As we all know injection moulding requires high initial investment, specialist equipment and lead time for tooling, this can significantly hinder the speed and cost to introduce new products to the market. However, with the continuous advancements in additive manufacturing 3D printing technology is now offering a cost-cutting, agile alternative solution to quickly design and fabricate mould for small runs of thermoplastics prototypes or end-use parts.
What is injection moulding?
Injection moulding is one of the leading processes for manufacturing plastics as it yields high-quality parts and is cost effective. Widely used for mass-producing identical parts with tight tolerances, it is a fast, intensive process where high heat and pressure are involved to melt thermoplastic and force it inside a mould.
Because of these extreme moulding conditions, the tools are traditionally made out of metal by CNC machining or electric discharge machining (EDM). However, these are expensive industrial methods that require specialised equipment, high-end software, and skilled labour.
Manufacturers are now turning to 3D printing to fabricate injection mould rapidly and at low cost. They can benefit from the speed and flexibility of in-house 3D printing to create the mould and couple it with the production force of injection moulding to deliver a series of units from common thermoplastics in a matter of days.
Even though 3D printing moulds can offer these advantages when used appropriately, there are still some limitations. We should not expect the same performance from a 3D printing polymer mould as from a machined metallic one. Critical dimensions are harder to meet, cooling time is longer because the thermal transfer occurs slower in plastic, and printed moulds can easily break under heat and pressure. However, low-run injection moulds are great assets for engineers to deliver limited batches of end-use parts or prototypes in the final plastic, for pre-production tests.
Unlocking in demand mould fabrication with stereolithography (SLA)
Stereolithography (SLA) printing technology is a great choice for moulding. It is characterised by a smooth surface finish and high precision that the mould will transfer to the final part and that also facilitates demoulding.
In a recent webinar, Formlabs discusses how SLA printing enables in-demand mould fabrication to generate hundreds of parts, from idea to production, in a matter of days, at a fraction of the cost. Catch the re-run of the webinar here, and learn:
- Expert processes to design a 3D printed mould for injection moulding.
- Which printing and moulding conditions ensure success, including an overview of the Formlabs resins that Novus Applications and Braskem use for the moulds.
Strategies for the post-processing workflow, including ejection and demoulding
Access the full white paper here and have a closer look at how this hybrid manufacturing process enables on-demand mould fabrication to quickly produce small batches of thermoplastic parts through real-life case studies with Braskem, Holimaker, and Novus Applications.
For more information, click here for an overview of methods and guidelines for using SLA 3D printed moulds in the injection moulding process.
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