Duet Polargraph

o_lampe

@droftarts I was noticed, you've edited a post, but couldn't find any big news.
Did you add the drawings lately?

THX
Olaf

droftarts

@o_lampe No, I just updated a link that I got wrong in the first post, to the motor mount. I'm updating it a little (moving it off the big board, onto a smaller bar like the original Makelangelo, to make it more portable) and fixing a couple of bits (the servo had broken loose), as I'm taking it to SMRRF in Manchester this weekend. Changing the motor mounts to make them shorter, too.

What drawings do you want?

Ian

o_lampe

@droftarts said in Duet Polargraph:

What drawings do you want?

No need for drawings, I was talking about the drawings you made with it. Didn't remember seeing the dragon before.

Good luck in Manchester
Olaf

droftarts

Polargraph Update...

I took the Polargraph to SMRRF 2024 in Manchester last weekend. As it was mounted on a large MDF sheet, and I was travelling by train, this required a little bit of re-engineering. I re-mounted it on a strip of MDF, the same width as the original piece (so I didn't have to change the config), and updated the motor mounts so the belts hang closer to the wall, as there was now a step down from the motors to the drawing surface. I also did a nice Voronoi case for Duet boards (produced the Voronoi in Inkscape, which I spent far to long playing around with, see https://youtu.be/0fzJdGRzjf8 then extruded that in Fusion 360), but of course that was invisible as it was behind the Duet!

When I got to Manchester, @T3P3Tony insisted that I update it from the old, white PCB prototype Duet 2 WiFi, to a Duet 3 Mini 5+. This induced some headaches, as I eventually realised the comments in the config.g relating to anchor positions and motors was not correct in the original version. I have updated the config.g first post in this thread so it is now correct. I also removed the endstops, intending to make homing sensorless, but didn't get around to that, and just ended up homing manually. It was mounted on a white board, so easy to wipe off the board and draw something else. I'm sure that says something about the impermanence yet repeatability of art...

Apart from that, it ran smoothly for the weekend. It mostly drew things I'd created before, but I eventually got around to doing a couple of new things. There was a bit of an Andy Warhol/art theme (there were some impressive Hueforge prints), so I used DrawingBot to produce some of my own:

Here's the Voronoi case. Let me know if you want the stl.

Ian

T3P3Tony

@droftarts really fun to have it at SMRRF. Next stop pen changing?

oliof

@droftarts that looks fun. Please share the case.

droftarts

@oliof said in Duet Polargraph:

Please share the case.

Here you go: Duet 3 Mini 5+ case.stl
It fits a Mini 5+ Ethernet or WiFi. I had to hack a bit out of the side around the WiFi module to get the Duet 2 WiFi to fit. Makes quite a nice bench test enclosure, though it's more of a board carrier than a full case. Doesn't use too much filament, so prints quite fast. Also mounting holes are for M3x8mm. I probably should have made the sides a tighter fit on the board, there's a 3mm gap all around between the board and side.

I printed two, and put the Mini 5+ Ethernet in it that runs a demonstration closed loop linear axis, with a M23CL. Now it can sit on top of metal things without shorting out! We found out that our little server PC (that was collecting the data from the closed loop axis and displaying it in Graphana) had a metal band around the edge the hard way, fortunately no damage.

Ian

o_lampe

@T3P3Tony said in Duet Polargraph:

Next stop pen changing?

I guess the hard part of that is: keeping the unused feltpen tips fresh without drying out. (A wipe-zone is not an option, unless it's outside of the actual drawing area)
I imagine a revolver-like parking device which holds the pens and covers the tips.
Electromagnets would hold/release the pens instead of a clamping screw.

Is reversing the e-magnets polarity an option with Duets heater ports? (required to attract/repell a neodym magnet)

i-draw-monkeys

@o_lampe kids' markers are your friend. I've left "Medium felt-tip pen STABILO power" markers (I'd post link but can't yet) without cap for months and they still write

droftarts

@i-draw-monkeys said in Duet Polargraph:

I'd post link but can't yet

You need a minimum reputation of 2 to be able to post links. I've given you one upvote, one to go!

Thanks for the hint about kid's marker pens, too. Funnily enough, my daughter has exactly this set... https://www.stabilo.com/uk/medium-felt-tip-pen-stabilo-power/280-24-01
Whiteboard marker pens might be different, though, haven't checked.

Ian

o_lampe

@droftarts I think whiteboards are a good base for testing, but you want to have a permanent drawing on paper once in a while.
Over at the "maslow" thread we even talked about technical drawings on wooden panels (cutting lines and laser markings). Even drywall could be an option (very thursty surface, they might need different pens)
A portable "strap-on" version could be useful on many construction sites. (where to put electric and water-cutouts)

droftarts

@o_lampe this was just for the show, to make it transportable. Using the whiteboard was convenient for demonstration purposes. Now it’s back home, I’m going to mount it to the wall, and see how it draws then. In the past, the board it was mounted on was always laid back a few degrees, which may both help and hinder drawing, by increasing the pressure on the pen.

It’s still not very precise, least accurate at the limits of its range by 1-2mm perhaps. I need to tune the speeds and accelerations a bit more, but we did find at the show that some low frequency, broad band input shaping helped with belt wobble a bit.

I could mount two more motors at the bottom, if I went back to using a full sheet board, but then I’d have to deal with winding the belts/cables onto a spool, and redesign the gondola to have 4 arms. 3 points would limit the drawing area.

It may be that something like the original CoreXY ‘Bot of the Cloth’ would make a better, more accurate, portable plotter. https://corexy.com/botofthecloth/index.html

Ian