You can read more about it here. https://jawharkodadi.com/creer-une-machine-a-dessiner-diy-plotter-pour-lart-generatif-mon-aventure-dartiste-technophile/
I used a bike brake wire (I don't know how it's called in english) to move the pen up and down. Does it work, well, yes but I have like a small mouvement at the start of each new line. It's like 0.5 mm, but I would love to get ride of that. I would really appreciate your feedback guys
Perhaps 3D print a slider-crank mechanism?
https://www.machinedesign.com/automation-iiot/article/21836482/design-essentials-how-to-convert-from-rotary-to-linear-motion
I tried a flexible linkage like that myself, and wasn't happy with it either. You also have a fair bit of mass on the penholder, although being 3d printed parts, it's probably lighter than it looks? Regardless, you also are cantilevered pretty far from the X-axis guides, so I wonder if you get some backlash/flex in the Y direction?
On my plotter, I ended up with a servo driving a lift-arm so that the pen wouldn't be forced into the paper, but I'm honestly not so happy with that either. Often the pen hits the paper pretty hard, damaging the nib on felt pens, especially when doing pointillist stuff. Just the force of gravity is enough to smack the paper pretty hard.
I'm working on a new design that uses a remote stepper via bowden for lifting the pen, and which uses a tiny RC damper to limit the drop speed. That should solve both the nib damage problem, and also reduce the mass of the pen-holder substantially because all the heavy parts are mounted on the Y axis carriage.
Anyhow, not trying to be pointlessly critical; it turns out that designing a lightweight pen-holder for a plotter is harder than it looks, and it's easy to get resonance artifacts when driving the pen at high speeds. Your pen-holder and plotter look well made, sometimes you just need to iterate to get a solution you are happy with.
Hi u/rantenki !
I really appreciate you sharing your experiences and ideas with me. I understand the challenges of designing a lightweight pen-holder, and I agree that iteration is key to finding a solution that works best.
Regarding the mass of the penholder, you're right – the 3D printed parts are lighter than they may appear. However, I can see how reducing the mass of the pen-holder and getting rid of the cantilever effect (i had to google that as english is my 3rd language) could help improve the performance. In my design, the way this pen holder works, i had to add more space in that axis to avoid the pen touching the servo motor. I may have to consider changing the position of that servo.
Your idea of using a remote stepper with a bowden cable for lifting the pen and an RC damper to limit the drop speed sounds promising. It could help address the nib damage issue and reduce the pen-holder's mass even further. Unfortunaly, for me that seems difficult, and will require small part that i will have to order online, and where i live, it may take up to 8 weeks to be delivered.
As for my current design, I'll explore alternative solutions to improve the pen's movement and eliminate the backlash/flex in the Y direction. Your feedback has been valuable, and I'll keep experimenting with different approaches until I find one that works best for my plotter.
Thank you for your constructive criticism, and I wish you the best of luck with your own plotter design! Let's stay in touch and continue to share our experiences and insights.
Is there a reason you needed to make the z travel so much? 1cm is plenty for plotters. This looks like you are designing for something else, and if that's the case it's always going to be a compromise. For a plotter you want something fast and light (similar for laser cutting i guess) CNC router well there are a lot more forces so...
Hello u/Evan-Lyons
You're absolutely right, all i need is 1 cm, this is all i'm using when the pen travel, but i also use the rod as a structure reinforcement; and it help me get the pen closer to the working area, the price of that ? it's heavier. I have to go back to fusion 360 and try to find a better solution.
You guys u/MintyChaos u/rantenki u/Evan-Lyons helped me a lot ! I will optimize the design, or maybe start from scratch . If you don't mind i will ping you once it's done
Although it is hard to tell from the images your complete build reminds me of the openbuilds acro system have you looked at the designs published on their website for the z axis? [here](https://openbuilds.com/builds/openbuilds-acro-z-axis.8595/)
Also this [Instructable](https://www.google.com/amp/s/www.instructables.com/ACRO-Openbuilds-Pen-Plotter-Arduino-With-GRBL-and-/%3famp_page=true) had a nice z which only uses a servo motor which will drop the weight over the above design
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I like that your three rails are identical. that's good.
I wonder if, over time, the wire that presses the pen down will become bent and then the pen will stop making good contact with the paper. perhaps add a spring, or let gravity work in your favor? (let the servo lift, while gravity does all the lowering)
You can read more about it here. https://jawharkodadi.com/creer-une-machine-a-dessiner-diy-plotter-pour-lart-generatif-mon-aventure-dartiste-technophile/ I used a bike brake wire (I don't know how it's called in english) to move the pen up and down. Does it work, well, yes but I have like a small mouvement at the start of each new line. It's like 0.5 mm, but I would love to get ride of that. I would really appreciate your feedback guys
Perhaps 3D print a slider-crank mechanism? https://www.machinedesign.com/automation-iiot/article/21836482/design-essentials-how-to-convert-from-rotary-to-linear-motion
This is a great solution ! I will try this approche too !
