Multiple model printing- CURA bug?

[yellowshark 153]

Hi I want to print 5 copies of a model but separately, copy1 then copy 2 etc.

I loaded the model and duplicated it 4 times. Under the "Tools" menu I selected "Print one at a time" rather than "Print all at once". I used 2 skirts no brim.

But it printed layer 1 for all copies, during which I cancelled the print. I tried again just in case I had picked up the wrong g-code file, same again.

Has anyone done this before or is it a known bug or is there another setting I have missed?

 

[woofy 12]

Cura slices "on the fly" so after setting Print all at once you need to re-slice by moving something slightly.

 

[yellowshark 153]

Thanks I did try changing another setting and then back again because of that, but I will try moving one of parts.

 

[yellowshark 153]

Ok tried again, it did not work but slightly different.

I reloaded the cube. This time the Tool menu setting was already on “Print one at a time”. I right clicked on the cube and selected 4 copies. It errored and said it could only make 1 copy or have 1 copy. I wonder if there is a problem with my Machine settings which is reducing the bed size. Settings are

 

Printer head size

===============

X min = 60

Y min = 25

X max = 80

Y max = 60

gantry = 15

 

I assumed Cura is asking about the clearances therefore how much space it must allow in the x-y vectors to fit the extruder assembly during the print. Perhaps I have got that wrong?

 

[gr5 2,192]

gantry is wrong. You can print parts MUCH taller than 15mm without hitting the X/Y gantry bars at the top when you home again.

Please be aware that you do not need to print to see if it is printing one-at-a-time - simply go to layer view and you will see only 1 part printing when you show layer 1. Second part won't start until first part finishes.

Right click (edit - actually I think you hover!) on these settings to see the default settings.

If any part is taller than the gantry height it will not print in one-at-a-time mode.

 

[Daid 306]

If any part is taller than the gantry height it will not print in one-at-a-time mode.

This. Because the gantry can hit the other printed objects when finishing the later objects.

I'm looking at the PrintrBotXL here for example, and it has about 10-15mm of clearance on the gantry. So no way you can print anything usefull one-at-a-time with a setup like the PrintrBotXL.

 

[gr5 2,192]

Daid the final object to be printed should be allowed to be as tall as you want. The gantry won't hit the last object. Only the objects before.

 

[Daid 306]

In theory, yes.

But how to you know what is the final object? And how extra confusing it will be towards the user? And how much extra work from me ;-)

 

[yellowshark 153]

thanks guys, I was not sure what the gantry was so I played it safe, the model is only 5mm high. But I will change it to 75 now. Actually I think I know what the problem is so I am going over to the workshop now to test and will report back.

 

[yellowshark 153]

It was as I thought, although I am not sure what made me think of it because it makes no sense to me, come to that in a moment.

Prior to trying the multi-model print (in PLA) I was using nylon and had set a skirt some distance from the model to give the pressure in the extruder time to equalise before starting the print.

What CURA was doing was to take the skirt as part of the model and of course when I asked for four additional copies there was not enough room on the print bed to do this, hence the error. So I set the skirt to be much closer to the model and then the request for four additional models worked.

 

But a skirt is not there for the benefit of a model, unlike a brim which is. It is there to get the flow regulated and working before starting to print, which is only needed for model copy one IMHO.

There is no way you could use this print one at a time mode with nylon because the first copy would be a disaster on layer 1.

CURA should take the overall shape & size of the multiple models on the bed and then draw a skirt around them all, as it does with a singlemodel. As it was I had to change the skirt to brims because even with PLA the first layer on model copy 1 had a minor defect (unacceptable for this print) because the flow had not settled.

 

[gr5 2,192]

But usually you need the skirt around each object in one-at-a-time mode to reprime the nozzle. After the first object completes there is a retraction but then I think there is a bug and it doesn't un-retract before printing the next model. Or maybe vice versa and it unretracts twice (some bug with extrusion going negative maybe?)

 

[yellowshark 153]

Sorry George but re- priming is not an issue (using 14.01). I have just successfully completed a 4 model print. This time I was using a small brim rather than a skirt. On copies 2,3& 4 the filament just laid down perfectly from the start, each of the 3 brims was perfect.

This supports my point that they are not needed - unless you want model brims, and that a single skirt at the start is all that is needed with 14.01.

What do you think Daid?

 

[yellowshark 153]

One aspect George maybe is on how tall the model is. My models were very low and to me watching it there was really no difference between my run and printing all models concurrently - you still have to jump between models when a layer has been done. The only difference is that the printer has to reset the Z-axis and on mine there was no perceivable delay; I guess with tall models there might be and that might be the issue.

But it is not an issue for low models and the software should give you the option to choose multiple brims/skirts or not.

14.2 Daid? (choosing no should provided a bed wide skirt at the start if skirt has been requested). This aspect may not be important to most people but it is to my business if I am doing a production run rather than a single prototype. Especially if it is nylon!!!

 

[samtaylor 0]

i like to lie to my slicer to allow printing multiple tall objects one at a time. i tell it the gantry is the full height of the z axis. this works well in an old version. problem im having right now with 3.2.1 is it wont let me place objects near the edge of the bed. im using a formbot trex which has room either side of the build plate for the print head and like many printers including my cr10 the head can hang over the ends of the bed.  I wish there was a planned feature. "print tall objects one at a time" where they would not be allowed to be side by side