density parts.

ILT overcame the restrictions by using a more powerful 1,000W laser instead of the conventional 200W SLM lasers used with aluminium, cobalt-chrome, titanium and steels. The institute optimised the process by choosing a particularly even beam profile and changing the inert gas control system and mechanical equipment.

ILT rapid manufacturing project manager David Becker says the process is now ready for industrial use as the company has achieved workpiece density of 99.9%.

The company produced the first copper alloy inserts in Schmelzmetall Hovadur K220 beryllium-free copper alloy, which contains 2.4% nickel, 0.4% chromium and 0.7% silicium. The alloy is one of six hardenable copper-nickel-silicium alloys for plastics processing moulds produced by Schmelzmetall in an inductively heated vacuum furnace and thermal precipitation casting process.

Hovadur K220 has Brinell hardness of 190-240 and its thermal conductivity of 220 W/mK is up to 10 times greater than conventional steel based mould metals. ILT researchers are already looking at the next target of applying SLM to pure copper, which presents further challenges due to higher heat dissipation.

Objet (11.0, D90) is coming to Euromold with a new 870 x 735 x 1200mm compact Objet260 Connex version of its Connex range multi-material 3D printers.

The company says the 264kg printer is “the world’s only compact, multi-material 3D printer for rapid prototyping and available at an attractive price”. Objet Eden260V users will be able to upgrade to the Objet260 Connex by the end of 2011.

The Objet260 Connex has a new build-size of 255 x 252 x 200mm and has similar features to the larger Connex, as two polymer inkjet jet heads simultaneously build up 14 different materials into a single part by building 16µm layers sheet-by-sheet.

According to Roland Essmann, laboratory manager at Elster, a Smart meter producer, the company has already used the Objet260 Connex and says it has significantly improved prototype visual and functional capabilities, “making them ideal for real functional testing”.

Users can choose from 60 different materials for the Objet260 Connex, including the clear, high temperature and ABS-like materials launched at Euromold 2010.

Portuguese CNC machine tool producer Heto (8.0 D24) has developed a single machine which can precision mill, tap, and bore with both conventional and deep hole drilling. Heto says this means 60% faster drilling time, a 40% reduction in machining time and a 20% shorter mould delivery time.

The company is also showing new mould production machinery concepts, including machines that can now also perform 3D finishing, by integrating a spindle running at 24,000 rpm and a “nose” for milling. The company says it is “the first machine builder to provide one complete solution with capacity to do one complete mould part only with two setup operations”.

Hochschule München (11.0, F80) has developed a flexible forming tool to produce prototypes for three-dimension glazing parts for automotive windscreens, sunroofs and headlamp covers.

While the university has already developed equipment for glazing parts in PMMA, it recognises that polycarbonate glazing has greater market potential. It is therefore developing the equipment and integrating more components for high quality polycarbonate glazing prototyping in terms of good optical properties and low internal stress.

V.G. Kunststofftechnik (11.0, D49) is showing plastic parts produced in laser sintering, stereolithography, vacuum casting processes or even injection moulding. The parts are clad with metal in a special coating process, making them indistinguishable from metal parts.

The process also enhances mechanical, physical, chemical, optical and hygienic properties, depending on the plastic used, coating thickness and surface. The samples are especially interesting for both aesthetic design and technical prototypes, the company suggests.

Among the exhibits on the Voxeljet (11.0, E62) stand is a conveyor belt-based, continuous 3D printer concept. The part building and removal processes run in parallel, without interruption to the printing equipment operation. Unprinted powder is funnelled back from the end of the line with low material loss to the build area for printing further parts.

Printing takes place on a horizontal tilted surface using a printing process that is “similar to conventional 3D printing”. The concept foresees 500 x 500mm build volume in practically unlimited length, as there is no practical length limit in the direction of the conveyor belt. A high definition 600dpi print head is foreseen for the concept machine, applying 150-400m layers.

Voxeljet managing director Dr Ingo Ederer says the first machines should be delivered by the end of 2012.

Via: http://www.europeanplasticsnews.com/subscriber/headlines2.html?cat=1&id=1321263299