Leveraging 3D Printing for optimised Injection Molds

A guideline from Formlabs on the factors to consider before using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs, reduce lead times, and bring better products to market

- Kruti Bharadva

Injection molding is one of the leading processes for manufacturing plastics. It is widely used for mass-producing identical parts with tight tolerances. It is a cost-effective and extremely repeatable technology that yields high-quality parts for large series. It can produce volumes from 1,000 to 100,000+ of parts at very low unit costs.

Injection molding has a short cycle time, with each machine capable of building new parts every 15 to 60 seconds. It is a fast, intensive process where high heat and pressure are involved to melt thermoplastic and force it inside a mold. Because of these extreme molding conditions, the tools are traditionally made of metal by using a CNC machine or electric discharge machining (EDM). These are expensive industrial methods that require specialised equipment, high-end software, and skilled labour. As a result, the production of a metal mold typically takes four to eight weeks. For smaller part quantities, the cost, time, specialised equipment, and skilled labour required to fabricate the mold out of common tooling metals and manufacturing methods often makes injection molding at this scale unobtainable.