Sequential print is executed non-sequential/not in the right order
 
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Ralf S.
(@ralf-s)
Active Member
Sequential print is executed non-sequential/not in the right order

Hi,

I am trying to print the following 16 objects in a specific order - from front to back. To do so I activated in PrusaSlicer "Complete individual objects" and specified "Extruder clearance (mm)". Furthermore, PrusaSlicer shows the right Seq.#1-16, but when it comes to printing, the printer starts to print brims for object 16, then brims for object 15, etc. so it is not executed neither in the right order nor sequentially.

Do I miss important settings or parameters to enable sequential printing? Thanks for your help!

Opublikowany : 01/12/2020 8:37 am
Neophyl
(@neophyl)
Illustrious Member
RE: Sequential print is executed non-sequential/not in the right order

Please post your project file (File Save As) then zip up the output .3mf and attach it here.  That way we can take a look at it ourselves and try different settings.

I suspect that its a limitation in the current version when it comes to printing brims / skirt lines as they get printed first.  I remember a similar issue being raised against Super Slicer (which is a fork of PS) 

Opublikowany : 01/12/2020 8:44 am
Ralf S.
(@ralf-s)
Active Member
Topic starter answered:
RE: Sequential print is executed non-sequential/not in the right order

Hi neophyl,

Thanks for your reply. Here you find the .3mf file.

sequential_printing

It seems, that you are right. I just started a print without brims and the printer starts at Seq.#1 like expected.

Opublikowany : 01/12/2020 9:00 am
Neophyl
(@neophyl)
Illustrious Member
RE: Sequential print is executed non-sequential/not in the right order

Actually one of the suggestions for an improvement to Super Slicer is to print the first layers of all objects and THEN go to the sequential printing order. 
This would allow the user to monitor that the first layers have gone down correctly and are sticking to the bed properly.  Then you could more safely turn your attention elsewhere.  Its usually first layers not sticking that causes print problems with disastrous ends.

So I wouldnt worry too much about it doing all the brims first, that's probably a good thing.

Opublikowany : 01/12/2020 9:24 am
Swiss_Cheese
(@swiss_cheese)
Noble Member
RE: Sequential print is executed non-sequential/not in the right order

Could it possibly be that printing the brims sequentially would end up causing a collision with one of the already printed models if they weren't printed first?

just a thought.

The Filament Whisperer

Opublikowany : 02/12/2020 3:41 am
Ralf S.
(@ralf-s)
Active Member
Topic starter answered:
RE: Sequential print is executed non-sequential/not in the right order

Good thought @swiss_cheese, but I tried to print with less elements on print bed and larger clearance. The result is still the same: brims are printed first.

Opublikowany : 02/12/2020 6:12 am
Ralf S.
(@ralf-s)
Active Member
Topic starter answered:
RE: Sequential print is executed non-sequential/not in the right order

In some cases, it can be helpful to print all brims first. In this particular case it causes shrinking defects, because the first layer takes about 17 minutes to print. If brim and 3 parts of one object are printed directly together, there is no shrinking effect.

I think the only option for my case is to manually adapt the gcode.

Opublikowany : 02/12/2020 11:16 am
Agkirk
(@agkirk)
Estimable Member
RE: Sequential print is executed non-sequential/not in the right order

Is it possible to change filament as the printer sequences to the different objects?  I would like to use my MMU2S to make different colored objects.

Opublikowany : 02/12/2020 5:12 pm
Ralf S.
(@ralf-s)
Active Member
Topic starter answered:
RE: Sequential print is executed non-sequential/not in the right order

Hi @agkirk,

I am not able to check this in practice (I don't own a MMU), but I can imagine, that it could work like this:

  1. Integrate a tower into your object which is one layer higher than the object you want to print
  2. On this last layer add color change in prusaslicer
  3. Go into your gcode and search for the color exchange positions (i.e. M600, filament change). This position you have to replace with code, which is telling your MMU to select the right filament

Alternatively, add a separate object instead of the tower to your prusaslicer on which you can perform the filament change.

Such a tower can be placed closer to your object, because it is printed layer by layer with the object. An separate object will need some clearance to your main object.

Opublikowany : 02/12/2020 9:18 pm
Swiss_Cheese
(@swiss_cheese)
Noble Member
RE: Sequential print is executed non-sequential/not in the right order

hmm, I'll be interested to know how this turns out. I've printed sequentially before but never using brims, I was unaware of this issue,

and the PLA your using is shrinking?

The Filament Whisperer

Opublikowany : 03/12/2020 7:10 am
Ralf S.
(@ralf-s)
Active Member
Topic starter answered:
RE: Sequential print is executed non-sequential/not in the right order

I will share my results with you as soon as I manage to provide the changes into gcode and test it with my printer.

Opublikowany : 03/12/2020 8:33 am
Ralf S.
(@ralf-s)
Active Member
Topic starter answered:
RE: Sequential print is executed non-sequential/not in the right order

PS. yes, there is some kind of shrinking going on with the PLA. Compare the walls on the pictures below. Left is with failure, right is fine.

Opublikowany : 03/12/2020 11:44 am
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