Tripteron Implementation November 03, 2016 07:45PM |
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Re: Tripteron Implementation November 04, 2016 12:44AM |
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Re: Tripteron Implementation November 04, 2016 04:50AM |
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Re: Tripteron Implementation November 04, 2016 09:54AM |
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the_digital_dentist
Interesting mechanism! I think the most critical part of the build is going to be the hinged joints. Once you get the platform/extruder moving around I think you'll find that the L shaped frame isn't going to be nearly rigid enough- look at the size of the frame members used on the machine in the video.
Re: Tripteron Implementation November 04, 2016 09:57AM |
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Re: Tripteron Implementation November 04, 2016 10:00AM |
Registered: 8 years ago Posts: 143 |
I don't think the Z will be any more difficult with accuracy, per se, but I'm currently using 20T pulleys on 1.8° steppers, which gives me 200 micron/0.2mm for full steps. 12T would give 125/0.125mm.Quote
o_lampe
*signed*
The z-axis will be the toughest part regarding accuracy. Like with deltas you might want to use 0.9° steppers. An 8bit controller would do, though.
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All the arms are working on side load only. A nightmare to make it stiff and light at the same time. Carbon rods would be my favourites.
Hinges were already mentioned, but doable.
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I have a few steppers with linear guides from DVD-drives laying around. Tempted to build a tiny demo version of it.
Print volume almost equals build frame and kinematics are easier than with CoreXY.
I love it!
-Olaf
Re: Tripteron Implementation November 04, 2016 10:13AM |
Registered: 8 years ago Posts: 143 |
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Origamib
The print volume doesn't match the arms unfortunately, so enclosing the printer is difficult. When the Z arm reaches 0,0 for X and y, it will extend outside the build volume by about half the distance of y, so a 40cm cubed build volume needs an 80cm wide and 60 cm tall frame. This is assuming the arm is nearly fully extended at the furthest point away from its base.
A corexy can reach a better build volume /frame size ratio if designed well I believe.
If well built though, this will be somewhere between a delta and corexy for speed, and can easily be made to have multiple degrees of freedom. It will possibly be cheaper to make than other machines too, depending on how the arms are made. I like it! Since you postest this in your other thread I have started designing my own.
Re: Tripteron Implementation November 04, 2016 10:17AM |
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Re: Tripteron Implementation November 04, 2016 03:22PM |
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Re: Tripteron Implementation November 05, 2016 04:14AM |
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Re: Tripteron Implementation November 05, 2016 06:07AM |
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o_lampe
I've used PETG to build semi-flexible but tough parts. Using CF reinforced PETG seems to be a step in the right direction, but is probably not the stiffest solution? ( and expensive too )
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Also you loose print volume with the way your joints intertwine. In robotics, arms are often placed side_by_side, so they are ( almost ) fully foldable.
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What if you print the joints only and build the arms by clamping them on real carbon tubes.
..but one step at a time
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PS: Do you think counterweights on the arms would help against platform sagging? ( My biggest concern regarding z-axis accuracy )
Re: Tripteron Implementation November 05, 2016 07:56PM |
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Re: Tripteron Implementation November 05, 2016 08:36PM |
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Re: Tripteron Implementation November 05, 2016 11:21PM |
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Re: Tripteron Implementation November 06, 2016 06:34AM |
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Re: Tripteron Implementation November 06, 2016 06:18PM |
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o_lampe
I'm still concerned about the z-axis sagging and would like to ask, if a second z-stepper on the diagonal opposite side of the cube would make sense?
From what I see, the other arms wouldn't interfere.
You know the z-axis accuracy is so important for 1st. layer adhesion, I'd accept the added weight and cost for an additional set of arms,pulleys etc., just to make sure the design is on the save side.
Maybe the individual arms could be lighter then, since they share the platform weight.
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I'm not a big fan of screws used as shafts, especially in such a critical place. Real 5mm shafts sure would have less play in the bearings...( You know all about it, but I guess, you want to get it running asap )
Re: Tripteron Implementation November 06, 2016 06:22PM |
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Re: Tripteron Implementation November 06, 2016 09:39PM |
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Re: Tripteron Implementation November 06, 2016 09:56PM |
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Re: Tripteron Implementation November 07, 2016 12:27AM |
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Re: Tripteron Implementation November 07, 2016 05:52AM |
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Re: Tripteron Implementation November 07, 2016 07:54AM |
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Re: Tripteron Implementation November 07, 2016 08:01AM |
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Re: Tripteron Implementation November 07, 2016 08:15AM |
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JonathanThompson
As I just mentioned in IRC: a funny thought is you could gang 4 of these together to use only 3 motors for the XYZ axes and a separate motor for each extruder, and have 4 things printed simultaneously for minimal costs
(Pretty hefty steppers, and of course, if one fails in the middle... well...)
Re: Tripteron Implementation November 07, 2016 09:15AM |
Registered: 8 years ago Posts: 143 |
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David J
The only significant disadvantage I can see so far is the space it takes on the bench with its "elbows" out. A bit like sitting next to a selfish eater at a dining table...
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It would be interesting to mount a dial indicator on the central part, to see if it can maintain an even height over the bed.
Re: Tripteron Implementation November 07, 2016 09:21AM |
Registered: 8 years ago Posts: 143 |
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o_lampe
What about your linear rails ( mgn12 I guess)? Do they show any slop or springy moves? I've replaced the balls of my rails and they run supersmooth now! ( German Wertarbeit )
Re: Tripteron Implementation November 07, 2016 12:21PM |
Registered: 10 years ago Posts: 893 |
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Apsu
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It would be interesting to mount a dial indicator on the central part, to see if it can maintain an even height over the bed.
Not sure if you mean if it's possible in theory or if the particular material choice and part tolerance I've ended up with can do it
Re: Tripteron Implementation November 07, 2016 12:29PM |
Registered: 8 years ago Posts: 143 |
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David J
I wouldn't be so spiteful! No, I just meant that it would only be of any use as a 3D printer if it could move in a flat plane - if it can't then it's of academic interest only. Nice if it does work OK though.
Re: Tripteron Implementation November 07, 2016 05:03PM |
Registered: 8 years ago Posts: 143 |
Re: Tripteron Implementation November 08, 2016 01:20AM |
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