Tri-Polar Bot Concept -- Meet Wally Hello, First post here. There has been a thread going on for a short while on the "Delta robot 3D printers" Google Group titled "Delta mechanism variant" by Billy Zelsnack. Billy started it to explore using different simple arm mechanisms to position X,Y with a fixed Z plane. A lot of ideas were brainstormed by several contributors over the last couple of weeks. One complete concept grew out of those sessions for a Tri-Polar Bot. X,Y, and Z axis are all along radial coordinates, rather than straight. This concept does not fit the Delta definition, so one contributor (Nicholas Seward of Simpson fame), suggested that the discussions should be moved to this forum. So, here I am (Dennis Brown aka see3d) to introduce Wally (yes, it is named for a geneticist, but on a first name basis). Wally is a wall bot. Everything is referenced of a back board. Nicholas also thought that Wally would lend itself well to a RepRap design. I put together a paper model of the arms to see how they would work, and then did some schematic drawings of a side view, and a view looking up from Yoda's point of view. They are attached here: [attachment 16179 SideZ32013-06-21at9.21.16PM.png] [attachment 16180 TopView2013-06-22at12.09.12AM.png] [attachment 16181 Paper32013-06-23at8.12.07PM.png] Wally evolved out of some prior design ideas. The arms look like a simplified early Simpson prototype. The fishing line drive came from other recent Delta and Cartesian bots. The wall bot idea came from some recent Delta design brainstorming. The crazy math to translate coordinate systems was shown to work for Delta bots. I have not identified any bot crazy enough to use a 4 bar linkage for the Z yet, but that can't be new. There was a lot of cross pollination to conceive Wally. The idea was to make Wally as simple and low cost as possible while maintaing a decent build volume and precision. Simple and build volume can be seen from the concept. Low cost is assumed due to only rotating bearings and no fancy linear actuators or precision lead screws. It will take a detailed design, a working prototype with BOM, and real 3D prints to verify the cost and precision are there. Details about the concept: > Built off a rigid back board. The board can have ribs attached to make it more rigid. The material is TBD based on prototype needs. > Wally could be designed to fold fairly flat for storage or portability. Think suitcase with a handle on the side. Legs could fold out to make it free standing, or it could be attached to a wall. > The design can be scaled. Perhaps a 12" backboard width at the small end. That might give more than a 6" cube build volume. A 15" backboard width might give something on the order of 10" Diameter, or an 8" square, or a 10" x 7" Rectangle -- all with a 10" height. I think this would be a good design center. > All axis are driven from stepper motors through a Spectra fishing line drive on preferably smooth pulleys. > The two X,Y arms are driven by rotating the elbows. This gives a build area that is limited by an arc from the shoulder with a straight elbow to the hot end. > The ratio of the stepper drive to large elbow pulley determines the resolution and torque. 0.025mm or better with a reasonable ratio with a 16-32x microstep. > The Z axis is a 4 bar linkage that keeps the bed flat as it is rotated up and down through an arc. Gravity lowers and a stepper winding a string raises it. > The build platform moves through an arc as the Z is changed. The X,Y Arms have to compensate for the displacement in the Y axis (perpendicular to the back board). > A convenient place for a spool is on the lower back. Filament would be fed up through a Bowden extruder and over the top and down to the hot end. If I missed some important point, please ask about it. I am doing this summary from memory of 5 pages of posts in Billy's thread. Other brainstorming ideas: An end stop for both arms and possibly a table leveling Z probe might be able to be designed with just one microswitch located on the effector. It might be possible to have a hot end tool changer. If the hot end is held with magnets on the effector, the hot end could be parked along the back wall to be picked up as needed. A strong hold magnet at the backboard could be magnetically adjusted to hold or release a tool. They would each have to have their own Bowden extruder. This would allow for multiple extrusion heads that stayed in the same center of arm rotation, and did not require any reduction in build area. With a universal holder design, things like a Laser Diode head, a light duty rotary cutter head, a magic marker, or a clay extruder could be accommodated. To offset some of the weight of a heavy tool, a counterbalancing string could be added from above. How practical these things would be would have to be tested in a prototype. Next steps: The next thing needed is to have real MCAD design work done to verify all the X,Y, and Z movements and build volumes. That is not my realm. Then some design work on the arms to make them into 3D printable form. Then building a prototype arm assembly to test the ideas in real life. Then likely change the design to make it work better. Then do the same for the Z axis. Finally put all the pieces together and put the juice to Wally to make him alive! My contribution to Wally was to pull the various pieces together into a complete printer concept. I would like to build Wally at some point, but need an experienced 3D bot maker to lead the way (or a group of collaborators). I am currently waiting for delivery of my first 3D printer kit from the RigidBot KickStarter. https://reprap.org/forum/read.php?185,220993,220993#msg-220993 Sun, 19 Jul 2026 01:40:48 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?185,220993,300912#msg-300912 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,300912#msg-300912 nicholas.seward Polar Machines, SCARA, Robot Arms Sat, 25 Jan 2014 14:02:23 -0500 https://reprap.org/forum/read.php?185,220993,300911#msg-300911 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,300911#msg-300911
It's NOT printing well

The bed raises up compressing my leveling springs
The first 5 minutes the hotend nozzle is slammed against the glass
shut off from squirting.

