I have got a bit further with my new Cablebot design. It now has a Z stage using cables. There are some photos on smugmug. So far I do not have an extruder working and the Bowden tube I got is to thin to pass 3mm filament. However it will zoom about the place and seems to be behaving well.
http://astro.smugmug.com/Hobbies/3D-Printer-Cablebot
Very clean design. The Z stepper looks twisted some. Is that due to the way the line is on the spool. I am always worried about using line, although ever body that uses it says it is good.
Awesome awesome awesome.
@Sanjay_Mortimer FYI
The V bars are they aluminum tubes?
Yes the V truss tube assembly is made of 12mm aluminium tubing about 500mm long. This shape is very, very, strong and rigid. It comes from my background in telescope building.
@Wayne_Friedt I have yet to do a final design and yes there are some parts of the Z axis that is twisted. I need to turn one pulley 90 degrees and alter the position of some parts to help things line up. I didn’t make a full 3d design so there are a few interference issues. This is a first cut so it will only get better, this is an Alpha model hahahaha. I have had it moving all afternoon and it seems to work fine. The Z axis does fall to the bottom if the motors are not engaged but I am thinking of a simple counterweight like on a lift to fix that, not that it really matters. Can’t wait to push plastic through it !
Fantastic!
@David_Moorhouse after hearing about problems with core xy and standard hbots having problems with sharp corners, I’m leaning more and more toward your design. Glad to see the great progress. Thanks for posting all your pictures
This is of course NOT a coreXY system there are two seperate cable paths and the motors only do X or Y unlike other H-Bot designs. So I can use normal marlin code. I have yet to push any plastic through it so these are early days. I still don’t know if I will get any cable slippage over a long print. It seems to be fairly positive in its movements. I am now waiting on some PTFE tubing for the extruder and have to make a bowden extruder motor unit as well. The tubing on the unit in the photos is slightly small ID so the PLA sticks in the tube.
I have added a few more photos to the smugmug site to show the cable layout. One is stolen from Tim (thanks for the great diagram) the other two are from a webpage about an old school ink pen plotter. http://capolight.wordpress.com/2012/04/14/old-school-scientific-pen-plotter-teardown/
This is awesome all round - I want to make something very similar, but probably with syncromesh on XY and leadscrews on Z.
What are those nice looking grooved bearing idler pulley things? They don’t look like ‘normal’ grooved bearings.
I just found another guy using the same idea from I think about a year ago but using belts. http://www.youtube.com/user/MaukCC/videos looks good, he calls his a Cartesio.
The grooved bearings are very cheap, from ebay US$10 for a bag of 20. Fairly poor quality but does not matter for a simple test machine. Something like this http://www.ebay.com/itm/261230886924?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
@David_Moorhouse , sorry my stupid phone has awful autocorrect. I edited my comment, in essence I’m liking your design much better than core xy, due to the independent axes. Isn’t it amazing multiple people coming up with identical designs, having never met? Never ceases to amaze me. Again great work, and thanks for the link to the grooved bearings
@David_Moorhouse
How’s your project? Can you upload Z axis files somewhere?
I have not really got much farther but it seems Richrap has made a finished design that has taken my idea and pushed to to a full working system.