Inverted polar kinematics 3d Printer with turning x axis

Basic Information: printer.cfg for inverted polar printer with endstop

Printer Model: Inverted polar
MCU / Printerboard: BIGTREETECH Manta M5P V1.0 32Bit

Describe your issue:

Could you please help me with a working pirinter.cfg for polar printer with standing table and rotating x axis ?

Hello @Istvan !

The by Klipper supported kinematics are listed here:

I’m afraid the one you look for is not among them.

Sure! I’m currently working on a normal polar printer, I’m happy to help.
What’s your problem? You should be able to simply use a normale polar kinematics, shouldn’t you?

Hi Neelix! Thanks for offering your help! I am afraid the normal kinematics turns the bed and I would like to turn the hotend around the X axis so the X should be my imaginary bed’s center . I am not familiar with python is that easy to change ?

Hi Ed! Thanks for your answer. I have seen it’s not on the list , but I thought someone might have changed the turning bed with the turning middle ax .

hmmm, let’s set some common ground:

  • Did you already build the printer, or is the video from someone else?
  • The normal kinematics transform the cartesian coordinates (X and Y) to polar coordinates (Phi and R).

Since the inverted polar printer is also operating in polar coordinates, it should be fine. Maybe you have to invert an axis (e.g. by inverting the motor in the .cfg). At the end, the toolhead “sees” the same XY movement, as in a standard polar printer.

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Thanks, this helps I will try to change the motor on the axis I am just not sure how to do that.
The youtube video is just for reference it is done by Edward Atkinson.
I didn’t built the structure yet it is only in the design stage. I would like to gather more information , to get a cleaner picture before printing the actual components.
I just found out that the hotend should be in the center of the turning axis because if there is an offset it is hard to correct in the software and that is pretty hard to resolve.

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Hello I’m also working on the exact same thing and im stuck configuring the firmware.i think a good solution would be to convert the arm holding the extruder in a scars printer to linear motion but I don’t know how to do that.

In my printer I made a mechanism to mechanically adjust that offset. It’s basically just “turning a screw” and the turn are calculated from printing a test print.

Where exactly are you stuck? From the theory it should technically work (except your R axis has an offset :smiley: )

I don’t what settings to change to get the exact result

will puting a threaded rod on the arm work or do i still need to make firmware changes

Do you want to change the belt drive to threaded rod ? I am sure you need to change the gear ratio. I also want to put ball screw on the Z axis and I guess I have to use a planetary gear to achieve enough force to turn the rod with a small nema 17

What kind of motherboard are you using and why? I would like to use the bigtreetech skr mini e3v3

I’m using ramps 1.4. I chose it cause it was the cheapest.but in the video he said he is USD an skr board with rep rap firmware

I asked chat gpt and that’s what it said. But you also need make some firmware changes

On marlin the polar print is sort of a modification on the scars printer you just define the number of segments on the circle.and there are 2 arm linkages it supports. If you define one arm that can serve as the rotation of the printer. It’s the x-axis I’m stuck on now

Did anyone stepped further with his project ? I finally have my design for the mechanism , hope I can put it together next week . I decided that I will use nema 23 steppers because the rotating arm will be around 10kg , I ordered the new tmc5160 drivers from bigtreetech.

Hi! Did you already built an inverse polar printer ? Could you send me your printer.cfg so I can see what needs to be changed at the axis ?

I finally built the printer , but I have a slight deformation in the print result , when I print two layers in different directions ( the printhead is going forward next time backwards) I have a 2mm difference on one side of the print . What can be the cause of this ? No backlash at all in the mechanics everything is tight as possible .