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Catering to Lego fans who can’t find the parts they want from the company (mostly minifig accessories, heavily weighted toward weaponry) BrickForge is a company which designs and molds these elements and sells them on the internet and at Lego conventions. Recently I interviewed BrickForge owner Kyle “Armothe” Peterson about what it was like to have his own plastic-molding operation.

Could you describe how you design the elements you want to manufacture?

It all begins with an idea. We do our best to navigate between what The LEGO Group already produces and what the fans are looking for. The elimination process can take several months! Once we secure a roster we use virtual tools such as Adobe Illustrator or Solidworks to draw out measurements and angles to get the element looking similar to how the original idea was envisioned. Maintaining a distinct LEGO aesthetic while including enough distinguishable details is key.

Having designed the element how do you create the mold?

Once the element is designed a mold is created out of aluminum stock using a CNC milling machine. Most of the time we bundle several accessories together on the same aluminum block. In dealing with such small scale elements we need to insure that every detail is accurate up to 1/10 of a millimeter!

I assume you use ABS. When you get it, in what sort of form does it arrive?

Once the aluminum mold is created it is slotted inside an injection machine and the magic begins. ABS pellets are mixed with a dye and then poured into a hopper. A heating cylinder and reciprocating screw located inside the injection machine feeds the molten ABS into the mold via gates and channels, that then defines the final shape of the object.

What is it like to work with ABS?

In its final form ABS is a fun material to work with! However, when dealing with the smelting and mixing of such polymer it is highly advised to use respiration equipment since the fumes are considered toxic.

I hear some 3rd party manufacturers of Lego accessories recycle old bricks in their ABS, grinding them up and adding them to the molten plastic. Can you talk a little about this?

Obviously the ABS has to come from somewhere. BrickForge deals with very large production runs – thus we use specifically dyed ABS pellets during the self-contained, automated injection process. Other vendors may use a smaller, lightweight injection press for smaller production runs. This requires a manual feed of plastic into the hopper. Either the artisan has to purchase pre-mixed pellets (that match the LEGO color palette) or simply grind up and smelt existing LEGO brick. The first option is expensive, the second option is time consuming (not to mention having to deal with toxic fumes).

Any suggestions you could offer to amateurs hoping to get into plastic molding?

If you are willing to spend the $$ the playing field is wide open. For the DIY crowd CNC machines and injection molding machines are available on a smaller scale. For larger runs like ours, it’s best to use heavy-capacity presses for better quality and mass production.

Interested in seeing what you can do with BrickForge parts? Check out their Flickr pool.

John Baichtal

My interests include writing, electronics, RPGs, scifi, hackers & hackerspaces, 3D printing, building sets & toys. @johnbaichtal nerdage.net


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