As anyone who has ever owned a standard 2D printer can tell you, it isn’t the cost of the machine that gets you. The general theory behind printer sales seems to be to sell the machines as a vehicle for selling you ink. While 3D printers aren’t quite as inexpensive to buy as their 2D brethren yet, the constant between the two seems to be the price of the material used to fuel them.
Two-pound spools of plastic filament run in price anywhere from $30 to $80 (for the really cool glow-in-the-dark variety), and any hobbyist that uses their 3D printer on a consistent basis will run through a roll of the stuff in short order. Oddly, though, you can get 5 pounds of pellets made from exactly the same material for $25 or less.
The people at Inventables, a kind of hardware store for the maker crowd, noticed this disparity and in partnership with the Ewing Marion Kauffman Foundation offered a $40,000 prize to anyone who could design an extruder that ground pellets into 3D printer usable filament. The catch, if you want to call it that, was that the extruder must be able to be assembled for under $250.
The contest captured the attention of 83-year-old Hugh Lyman, a retired manufacturer. Since his retirement in 1996, Lyman had been tinkering around with a number of inventions, and the contest caught his eye. Not coincidentally, Lyman owns a 3D printer as well.
“Every time I buy a couple of pounds of filament, it costs me 40 to 50 bucks,” said Lyman. “I was burning through it pretty fast.”
Through some trial-and-error, Lyman designed and built the Lyman Filament Extruder and submitted it. The design was then rejected because he had miscalculated the cost of some of the parts he created himself. Undeterred, Lyman went back to the drawing board and produced the Lyman Filament Extruder II. The second machine came in under the price limit, and Lyman was awarded the $40,000 prize.
In principle, the design of the extruder is simple enough. You fill a hopper with the cheaper plastic pellets, and the machine melts the pellets before squeezing them out through a nozzle to form filament. Lyman hasn’t kept the design to himself, either. You can find the specs at Thingiverse. Being what it is, the maker community has already expanded on the design.
The Lyman Filament Extruder II marks the second device to produce inexpensive filament for 3D printers that we’ve seen, the first being the Filabot, which uses recyclable plastic to make filament. I’m sure we’ll see more of this type of invention as more hobbyist machines make their way into home workshops.
Below you’ll find a video of the Lyman Filament Extruder II.