Dual Extrusion Strategy and Prime Tower

[GalaxAjh]

Application version
Cura 4.6.1

Platform
Mac OSX 10.13.6

Printer
Dagoma DicoEasy 200 (2 extruders, 1 nozzle)

Reproduction steps
I want to print a piece in 2 colors. I set my parameters. For the first layer, If I decide to chose Extruder 1 for build plate adhesion, the prime tower is generated only with extruder 1. If I choose Extruder 2 with the same other parameters, the prime tower is generated with the 2 extruder. Wich in my opinion is the better solution to prime/purge the extruder. As you can see, there is only 1 line on the skirt to prime extruder 2 (1st picture)

Screenshot(s)

Build Plate Adhesion : Extruder 1

Build Plate Adhesion : Extruder 2

Reproduction steps
An other thing is : if a layer ends with extruder 1, at the begin of the next layer, there is a new prime. If the extruder 2 ends the layer, there is no prime on the next layer. This means that for the prime tower, 1 layer on 2 is not fully completed and on the next layer, Extruder 2 extrude on the prime tower on empty layer space

Layer 6 finished

Very beginning of layer 7

Project file
In my opinion, the first layer must allow the prime of the 2 extruders whatever the selected extruder for the buid plate adhesion(sometimes the second extruder in not ready to print and must be primed). For the next layers, extruders must be purged one by layer. No need to purge extruder 1 when it finished the layer and begin the next.

Request
Is it possible to change the running extruder when the nozzle is on the tower not on the subjet. Sometimes, it is necessary to change the t° of the nozzle and I think i's better to wait the good T° outside the piece

Log file
Another issue : The saved file does not save the distribution of the extrudeurs
DD_couvercle.3mf.zip

Additional information
Relevant with issue #7864

Sorry I am not aware of how to fill an issue and english is not my native language

[rburema]

As you can see, there is only 1 line on the skirt to prime extruder 2 (1st picture)

This might be a bug, since the settings specify at least two lines (only works for extruder 1). You can work around this by setting 'skirt/brim minimum length' to a higher value.

An other thing is : if a layer ends with extruder 1, at the begin of the next layer, there is a new prime. If the extruder 2 ends the layer, there is no prime on the next layer.

This is correct. We print with the main extruder every layer, so there is a stable tower. We otherwise only prime an extruder when it's necessary; if the last extruder that is still active on a layer is the same one as the first one on the next, we do not prime, as it's basically just a travel (though one that involves the z direction as well).

Is it possible to change the running extruder when the nozzle is on the tower not on the subjet.

I'll get back to you on that.

[rburema]

(Also, we prefer to have multiple issues split out over multiple tickets. Reporting multiple issues in one report can create confusion if we refer to the tickets.)

[Ghostkeeper]

As you can see, there is only 1 line on the skirt to prime extruder 2 (1st picture)

This might be a bug, since the settings specify at least two lines (only works for extruder 1). You can work around this by setting 'skirt/brim minimum length' to a higher value.

It's currently the expected behaviour. The skirt is printed with the Platform Adhesion Extruder, but the other extruders are also primed but only until their "minimum skirt length" has been achieved.
I don't see a reason why it should work like this though. Logically all extruders that are used in the print should prime the same way, whether they are the first to start or not. I think the priming of additional extruders was implemented more with the brim in mind. They are the same algorithm in CuraEngine.

[mahtDFR]

This is added to the backlog as CURA-7504

[rburema]

Concerning the '2nd extruder doesn't listen to skin line number', we've made internal ticket CURA-7504, so it'll get picked up at some point.

When it comes to the nozzle heating over the object, the extruder start and extruder end positions should have been set for the machine.

[fvrmr]

We are constantly working on making Ultimaker Cura better. Our community is a big part of that by requesting new features and reporting bugs.

To be able to focus on the most requested and needed features and bug fixes from our community and from Ultimaker, we have decided to remove this bug from our backlog. We believe we will not work on this anytime soon and will therefore defer this issue.

Since Cura is open source, you or anyone else is more than welcome to work on this issue and create a pull request yourself.

[github-actions]

Hi 👋,
We are cleaning our list of issues to improve our focus.
This bug seems to be older than a year, which is at least three major Cura releases ago.
It also received the label Deferred indicating that we did not have time to work on it back then and haven't found time to work on it since.

If this is still a problem for you in the current version of Cura, can you please leave a comment?
We will have a fresh set of eyes to look at it.

If it is not a problem anymore, you don't have to do anything, and this issue will be automatically closed in 14 days.

[github-actions]

This issue was closed because it has been inactive for 14 days since being marked as stale.
If you encounter this issue and still experience this to be a problem, you are welcome to make a fresh new issue with an updated description and screenshots.