pozzello

hm. I don't really see why that should be the case, but it does seem to explain it... I suppose it may make some sense for an IDEX, where it may be harder to prevent the second moving print head from hitting an already-printed object on the bed, but for the GEETech a10/20/30/M/T's, they all share the same nozzle, so there's really no extra complexity/risk to allowing 'one-at-a-time'... But even for an IDEX, let me try it at least. It could be made to work if one is careful about it... How would one do that? Setting 'Number of Extruders' in Machine settings to 1 (from 8, in my case!) destructively looses any start/end gcode one might have set up, so it's not a very friendly workaround... Is there another way? Thanx, Paul.

Machine profile for Creality Ender 3 and for CR10 shows/allows me to select "one at a time" (vs default "all at once") mode, but when I select Geetech A20T as the printer, that option is hidden, despite having 'all' config settings enabled. This seems to be the case in Cura 5.2.1 and 5.3.0... Any specific reason for this behavior? Any workaround in config files somewhere? TIA, Paul.

Thanx for the insights! Fixed that, but was still having tool-change blobs (and was previously blobbing on all extruder changes, not just when engaging that one). Played around with the various retraction settings, and it seems the culprit was the relatively large *difference* between the 'regular' and the 'tool change' retractions. With the 6mm (regular) retraction and default 16mm 'nozzle switch retraction', you showed how Cura was first doing the E-16, Tx (tool change) then E+10 (=16-6, pre-priming?) of the new color. It's that E+10 on the new tool/color/extruder that causes the blob before moving to the prime tower, where it un-retracts 6mm before printing/priming on the tower. I set the 'nozzle switch retraction' to 6mm (matching the 'regular' retraction distance), and the blobs disappeared. This means I need more priming after the tool change to clear out the previous color, but increasing prime tower volume seems to help compensate, as well as printing walls from inside out to hide the still-transitioning color... It's a mystery to me why Cura does the new tool un-retraction/pre-priming BEFORE moving over to the prime tower, but there it is. (probably just easier to program that way for the case where no prime tower is in use...) Thanx again for the pointers! I think i can at least try a real multi-color print now with some hope of success... PS, I think I grok the math of how it's trying to maintain the working nozzle pressure by pre-priming the new extruder by as much as it does, but perhaps the idle extruder sitting at temp leads to a very molten first squirt of the new extruder? ie, why else would not even equalizing the previous pressure cause a blob? (as you pointed out E-16, E+10 should leave the filament 6mm behind the tip, but it doesn't, for some reason) I may play around with a NEGATIVE value for "Nozzle Switch Extra Prime Amount" (instead of a giant positive one!) to see if that helps...

Hiya, having some issues with Cura 5.2.1 and GeeTech A20T (triple extruder) myself. Main problem I haven't been able to work around is that tool/extruder/color change is leaving a hug blob of the current color on the print before moving over to the tower and priming the next extruder/color. Tried GV's profile above to no effect... see post and image at

Hi all. Not sure if this is a bug or simple mis-config somewhere. New Geeetech A20T (triple extruder, single nozzle) Cura 5.2.1. Tried a simple test print with 3 disk shapes (each in a different color PLA from the 3 extruders) and a prime tower. Getting large BLOBS on print just at the extruder switch (finished printing one color on layer X, switching to next color.) Just before moving over to the prime tower, it drops a big blob of the current color. (see image below) I have "Nozzle Switch Retraction Distance" set to 16mm (as part of the A20T profile,) yet there is no "G1 E-16" found in the gcode anywhere near the Tx command that switches extruders. When i mock up a similar print on Repetier Host, it does generate the "G1 E-16" and I don't get the blobs, so it appears Cura is not applying the 16mm retraction I think I've configured at tool/extruder change. I suppose I could try doing it manually in the extruder end & start gcode sections, but what's the "Nozzle Switch Retraction Distance" for, if not this? TIA for any tips or explanation... Paul. attaching image showing the blobs dropped before moving to prime tower, the .3mf file and the generated gcode. GA_A20T_test_disks.gcode GA_A20T_test_disks.3mf

Success (maybe) the solution presented here sort of does the trick: I added another 'cutting mesh' encompassing the entire object just few mm off the base. (see attached) I'm still trying to get my head around WHY this works, but there it is... BUT I seem to have lost the lightning infill I need to get this print. Always something...

Getting closer... I found that setting the cutting mesh 'Bottom layer' COUNT (not 'top/bottom THICKNESS') to 0 does remove the first layer floor (see attached,) but I still get a top layer as in the image posted with the OP above. I'm guessing that's really a bottom layer for the main model (raised above the build plate due to the cutting mesh below) but not having any luck removing that to leave the entire disk cross-section as an opening into the model cavity... I could just drill a hole into that layer to allow the 'flame' part of the tea light into the body, but will require putting that layer at just the right height for these specific lights, so still not optimal...

I've got a model of a shoe that printed nicely in clear PLA with 10% lightning infill on my CR10v3. I'd like to add a hole in the bottom (that sits on the build plate at Z=0) so I can set it over an LED tea light. I added a disk and set per-model settings/modify-setting-for-overlaps to 'cutting mesh', with 'wall thickness', 'top/bottom thickness' and 'infill density' all set to 0. Slicing results in a hollow where the disk is placed inside the shoe, but it has top & bottom layers, thus not a hole. See attached image. If I scale the disk vertically up through the top, it does make a cavity all the way down, but it still has a 'floor' printed. How do I get rid of the printed floor and ceiling where the cutting object intersects/overlaps with the main model? The model is too big to import into Tinkercad and I'm hopeless with any other 3d design software, so looking for a way to do this in the slicer. Seems like it should be do-able... TIA, Paul Cura 5.1.0 (and 5.2.1) on Windows 10.