RE: [CAD_CAM_EDM_DRO] Re: Open (i think) design for a parallel robot (reprap may be interested)

> Is it just me, or are there others wondering what these
> machines are intended for?
>
> How can the apparent goal of self-replication (of a largely metalic
> machine) be
> accomplished by squirting layers of hot-melt plastics? Or
> carving foam??
>
> They're fascinating to watch .. but other than
> rapid-prototyping (making plastic models of things), and/or
> as a conceptual challenge, of what utility are they for
> getting -real work- done??? Or is that not the point?? Is it
> all really academic for you folks? Engineering student toys,
> in other words. That's how it sounds to me, so far. Maybe
> it's enough to get it built and moving, with little thought
> as to what can actually be -done- with the thing?? A useless
> robot, in other words. But utility may not be the point. In
> which case, why is the whole thing relevant here?
>
> Things have to be really beefy to do heavy, yet precise, work
> in steel, and I don't see how eliminating mass is going to
> work at all for us home- shop types doing metal. Plastic
> bearings wouldn't last long at all, either.
>
> Yes, I know a tripod is a very strong structure. And I do get
> the concept of the things. But, there has to be mass
> somewhere, doesn't there?? How can a decent spindle holding
> real milling cutters hang off spindly legs?? Or is there a
> 'scale' thing here I'm not getting?
>
> I DO admire those who think out-of-the-box, tho. And I sure
> hope you smart folks can come up with a revolutionary
> home-built, -useful- for everyday work, machine.
>
> Ron Yost .. looks at his quaint mill and lathe and ponders
> the universe.

Something else for you to ponder -
http://www.bathsheba.com/sculpt/process/index.html#3dprint

Rapid prototyping in itself can be real work, the ability to quickly come up
with a few mockups is quite handy. One use for these machine is for
jewellers, carving stuff out of wax, then casting it out of metal.

A hexapod has more degrees of freedom than a normal mill, they come close to
the abilities of a 5-axis one. Consider an engine block with angled ports,
on a normal mill you'd need to tilt & rotate the block to drill or polish
them, but a hexapod can do it without moving the block.

I've seen pictures of very hefty hexapods, so scaling isn't a problem. Look
at how fast normal mills are today compared to 20 years ago.

The mill & lathe combination in the workshop probably won't change anytime
soon, you don't need a hexapod to drill a few holes in a bit of steel.
Inertia plus the fact there's nothing a hexapod can do that a normal mill
can't means there won't be a rush to replace them. A bit like 4-cylinder
engines vs rotary ones. If the rotary was 10 times as good, then we'd all
have them. A little better or just the same means 'why bother?'

Be careful about dismissing something as a toy, history is littered with the
remains of those who made that mistake, from steam shovel makers about
hydraulic diggers, to mainframe computer makers about personal computers.

Tony