uptownmaker wrote:I'm mixed between a Darwin as designed and trying to do something slightly, but not radically, different.
Primarily, I see no reason to adhere dogmatically to their parts list and parts design when any X-Y gantry with a Z adjustable table under it will do what we need. This opens up the possibility of scrounging a lot more parts.
Today I got from a coworker a large-format printer with a 24" print head displacement. It's a REALLY good start- we'd be hard pressed to make as good a stage as that.
I'm also going to suggest that we forgo trying to make this capable of cutting anything more durable than vinyl. Resisting the deflection of the tool tip is hard work, if you're trying to drive a tool through a rigid material.
jwb wrote:Mike, the Darwin is a 3D printer not a cutter.
I have had the same thought running in my mind for quite some time. I can see definite advantages. I like this!:uptownmaker wrote:A less intuitive fix (the one I'll advocate for) is to abandon XYZ entirely in favor of RӨZ... it'd be wicked cool, and WAY cheaper. Time to get ready for work. Anybody have any thoughts on this?
Lancaster provides plenty of helpful references too!Even more elegant is a revolutionary new virtual ways
system. Described in the August 15, 1994 issue of Design
News. Take a base plate and place six ballscrews or linear
steppers uniformly around a large circle on it. Now lean
each ballscrew by 45 degrees or so and attach them all to a
smaller upper head plate. The head plate can easily assume
all of the normal lathe or mill motions. But there are no
precision sliding contacts anywhere! All bearings are plain
old round ones. All forces are pure tension or compression
with zero side loadings.
This article was written in '94. Perhaps there's even a lot more information on this now.Additional support can be found on the Flutterwumper
Library shelf of my http://www.tinaja.com web site. And in my
Blatant Opportunist reprints.
Consulting services are also available on the concepts
shown. Let’s hear from you.
uptownmaker wrote:Time to get ready for work. Anybody have any thoughts on this?
I think this problem has been addressed with closed loop (feedback) mechanisms, but I don't know how much that would elevate the cost. Lancaster talks about using a dedicated computer to do complex math and just leaving the core or kernel operations to be handled by the flutterwumper.Judeling wrote:uptownmaker wrote:Time to get ready for work. Anybody have any thoughts on this?
...There really is no way to position the part to minimize tool movement and no software fix that can compensate for tool maladjustment.
But it is certainly cool and we should do it.
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