And it sure NOT a Square and a circle.

Not anywhere close to Wally_0 squirrel

Its called asymtotic progress you really never get there!!

Hope you guys have better success

:S]]> cozmicray Polar Machines, SCARA, Robot Arms Sat, 25 Jan 2014 14:00:10 -0500 https://reprap.org/forum/read.php?185,220993,300762#msg-300762 Re: Tri-Polar Bot Concept -- Wally Chrome https://reprap.org/forum/read.php?185,220993,300762#msg-300762
There's hope for ours yet :-)]]> smooshed Polar Machines, SCARA, Robot Arms Sat, 25 Jan 2014 08:47:41 -0500 https://reprap.org/forum/read.php?185,220993,300627#msg-300627 Re: Tri-Polar Bot Concept -- Wally Chrome https://reprap.org/forum/read.php?185,220993,300627#msg-300627 see3d Polar Machines, SCARA, Robot Arms Fri, 24 Jan 2014 23:17:11 -0500 https://reprap.org/forum/read.php?185,220993,300619#msg-300619 Re: Tri-Polar Bot Concept -- Wally Chrome https://reprap.org/forum/read.php?185,220993,300619#msg-300619 something that looks like a real print

[attachment 25614 Sqr_Circle_j.jpg]

Ride along with Wally see the movie at

[www.youtube.com]

;)]]> cozmicray Polar Machines, SCARA, Robot Arms Fri, 24 Jan 2014 22:09:20 -0500 https://reprap.org/forum/read.php?185,220993,300005#msg-300005 Re: Tri-Polar Bot Concept -- Wally Chrome https://reprap.org/forum/read.php?185,220993,300005#msg-300005
Must be something in the air.]]> DonaldJ Polar Machines, SCARA, Robot Arms Thu, 23 Jan 2014 16:35:42 -0500 https://reprap.org/forum/read.php?185,220993,299988#msg-299988 Re: Tri-Polar Bot Concept -- Wally Chrome https://reprap.org/forum/read.php?185,220993,299988#msg-299988 GUS also.]]> nicholas.seward Polar Machines, SCARA, Robot Arms Thu, 23 Jan 2014 15:59:26 -0500 https://reprap.org/forum/read.php?185,220993,299964#msg-299964 Re: Tri-Polar Bot Concept -- Wally Chrome https://reprap.org/forum/read.php?185,220993,299964#msg-299964
[www.printrbottalk.com]]]> DonaldJ Polar Machines, SCARA, Robot Arms Thu, 23 Jan 2014 15:27:03 -0500 https://reprap.org/forum/read.php?185,220993,299892#msg-299892 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,299892#msg-299892
Made a better filament drive! About time.
[attachment 25500 WALLYFILAMENTDRIVE1.jpg]
[attachment 25501 WALLYFILAMENTDRIVE2.jpg]

I added an optional mount for a guitar tuner. Love it!
[attachment 25502 WALLYGUITARTUNER1.jpg]
[attachment 25503 WALLYGUITARTUNER2.jpg]

I made a new arm with a kossel compatible mounting ring. You can now use all the accessories for kossel on a Wally. Fan mounts. Auto level probes.
[attachment 25504 WALLYNEWARM.jpg]


I finished my first draft on Wally's new segmentize. It seems to address all the problem areas. It makes calibration easier. It scales speed correctly. (Thanks Charles Steinkuehler for the speed fixes!) It does bed leveling. It does bed arc adjustment. The one problem is it slower than molasses. I can fix that. (The problem is that I have the inverse kinematics but not the forward kinematics. This is needed to some calibration. My bandaid solution is to get from the machine coordinates to the reference coordinates using numerical techniques.)

[attachment 25499 WALLYSQUIRREL.jpg]

There is one band around the middle. I am not sure what the cause is. It could just be a bad value in the calibration table. If other prints have the same band then that will be confirmation for that theory. Other than that, the surface quality is top notch and the retract settings left little to clean up. (At this point it is leaving less to clean up then my Printrbot. I think I have a slight blockage.)

