Bad print quality with dual prints vs. single extruder prints

Alex.cr · 30 Mar 2021, 13:42

Is been awhile since I have done any dual extrusion prints with a duet but here’s what I found in the past that led to similar problems.

You said you are using cura, when it’s printing two layers at the same time does it run one counter-clockwise then the next one clockwise? This would mean you could have backlash issues.

Next, are the temperatures stable when printing? When one head is parked are you dropping the temp to standby? If so how hot is it when it starts to print? If you don’t have temp wait commands or if the PID is not set up properly I could see this being an issue as well. It might be worth putting some G4 commands in to help temp stability, just for testing.

The difference in sheen from the lower to the upper section looks like the lower section printed hotter than the upper. What material is this?

Third and most likely unrelated, it looks like you retractions/pressure advance are leaving holes. I would look into that at some point.

Just my thoughts on places to look.

timcurtis67 · 30 Mar 2021, 13:54

@visionary said in Bad print quality with dual prints vs. single extruder prints:

For some reason my prints that use both extruders look awful. Corners look more jagged and even straight lines are not consistent from layer to layer.

I printed two one wall towers (taller tower in the picture) about 50mm apart from each other and used extruder 0 for the other and extruder 1 for the other. The other tower was about 40% shorter (extr0 tower). It is easy to see at which height the other tower was completed.

Printer I use is Duet 3 with RRF 3.2 configured to IDEX.

I can't figure what could cause this.

Did you print 2 towers at the same time (ditto printing)?

Or were you switching heads for each tower by level?

I ditto print all the time with my IDEX with no issues.

If you are printing by switching heads then are the heads even off of the bed or do you have an offset in one of them? You could have a Z backlash issue. The heads are constantly changing the Z axis for the tool offsets.

The other issues on the part look like pressure advance settings to me.

Visionary · 30 Mar 2021, 14:59

@alex-cr
@timcurtis67

All layers are printed counter clockwise.
My printing extruder temperatures vary quite a bit, maybe about 4-6 degrees of overshoot and 3-4 degrees max under. I'll try add extra waiting commands (maybe about 10s) after each temperature reach to test how this affects print quality. For some reason Auto PID tuning didn't give very good results for my heaters, but I'll try run it again.
Print material is ABS with 242 Celsius temp.
Both towers are printed separately with only one extruder extruding at once.
I try not use Z-hop and other backlash causing settings on Z-axis.
I probably should re-tune PA, although it used to be ok.

timcurtis67 · 30 Mar 2021, 15:05

@visionary So your heads are set the same off of the table? No G10 Z offset for Tool1?

timcurtis67 · 30 Mar 2021, 15:06

@visionary said in Bad print quality with dual prints vs. single extruder prints:

@alex-cr
@timcurtis67

All layers are printed counter clockwise.

My printing extruder temperatures vary quite a bit, maybe about 4-6 degrees of overshoot and 3-4 degrees max under. I'll try add extra waiting commands (maybe about 10s) after each temperature reach to test how this affects print quality. For some reason Auto PID tuning didn't give very good results for my heaters, but I'll try run it again.

Print material is ABS with 242 Celsius temp.

Both towers are printed separately with only one extruder extruding at once.

I try not use Z-hop and other backlash causing settings on Z-axis.

I probably should re-tune PA, although it used to be ok.

Also you need a good PID tune first on both heads to get good printed parts. Why wasn't autotune working well? What errors did you get?

Visionary · 30 Mar 2021, 15:12

@timcurtis67

No Z-axis offsets, but I have offsets on X and Y.
I didn't get errors with PID auto tune, except errors from too slow heating temp rise speed. I raised one the settings for the heater to prevent that error. The PID settings just don't work as well I'd expect. Temperatures settles too slowly.

Note that my extruders have custom water cooled setup, with different types of extruders: Flexion extruder on the other and Zesty nimble on the other.

timcurtis67 · 30 Mar 2021, 16:14

@visionary
Different extruders shouldn't matter if the are calibrated correctly.

So if you just print the tower with tool 0 and then print a tower with the other tool 1 do they both look the same? Do they both have the same measurements when compared?

Alex.cr · 31 Mar 2021, 03:56

@visionary said in Bad print quality with dual prints vs. single extruder prints:

I didn't get errors with PID auto tune, except errors from too slow heating temp rise speed. I raised one the settings for the heater to prevent that error. The PID

@Visionary When people mention that they had heating too slowly after autotuning it usually leads me to believe that they either did not do one of the following things:

Save the results to config.g
Use M500 to save the results to config-override.g and use M501 at the end of config.g
They don't realize they have an M501 at then end of their config.g and are only changing the settings in config.g and not config-override.g

Can you confirm that your M307 settings from your autotuning is set up correctly? I am really starting to think this is your main problem considering the overshoot you are describing above. I hate to see +-1...

