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14 May 2008  -  Italy

CRP launches Windform PS

CRP has launched Windform® PS, a new Polystyrene-based material, optimized for the selective Laser Sintered disposable patterns for Rapid Casting Technology.

CRP’s R&D Department has been involved in the Rapid Casting technology since 1997 and is a pioneer in hi-tech casting. Its Rapid Casting Method has been highly respected worldwide for more than 10 years.

In 1997, CRP began to study Laser Sintering technology to manufacture disposable patterns using Polycarbonate and Trueform materials. Although these materials were not suitable for Titanium alloy pouring, because the high ash content remaining inside the shell reacted with the titanium alloys, producing porosity, and thus scrubs, they proved perfect for steel and aluminium alloys.

CRP, therefore, decided to develop new materials for Rapid Casting patterns sintering, and partnered with DTM Corp. in 1998 to be the first to use Rapid Casting for hard to cast shapes such as F1 uprights and gearboxes, and alloys such as Titanium. They were first to optimize a polystyrene material for laser sintered patterns, the CastForm®.

That year, CRP also began to optimize the engineering process and the manufacturing process, studying titanium rapid casting, based on the combination of rapid prototyping (RP) technology, to manufacture the disposable pattern, and investment-casting technology (lost wax casting) with titanium alloys.

CRP has utilized Castform from DTM Corp for many years. Their R&D department built on DTM’s knowledge and experience in rapid prototyping, casting, and machining to become experts in the Rapid Casting process. This work has led to CRP being recognized as a leader in the use of Rapid Casting for motor sport applications throughout the world. These efforts have now yielded a breakthrough in this arena, Windform® PS.

Windform® PS is a new polystyrene-based material able to produce complex investment casting patterns. The sintered patterns are porous in order to allow wax infiltration, making them easy to handle and finish.

Windform® PS patterns can undergo the typical rapid casting procedure, including autoclaves and flash firing steps, low-temperature furnaces and vacuum plaster casting methods.

Compared to other polystyrene materials available on the market, Windform® has:
• Improved surface quality and details reproduction
• Less “curling” effect on the first layers
• Very low ash content suitable for highly reactive alloys, such as Titanium, aluminium, magnesium, steel and nickel-based alloys.

It’s particular suited for the foundry and RP market since the main applications are:
• Complex investment casting patterns
• Casting with highly reactive alloys, in addition to typical cast alloys.

The casting structure is formed of an aggregate of grains, or polyhedral crystallites, which produce isotropy compensation, a solid metal that is an isotropic. Thanks to isotropy, FEM calculations are very close to the real behaviour of the part.

Rapid Casting with laser-sintered patterns also allows complete shape conception freedom, needing no even supports and reducing undercut and tool path problems during CNC machining. It also allows for perfect optimization of the project to the working conditions, making it possible to create a product along its mechanical stress axes, and to obtain a perfect reproduction of all details of the RP pattern, with tolerances and surface finishing of fully machined parts that are of a very high quality. 

FS Precision Tech is an investment casting foundry. They cast complex castings for CRP in both Titanium and Steel. Greg Gregory, Technical Director of FSPT said “I find that Windform PS material works well with our process and produces castings of equal or greater quality than the standard material. FSPT would recommend using Windform PS as the rapid prototype material for any casting house”. 

CRP Technology produces Windform® PS powder and distributes the material worldwide. Windform® PS ships in 10kg stackable metal drums that are certified (CoC attached), as is standard with all Windform products. 

The recommended wax is a standard 100% paraffin wax (with melting point of about 54°C) and infiltration is for about 10” @ 70°C. 

CRP continues to improve the Rapid Casting process because they know what their customers need. Their slogan is, “At 300kmh, quality isn't optional, it's your life.” Their belief is that failure is far more expensive than quality.

Source : CRP