[attachment 25497 WALLYLISASQUIRREL.jpg]

Wally squirrel on the left and LISA squirrel (LISA Simpson) on the right. Pretty dang close if I do say so myself.

[attachment 25498 WALLYCUBE.jpg]

20.6mm x 19.6mm x 19.8mm
The height is within the layer height so I am good there. The test cube printed about 7.5mm from the location I expected so I have a lead on getting this fixed.

Now, I plan on getting a fresh computer and doing video documentation of the following.

*Loading firmware
*Setting up the host
*Calibration
*STL to print workflow

Exciting times. GUS and Wally and getting pretty close to being able to print their own parts.

There are more detailed posts and individual build logs for Wally, LISA, and GUS at http://forum.conceptforge.org/]]> nicholas.seward Polar Machines, SCARA, Robot Arms Thu, 23 Jan 2014 12:33:29 -0500 https://reprap.org/forum/read.php?185,220993,297326#msg-297326 Re: Tri-Polar Bot Concept -- Wally Chrome https://reprap.org/forum/read.php?185,220993,297326#msg-297326
5 ply birchply painted chrome
Arduino mega 2560 and RAMPS 1.4
Hard PC bed heater and glass surface
J-Head hotend 1.75mm Airtripper extruder
white PVC extender to make it as long as Ubis
Repertier Firmware Repetier-Host SW on XP 64 PC

Only goes up 133mm Z-pulley and extruder limit
Have NOT got firmware / software parameters set up right yet
Loses knowledge of home and doesn't go all over table
Python -- errors out with 133 height

[attachment 25121 Wally_Chrome_F.jpg]

[attachment 25120 Wally_Chrome_B.jpg]



Waiting for help to catch up

:S]]> cozmicray Polar Machines, SCARA, Robot Arms Sat, 18 Jan 2014 23:37:54 -0500 https://reprap.org/forum/read.php?185,220993,296796#msg-296796 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,296796#msg-296796 see3d Polar Machines, SCARA, Robot Arms Fri, 17 Jan 2014 23:05:30 -0500 https://reprap.org/forum/read.php?185,220993,288612#msg-288612 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,288612#msg-288612
running on PC with Win XP-64
Replaced Freaduino
with genuine Arduino Mega 2560
and different RAMPS board and Polulu drivers

all functions work X,Y,Z, extruder motors, bed heater, Bed temp, Extruder heater, extruder temp

Need some help setting Marlin and Repetier-Host.

my (set in Marlin config.h)
X 8 steps/mm
Y 8 steps/mm
Z 166 steps/mm
E 100 steps/mm

Wally on "Home Z" pulls bed up 110mm
after about 30 sec Z-motor disables and bed drops

If I home Z and then move bed up/down
then Home again home position is forgotten and Z pulls table up 110mm
(breaking the string)
Motor stop doesn't work on Z-Axis? (must use emergency stop)

X and Y move but can't correlate to R-H commands
best I can see is R-H commands are like deg of rotation of big pulley?

Scratchin all my hair off trying to figure out!
changing marlin code/config and R-H parameters.

:S]]> cozmicray Polar Machines, SCARA, Robot Arms Fri, 03 Jan 2014 12:50:25 -0500 https://reprap.org/forum/read.php?185,220993,283164#msg-283164 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,283164#msg-283164
[attachment 23358 Wally_front_s.jpg]

[attachment 23359 Wally_Back_s.jpg]


Black forearm reprint to get beter internal threads

Freaduino Mega 2560, RAMPS (all to be replaced --- real pain)
Arduino Mega 2560, New RAMPS
30A 12V power supply
Square hard PC Bed Heater
Airtripper extruder (1.75mm)
Hotend not in yet

