MMU2: reliable printing by moving temperature settings within the gcode
 
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Frimmel
(@frimmel)
Active Member
MMU2: reliable printing by moving temperature settings within the gcode

Dear all,

I have experimented for a while in adjusting the temperature settings within the gcodes - not only temperatures, but when and where it happens. The reason is, current slic3r output does not work well for me when mixing different materials. What I do is (via a python script, as linked to below) basically replacing the current settings with the following scheme:
A. I first slice the object using the i3mk3 filament settings (not the MMU2 temperatures, which I often find too low)
B. Just before the filament change begins, the temperature is lowered
C. Just after the filament was changed (before wiping), the temperature is restored (with a pause). At that stage, the NEW filament temperature is set and IMMEDIATELY the wipe begins, which means wiping in a temperature gradient.

The idea is to improve the wiping, as poor wipe means, old filament remains in the extruder.

My experience so far is, I have now been able to print quite tricky PLA-PETG-prints as the wipe tower now looks pretty good (not bushy as before). PLA-prints print with less hazzle and not the least, I can use less amount of wiping, BVOH works fine and only sometimes still, the FINDA clogs by thin strings collecting in it.

I would love to hear if someone shares my experience in this? If you want to, please try the python code (it is not nicely written and I give no promises it will always work, but for me it works with slic3rPE 1.41.2). During print, you should be able to follow how the temperature is shifting, experience some short pauses during the print etc (you can seek for the changes within the gcode by searching for the key word "frimmel"). I put the python code (and some other tips & tricks wrt vase mode and others) at:
http://www.frimmel.se/print3D/
Use the code as follows (it's at your own risk, I use it without problems):

>python korrigera_gcode_temperaturer.py slicedinput.gcode slicedandadjustedoutput.gcode

It will print out key words (in Swedish, sorry...) after which the resulting file should be stored.
Please change the (hard coded) temperatures if you want (lines 201, 204, 208) and possibly temp.delay coefficient and offset (lines 57, 58)

Is this useful? Waste of time?

Best regards, Hans

Napsal : 19/02/2019 10:58 pm
michael.r28
(@michael-r28)
Active Member
RE: MMU2: reliable printing by moving temperature settings within the gcode

Thank you for your post. YES, alle your scripts are useful. Perhaps if the variable names where in english I could adapt it a little bit easier...

To print with a soluble filament I tested your modifications and inserted them manually in my GCode: I could print the parts!!

There are so many settings for the MMU2S and why nobody had your idea?

Napsal : 18/06/2019 1:21 pm
Nikolai
(@nikolai)
Noble Member
RE: MMU2: reliable printing by moving temperature settings within the gcode

Hello Hans,

Similar project:

You might also differentiate between the transitions (low->high, high->low). Based on my experience you want to avoid pause printing at any costs. This leads to other issues.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Napsal : 18/06/2019 5:22 pm
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