Eliminating issues that come with linear rails vs. eliminating issues of toothed belts

@mykepredko

I think we shouldn’t spoil that thread Creality violating Klipper license? - #20 by Mendax

Could you elaborate on that? I’m curious and don’t get it

Good idea.

If you read through the original announcement for the printer (and watch the linked video):

You’ll see that Peopoly makes a big deal about how they use “maglev” technology to eliminate belts and pulleys and the issues surround them.

When I watched the attached video, I was surprised to see that they use linear rails as I was expecting the “maglev” to replace both the force part of the equation along with the bearing (as in a maglev train).

Over the years, I’ve had a lot more problems with linear rails than belts and pulleys with poor quality on commercial printers and keeping them properly lubricated when I did shell out for HiWin rails.

I actually think that Peopoly have chosen a quite clever concept and that it makes sense.

A true “maglev train” actually has 3 components that work magnetically:

  • Levitation → The train hovers above the ground
  • Guidance → The train is kept where it is supposed to be regarding left and right movement
  • Propulsion → The train moves forward

Peopoly only chose to implement the propulsion part and IMO this absolutely makes sense with respect to cost and complexity.
Also the belt stuff is one of the weakest points in a printer today:

  • The commonly used trapezoid profile is the weakest available and the much better curvlinear profile is only available on bigger belts, e.g. GT3
  • The belt is subject to high wear and tear
  • The belt forces tense up the printer
  • The pulley often have abysmal quality and suffer from run-out
  • A proper belt path is hard to design and there are a lot of fails already available, e.g. the Ender to name one popular
  • A CoreXY kinematic suffers from extremely long belt paths that can sustainably contribute to ringing due to their natural frequency

Given that they did not introduce some design fails, this really looks promising and I’d love to have one of these printers to try it out.

2 Likes

I agree, very promising.


A very rough paint sketch from the top (hope I got that right).

I agree with mykepredko using a very good linear rail for y-axis.

In my eyes there will be high torque, where the y-axis is accelerated. The y-axis is a long lever with a toolhead on top, so there is mass/weight. That could cause problems.

From what I could see in the various videos, it looks like the “X” axis is driven on both ends.

Did you see something different?

Hopefully other vendors will bring those linear motors as well.
But before buying a new printer I need to sell others…
My new room is smaller than the old one. :confused:

Correct x axis, but it’s driven on one end. The other side runs on a linear rail.

Here is a videoframe

from https://www.youtube.com/watch?v=9YaW8DIxWTc at timecode 2:33.

1 Like

Looks like there is a linear rail below the linear motor as well.

1 Like

Peopoly have just lifted the NDA on their printer and Michael from Teaching Tech has a great video on it.

3 Likes

Interesting. Thank you for posting the link to the video.

I would have liked to see a more in depth discussion of the movement hardware/actuators. Hopefully more will be coming about that soon.

My first impression is that the electronics are more complex than they need to be - the Orange Pi/Octopus set up seemed to be somewhat clunky.

It will be interesting reading more about the printer.

2 Likes

No worries. I think Michael was keen to describe the testing process as much as the printer in this video. He mentions at the end that he will be doing a full in depth review of it as well.

Thinking about this, I think going with known hardware and open source software is really smart. It will give those of us who like what Bambu have done, but not their closed source ecosystem something we would be happy to buy as we know we can tinker with it if we want to.

We aren’t locked out like with Bambu and even Prusa.

Oh and it likely makes the development costs much lower for them.

I’m not criticizing the choice of using the Octopus/OPi & Klipper - I think it’s the right approach.

I just thought that the implementation was poorly done. I think Michael thought so too, especially in regard to the OPi’s cooling fan.

1 Like

Ah good point - these are testing units, so I guess mistakes are best made on them and fixed before production units are made.

I’m following this on its Discord as well.
So far it looks promising and Peopoly is listening to its testers.

2 Likes

Another good video from Michael taking a closer look at the linear motors.

1 Like