Cura LE Version: 3.6.* (all versions)
Operating System: Windows 10
Printer: TAZ 6 (probably all)
Tool Head: Dual Extruder V3 (V2 probably fails as well)
Description of issue:
The prime tower in CuraLE 3.6.* prints each extruder in a different X,Y space (concentric squares). Because of this, the first time the second extruder prints the prime tower, it is printing on air. There is nothing underneath for it to print on. This problem was introduced in 3.6.3 and continues into 3.6.18. Note that Ultimaker Cura 4.2.1 exhibits the same behavior. I did not investigate when this problem was introduced into Ultimaker Cura.
CuraLE 3.2.32 does NOT have this problem. It uses a different pattern for the prime tower.
While the 3.6 prime tower appears to use less filament, the X,Y coordinates for each extruder should overlap so that layers that are printed with one extruder provide a base for the layers that print with the other (or both) extruder(s).
Simplify 3D uses two adjacent square areas. When a layer has only one extruder, both squares are printed with that extruder and when both extruders are used on a layer, each square of the prime tower gets printed with its extruder.
I believe this is probably how the new prime tower is supposed to work.
Steps to reproduce:
I used the 3DBenchy dual print .stl files but just about any .stl files designed for dual extrusion printing will work.
- Add two .stl files designed for dual extrusion printing.
- Assign an extruder to each file.
- Change the material of the second extruder to something with a different material color (i.e PLA and ABS).
- Merge models
- Switch to Layer View, Material color (high contrast between materials makes it easier to see)
- Examine the prime tower layer by layer.
Upload cura-lulzbot.log (attachment)