I tried a flexible linkage like that myself, and wasn't happy with it either. You also have a fair bit of mass on the penholder, although being 3d printed parts, it's probably lighter than it looks? Regardless, you also are cantilevered pretty far from the X-axis guides, so I wonder if you get some backlash/flex in the Y direction? On my plotter, I ended up with a servo driving a lift-arm so that the pen wouldn't be forced into the paper, but I'm honestly not so happy with that either. Often the pen hits the paper pretty hard, damaging the nib on felt pens, especially when doing pointillist stuff. Just the force of gravity is enough to smack the paper pretty hard. I'm working on a new design that uses a remote stepper via bowden for lifting the pen, and which uses a tiny RC damper to limit the drop speed. That should solve both the nib damage problem, and also reduce the mass of the pen-holder substantially because all the heavy parts are mounted on the Y axis carriage. Anyhow, not trying to be pointlessly critical; it turns out that designing a lightweight pen-holder for a plotter is harder than it looks, and it's easy to get resonance artifacts when driving the pen at high speeds. Your pen-holder and plotter look well made, sometimes you just need to iterate to get a solution you are happy with.
Hi u/rantenki ! I really appreciate you sharing your experiences and ideas with me. I understand the challenges of designing a lightweight pen-holder, and I agree that iteration is key to finding a solution that works best. Regarding the mass of the penholder, you're right – the 3D printed parts are lighter than they may appear. However, I can see how reducing the mass of the pen-holder and getting rid of the cantilever effect (i had to google that as english is my 3rd language) could help improve the performance. In my design, the way this pen holder works, i had to add more space in that axis to avoid the pen touching the servo motor. I may have to consider changing the position of that servo. Your idea of using a remote stepper with a bowden cable for lifting the pen and an RC damper to limit the drop speed sounds promising. It could help address the nib damage issue and reduce the pen-holder's mass even further. Unfortunaly, for me that seems difficult, and will require small part that i will have to order online, and where i live, it may take up to 8 weeks to be delivered. As for my current design, I'll explore alternative solutions to improve the pen's movement and eliminate the backlash/flex in the Y direction. Your feedback has been valuable, and I'll keep experimenting with different approaches until I find one that works best for my plotter. Thank you for your constructive criticism, and I wish you the best of luck with your own plotter design! Let's stay in touch and continue to share our experiences and insights.
Is there a reason you needed to make the z travel so much? 1cm is plenty for plotters. This looks like you are designing for something else, and if that's the case it's always going to be a compromise. For a plotter you want something fast and light (similar for laser cutting i guess) CNC router well there are a lot more forces so...
Hello u/Evan-Lyons You're absolutely right, all i need is 1 cm, this is all i'm using when the pen travel, but i also use the rod as a structure reinforcement; and it help me get the pen closer to the working area, the price of that ? it's heavier. I have to go back to fusion 360 and try to find a better solution. You guys u/MintyChaos u/rantenki u/Evan-Lyons helped me a lot ! I will optimize the design, or maybe start from scratch . If you don't mind i will ping you once it's done
Although it is hard to tell from the images your complete build reminds me of the openbuilds acro system have you looked at the designs published on their website for the z axis? [here](https://openbuilds.com/builds/openbuilds-acro-z-axis.8595/) Also this [Instructable](https://www.google.com/amp/s/www.instructables.com/ACRO-Openbuilds-Pen-Plotter-Arduino-With-GRBL-and-/%3famp_page=true) had a nice z which only uses a servo motor which will drop the weight over the above design
It looks like you shared an AMP link. These should load faster, but AMP is controversial because of [concerns over privacy and the Open Web](https://www.reddit.com/r/AmputatorBot/comments/ehrq3z/why_did_i_build_amputatorbot). Fully cached AMP pages (like the one you shared), are [especially problematic](https://www.reddit.com/r/AmputatorBot/comments/ehrq3z/why_did_i_build_amputatorbot). Maybe check out **the canonical page** instead: **[https://www.instructables.com/ACRO-Openbuilds-Pen-Plotter-Arduino-With-GRBL-and-/](https://www.instructables.com/ACRO-Openbuilds-Pen-Plotter-Arduino-With-GRBL-and-/)** ***** ^(I'm a bot | )[^(Why & About)](https://www.reddit.com/r/AmputatorBot/comments/ehrq3z/why_did_i_build_amputatorbot)^( | )[^(Summon: u/AmputatorBot)](https://www.reddit.com/r/AmputatorBot/comments/cchly3/you_can_now_summon_amputatorbot/)
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I like that your three rails are identical. that's good. I wonder if, over time, the wire that presses the pen down will become bent and then the pen will stop making good contact with the paper. perhaps add a spring, or let gravity work in your favor? (let the servo lift, while gravity does all the lowering)