Dual Extrusion - First Retraction

[LeoLautsprecher]

Hi guys,
I'm not new to dual extrusion, but after a hole lot of trouble with tow hotends and a E3d Cyclops I decided to try out a single hotend, dual extruder concept. The filament which is fed to the hotend gets switched in a Y piece before it enters the Hotend. Like this: http://www.thingiverse.com/thing:1680034

I got a problem with the very first tool change. To make stuff easier, extruder1 is loaded with white, extruder2 with black.
The prints starts with a white part and everything is fine. When the first color change occurs, it retracts white, but it doesn't push black forward afterwards. But at this point black is still 100mm behind the nozzle. Every color change in the next layers works fine.

Has anyone got ideas how to fix it? Maybe with a custom toolchange script that is only enabeled in the first layer?

Best regards,
Leo

[dorsai3d]

I've run into a similar thing before. Simplify3D sent me a profile for the Axiom Dual that had a fix for this (even though it's not a 2in1out). The start script primes one extruder, then retracts it, then primes the next extruder without retracting (this is important). Then the tool change script is as follows:

Code: Select all

G92 E0
G1 E-[toolchange_retract_distance] F[toolchange_retract_speed] ; retract previous tool
T[new_tool] ; switch to new tool and offsets
G1 X[next_position_x] Y[next_position_y] F[travel_speed] ; move to next printing location
G92 E0
G1 E[toolchange_prime_distance] F1800 ; prime new tool
G92 E0

This isn't really any different than what they do for a normal toolchange, but this fires off at the beginning of a print and solves the issue of toolchange retraction in the first layer of a print.

[LeoLautsprecher]

Thanks a lot, I will give it a try

[Zorgonaute84]

Thanks god !!!

I'm not alone to cry about this issue.... The Simplify3D Support never proposed me this script. I'll test it very soon ! Thanks a lot


@dorsai3d, you look to have more success than me to find solution from Simplify3D support. Do you find a solution to perform a retraction between the prime pillar and the part with the option "only retract when crossing open space" checked ? In my case I have retraction when the option is unchecked, but no retraction when I check this option.

[dorsai3d]

I've not had any luck with that. There's actually quite a few cases where it doesn't retract over open spaces, like between the last support and a model, or between two models with different processes, or prime pillar to model, and I think this also happens with the ooze shield in some cases, practically defeating the whole purpose.

I've taken to just having it retract for everything, but my printer handles lots of retracts quickly and reliably.

[Zorgonaute84]

I've run into a similar thing before. Simplify3D sent me a profile for the Axiom Dual that had a fix for this (even though it's not a 2in1out). The start script primes one extruder, then retracts it, then primes the next extruder without retracting (this is important). Then the tool change script is as follows:

Code: Select all

G92 E0
G1 E-[toolchange_retract_distance] F[toolchange_retract_speed] ; retract previous tool
T[new_tool] ; switch to new tool and offsets
G1 X[next_position_x] Y[next_position_y] F[travel_speed] ; move to next printing location
G92 E0
G1 E[toolchange_prime_distance] F1800 ; prime new tool
G92 E0

This isn't really any different than what they do for a normal toolchange, but this fires off at the beginning of a print and solves the issue of toolchange retraction in the first layer of a print.

Thanks a lot for your script ! It works perfectly !

Now please Simplify3D team, fix the missing retractions between prime tower and the parts and it will be finally fully operationnal for dual extrusion !

[wiley]

+1 to this. This script works, but using it means we can't wipe or lift during the retraction. The problem seems to be that on the first tool change, we get

Code: Select all

; print some stuff with T0
G92 E0
G1 X-14.880 Y56.938 E-80.0000 ; wipe and retract
G1 Z2.600 F7200 ; lift
T1
G1 X-34.480 Y47.520 F7200 ; move to the next location
G1 Z0.600 F7200 ; drop back to print height
G92 E0 ; zero extruded length <---- BUG IS HERE
; print some stuff with T1

but on subsequent tool changes, we get

Code: Select all

; print some stuff with T0
G92 E0
G1 X-49.200 Y10.982 E-80.0000 ; wipe and retract
G1 Z2.600 F7200 ; lift
T1
G1 X-48.240 Y17.760 F7200 ; move to the next location
G1 Z0.600 F7200 ; drop back to print height
G1 E-1.0000 F3300 ; prime <--- THIS IS CORRECT
G92 E0

(with comments added by me)

Ideally, I would like to just use G92 to set the positions of the extruders during the start script and then always get the second script during tool changes. Right now I'm patching the gcode manually because I don't want to give up wipe + lift.

