Hey,
Agree, robot arm not a good choice for a first machine even if budget allowed.
[Frankly, they scare me. Regular CNC machines are dangerous enough, but they won't reach out and whack you.]
Indeed farming out the job to a 3rd party is prohibitive right now. But is a good option in case I get commissioned work or I manage to sell something from a render. Btw, do you know the names of any of these companies that would do a carving with a robot arm for me? I searched online some time ago but didn't really get anywhere.. any info you have would be great.
[I know of a place in Italy:
]
The sand molds are a great idea. I didn't know about Hoosier but had been in talks directly with ExOne before. They are relatively inexpensive. And you are absolutely right the expensive thing about the casting is the manual labor that goes into finishing the piece, not the casting itself. From quotes I have asked from artistic foundries casting in stainless, polishing to a mirror finish for example can increase the cost 3-4x. But that is exactly it, if I just cast the piece its no good to me how it comes out of the cast, I actually need it finished really nice because how it looks is everything in this case. So again we're back to square one.
[Yes, if you really need a mirror polish on everything. But there are other finishes that will also work that aren't as labor-intensive.]
The printing/casting/finishing is something I have already more or less figured out for my higher end pieces (see attached pic as example of table I cast recently in aluminum. Even with all the work that went into it up close you can still see lots of imperfections which I'm not happy about).
[That's pretty cool. Everything real is going to have imperfections; get used to it.]
The idea here is to be able to sell something close to 'mass market', that would cost me less than $100 to make, and can sell for a couple of hundred. (A stainless steel sculpture for example is in the thousands or tens of thousands), that would still allow me creative freedom and the ability to work from 3d and make each piece unique if I wanted to. Milling wood (or plastic and finishing maybe) seems to come pretty close to this.
I wasn't aware lathes were restricted to radial symmetry, thanks for pointing that out. What I meant then was a 4th axis. Specifically a '4-axis with a deep Z'. What you built seems to be exactly what I need for many of my pieces. The dimensions are more than enough for most of the things I could imagine. I have been unable to find anything like that commercially available however. Are there any companies that do it? From the fact that you built yours Im afraid I know the answer. Would you be able to build me one?
[Sorry, but if you want to build one I'll be happy to stand on the sidelines and offer advice...]
Im not too worried about the hollowing. I have a friend that does a lot of wooden furniture that I think would be able to take care of it.
Im not sure what you mean by 'it would make more sense to create a master and and mold it, machining a plug to create the interior volume of the casting'. Are you talking about making the vase out of metal? Does that mean that your machine can carve a cylinder made of metal? I was under the impression we were talking about wood or other soft materials here.
[I was talking about making a master in wood, wax, or something else that's soft and relatively cheap, but casting the actual vases in concrete or something. similar. The "plug" would function as a removable core, so the thing could be hollow.]
I agree the tool length is my limitation. That's why I've been looking around for a rotary that can do more than 6", but as you point out, I haven't been able to find it much more than that. Why do you say the shorter the better? How did you get to 36"?
[Carving with a 6" tool means that you have about 5" sticking out, which is a lot. There's a lot of stress on a tool like that, so it can easily break. Also, cut quality suffers with a longer tool - there's more leverage to amplify tool chatter, and more deflection. Any machinist will tell you to cut your part with the shortest tool that will work. I made my machine capable of rotating a piece that was 36" in diameter because I wanted to be able to cut all the way around a large part, not because I thought I'd be able to carve everything I could imagine that would fit within that space.]
For the small aluminum pieces I think the 11" by 3" is still too small.. that's why I'm leaving those in the back burner for now..