Welcome! Log In Create A New Profile

Advanced

pantograph 3d printer

Posted by herve robert 
pantograph 3d printer
November 20, 2018 03:39PM
hello folk's

I've got this idea since a couple of weeks.

see pictures.

it's just a model.

lot to do before it works. but it seems interesting.


+




Edited 3 time(s). Last edit at 11/20/2018 03:51PM by herve robert.
Re: pantograph 3d printer
November 20, 2018 09:18PM
Ie a polar system...

eg like the R360 [reprap.org]

I note the video likes are broken so ill repost them here..
[www.youtube.com]
[www.youtube.com]
Re: pantograph 3d printer
November 21, 2018 01:56AM
this is two videos:

videoA

videoB


it's not exactly like R360 printer.


you've got a turntable too but there are three angular movements (θ, φ, t).

(r360 have two linear movements X,Z and a angular movement)

Edited 2 time(s). Last edit at 11/21/2018 12:04PM by herve robert.
Re: pantograph 3d printer
November 21, 2018 09:07AM
With a pantograph, your Z motor movements and speeds will be amplified significantly, (Assuming you don't attach it at a 1:1 point which would defeat the purpose of a pantograph by making it huge) so you will have to incorporate lots of extra Z resolution, compared to the R360 linked.

It looks like a lot to deal with in slicing due to all the tangents, but you must already have that part sorted.

Neat design.
Re: pantograph 3d printer
November 21, 2018 12:10PM
hi everyone

some features "expected".

- balanced-arm with a counterweight
- least amount of parts, no or no long belts, no rods, ..
- majority of printed (or cnc) parts
- easy to built
- bargain price but good quality too
- (θ,t) simple bearing like in record player turntable
- small printing size (about pantograph, I'm worried about the size of he arm. if it's too long, it could be wagging (and so poor accuracy).

maybe it's not a good design and it'll never work but someone could have a better idea... who knows ?



Re: pantograph 3d printer
November 21, 2018 03:19PM
It would work, might make a good large scale printer because the cantilever is half the size because of the turntable. The frame would me much simpler and therefor might be somewhat more practical then other large scale designs.
Re: pantograph 3d printer
November 22, 2018 11:34PM

Re: pantograph 3d printer
November 23, 2018 08:11AM
Same issues as here:: [reprap.org],

"....- easy to built
- bargain price but good quality too
...."
?


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: pantograph 3d printer
November 25, 2018 03:00AM
Instead of rotating the arm, you could move the bed in Y-direction.
Otherwise you'll have limited movement when the printhead is closer to it's center of rotation. (eg. at low and high Z-coords)
Re: pantograph 3d printer
November 26, 2018 11:41AM
yes , it's true.
it's not easy to print near to the center of rotation.
if you move in the Y-direction, you have to move the turntable mecanism too or the pantograph.
but look a this (it's only hypothetical):




but the main idea is the pantograph.

one point is to built a direct drive (instead of the bowden system) but without an overload

the filament drive motor is not at the end of the cantilever but centered on the main axis



another point is to use a dual-shaft motor to drive each side of the pantograph up and down



Edited 2 time(s). Last edit at 11/26/2018 12:21PM by herve robert.
Re: pantograph 3d printer
December 01, 2018 12:19PM
sketch with openSCAD






Edited 2 time(s). Last edit at 12/01/2018 03:33PM by herve robert.
Re: pantograph 3d printer
December 02, 2018 03:24AM
I thought about that angle too. It changes with Z-position. A CV-joint at the far end of the stepper shaft would help.
Shop for 4WD RC-car-spareparts, you'll sure find plenty.

BTW: Why not use the extruder-motor as counterweight?

Edited 1 time(s). Last edit at 12/02/2018 03:26AM by o_lampe.
Re: pantograph 3d printer
December 02, 2018 01:39PM
maybe CV-joint could be a very good design to cancel the angle.

not very easy to drive the filament in the heater

and today I made this
sample of gears to drive the turntable.

the motor as a counterweight is a good idea too smileys with beer



Edited 2 time(s). Last edit at 12/02/2018 01:44PM by herve robert.
Re: pantograph 3d printer
December 02, 2018 04:14PM
Maybe a belt would have less play?
Re: pantograph 3d printer
December 04, 2018 01:36PM
The Z movement is an arc.
? Slicer post processing to correct ?

