Is this the goal?

Is this project trying to develop and reduce the cost of this kind of machine?
[www.zcorp.com]

Not really. ZCorp builds models out of plaster or starch set in place with a fixative. Our systems use Fused Deposition Modelling (FDM) which builds up models by extruding layers of molten plastic.

both yes and no. as forrest pointed out, we are not mimicking their deposition technique. however, we are aiming to build a 3d printer which is what that machine does. other than that, the major differences are that we are open source, ours costs a tiny fraction of what that machine costs, and this is the kicker: that we're designing the machine with the goal of it being able to fabricate its own parts. that makes it self replicating which is a hugely powerful thing.

we hope you'll help us =)

I am just curious that if i can build up a prototype which has a small bottom but a bigger top or some holes on it by extruding layers of molten plastic? Thanks.

That's possible, though its better to orient your design so that it tapers upwards and all holes run verticaly. This isnt always achievable. Reprap has achieved around 30 degrees of overhang. This might change with different materials. The stratasys FDM machine can achieve 45 degree overhangs, so reprap has some room for improvement yet.

Overhangs too great to support themselves require a support material, which will be removed from the model after extrusion is complete.

The RepRap prototype Zaphod has already achieved 45 degree overhangs. For small gaps, >45 degrees has been demonstrated.

Vik :v)

Very cool project.

I have often wondered how I would go about designing something like this. I think the point at which I stumble each time is requiring a support material. If I have to build everything tapering upwards, then it usefulness decreases substaially, as there are designs where this just isn't feasable...

Great idea none-the-less!

Carlo

Well, we want support material too. We're probably going to use a second head to deposit polyethylene glycol, or perhaps some other material.
[en.wikipedia.org]

-Sebastien

Sebastien,

I like the sound of that. That's the only way to do it right IMO.

You guys are winning me over with your ideas here. I'm currently working with a CNC milling machine, but ultimately I'd like to be adding material rather than removing it. I've dreamt of replacing my spindle with a pump for a while now, but figuring out how to create a program that knows where to add support material sounds complex (I don't know the first thing about writting software)... For your project I guess that's where the programmers come in, right?

That's what's so great about what you are doing. You are able to pool the knowledge base of a very wide range of people.


BTW, are you guys writting the control software from the ground up, or using a commercial solution?

Carlo

From the ground up. It has to be freely distributable or we can;t spread RepRaps as we see fit.

Vik :v)