Post your config.g for us to take a look.

o_lampe · 31 Mar 2021, 07:18

@Visionary
You could print both towers with only one tool (then the other tool) just to see, if it's an temp-drop issue or bad retraction/PA settings.
The picture shows the result of the Flexion or the Nimble?

Your setup is a good testrig for retraction/PA with idle time compensation. I hope that this feature is already on the FW-whishlist?
Until it is released, we have to use wipe-towers or prime-towers. Did you use any tool-prep towers?

Visionary · 31 Mar 2021, 09:10

@alex-cr said in Bad print quality with dual prints vs. single extruder prints:

@visionary said in Bad print quality with dual prints vs. single extruder prints:

I didn't get errors with PID auto tune, except errors from too slow heating temp rise speed. I raised one the settings for the heater to prevent that error. The PID

@Visionary When people mention that they had heating too slowly after autotuning it usually leads me to believe that they either did not do one of the following things:

Save the results to config.g

Use M500 to save the results to config-override.g and use M501 at the end of config.g

They don't realize they have an M501 at then end of their config.g and are only changing the settings in config.g and not config-override.g

Can you confirm that your M307 settings from your autotuning is set up correctly? I am really starting to think this is your main problem considering the overshoot you are describing above. I hate to see +-1...

Post your config.g for us to take a look.

G90                                                ; send absolute coordinates...
M83                                                ; ...but relative extruder moves
M550 P"My Printer"                                 ; set printer name                                
M669 K11 Y-1:-1:0:1  

; Network
M552 P0.0.0.0 S1                                   ; enable network and acquire dynamic address via DHCP
M586 P0 S1                                         ; enable HTTP
M586 P1 S0                                         ; disable FTP
M586 P2 S0                                         ; disable Telnet

; Drives
M569 P0.0 S1                              		   ; physical drive 0.0 goes forwards X
M569 P0.1 S1                               		   ; physical drive 0.1 goes forwards U
M569 P0.2 S0                                       ; physical drive 0.2 goes forwards Y
M569 P0.3 S1                                       ; physical drive 0.3 goes forwards Z
M569 P0.4 S1                                       ; physical drive 0.4 goes forwards E0
M569 P0.5 S1                                       ; physical drive 0.5 goes forwards E1

M584 X0.1 U0.0 Y0.2 Z0.3 E0.4:0.5                          	; set drive mapping
M350 X16 U16 Y16 Z16 E16:16 I1                              ; configure microstepping with interpolation
M92 X80.00 U80.00 Y80.00 Z640.00 E2700:185          		; set steps per mm
M566 X350.00 U350.00 Y350.00 Z60.00 E120.00:3200              ; set maximum instantaneous speed changes (mm/min)
M203 X12000.00 U12000.00 Y12000.00 Z180.00 E1800.00:2000          ; set maximum speeds (mm/min)
M201 X600.00 U600.00 Y600.00 Z20.00 E120.00:3000                ; set accelerations (mm/s^2)
M906 X950 U950 Y1400 Z1000 E700:1500 I45                    	; set motor currents (mA) and motor idle factor in per cent
M84 S30                                            				; Set idle timeout

M569 P0.0 V25 H25 D3  
M569 P0.1 V25 H25 D3                           
M569 P0.2 V25 H25 D3                         

M915 P0.0 S3 R0 H134 T25 F1	
M915 P0.1 S3 R0 H134 T25 F1			
M915 P0.2 S3 R0 H134 T25 F1

; Axis Limits
M208 X-58.4 U5 Y0 Z0 S1                                   	; set axis minima
M208 X391 U429 Y400 Z375 S0                             	; set axis maxima

; Endstops
;M574 X1 S1 P"io1.in"                             	; configure active-high endstop for low end on X via pin !^io2.in
;M574 U2 S1 P"io2.in"                             	; configure active-high endstop for high end on U via pin !^io1.in
M574 X1 S1 P"!^io1.in"                             	; Inductive sensor NPN straight on
M574 U2 S1 P"io2.in"                             	; Inductive sensor PNP straight on + pull down
M574 Y1 S1 P"io5.in"                             	; configure active-high endstop for low end on Y via pin !^io3.in
M574 Z1 S1 P"io4.in"                             	; configure active-high endstop for low end on Z via pin !^io4.in

; Z-Probe: NOT USED
M558 P0 H5 F120 T6000                              ; disable Z probe but set dive height, probe speed and travel speed
M557 X15:215 Y15:195 S20                           ; define mesh grid

