Plastic Injection molding is simple with the right equipment. All that you need is a heater and some plastic. Recycled plastics will yield the best results if kept to their respective groupings. Refer to the recycle symbols and do not mix types. ABS is my plastic of choice, I used an old HP inkjet printer as the raw materials for this example.

I used a commercially available temperature control for this project but I have posted an accurate precision temperature controller in another Instructable. All told this project took me about 2 hours and about $50 to assemble and test. shown below is a 3mm ABS extrusion being done.

So I built an injection molder based on the plans in Vincent R. Gingery’s book Secrets of Building a Plastic Injection Molding Machine. David Gingery could be considered a forerunner of the Maker Movement — he and his son Vincent have written a whole series of books on building tools for the machine shop.

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This project should cost between $100 and $200. It depends a lot on where the metal is purchased. I had a lot of the metal already, left over from other projects. Try to find a friendly local iron dealer, rather than getting the metal online or from a hardware store. They’ll often let you pick through their cut-off pile and sell it for almost scrap prices