Wally 3D printer used a parallel arm to move table

[reprap.org]

[archive.fabacademy.org]

Wally really never worked
I have one sitting on a shelf gathering dust!

confused smiley
Re: pantograph 3d printer
December 05, 2018 01:30PM
thanks.

I didn't know the wally printer concept

as far as I understand, it seems that the bed elevation is not balanced ...


yes, probably need some code tweaks to had the right print head movements.


about the use of belt.. maybe... strings or ribbon... with weight for backward movements of θ, t .

not quite totaly sure...


Re: pantograph 3d printer
December 07, 2018 05:45PM
On wally a movable pulley on bed was no problem to lift bed
When motor turned OFF -- stage fell to bottom --- really need stepper with brake

Correcting arc to linear NOT trivial in slicer code or post processor

Here is python code by Nick Seward (inventor of wally) to correct arc in Z motion

wallysegmentize.py

Good Luck

confused smiley
Re: pantograph 3d printer
December 08, 2018 07:10AM
yes probaly need of lot experiment to fix all this stuff !

thank you for the code
I will look closer to the work of Nick Seward



I want to try this too
it s more about the extruder so I made a another topic.
Dual drive extruder
Re: pantograph 3d printer
December 08, 2018 11:02AM
Quote
cozmicray
On wally a movable pulley on bed was no problem to lift bed
When motor turned OFF -- stage fell to bottom --- really need stepper with brake

Correcting arc to linear NOT trivial in slicer code or post processor

Here is python code by Nick Seward (inventor of wally) to correct arc in Z motion

[attachment 108504 wallysegmentize.py]

Good Luck

confused smiley

Is the Wally failure due to bad luck ?


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: pantograph 3d printer
December 22, 2018 04:44AM
I have try this with an elastic:








work not so bad.. see video too. video










Edited 2 time(s). Last edit at 12/22/2018 04:45AM by herve robert.
Re: pantograph 3d printer
December 24, 2018 06:25AM
re purpose the rotating base from this [www.thingiverse.com]
Re: pantograph 3d printer
December 26, 2018 05:39AM
Quote
MechaBits
re purpose the rotating base from this [www.thingiverse.com]

interesting
you've 10 teethes gear and a 100 teethes gear ==> 10 ratio.

with tape I hope an higher ratio ==> 16 or 20 or higher..

and maybe for the z axis, this design:



Edited 1 time(s). Last edit at 12/26/2018 05:47AM by herve robert.
Re: pantograph 3d printer
December 27, 2018 02:30AM
The tape is thin, but it will build up in diameter. That will change your ratio.
You'll have to take countermeasures like nonlinear kinematics or increase the diameter of the bed accordingly.
Re: pantograph 3d printer
December 27, 2018 03:50AM
Seriously ? For a 3D printer ? Even with properly built parts !

BUT you should try "Gestural Engineering" ! Artist Arthur Ganson
Last spring in Boston, I visited the MIT museum and really it is a kind of art I like. Worth the visit !

[mitmuseum.mit.edu]

Edited 3 time(s). Last edit at 12/27/2018 04:24AM by MKSA.


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: pantograph 3d printer
December 29, 2018 03:16AM
@o_lampe

that's the point. I suppose an appropriate spiral shape for each angle (θ, φ, t)... cancel tracking error.

in the case above spiratic shape: smallest diameter 10 cm / biggest diameter 12 cm, tape 30 microns and motor shaft diameter 5 mm = constant ratio 20 ( vs cylinder with 10 cm "constant" diameter = ratio between 16 - 20)


@MKSA

lucky you are if you have the paul graham's mood...

http://mediation.centrepompidou.fr/education/ressources/ENS-Duchamp/popup02.html

Edited 1 time(s). Last edit at 12/29/2018 03:24AM by herve robert.
Re: pantograph 3d printer
December 29, 2018 11:13AM
Quote
herve robert


@MKSA

lucky you are if you have the paul graham's mood...

http://mediation.centrepompidou.fr/education/ressources/ENS-Duchamp/popup02.html

Not at all the same as Arthur Ganson ! His creations are really "working" and based on gears, belts, chain, even oil viscosity ....


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: pantograph 3d printer
December 29, 2018 01:48PM
Wally development

Some designs were proposed to make Z Axis linear.
Don't know if anybody implemented them?

Inventor went on to better designs!

confused smiley
Sorry, only registered users may post in this forum.

Click here to login