I tried to work around this by printing a skirt with both extruders. If the extruded length for the skirt was longer than the tool switch retraction length, it would prime T1 and bypass this issue. Unfortunately, it looks like S3D wants to switch to T1 (with a zeroed position even though it starts out retracted), then print the prime tower, then print the skirt. I can't have a skipped layer in the prime tower, so I think this won't work.

[Zorgonaute84]

With the new v4.0 this script doesn't work properly, because of a new retraction added at the begining.

I changed it to that, and it's work perfectly :

Code: Select all

{IF NEWTOOL=0} T0					;Start tool switch 0
{IF NEWTOOL=0} G1 X[next_position_x] Y[next_position_y] F[travel_speed] 	; move to next printing location
{IF NEWTOOL=0} G1 Z[next_position_z] F1002
{IF NEWTOOL=0} G1 E0 F[toolchange_retract_speed] 		; prime new tool


{IF NEWTOOL=1} T1					;Start tool switch 1
{IF NEWTOOL=1} G1 X[next_position_x] Y[next_position_y] F[travel_speed] 	; move to next printing location
{IF NEWTOOL=1} G1 Z[next_position_z] F1002
{IF NEWTOOL=1} G1 E0 F[toolchange_retract_speed] 		; prime new tool

G92 E0

[Tif]

With the new v4.0 this script doesn't work properly, because of a new retraction added at the begining.

I changed it to that, and it's work perfectly :

Code: Select all

{IF NEWTOOL=0} T0					;Start tool switch 0
{IF NEWTOOL=0} G1 X[next_position_x] Y[next_position_y] F[travel_speed] 	; move to next printing location
{IF NEWTOOL=0} G1 Z[next_position_z] F1002
{IF NEWTOOL=0} G1 E0 F[toolchange_retract_speed] 		; prime new tool


{IF NEWTOOL=1} T1					;Start tool switch 1
{IF NEWTOOL=1} G1 X[next_position_x] Y[next_position_y] F[travel_speed] 	; move to next printing location
{IF NEWTOOL=1} G1 Z[next_position_z] F1002
{IF NEWTOOL=1} G1 E0 F[toolchange_retract_speed] 		; prime new tool

G92 E0

Many thanks for your script!
The problem I had was the hotend was staying on the part being printed while retracting 17cm for tool change (lots of blobs...). I then put 5mm for tool change retraction distance and I used the following script :

Code: Select all

{IF NEWTOOL=0} G1 X[next_position_x] Y[next_position_y] F[travel_speed]    ; move to next printing location
{IF NEWTOOL=0} G1 Z[next_position_z] F1002
{IF NEWTOOL=0} G1 E0 F[toolchange_retract_speed]       ; prime new tool
{IF OLDTOOL=1}  G1 E-170 F[toolchange_retract_speed] ; retract filament (17cm)
{IF NEWTOOL=0} T0               ;Start tool switch 0
{IF NEWTOOL=0} G1 E0 F[toolchange_retract_speed]       ; prime new tool

{IF NEWTOOL=1} G1 X[next_position_x] Y[next_position_y] F[travel_speed]    ; move to next printing location
{IF NEWTOOL=1} G1 Z[next_position_z] F1002
{IF OLDTOOL=0}  G1 E-170 F[toolchange_retract_speed] ; retract filament (17cm)
{IF NEWTOOL=1} T1               ;Start tool switch 1
{IF NEWTOOL=1} G1 E0 F[toolchange_retract_speed]       ; prime new tool

G92 E0

It now works great as the retraction happens above the prime pillar. Hope it will help someone

[Lynnch51]

Hey guys I’m super new to this I’m using the same 2 in 1 out and don’t really understand code like this at all are y’all just coping this script and pasting it in the script tab in s3d thank you any info in appreciated dual is very frustrating