Desktop molding machines look awesome, and are way high on my list of things to build. Apparently you can make a hand crank version that works like a bottle capper for a few hundred bucks. It can make dozens of parts an hour from nothing but raw pellets, electricity and elbow grease. Pretty exciting. http://makezine.com/projects/make-41-tinkering-toys/diy-injection-molding/
They got me thinking about a 3D printer hack to replace the print surface with a clamping plate and the print head with some sort of super high flow extruder so you could use 3mm filament as feedstock. You could clamp 2 halves of a small mold into a vice on the bed, then program the printhead to move down to the filling hole (I know next to nothing about injection molding ) and extrude the right amount of plastic at the right time.
I have a small home made injection molding machine, fun little things. A 3D printer print head would have a hard time filling the mold before the plastic hardens. I inject at about 125psi. The plastic pellets all melt at once in the melt chamber, when all melted you pull on a plunger targeting about 125psi. This fills the mold almost instantly and that’s the key. You need the plastic in all the nooks and crannies before it cools at all. Also the injection head needs to fit the mold tight. Last thing you want is 200C plastic squirting out in you at 125 psi.
Of course he’s not doing anything more than holding a small mold up to his extruder’s nozzle. But maybe you’ll find some more info linked from that article.
Hey Everyone,
Some quick idea and features about desktop injection moulding… It has some bigger space between tie-bars and high precision, Stable and super long life. High Quality Linear Motion Guide ensure the smooth & accuracy of injection process
They got me thinking about a 3D printer hack to replace the print surface with a clamping plate and the print head with some sort of super high flow extruder so you could use 3mm filament as feedstock. You could clamp 2 halves of a small mold into a vice on the bed, then program the printhead to move down to the filling hole (I know next to nothing about injection molding ) and extrude the right amount of plastic at the right time.
There is a huge amount of science, mathematics and engineering that goes into one injection molding.
Plastic has to flow smoothly into the mold, it has to be fast, the plastic needs to cool evenly, it needs to be removable, it needs get into all the crevices before it starts to cool, ect.
There is a reason there are titles and life long careers in engineering and plastic injection molding.
) and extrude the right amount of plastic at the right time.
) and extrude the right amount of plastic at the right time.