A big'ish MP3DP build

Hi - thought it might be of interest to someone that i have built a 400mm3 MP3DP and have it running. Its printed with ASA, running an SKR pro, a 6mm thick mic 6 heated bed and currently Marlin. Plan is for an enclosure. Lots of details need to be finished, but it prints really nicely and I can’t thank the development team enough. There are some bugs I need to sort out, especially getting G34 to work properly but it’s real good.


Hello Godzilla! :slight_smile: Congrats on your build @CoupePete!

Like the clean front and sides. Guessing controller, PSU and electronics mounted on the back?

Given your monster sized bed, guessing you’re tracking https://forum.v1e.com/t/e-brake-for-belted-z-axis/41979.

Thanks Aza - yes the electronics are on the back. Following the thread you mentioned. I have had about 6 falls of the bed but so far have not damaged the SKR (as far as I know). I have no idea why mine has survived and others have failed. But the end brackets for the bed kept breaking and needed an upgrade.

those look like the ones I made. I am about to do a redesign on them. I have a couple ideas I want to implement and may be able to make them stronger.

They are based on yours - but with significantly upgraded thickness everywhere and holes to suit M5 hardware. The old ones broke every time I had a bed drop, with my very heavy bed. The new ones mostly survived a drop. I will share it later today. None of the interfaces changed with the upgrade.

Here is the link - if that’s of any help!
MP3DP V4.1 Z 2020 End bracket by Coupe Pete | Download free STL model | Printables.com

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Can anyone please offer some guidance re calibrating G34 in Marlin? I have set the probing points as close to the Z motor mounts as I can. I have not changed anything else except the A value(amplification). I have had lots of testing with the A value set to 0.6. It appears to align successfully and goes through its 8 cycles but i end up with a bed that is poorly aligned when I print.

I have tried an A value of 1.1. Three times it aligned successfully but one time it went badly unstable.

The Marlin reference website says the value can be between 0.5 and 2. In configuration_adv.h it says " Use a value > 1.0 NOTE: This may cause instability!"
If someone could share the values that worked for them that would be great !!

I’m not sure on your main question but wanted to throw this out just incase. I had problems with mine originally and it was because I was losing steps on one or more of the z motors. I had to bump the current up a little and lower accelerations on z. Once I did that it was all good

Thanks Jonathon - I had increase the Z current to 900mA and that seems to be working pretty well. Can you share what yours is ?

I’m running .8 on all 3 of mine. But I’m running klipper now so I’m not sure if that makes a difference. I also don’t have homing set quite as fast as the marlin firmware did.

Thanks for that. Is Klipper worth the effort to change ?

If you don’t have a feature you want from klipper, I wouldn’t feel too much FOMO. It is a good firmware, but so is Marlin. That’s just my $0.02.

Backup of Jonathan’s config is pushed to… MP3DP_V4/printer.cfg at 6069dfc4b1108e3a508a7ca95ed425b8f02bee1a · jonathjon/MP3DP_V4 · GitHub

Are any of them SKR Pro ? I will get Marlin running properly, and then see how I feel about it.

My problem with G34 mentioned earlier was because I had 2 Z steppers wired incorrectly. What confused me was the printer appeared to level often even with the mix up, and only became unstable sometimes. Swapping the wires has this seemingly working perfectly.

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Think @Jonathjon’s config is for his SKR Pro 1.2 (based on the STM CPU referenced in his config).

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Yes mine is for a SKR Pro 1.2. But is is also setup with an EBB36 can tool head board

Ok thanks - it sounds like a good head start !

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If it helps I started with the example config from kipper.