Have been using Macbook, Repetire-Host, Marlin

Real hassel with electronics

:S]]> cozmicray Polar Machines, SCARA, Robot Arms Sat, 21 Dec 2013 22:33:26 -0500 https://reprap.org/forum/read.php?185,220993,283104#msg-283104 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,283104#msg-283104 AbuMaia Polar Machines, SCARA, Robot Arms Sat, 21 Dec 2013 18:14:19 -0500 https://reprap.org/forum/read.php?185,220993,283097#msg-283097 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,283097#msg-283097 largest part 175mm (6.89" inches)
[reprap.org]]]> A2 Polar Machines, SCARA, Robot Arms Sat, 21 Dec 2013 18:02:25 -0500 https://reprap.org/forum/read.php?185,220993,283095#msg-283095 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,283095#msg-283095 AbuMaia Polar Machines, SCARA, Robot Arms Sat, 21 Dec 2013 17:55:12 -0500 https://reprap.org/forum/read.php?185,220993,283089#msg-283089 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,283089#msg-283089 Build Area: 150 x 150mm or 200mm circle
[reprap.org]]]> A2 Polar Machines, SCARA, Robot Arms Sat, 21 Dec 2013 17:39:46 -0500 https://reprap.org/forum/read.php?185,220993,283088#msg-283088 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,283088#msg-283088 AbuMaia Polar Machines, SCARA, Robot Arms Sat, 21 Dec 2013 17:37:21 -0500 https://reprap.org/forum/read.php?185,220993,281739#msg-281739 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,281739#msg-281739 Vladimir_Lukashuk Polar Machines, SCARA, Robot Arms Wed, 18 Dec 2013 14:30:56 -0500 https://reprap.org/forum/read.php?185,220993,281472#msg-281472 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,281472#msg-281472 nicholas.seward Polar Machines, SCARA, Robot Arms Wed, 18 Dec 2013 05:04:32 -0500 https://reprap.org/forum/read.php?185,220993,281412#msg-281412 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,281412#msg-281412
I don't know how to insert the picture into the text.]]> Vladimir_Lukashuk Polar Machines, SCARA, Robot Arms Wed, 18 Dec 2013 01:48:38 -0500 https://reprap.org/forum/read.php?185,220993,281162#msg-281162 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,281162#msg-281162 nicholas.seward Polar Machines, SCARA, Robot Arms Tue, 17 Dec 2013 12:16:16 -0500 https://reprap.org/forum/read.php?185,220993,281045#msg-281045 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,281045#msg-281045 dpharris Polar Machines, SCARA, Robot Arms Tue, 17 Dec 2013 07:28:58 -0500 https://reprap.org/forum/read.php?185,220993,280562#msg-280562 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,280562#msg-280562
Quote
nicholas.seward
[attachment 22949 wallyparts.jpg]

Something bright to cheer people up on a Friday night!

I'm impressed by the quality, they look like injection molded parts!]]> Guizmo Polar Machines, SCARA, Robot Arms Mon, 16 Dec 2013 10:45:25 -0500 https://reprap.org/forum/read.php?185,220993,280199#msg-280199 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,280199#msg-280199
Quote
nicholas.seward
[attachment 22949 wallyparts.jpg]

Something bright to cheer people up on a Friday night!

I would to buy it... 8-)]]> Serenum Polar Machines, SCARA, Robot Arms Sun, 15 Dec 2013 13:29:58 -0500 https://reprap.org/forum/read.php?185,220993,279808#msg-279808 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,279808#msg-279808 It seems to me that any color will badly look, if it one. contrast is necessary. for example - plastic lilac, and the case green or as to you will run, but colors have to be different.
I think that it is the most interesting and successful your design, today.
I hope that in these days off my Wally, will work.
How many printers work at the same time for Wally press? how many in general works? And what?]]> Vladimir_Lukashuk Polar Machines, SCARA, Robot Arms Sat, 14 Dec 2013 08:47:06 -0500 https://reprap.org/forum/read.php?185,220993,279704#msg-279704 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,279704#msg-279704
Quote
nicholas.seward
Something bright to cheer people up on a Friday night!

Lots of Wally!!!

Looks great, I love the mix of colors and that purple looks pretty cool!]]> cdsteinkuehler Polar Machines, SCARA, Robot Arms Fri, 13 Dec 2013 22:12:00 -0500 https://reprap.org/forum/read.php?185,220993,279703#msg-279703 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,279703#msg-279703
Something bright to cheer people up on a Friday night!]]> nicholas.seward Polar Machines, SCARA, Robot Arms Fri, 13 Dec 2013 21:57:22 -0500 https://reprap.org/forum/read.php?185,220993,278607#msg-278607 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,278607#msg-278607
Quote
nicholas.seward

Your reward for building a Wally without instructions is a more complete understanding of the universe.

Hahahaha. You 're right]]> Guizmo Polar Machines, SCARA, Robot Arms Wed, 11 Dec 2013 10:22:34 -0500 https://reprap.org/forum/read.php?185,220993,278330#msg-278330 Re: Tri-Polar Bot Concept -- Meet Wally https://reprap.org/forum/read.php?185,220993,278330#msg-278330
Quote
cozmicray
What does this mean?
We get instructions if we pay a bounty?
or
Is this just contribution to the effort?

Does this violate "Open source" ?

Does one get a reward for building Wally without instructions?

Meaning: This is a way to give a donation with strings attached.

Everyone gets instruction whether you pay or not.

Files will still be GPL so they are still open souce.

Your reward for building a Wally without instructions is a more complete understanding of the universe.]]> nicholas.seward Polar Machines, SCARA, Robot Arms Tue, 10 Dec 2013 17:10:38 -0500