Silicone Tooling and Cast Urethane FAQs
How are silicone tools made?
A 3D printed, SLA master model is made, and then finished to spec. Liquid silicone rubber is poured around the SLA master and set to cure. Once the rubber is completely cured, the SLA is removed and a cavity of your part is left for urethane to be cast into and produce parts.
What is the difference between RTV molding and silicone tooling/cast urethane?
RTV molding and silicone tooling are synonymous terms for the same process. RTV (room temperature vulcanized) describes the kind of silicone used in the mold making process.
How many shots can an IMPM silicone tool yield?
We guarantee 100 shots from our silicone tools. Exceptions to this rule apply to molds made for FDA compliant and clear parts. It should be noted that 100 shots is not a typical industry standard and only an IMPM guarantee; most shops will guarantee 20-30 shots from their silicone tools.
What tolerances can an IMPM silicone tool hold?
Our silicone tooling and cast urethane process will hold tolerances of ± .005″ per inch.
What kind of materials can IMPM cast?
We have access to hundreds of different urethanes and work closely with our vendors to have new materials developed. Materials come in an array of 10-90 Shore A and D durometers with various regulatory ratings, such as UL ratings, FDA compliant ratings, etc.. Urethanes can be rigid, elastomeric, colored, clear, painted, and coated. Materials are mainly developed to mimic common production plastics.
Do I have to sacrifice appearance with this process?
No, our urethane parts are production quality. We have 5 different textures that can be applied to parts, and the ability to do secondary painting for more complicated finishes. Urethane parts can have labels applied and does lend itself to pad printing for higher quality detail work. In most cases, the only aesthetic difference between an injection molded part and a urethane part is the ejector pin marks.
Can urethane parts be used as final products for end users?
Yes they can, and they are. While this process is utilized for prototyping more often than not, often customers will use this as a bridge tooling process to get product out into the market while production tooling is being made. For very specialized products, such as medical devices, this process is used for production as very low up-front cost is attractive for short runs. Production quality appearance and urethanes developed for the purpose of functionality make this process great for end use.
Can IMPM produce large silicone tools?
Yes, we do not limit ourselves to any size restrictions. We are capable of producing parts much larger than the build envelope of our printers and have a 113 cubic ft. pressure chamber to maintain quality control for large molds and parts.
What is a typical lead time for this process?
Lead times are always dependent on current shop capacity and the individual project, however, a standard lead time for the silicone tooling and cast urethane process is 2 weeks for the first article shipment.