Discover How Prototype Injection Molding Works from Start to Finish When you need a prototype of your product made fast and cost-effectively, consider rapid injection molding that can build your product out of aluminum or steel. Prototype injection molding satisfies your rapid prototyping requirements by delivering high-quality results that are identical to end-use production parts, but made at a lower cost and reduced lead times unlike with full production tooling. Here is an overview of how it’s done:
Selection of materials – A reputable rapid prototyping company can build plastic molding tools from steel or aluminum, but they typically recommend the former to deliver more value to your project, especially if you want to produce more parts. Steel molds are found to be capable of delivering beyond double the number of parts than what an aluminum mold can.
Picking thermoplastics – Any thermoplastic can be injection molded. Some thermoset resins and certain types of silicone may also be used. Prototype injection molding will typically involve materials like polypropylene (PP), polyethylene (PE), ABS, or polystyrene (PS).
Polymer granules – These are dried before they are placed in a hopper to be mixed with reinforcing additives and coloring pigment. When they are fed into a barrel, the heating and mixing process begins before they are moved to the mold using a variable pitch screw. The geometry of the barrel and screw must be optimized to ensure sufficient pressure for melting the material.
Injection molding – In prototype injection molding, a ram moves forward to inject the plastic into the mold through a runner to fill the entire cavity. The material solidifies as it cools down, while taking the mold’s shape. The mold opens after cool down to release the solid part.
Surface finishing – The less processing involved in prototype injection molding to attain your desired surface finish, the cheaper and quicker the project can be completed. You might want to consider an SPI Finish B-1 600 Grit paper. If you’re not sure, the service provider will work closely with you to make sure that you can make informed choices and design decisions.