My deal.

((note, this post has been sitting in draft status for a little while now. i'm going to try to catch myself up and hopefully soon, start posting about what i'm dealing with in more or less real time.))


This is where we quickly go through the mechanicals and some of the hurdles I've seen and some that I expect.

There's a few ways of getting into the project. The best, and hopefully eventually the easiest way, is to get in with someone or some group who have one up and running. They can print you the parts and you can be on the merry way (though the non-printed portions are still a bit expensive, you'll still save a bunch).

We've haven't hit saturation yet, so it might be a bit hard to get a hold of some reprapped pieces. That's where the concept of repstrap comes in. A reprap is a self-REPlicating RAPid prototyper. a repstrap is a bootstrapped method of making a repstrap, it can't make itself, but it can make parts for a reprap.

There are quite a few ways of doing this. Two common paths include a Mcwire, or a Darwin clone (Darwin is the name for the "standard" community designed reprap, but you knew that if you checked the link I gave in the last post.). Mcwires are a good quick and cheap way of getting a cartesian bot setup up and running. Darwin clones look and feel like a standard reprap, but are generally made of differnet materials. Laser cut acrylic is very common (ponoko or bits from bytes), the original darwin unit was made with cast plastice parts, and some have even successfully cut and carved darwin pieces out of wood.

the benefits of the clones is that you can replace parts as you go, a corner bracket here, a motor mount there. with the mcwire, you can fabricate all of the darwin parts, and then build it up and swap your motors and electronics. right now all use the FDM head, and that would simply be transfered (oh don't worry, people are working on all sorts of fabrication heads and methods, dunno how close they are though.)

oh, and there is also the little and cute Cupcake from Makerbot. basically a small modified mcwire (by what i can tell, moveable stage, though i can't see how the z-axis is implimented.) It's made to use the generation 3 electronics which look real good, but since it is so small and cute it is limited to a 10x10x10cm build volume.

I knew I only wanted to buy one set of the electonics, and only one set of motors so I didn't want an eviscerated mcwire sitting about. Not many reprappers in these parts so no reprapped parts available, and I'm sure that normal demand for parts is through the roof anyway, or at least great enough that the laser cut solutions can charge me $300+ for the privilege. So that's what I went with. Vik on the forums was able to provide a slight discount through Ponoko, which is definitely nice.

Now, when I start building parts I can replace them as I go (or as they break; unfortunately acrylic is fragile and so I have to avoid over tightening, and so it can loosen, and as I re tighten, there's another chance of breaking, etc.) The build instructions aren't identical, but they are similar enough to make it work (as far as I can tell)

As an mechanical engineer, the physical build is where I think I can help the most. Of course one member of the forum, Forrest, is quick to dismiss if he doesn't feel you've put in the time and I'd have to agree, so I quietly decided to hold my cards until I've followed the group and built a working unit. Then I can start pushing out modifications and updates that can maybe simplify or refine issues I feel the design still has. Of course the community doesn't have to follow, but I'll state my case here on this blog and we'll see if the refinements are determined to have merit and are adopted or at least considered in the general design direction. When I first got involved in the project I made some comments on some gaping holes I saw in the heat transfer design of the extruder, and hopefully that helped one of the key engineers, nophead, decide to look into it a bit more with some fantastic experiments and prototypes. Even if my comments just happened to coincide with his efforts, I'm glad I made them. When I have my hapsrap running I'll be right up there with them, testing the state of the art.