Injection molding has long been the best method of bulk production, while 3D printing has recently become the best choice for early stage prototyping. But when and how should you make the switch from single volume production with 3D prints to high volume production? With small run production it can be hard to find the balance between upfront costs, production costs, and quality, but silicone molds can be an effective way to bridge the low-volume chasm.
Silicone molding – most commonly known as room temperature vulcanizing (RTV) molding – offers a great solution for small batch production. The mold material has no problem retaining tiny and detailed features and tolerances similar to those in your 3D printed parts (minimum features 0.025"/0.6mm). First, a pattern of the item to be manufactured must be produced. You may be starting with an existing item you wish to reproduce, in which case the silicone can be applied directly (assuming the material is suitable). A pattern will be made with 3D printing. 3D printing the mold pattern has shown to reduce lead times up to 90% and reduce costs up to 70%, depending on the geometry of your original part. Once the pattern is ready, the silicone is mixed with curing agent and poured over the pattern; curing can take up to 24 hours and the resulting mold is strong and flexible and then ready to use almost immediately.
Urethanes, a type of thermoset plastic, are the most commonly used casting material and offer a wide range of mechanical, visual and electrical properties; post production work can be reduced to almost nil. The mold can be used for runs of up to 100 parts, although typically the usage range is between 15-30 units per mold, depending on the casting material and part geometry.
RTV molding creates finished products for prototyping, functional testing and short-run production. Considering tool life and cycle times, it is ideal for small quantities (25 - 100 castings) because it offers lead times and costs that are well below that of machining or injection molding.
Silicone molds are made by pouring silicone rubber over a 3D printed pattern. After curing, the resulting firm but flexible mold can produce parts with extremely complex geometry, intricate detail and tight tolerances. The parts are cast from a silicone mold made with thermoset materials (commonly urethanes) that are available with a vast array of mechanical, thermal and electrical properties.
We offer a wide range of material durometers from soft to a hard plastic. Durometer is one of several measures of the hardness of a material. Hardness may be defined as a materials resistance to permanent indentation.