Welcome! Log In Create A New Profile

Advanced

Motion unit development

Posted by atmark 
Re: Motion unit development
December 18, 2019 12:05PM
It has been quiet for some time now around the motion system. I've been waiting for the 1 mm braided Dyneema line with a reflective pattern. I should have paid a little bit for shipping with a faster parcel... Hopefully I get the line before Christmas
VDX
Re: Motion unit development
December 18, 2019 02:07PM
... here something as sort of "heads-up", to show, what's possible with wire-kinematics cool smiley

[www.youtube.com]


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]
Re: Motion unit development
December 18, 2019 03:15PM
This is so cool! I love the fact, that you can upgrade from 3 DOF to 6 DOF fairly easy (at least mechanically).

The Fraunhofer Institute has also some pretty impressive CDPR-machines.
VDX
Re: Motion unit development
December 18, 2019 03:58PM
... are you aware of this 12 years old thread? - [reprap.org]

This "3-fold wire setup" can too easily be updated/modified for 6DOF cool smiley




Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]
Re: Motion unit development
December 22, 2019 06:50AM
Just wow! eye popping smiley
I'm impressed, so you basically described the Hangprinter concept 12 years ago!?

The idea with the ball-gliders was something I didn't get completely. Did you mean ball bearings for routing the wires?

Quote
VDX
Re: Parallel-kinematics versus string-pod
December 04, 2007 09:51PM Admin
Registered: 12 years ago
Posts: 12,332
... by the way - by rethinking the wire-systems i realized, that this could be an extreme cheap'n'easy repstrap-basis ...

With some ball-gliders, magnets and a steel-plate (or a MDF-plate with an atached iron-sheet) above the wire-plane i can apply a toolhead, which is fixed through the magnets upside-down at the plate, glides freely around with the ball-gliders and is positioned by the wire-tripod.

With good magnets it's no problem to hold some kilograms upside-down, so the toolhead, the extruder/syringe and the support should be manageable ...

With a second wire-setup there could be a hoovering plate under the construction, which could be elevated in Z up and down, to complete the 3-dimensional repstrap.

Imagine a wire-tripod-repstrap fixed under the ceiling, which lowers the bottom-plate with the fabbing-process, so the ready parts comes down automatically and in idle-mode the aparatus is 'vanished' to a thin plate under the ceiling - maybe with some keen paintings on the bottom winking smiley

I estimate an extreme low count of mechanical parts and assembly-working:
- 4 driving motors: 3 for the wire-tripod, 1 for the elevator
- some meters of thin steel-wire
- basis-plate with iron-sheet (for the magnetic fixing)
- bottom-/elevator-plate
- 3 ball-rollers
- 3 strong NdFeB-magnets
- upside-down-tool-head with extruder and feeding
- rolls for wire-feeding
- some scrap for assembly ...

The electronic is the same (with 4 motors) and the software has an additive converter from X,Y- to {La,Lb,Lc},Z-paths, as mentioned in the post above ...

Viktor
VDX
Re: Motion unit development
December 22, 2019 09:58AM
... yes, in the "first years" we're discussing and testing many of concepts, which (when ever) came to life years later ... my first "delta" concept was from 2007 cool smiley

Quote
atmark
The idea with the ball-gliders was something I didn't get completely. Did you mean ball bearings for routing the wires?

- no, it was meant for the (triangular shaped) toolhead, sitting upside-down on an iron plate (which is fixed to the ceiling) ... attracted with magnets to the plate ... and 3 balls in the edges were used as "rollers" winking smiley


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]
Re: Motion unit development
December 27, 2019 10:07AM
Quote
Atmark
... the Hangprinter concept ...
I think Seil-Tripod is more similar to Tetra (than to Hangprinter). They both constrain xy-rotations with vertical parallelograms spanned up by lines, tool-head and anchors. They both also have three high anchors and no low anchors. Hangprinter constrain xy-rotations by having three low anchors, and constrains z-rotations with non-vertical parallelograms. Many other interesting setups have been described in the wider literature on cable driven parallel robots.

Cable driven robots in still haven't had the big breakthrough in usage that many anticipated 10-15 years ago. I don't know why, maybe I just haven't looked hard enough for it.

RepRap forums (and also blog) from the early days are real gold mines for ideas, inspiration, and for learning way-of-working within RepRap development. Clicking a knowledgeable user's name (like VDX), and reading all their posts is something I would do around the time when I made the first Hangprinter. I would also search the forum with Google searches like
cable driven site:forums.reprap.org

Highly recommended smiling smiley


blog
Re: Motion unit development
December 30, 2019 12:53PM
My intention wasn't to dismiss your work, Tobben. Not at all! I was just amazed how far back in time the cable driven robot/printer concepts go.
VDX
Re: Motion unit development
December 30, 2019 04:12PM
... the first years of RepRap was a pretty "innovative" phase - the Delta-concept was too born around 2007 (named it then "tripod").

Other ideas, like "endless belt printing" or "fluid support printing" or "tree-like supports", and many more too, were discussed in the forums, but not all were realized by time ...


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]
Re: Motion unit development
December 30, 2019 04:42PM
My point too was that cable driven 3d printing is an older and wider concept than just HP. No worries, you're not dismissing my work, rather the opposite winking smiley


blog
Re: Motion unit development
December 31, 2019 08:07AM
Couple of interesting photos before the end of year! The mail-man dropped at last the dyneema line I've been waiting for.
Check especially the video! It reveals a distinctive pattern on two sides and perpendicular to that pattern a second pattern, that repeats itself every 5 mm.
Those patterns are formed by two reflective yarns that go through the braid in opposite directions.

The line is a 1 mm line with UHMWPE (dyneema) core and a polyester jacket.
It should be able to withstand at least 40 kg of drag. And it is, as advertised, stiff and round with a smooth surface, although the reflective yarn makes little bit wavy on the side. That might cause a pattern, similar to Z-wobble. But anyway, I bought this line for testing purpose. If the sensor readout works with this line flawlessly, I might tend to invest a bit more for a heavy duty dyneema rope 2-3 mm. Those are rated between 200-400 kg of drag.

I'm pretty convinced by this so far! Next year, I get back to business. Happy New Year!! smileys with beer





Close-up video
Re: Motion unit development
December 31, 2019 09:00AM
Quote
atmark
Couple of interesting photos before the end of year! The mail-man dropped at last the dyneema line I've been waiting for.
Check especially the video! It reveals a distinctive pattern on two sides and perpendicular to that pattern a second pattern, that repeats itself every 5 mm.
Those patterns are formed by two reflective yarns that go through the braid in opposite directions.

The line is a 1 mm line with UHMWPE (dyneema) core and a polyester jacket.
It should be able to withstand at least 40 kg of drag. And it is, as advertised, stiff and round with a smooth surface, although the reflective yarn makes little bit wavy on the side. That might cause a pattern, similar to Z-wobble. But anyway, I bought this line for testing purpose. If the sensor readout works with this line flawlessly, I might tend to invest a bit more for a heavy duty dyneema rope 2-3 mm. Those are rated between 200-400 kg of drag.

I'm pretty convinced by this so far! Next year, I get back to business. Happy New Year!! smileys with beer





Close-up video

Let's hope the patterns on the rope don't leave any artifacts on what the machine is making!


http://www.marinusdebeer.nl/
Sorry, only registered users may post in this forum.

Click here to login