Multiple heads for faster printing

[noodles 0]

This is one of those "shot-in-the-dark" naive kinds of ideas, but here goes...

I remember seeing on here previously people talking about different ideas for printing in colors (mixing plastic, multiple print heads, etc). I think there's even a new Makerbot that has two print heads. I was watching a video of a print running (I don't have my printer yet) and what I noticed is that it prints the wall of a layer very quickly, but then proceeds to spend a lot of time pushing the print-head back and forth to fill in the interior area with thin little stripes (I'm talking about solid layers, not the internal support hexagons for hollow objects). Anyway, why not add another print head, not for the sake of color, but with a wider nozzle to fill large interior areas of a layer more quickly. The tiny nozzle would build the detailed sections first and then the large one would fill in the open spaces. I realize you'd probably go through engineering hell trying to get the layer thicknesses the same between two nozzles extruding different volumes of goo, but the upshot is that once you achieved that, you could make drastically fewer "swipes" over large open areas, which would probably mean faster prints and maybe even better print consistency, since you'd probably be less likely to skip steps if your paths were shorter and you're turning fewer tight corners. I guess it would only help to the extent that you have large flat areas that need to be printed. The first few and last few layers of the whistle would go much faster, but the others probably less so.

Anyway, just a random thought on a Wednesday night.

[Daid 278]

The problem with a 2nd printer head is that it's almost impossible to stop a head from dripping a bit. So while you are using the 2nd head the first head is still dripping bits of plastic, same the other way around. The bowden tube makes this even worse.

So it can be done, but it would be pretty experimental, and you'll need a lot of calibrating and tweaking to get it right.

[somerwil 0]

I was looking at a welding torch we use at work (not by me since that will be a very bad idea :-)). Our torch is 6 meters and pretty long for a torch. It's a MIG machine so welding material is added through a 6meter cable.

The system uses a so called push-pull system. On the base unit there's a push motor assembly. On the torch side there's a (much smaller) pull system which is integrated in the pistol. The push system pushes the weld wire through the 6meter cable while the pull system is for the final tuning of the wire feed.

When you think of the push system as the standard extruder motor assembly at the back, probably a really tiny pull system on the print head side may prevent dripping(?).

It's just an idea, don't know how to easily implement this idea on the UM to be honest but perhaps someone comes up with good suggestions. motor synchronisation will be a point of attention as well as print jead weight

[andrev 0]

anybody tried a needle shutter or something like in the printhead?

[andrev 0]

anybody tried a needle shutter or something like in the printhead?

I meen a needle valve like in a hotrunner from an injection moulding machine.

[somerwil 0]

Basically the same idea but sounds like a solution requiring less space and weight! The only thing I can think of as a downside is reliability although I think these can be tackled in some way.