[Cerrado] Fine tune your MK3 Z axis  

Re: Fine tune your MK3 Z axis

I made a set with 30% infill .02 layer and it seems plenty strong. I used ABS though. I haven't installed yet, but the parts came out great.

Re: Fine tune your MK3 Z axis

The modified and attached components have been adjusted for a better function.
The two motor brackets have been widened 0.5 mm so that the Z motor can be centered correctly and the screw hole dimension has changed from ø3,6 mm (large) ø3,2 mm (fine).
This adjustment should Prusa implement as soon as there is an obvious error in the original details.

Can you clarify whether the top parts have been redesigned too? You don't mention them in the description, but they are shown in one of the diagrams and included in the ZIP, so I am not sure if i use the standard ones, or yours...

Re: Fine tune your MK3 Z axis

Can you clarify whether the top parts have been redesigned too? You don't mention them in the description, but they are shown in one of the diagrams and included in the ZIP, so I am not sure if i use the standard ones, or yours...

The upper brackets are almost identical to originals. I have only reduced the diameter of the screw holes from ø3,6 to ø3,2 mm.
I have also done less cosmetic adjustments on the exterior surfaces.
So it is not necessary to replace the original, the function is the same.

Re: Fine tune your MK3 Z axis

Can you clarify whether the top parts have been redesigned too? You don't mention them in the description, but they are shown in one of the diagrams and included in the ZIP, so I am not sure if i use the standard ones, or yours...

The upper brackets are almost identical to originals. I have only reduced the diameter of the screw holes from ø3,6 to ø3,2 mm.
I have also done less cosmetic adjustments on the exterior surfaces.
So it is not necessary to replace the original, the function is the same.

Thanks for clarifying. Might as well install the matching set. I printed them. Any easy way to disasemble and install these parts. There must be a hack which is quicker than taking the whole thing down.

Re: Fine tune your MK3 Z axis

Thanks for clarifying. Might as well install the matching set. I printed them. Any easy way to disasemble and install these parts. There must be a hack which is quicker than taking the whole thing down.

Agreed. If your dimensions are off slightly (filament shrinkage, slicing issue, etc.) there may be value in having a matching set where the imperfections may cancel.

Re: Fine tune your MK3 Z axis

RHDreambox, you should open GitHub issues to show your work to Prusa, if this is not already done. 💡

Re: Fine tune your MK3 Z axis

RHDreambox, you should open GitHub issues to show your work to Prusa, if this is not already done. 💡

Unfortunately, I have not found any forum where I can submit suggestions for improvements.
Maybe any of you can do it?

Re: Fine tune your MK3 Z axis

He just told you the name of the forum, but I suppose it can be hard to find unless you are used to coding on github. The link is here: https://github.com/prusa3d/Original-Prusa-i3/issues

Re: Fine tune your MK3 Z axis

He just told you the name of the forum, but I suppose it can be hard to find unless you are used to coding on github. The link is here: https://github.com/prusa3d/Original-Prusa-i3/issues

I am glad I read this.... Specifically the very first thread:

https://github.com/prusa3d/Original-Prusa-i3/issues/48

Explains exactly what happened last night.. I did my first ever PETG print and chose the new Hotbed cover... I couldn't understand why the bottom (biggest) part came out well.. But the smaller top part looked like it had never even touched the bed.. I put this down to teething problems, but I just couldn't understand how/why it was so bad..

And this post explains exactly what happened as the smaller part is floating in air...

Re: Fine tune your MK3 Z axis

He just told you the name of the forum, but I suppose it can be hard to find unless you are used to coding on github. The link is here: https://github.com/prusa3d/Original-Prusa-i3/issues

It's done! Thank you for info 😀

Re: Fine tune your MK3 Z axis

He just told you the name of the forum, but I suppose it can be hard to find unless you are used to coding on github. The link is here: https://github.com/prusa3d/Original-Prusa-i3/issues

I am glad I read this.... Specifically the very first thread:

https://github.com/prusa3d/Original-Prusa-i3/issues/48

Explains exactly what happened last night.. I did my first ever PETG print and chose the new Hotbed cover... I couldn't understand why the bottom (biggest) part came out well.. But the smaller top part looked like it had never even touched the bed.. I put this down to teething problems, but I just couldn't understand how/why it was so bad..

And this post explains exactly what happened as the smaller part is floating in air...

Did you use “split” in slic3r. That usually fixes that by allowing each part to set on bed.

Re: Fine tune your MK3 Z axis

Thanks for finding and sharing this issue. I have verified on my side as well and I confirm the problem on both MK3 and MK2s.

Re: Fine tune your MK3 Z axis

Did you use “split” in slic3r. That usually fixes that by allowing each part to set on bed.

I use CURA, so I just separated the parts into individual models and printed the small one again.. Now I realise that by doing so it just allowed the high (small) part to drop onto the bed.. But at the time, I just thought it was a failed print.

Re: Fine tune your MK3 Z axis

Full plate ready for my new MK3. I should be able to do a side by side compare with the existing one I used to print the parts afterward, so stay tuned.

Re: Fine tune your MK3 Z axis

Looks really nice!

Re: Fine tune your MK3 Z axis

He just told you the name of the forum, but I suppose it can be hard to find unless you are used to coding on github. The link is here: https://github.com/prusa3d/Original-Prusa-i3/issues

It's done! Thank you for info 😀

Thanks!

Re: Fine tune your MK3 Z axis

I printed the new motor mounts and my PETG is really shiny and I don't like the look of it.

When I mounted the motor I could see that the shaft and surrounding was perfectly in the center of the hole.

But when I used the original, whilst it was slightly off center, i there was a bit of slack and I was able to get it in the middle with a bit of fiddling.

So I don't know whether my shafts are actually central, or whether the new mounts move the center hole too.. Either way, I don't like the finish on my new ones, so I am going to go with the originals for now and see how it goes.

Jon

Edit: I just measured the new parts and there is certainly a difference.. So it looks like it not as simple as getting the shaft in the middle of the hole.. its moving the entire motor over..

Looking at little closer at the parts, mine are visually better than Prusa EXCEPT the bottom surface (which is the top).. I have given mine a little sand to dull them and they look at little better, so I may go with them after all...

Re: Fine tune your MK3 Z axis

One of the issues I've had reprinting the mk3 parts listed by prusa on github is the holes for the smooth rods are oversized. Especially on the right side z axis parts. My printer prints accurate dimensions so It's not that. There is just play on the right side pieces as others noted earlier in this thread.

Re: Fine tune your MK3 Z axis

The hole should be ø8.2 mm according to Prusas SCAD file.
On a well calibrated printer, the hole will be a bit too big.

Re: Fine tune your MK3 Z axis

Well. The rod itself is 7.98. So. There's play