Wipe and Prime Tower Filament Order

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danielwells
Posts: 1
Joined: Wed Jul 12, 2017 9:39 am

Wipe and Prime Tower Filament Order

Post by danielwells » Wed Jul 12, 2017 9:54 am

We have been experimenting with our new dual extruder and have been having some great success. However we are having minor issues with the Wipe and Prime tower falling down on occasion.

The issue seems to me that Cura is choosing to use the 2nd extruder to lay down the first layer of the tower. This is an issue since the bed temp is usually optimized for the first extruder filament.

For example, we are having good success with NGEN in extruder 1 and HIPS in extruder 2 for support (the HIPS just comes off so easily without the need to even try to dissolve it with limonene). But NGEN likes the bed to be around 80-85 degrees. HIPS seems to work best between 100-110. But since NGEN is the primary filament for our part we need to set the bed at 80-85. And since Cura lays the first layer of the tower down using the HIPS, the tower does not adhere as well as it could.

My theory is that if we could get Cura to lay down NGEN first, then the tower would work better. Any ideas how to make that happen on my own?

Thanks.

radensb
Posts: 35
Joined: Sun Jul 23, 2017 3:21 pm

Re: Wipe and Prime Tower Filament Order

Post by radensb » Wed Nov 21, 2018 3:23 pm

I am running into the same issue. I think this might be a bug caused by an ordering mishap and the behavior changes by changing the Build Plate Adhesion Type...
I have a part setup to use interface support layers with PLA model material in E1 and support material in E2. This prints all the support lattes with the model PLA material and support layers on top of the lattes (roof interface). I noticed that the prime tower kept losing adhesion and it was because the gcode was printing the first layer of the tower in the support material, not the PLA (which the bed temp was set for). I had the Build Plate Adhesion Type set to Skirt and Build Plate Adhesion Layer Extruder set to Hot End 1, so it didn't make sense why it was printing the first layer with Hot End 2. Then I noticed that things changed when I changed the Build Plate Adhesion Type to None. It didnt generate a skirt and printed the base layer of the prime tower with E1, like I wanted it to.

Below is the first layer of a round part with is extruded with model PLA from E1 (black) and support material (Blue) and the order of the print.
PrimeTowerOrder.png
When the skirt is enabled, there is an ordering problem as it prints the PLA skirt, support lattes, and part outline first using E1, then switches to E2 to print a skirt line, followed by the base of the prime tower. It seems like it should print the base of the prime tower before switching nozzles and printing the outer skirt line with the support. So instead of an ordering of 1->2->3->4->5, it should have been 1->2->3->5->4.

Below is what it looks like without the skirt. Since there is no need to print the skirt path for E2, it keeps E1 active and prints the base layer of the prime tower as expected.
PrimeTowerOrder_noSkirt.png

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