A new range of rapid prototyping materials developed for DTM’s Selective Laser Sintering (SLS) system will allow the simulation of materials such as rubber, enabling the techniques to become more competitive with older, more established techniques such as stereolithography. The five materials, to be launched at Manufacturing Week ’97, bring DTM’s range to 11. All can be processed on one machine.
Whereas stereolithography builds up a prototype in layers from a liquid resin which solidifies under a laser, the SLS process uses powder-based materials.
The chosen powder is applied in layers on to a work platform, where a laser interprets a 3D CAD file to ‘draw’ the cross-section on to the powder.
This heats it to a temperature just below the material’s melting point, causing the powder to bond with the rest of the cross-section and to the previous layer.
Using nylon-based materials, SLS models can achieve properties similar to those of conventionally manufactured parts. Two of DTM’s new range are nylon based. Veriform is the latest development of durable nylon materials, and has improved surface finish and high levels of definition. Fine Nylon Medical Grade has been approved for use by the US testing company, NAMSA, in medical device applications. The USP Class VI certification allows FNMG prototypes to be used in operations.
DTM is also presenting an elastomeric polymer material developed by DuPont materials engineers, DuPont Somos 201.
This has rubber-like properties, allowing the construction of flexible prototypes such as gaskets and seals. However, sports, toys, medical and automotive markets are also interested in the material, which is resistant to temperature and some chemicals.
The other materials are a new sand material, Sandform Si, for producing sand-casting moulds, and a new version of RapidSteel, for producing tool inserts. The process is now claimed to be able to produce a tool insert in as little as two days.
Rapid prototyping systems’ race, CimFocus, page 3