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Print order of skirt, ooze shield, and nozzles is wrong

Posted: Thu Mar 17, 2016 6:39 am
by jasu
The skirt has to be printed before parts actually important for the model. That includes the ooze shield, the first layers of which are crucial for correct upper layers. Alas, the order of skirt and ooze shield as well as the print head order are wrong.

Consider the dual extrusion model of a biological membrane (https://onedrive.live.com/redir?resid=3 ... le%2cgcode).

It starts with the skirt alright as it should.
path 1.png
But then it swaps tool head. That destroys all advantages of priming the nozzle before an important part of the model. It should print the skirt and then go right to parts of the model to be printed with the same nozzle.
path 2.png
Then, it prints the 2nd line ((Skirt/All Extruder setting) of the skirt AFTER the shield. Again it makes no sense, since the beginning of the green line will often not extrude well. These extrusion problems should be in the skirt not in the shield.
path 3.png
After that it swaps nozzle again from green to blue to print the actual model. Another mistake. Now, that the green nozzle is primed it should print the green parts of the model on the same layer first before changing to the blue tool head.

It is very important that the 1st layer of the ooze shield is printed after priming the nozzle with a skirt. Especially, if you print directly onto the build plate without a raft, the first millimeters of the ooze shield will often be badly printed. This will cause problems in the subsequent layers. The shield often comes closer to the model and can even stick to it. This is why the 1st shield layer should be printed after priming the nozzle with a skirt.

In summary, the best order in the print code generated by Simplify3D should be:

  • skirt blue
  • model blue 1st layer

  • skirt green
  • shield green 1st layer
  • model green 1st layer

  • shield blue 2nd layer
  • model blue 2nd layer..

Re: Print order of skirt, ooze shield, and nozzles is wrong

Posted: Fri Mar 18, 2016 6:52 am
by CompoundCarl
Can you attach your factory file?

Re: Print order of skirt, ooze shield, and nozzles is wrong

Posted: Fri Mar 18, 2016 10:19 am
by beerdart
Ive noticed the same think when printing the ooze shield the models first layer prints first and acts like the ooze shield for the first layer. It should print the ooze shield first so I can do its job.

Re: Print order of skirt, ooze shield, and nozzles is wrong

Posted: Fri Mar 18, 2016 6:09 pm
by jasu
CompoundCarl wrote:Can you attach your factory file?
Hi Carl,

I didn't save the factory file then, only the gcode (see above). So, I reconstructed it just now and it turns out to be very similar to the first run: blue skirt (not followed by anything meaningful in blue, wasting the priming), green ooze shield (w/o priming which usually causes a missing inch of so of shield), green skirt, blue level 1, green level 1,..

All the best

Re: Print order of skirt, ooze shield, and nozzles is wrong

Posted: Sat Mar 19, 2016 10:40 am
by CompoundCarl
Does this happen with every model or just this one?

Re: Print order of skirt, ooze shield, and nozzles is wrong

Posted: Sat Mar 19, 2016 11:41 am
by beerdart
It does it for every model ive tried.

Re: Print order of skirt, ooze shield, and nozzles is wrong

Posted: Sun Mar 20, 2016 2:58 am
by KC_703
I'm seeing the same thing. When printing skirt, it will print the first perimeter with T0, T1 ooze shield then first perimeter of skirt with T1, then second T0 skirt, second T1 skirt... If you have a dual extruder setup, the print simulation (set to line) should show this.

I think S3D performs the ooze shield after each tool change... so while wrong, its the intended behavior with ooze shield. Factory files attached.

What should happen is, IMO:
- T1 skirt 1
- T0 skirt 1
- T1 skirt 2
- T0 skirt 2
- T1 first layer Color1
- T0 ooze shield
- T0 first layer Color2
- T0 second layer Color2
- T1 ooze shield
- T1 second layer Color1
.... etc

This would essentially prime both extruders, then prime the T1 before it actually needs to print the object.

Re: Print order of skirt, ooze shield, and nozzles is wrong

Posted: Fri Jan 12, 2018 1:42 pm
by jacoscar
Hi, I'm having the same problem. Has this ever been solved?

Re: Print order of skirt, ooze shield, and nozzles is wrong

Posted: Sun Feb 18, 2018 8:56 pm
by Aha
Ug, I'm wondering this as well! First few test prints had to be done in cura, it's a mess, and I'm trying to move back to the better s3d, but this isn't good behavior at all. Trying to move beyond cura's poor settings that seem to be as half baked as this problem. Don't want to come back to more of the things that just aren't thought out!

Re: Print order of skirt, ooze shield, and nozzles is wrong

Posted: Mon Mar 19, 2018 4:35 pm
by Chadd
I am having this same issue also, it is so damn frustrating that S3D takes so long to fix bugs.