; Heaters
M308 S0 P"temp0" Y"thermistor" T100000 B3974       ; configure sensor 0 as thermistor on pin temp0
M950 H0 C"out0" T0                                 ; create bed heater output on out0 and map it to sensor 0
M307 H0 B1 S1.00                                   ; enable bang-bang mode for the bed heater and set PWM limit
M140 H0                                            ; map heated bed to heater 0
M143 H0 S130                                       ; set temperature limit for heater 0 to 120C

M308 S1 P"temp1" Y"thermistor" T100000 B4725 C7.06e-8       ; configure sensor 1 as thermistor on pin temp2
M950 H1 C"out1" T1                                 ; create nozzle heater output on out1 and map it to sensor 1
M307 H1 B0 S1.00 D30                                  ; disable bang-bang mode for heater  and set PWM limit
M307 H1 R2.399 C262.2 D5.02 S1 V23.8
M143 H1 S280                                       ; set temperature limit for heater 1 to 280C

M308 S2 P"temp2" Y"thermistor" T100000 B4725 C7.06e-8       ; configure sensor 1 as thermistor on pin temp2
M950 H2 C"out2" T2                                 ; create nozzle heater output on out1 and map it to sensor 1
M307 H2 B0 S1.00 D30                                   ; disable bang-bang mode for heater  and set PWM limit
M307 H2 R2.125 C261.6 D5.93 S1.00 V23.8
M143 H2 S280                                       ; set temperature limit for heater 1 to 280C

M307 H0 A110 C180 D5 B1 						   ; Bed slow temperature rise

; Fans
M950 F0 C"out7" Q500                               ; create fan 0 on pin out7 and set its frequency
M106 P0 S0 H-1                                     ; set fan 0 value. Thermostatic control is turned off
M950 F1 C"out8" Q500                               ; create fan 1 on pin out8 and set its frequency
M106 P1 S0 H-1                                     ; set fan 1 value. Thermostatic control is turned off

; Tools 
; tool 0, X-axis
M563 P0 D0 H1 X0 F0                                 		; define tool 0
G10 P0 R0 S0 X0 Y0 Z0                                    	; set tool 0 axis offsets
; tool 1, U-axis 
M563 P1 D1 H2 X3 F1
G10 P1 R0 S0 Y0.57 U1.2 Z0                                    	;  plus U shifts to left OLD VALUES: 1,195 (20.3), 
									


; Miscellaneous
M575 P1 S1 B57600                                  ; enable support for PanelDue
M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; set voltage thresholds and actions to run on power loss

T0													; select tool

M501

M307 report results:
M307 H2
Heater 2 model: heating rate 2.032, cooling time constant 260.1, dead time 6.75, max PWM 1.00, calibration voltage 23.7, mode PID
Computed PID parameters: setpoint change: P13.0, I0.311, D61.5, load change: P13.0, I0.679, D61.5

M307 H1
Heater 1 model: heating rate 2.361, cooling time constant 139.7, dead time 4.33, max PWM 1.00, calibration voltage 23.7, mode PID
Computed PID parameters: setpoint change: P17.5, I0.710, D52.9, load change: P17.5, I1.484, D52.9

I did do M500 after tuning with M501 in config.

Visionary · 31 Mar 2021, 09:11

@o_lampe said in Bad print quality with dual prints vs. single extruder prints:

@Visionary
You could print both towers with only one tool (then the other tool) just to see, if it's an temp-drop issue or bad retraction/PA settings.
The picture shows the result of the Flexion or the Nimble?

Your setup is a good testrig for retraction/PA with idle time compensation. I hope that this feature is already on the FW-whishlist?
Until it is released, we have to use wipe-towers or prime-towers. Did you use any tool-prep towers?

Print shown in the picture is done with flexion. I didn't use prime towers for it.

Alex.cr · 1 Apr 2021, 09:09

@visionary

What hotend/thermistor/heater are you using? Are both of them the same hot ends?

You said you were running a custom water cooled setup, is everything custom (heat break, spreader, heater block)?

The auto tuned numbers are significantly different between the two.

Visionary · 1 Apr 2021, 09:09

@alex-cr said in Bad print quality with dual prints vs. single extruder prints:

@visionary

What hotend/thermistor/heater are you using? Are both of them the same hot ends?

You said you were running a custom water cooled setup, is everything custom (heat break, spreader, heater block)?

The auto tuned numbers are significantly different between the two.

Only nozzle, heat block, thermistor and heat break are the same. I'm not sure if heater cartridge is the same with both. All of the shelf parts are from E3D.

o_lampe · 1 Apr 2021, 09:25

@visionary said in Bad print quality with dual prints vs. single extruder prints:

I'm not sure if heater cartridge is the same with both

That would be intersting..do you have a multimeter? The resistance of the cartridges would tell a lot. (maybe you have a mixup of 12V/24V heaters?)