Urethane Casting is most commonly used during the prototyping process, and can generally be expected to hold +/- .010″ tolerances with +/-0.0015 in/in (parts larger than 20″ may result in tolerances even beyond those stated). For parts with tight tolerance requirements, FATHOM generally recommends CNC machining or injection molding. Regarding soft parts, there is a Shore A tolerance of +/-10. Every application is different, though, so please speak directly with a FATHOM expert.
|Soft Tool Casting||Requires a master pattern and a silicone tool be made.|
|Master Patterns||Usually CNC machined master patterns that last up to one year for most geometries, though masters can break during the making of the silicone tool. 3D printed (e.g. PolyJet or SLA) masters have a shorter shelf life. Masters are destroyed after their useful life.|
|3D Printed Tools||Tools are good for up to 20 parts for most geometries and can deliver quality parts up to 90 days from being made—tools are destroyed after their useful life.|
|Overmold||Complex parts such as overmolds can be achieved, however casting process does not result in a very strong chemical bond between shots, regardless of material selection. Parts should be designed to maximize mechanical bonding between shots.|
|Color||Parts can be casted in color and will approximately match specified Pantone color, however, paint is recommended for show models (greater cosmetic result) and parts that require exact Pantone color matching.|
|STANDARD MATERIALS||SHORE VALUE||COLOR OPTIONS||NOTES||RECOMMENDED PRODUCTION METHOD AFTER PROTOTYPING|
|ABS-Like||85 D||Can Be Colored For Near Match To Pantone||Common Material Choice||Injection Molding|
|UL94V0 Rated||74 D||UL94V0 Rated Material Meets Specified Flammability Standard|
|High Temp||80 D||Light Tints Are Very Difficult As Resin Is Naturally An Off White||Glass Transition (Tg) At Over 120°C|
|Clear High Temp||87 D||Clear Only||Requires A High Polish To Achieve Water Clear Finish, Glass Transition (Tg) At 110°C|
|Silicone||20A-50A||Can Be Colored For Near Match To Pantone||Cannot Paint, Food Grade||Compression Molding Or Liquid Silicone Injection Molding|
|Rubber-Like||20-90 A||Cannot Paint||Injection Molding, Compression Molding, Or Liquid Silicone Injection Molding|
|Clear Rubber-Like||30-80 A||Clear, Can Be Tinted To Achieve Transparency||Clear, Cannot Be Painted|
Additional Notes // If color matching needs to be exact, FATHOM often recommends doing a first article (which will extend the timeline). If a color or assembly match needs to be made for other parts, a sample part is recommended to confirm color match. Parts can be molded in glossy, or matte finish—please always specify. If Shore A needs to be exact, FATHOM recommends a first article, as well as casting in a .25″ thick test slug for durometer measurement. This may add to the timeline.
Need A Material Not Listed? Please Speak With A FATHOM Expert Directly About Additional Material Options.
Urethane Casting enables designers and engineers to get production-like material parts in their hands quickly, whether a company is in the midst of the prototyping phase of product development or needing finished looking parts for final tests and presentations.
From models to prototypes for short-run applications like product trials, urethane casting is a great way to fabricate a low volume of parts that accurately mimic the color, texture, feel, and other physical properties achieved if it was an injection molded part. To learn more about a FATHOM customer who used our urethane casting services, check out this application story.