Hi Will, welcome to the Zone! It sounds like you're pretty much up to speed with the modeling side of all this, but new to the machining end. There are several reasons why more people don't use robot arms for
carving, although it has been done to some extent. First off, they don't have much mechanical advantage or rigidity. Both are things that really help when dealing with carvable materials, and the harder the materials are, the more you need them. The arm in your video wasn't exactly a light-weight machine, but it was only capable of carving light-weight materials.
The second factor is the software. In order to take advantage of all those potential axes, you need some very powerful CAM software. It didn't look like the toolpath being executed in your video was any different from something that would run on a regular Cartesian machine with an additional rotary axis, but you would have to pay a lot more for the software that would tell it what to do. The math just gets a lot more complex with each rotary axis you add, and if all the axes are rotary, you're locked into some pretty expensive software.
The third factor, and the one that's kept me from jumping on some good deals on robot arms that have come up, is safety. Okay, I confess I'm a chicken, but I'm still a live chicken.
I've seen regular routers do odd things unexpectedly, but have fortunately been out of their reach when they misbehaved. These robot arms, however, aren't confined to an easily observable danger zone; it seems like they can easily reach out and smack you - in which case, you'd stay good and smacked...
But if you're undeterred by any of this....]
OK so enough commentary. Here are my questions.
1) What size of an arm do I need? Since this thing is only milling foam and clay. I need speed and accuracy. Mill 4 or 5 foot blocks of foam and clay. I don't need a huge 2 ton robot arm.
[I think you might, if you're to get an accurate surface. And I've never heard of anyone milling clay; I don't think that would work too well if it was wet, and if it was dry it would be hard on tooling as well as extremely messy.]
2) I need it to change tools and a coordinated 7th axis rotary table (any info on this working with Robotmaster would be helpful)
[You might call Robotmaster and ask them about that.]
3) Source for foam blocks so I can price them.
[Here are some links:
Foam Sheet: General Plastics Manufacturing Company
Elliott Company, Manufacturer, Fabricator, ELFOAM, Polyisocyanurate and Polyurethane Foam Products
Dimensional stability, machinability-Precision Board Plus HDU ]
4) Does the robot arm need the large refrigerator (computer, controller? Not sure what it is) attached to it? If so how does Mastercam and RobotMaster running on a PC connect and control the robot arm (or does it?)
[MasterCam is just a software program; it writes the toolpath G-code program but doesn't directly run a CNC machine. It seems like Robotmaster is essentially a plugin to MasterCAM that allows it to deal with the peculiarities of robot arms, but it doesn't actually run the arm either. I think you'd have to rely on the original (refrigerator-sized) controller/driver for the arm you selected to interpret the code and actually move the arm.]
5) Alot of these robots are built for Palleting and arc welding and painting. Are milling attachments universal to find and add to an exsisting robot arm? Source or link?
[There are reasons, touched on above, why they aren't used for milling very much, but there are companies that will provide spindles for them. Here's one: PushCorp - The Leader in Force Control Tooling ]
6)Thanks for your time answering to a newbie
[No problem, Will - let us know if you really get one of these things, and how it goes with that, okay?]
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