Silicone Moldmaking Services
in Los Angeles

Silicone Moldmaking: Overview

Summary: What is a Silicone Rubber Mold?

A silicone mold is a block of rubber with an internal empty cavity. This empty cavity has the precise negative shape of an object which is to be cast by pouring material into the cavity. Silicone molds are made using a "master" 3D Printed part.

A one-piece silicone dump mold is a single square of silicone with an exposed cavity on top. Casting material is poured into the cavity until it reaches a flat surface, flush with the flat top of the dump mold. Silicone dump molds are used for creating items with flat bottom surfaces and positively angled geometry without undercuts: soap molds, candle molds, and chocolate molds, for example.

If your part is more complex than a dump mold allows for, a two-part silicone mold can be created. This is a block of rubber that is sliced into two halves, with a top spout tube for pouring in casting material. Two-part silicone molds are commonly used for more complex geometry like mechanical parts, statues, and sculptures.

What kinds of materials can be poured into a silicone mold?

Creating parts from a silicone mold is commonly called Vacuum Casting, RTV Molding, RTV Casting, or simply: casting. The material poured into the silicone mold -- the material in which your copied parts are made -- is called casting material.

Popular casting materials that work with silicone molds are urethane resin plastic, epoxy resin, plaster, polyurethane foam, wax, soap, and concrete.

How does it work?

The process requires a physical 3D Printed part, called the "master." The master part is a 3D Printed part made in high-resolution SLA Resin, and is perfectly smooth so as to allow for a high-quality mold and smooth cast parts.

To produce your silicone mold, we will first 3D Print your master part in SLA Resin, and then create a silicone mold from that part.

What do I need to provide in order to get a silicone mold made?

You will need to provide your 3D Model / CAD files in one of the following formats: STL, OBJ, STEP/STP, or IGES/IGS. Your 3D Model will be 3D Printed in SLA Resin, and this master part will be used to create your silicone rubber mold. We must 3D Print your master part -- physical parts are not accepted from customers to serve as the mold master.

If you don't have a 3D Model CAD file, we offer 3D Scanning and 3D Design services to create a 3D Model for you, based on a physical sample part or drawings/dimensions/images that you provide.

How many cast parts can I make from a single silicone mold?

Your silicone mold is affected by the material curing inside the mold, as well as the mechanical stress of removing each cast part from the mold. Generally speaking, silicone molds are good for casting 30-50 copies if you're using a hard casting material like epoxy or urethane resin. If you're using a soft material like wax, you can expect your mold to have a higher yield before noticeable degradation.

It is possible to continue using your mold to cast any quantity of parts, but you can expect to start seeing visible signs of mold degradation on your cast parts as you continue to cast out higher quantities.

How long does it take to get my silicone mold?

Since this is a two-step process involving 3D Printing and moldmaking, the lead-time to deliver a finished silicone rubber mold is ~2 weeks.