Thursday, August 2, 2012

my rostock moving





7 comments:

Have Blue said...

Daaaaaaamn. Just like your grinder projects, you absolutely went from 0-60 on this in record time! Fantastic work - this will be a fascinating machine to watch when complete!

Frankie Flood said...

ha,ha, ha....

It's fascinating to watch it home itself. Today, it drew a picture and that was fun too.

eric said...

oh balls, you're so annoying franklin.

Frankie Flood said...

I don't have a clue about that which you speak of...

Have Blue said...

What's the rigidity looking like at the extruder mount? These hexapod type machines are fascinating to watch, but I always wonder about the resulting accuracy when compared to a traditional cartesian system. Do you think you'll wind up with repeatability comparable to a belt drive Mendel? Better? Worse?

Frankie Flood said...

Well right now the rigidity is junk. I put a dial indicator on it and it's all over the place. There are a couple reasons though and they are my own issues. One being that I haven't properly braced the frame with side supports yet. I'm also getting flexing (twisting) at the carriage where the linear bearing mount (the carriage should probably be extended to utilize another set of bearings). I also printed all of the parts in abs and they are probably not as rigid as if they were in pla. These are just a few of my immediate observations and like I said, I'm jumping the gun a bit because I just wanted to see it move.

There will be a lot of tweaking to do though once all is said and done because the positioning of the arms is really different out at the edge of the table vs. the center. I just don't think this design will be as forgiving on something not being "quite right" in the construction of the machine, as what a traditional cartesian system would be.

From the Rostock wiki:
"The steps per mm for X and Y is not constant across the print area. In the middle it is around 30 steps per mm, and near the edge it's more than 300 steps per mm because the push rods will be nearly horizontal."

I really want to build one that uses proper bearings at all of the joints and make the bearing holders very accurate and rigid. There really is something cool about the simplicity and then the amazing movement of these though. So mesmerizing to watch!

Unknown said...

I blinked, and then BAM! Frankie's got another sweet machine on the bench. Sheesh!

Seriously, though, that's so cool.

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