Dolly MK52 upgrade

#1

Hi Guy’s,

quick - “or not so quick” - question - I build the “dolly” clone and was thinking of upgrading to a MK52 + spring steel sheet. Here are a few questions:

My clone is exactly Tom’s dolly clone - Ramps1.4, A4988 drivers (X,Y,Z (single driver for 2 motors), etc.) (I was upgrading to the TMC2130 but removed them again because they were overheating all the time).

So, besides switching from Marlin to slippyr4’s pursa-firmware what else needs to change in terms of hardware e.g. endstops, 2nd Z-driver?

Has anyone done that?

Thanks!

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#2

Hi Larry,

I’ve also built the dolly clone. And quite frankly I also do have a cloned MK52 bed with springsteel sheet ;). Sad to hear that your TMC’s kept overheating, mine are working but I doubt they work 100% as they should (original TMC’s from Waterott).
To answer your question:
Since I couldn’t find a 12V variant of the MK52 bed, I used a step up converter to 24V which works wonders, just for the bed. You do not need to change endstops in the beginning, you could change to sensorless homing later. It’s very simple to configure though, let me know if you want me to elaborate on this. You shouldn’t need a 2nd Z driver, one should be sufficient.

Kind regards,
Bob

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#3

lol i had the opposite problem
I only found the 12V versions :smiley:
as example

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#4

MrBoub - thanks for the answer - about the TMCs - I could not cool them down even with a 80mm fan and low current stetting around 600mA(x/y) and 800(z) - they were always giving me temperature errors and I lost quite a few prints. Lower current setting would let the steppers stall - From what I was reading if you don’t have a 24V system and “low current” steppers don’t bother adding them to your clone. While I had them installed I was bothered by the loud fans :wink: No questions they are nice if would would work on the clone.

About the Mk52 - I was planing to use the 12V version from India https://www.3dprintronics.com. Did you install a pinda2 probe and if yes, how to connect the additional thermistor of the probe to the ramps1.4. Also, looking at the Prusa video https://www.youtube.com/watch?v=rYrLT5G-a9I&t=54s about auto xyz calibration - the printer drives first against the top - how will it stop without endstops or the TMCs? While driving against the top I can see the value of having 2 Z motors to align left and right side - I assume there are a few manual corrections in the firmware needed to make sure after x/y home that the probe is aligned with the first calibration point?

Thanks!

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#5

check this video before buy the india one:

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#6

Yeah - I saw that - but there are not really a lot of choices out there. Unfortunately, prusa3d MK2.5 upgrade for $199 is not available until later December as of today?

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#7

Weird that you can’t keep those TMC’s cool, I don’t have any problems with mine. Do you have genuine (waterott) TMC’s and do you have a heatsink on them?

No I don’t have a pinda probe, I use a regular inductive sensor. I have not found out how to work with XYZ calibration in marlin.
For the Z calibration; when the calibration is started, the printer will go 10mm higher than it’s maximum set height. This way the printer makes sure that both ends are at it’s max position. The machine is acting really ‘dumb’ at this point, but it’ll correct the z heights on both sides and losing some steps doesn’t hurt the machine.

Hope this bit helps.

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