Desktop Injection Molding

by Joseph Flaherty on February 1, 2010

Micron smooth plastics are an indicator of professionalism in consumer products. Anyone with a credit card can have a 3D print made at a great printing service, but the cost and complexity of injection molding keeps it limited to professionals. At least that is what I thought until reading Chris Anderson’s new article about Atoms being the New Bits. He talks about BrickArms a one man operation that makes period authentic weapons for Lego Minifigs using a bench top injection molding machine.


In the article Anderson mentions that early prototypes are made with a mini mill and a hand powered injection molding machine. I was unaware that these machines existed, but a quick google search shows they are available for under $1,500.

If you are unfamiliar with the process, I’ve included a video below, but it is the manufacturing technique used to make most consumer products. Your alarm clock was almost certainly injection molded.

These tools have serious limitations in size and quality. To be effective it will also need to be paired with a CNC mill to make nicely polished mold. The biggest limitation is probably size, but if you are looking to do short run prototypes of a fairly small device, the injection molding process is a great way to make your product seem more professional.


If $1,500 is too steep, you might have some success hacking an old Kenner MoldMaster if you can find one. The MoldMaster was an injection molding toy sold in the 1960’s that allowed boys of the time to manufacture their own toy soldiers, tanks, and other playthings. It required the use of scalding metals and plastics so it didn’t last long on the market, but the basic principle is the same as the professional models. Unfortunately, none are currently available on Ebay.

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