Liquid Silicone Rubber is a broadly used non-reactive compound. Its high resistance to extreme environments and temperatures make it a perfect seal material for aerospace, defense, and automotive components, but it is also used in sporting goods, medical devices, and consumer products.
Unlike traditional thermoplastics which are melted before injection molding, LSR starts as a liquid which then cures into a solid after injected into a heated mold.
It has a lower viscosity, which allows for shorter cavity fill time, but a parting line can sometimes be visible in finished parts. Mass production of LSR parts requires specialized injection molding machines that meter, mix, and inject into molds.
Prototyping in this manner is cost prohibitive, so prototypes are instead made through manual casting methods using modeling boards, RTV rubber, or soft metal. Although cheaper to produce, they require significant time and labor, and there are limitations to geometrical complexity.
PolyJet technology can be employed to produce LSR molds with smooth surfaces. With the achievable layer thickness of 16 microns, PolyJet can create highly detailed molds, which in turn generate LSR parts with fine surface finish. Upon completion of the CAD design, the mold can be printed overnight without operator attendance, and complexity doesn’t affect the time.
Once a PolyJet mold is printed, it is preheated before LSR is injected. Upon curing, the LSR part is removed revealing a finished part. LSR parts produced with PolyJet molds feature the same attributes of mass produced parts, including subtle details, distinguished aesthetics, and high accuracy. They also exhibit the unique mechanical and thermal properties of production-grade LSR.
PolyJet extends an effective method for producing LSR parts, parts that can be used for functional testing and even low-volume production. For more information on our Stratasys line of 3D printers, please click the button below.