How to do multicolor starter layers with multimodel and one extruder printing "one at a time"?

[FabioRS 0]

Hi!

 

I would like to know how can I do to Cura slice the models to print "one at a time" without the interference error. My objective is to print each part with one color.

 

I already did this and had success aligning and printing manually each object in separated gcode files (with Z-Hop configured to 0.5mm and the wall ordering to external first) keeping the bed hot between prints. But I would like, if it is possible, to do it in a single gcode without slicing manually each object.

 

The manual method I did:

Layer height 0.2mm

Z-Hop 0.5mm

Wall ordering: external first

The text models are with 0.4mm height

The bigger part has a "negative" from the other printed parts

Align everything in Cura, delete and slice one model at the time and send it to the SDCard.

Print manually first the text, change the filament, then the bigger part over it.

 

In the attachment the error message when trying to align each object and clicking slice and my test with the manual method.

 

My printer is an Ender 3 Pro with 32 bits board.

 

Thanks.

[Slashee_the_Cow 493]

In one at a time mode, even if the models don't physically overlap in the Z direction, Cura dedicates the footprint of the model, plus the size of the print head around it, on the build plate to that model, and no other model can be in that area (to prevent the print head crashing into an existing model when doing another).

 

I don't think it's possible to change the behaviour, it's a built in mechanism in Cura to so that it doesn't produce gcode which might damage a printer.

 

Most of the time, multicolour prints (on a single extruder printer) are done by doing a certain number of layers in each colour and then pausing to change filament for the next colour.

 

If doing it that way doesn't work for you, then the best way to do it is to print them separately and glue them together (if you're just printing PLA, cyanoacrylate - regular old superglue - works very well).

 

I don't recommend this (in fact I recommend against it, unless you really know what you're doing), but you could align them, delete the top one, slice, undo the delete and delete the other one and slice, and then take all the layers from the second file (not the startup or end g-code) and place them after all the layers of the first file but before the end gcode, and insert an M100 pause at the start of the layers for the upper model so you can change filament.

[FabioRS 0]

23 hours ago, Slashee_the_Cow said:

In one at a time mode, even if the models don't physically overlap in the Z direction, Cura dedicates the footprint of the model, plus the size of the print head around it, on the build plate to that model, and no other model can be in that area (to prevent the print head crashing into an existing model when doing another).

 

I don't think it's possible to change the behaviour, it's a built in mechanism in Cura to so that it doesn't produce gcode which might damage a printer.

 

Most of the time, multicolour prints (on a single extruder printer) are done by doing a certain number of layers in each colour and then pausing to change filament for the next colour.

 

If doing it that way doesn't work for you, then the best way to do it is to print them separately and glue them together (if you're just printing PLA, cyanoacrylate - regular old superglue - works very well).

 

I don't recommend this (in fact I recommend against it, unless you really know what you're doing), but you could align them, delete the top one, slice, undo the delete and delete the other one and slice, and then take all the layers from the second file (not the startup or end g-code) and place them after all the layers of the first file but before the end gcode, and insert an M100 pause at the start of the layers for the upper model so you can change filament.

 

The idea from this test project is the colors and the background to be printed at the same height.

 

Gluing the parts in this case I am testing would add manual posprocessing and will be hard to create a flush surface without much elbow grease.

 

I think the risk to the printer of merging all the files is the same as printing them choosing each in the SDCard menu.

 

Thank you.

[Slashee_the_Cow 493]

3 hours ago, FabioRS said:

The idea from this test project is the colors and the background to be printed at the same height.

Just be aware that's only going to work if the surface they're on is flat and you don't want the letters to be more than a layer or two high or else the nozzle will run into the background part.

 

3 hours ago, FabioRS said:

I think the risk to the printer of merging all the files is the same as printing them choosing each in the SDCard menu.

If you slice them separately, just bear the home position in mind: homing the printer is almost always in the printer's startup gcode and if your first print is where it homes the Z position is, it'll run into that.

 

You can fix this by changing the startup gcode for the second file: there's probably a G28 in there, you'd have to replace it with:

G28 X Y
G0 F3000 X0 Y0
G28 Z

that will home the X and Y positions and then move to the corner of the bed to home the Z position (if that corner is taken, you need to change the co-ordinates to one which is free, if you have no corners free, then find the co-ordinates of somewhere there's a bit of space and put them in the G0 line instead of the 0s for the corner).