Printing of some layers of ooze shield slower than expected.

[jorisjanssen]

When printing gcode sliced with Simplify3d V4 for a dual extruder printer, I noticed that some layers of the ooze shield were printing very slowly. After further analysis I noticed that the gcode had the following structure:

Code: Select all

; G-Code generated by Simplify3D(R) Version 4.0.0
; layer 1, Z = 0.200
; ooze shield
; inner perimeter
; outer perimeter
; solid layer
; layer 2, Z = 0.200
; layer 3, Z = 0.400
; layer 4, Z = 0.400
; inner perimeter
; outer perimeter
; solid layer
; ooze shield
; layer 5, Z = 0.600
; inner perimeter
; outer perimeter
; solid layer
; layer 6, Z = 0.600
; ooze shield
G1 X155.942 Y132.830 E0.0026 F720
; layer 7, Z = 0.800
; layer 8, Z = 0.800
; inner perimeter
; outer perimeter
; infill
; ooze shield

Note that both layer 5 and layer 6 are printing at Z=0.600. Layer 5 contains the gcode for the inner and outer perimeter and the solid layer, layer 6 only the ooze shield.

This means that layer 6 (at the same Z level as layer 5, so to all intents and purposes the same layer) finishes very quickly and hence, the cooling speed overrides kick in, unnecessarily slowing down the printing of the ooze shield.

This behavior seems erratic and does not occur on all layers.

[jorisjanssen]

Adding a picture to visualize this issue ... You will notice the slow and fast layers of the ooze shield ...

[shocksofmighty]

This comes from the printing layer being below the time threshold to slow down the printing move. Remove the "slow down for layers below X seconds" (forgot what it is called) and it should look better.

EDIT: as you seem to have already determined. Started replying before I read it all the way through!

[jorisjanssen]

That may be a viable workaround, but it does not explain why this happens only on some layers and not on others ...

[shocksofmighty]

I agree. This is a bug. Just worked up a dual extrusion print that shows the same behavior.

[blackbird2016]

In my experience thus already happened with the 3.1.1. Unchecking the box for deceleration for Layers unser "x"-seconds does the Trick nur certainly is just a workaround and is not suitable for all designs...