Tuning new build DBot Bowden E3D v6 - Beyond the First Layer

I had an earlier thread regarding my first layer, and that has been resolved with a combination of the new Titan extruder and refinement of the print settings for my DuetWiFi install and S3D settings. Printing in general is now working but I'm getting fair amount of inconsistent blobbing and what looks like under extrusion in some areas but over in others.

As a recap here is my build:

"D-Bot Blue" D-Bot build 300 x 300 x 300
Hotend: E3D V6 (full)
Nozzle: 0.4mm
Extruder: Titan
Bowden Tube Length: 795mm
Print Bed: Mic6 Aluminum (8 x 325 x 325)
Print Bed Heater: Keenovo Silicone heater (120v, 750w)
Controller: DuetWiFi (firmware 1.19)
Steppers: 1.8 degree, 2.0 amp, 84 oz
Leadscrews: 8mm x 400mm - single start, 2mm / turn - w/anti-backlash nuts
Filament width: 1.75mm

Slicer: Simplify3D
Layer Height: 0.2mm
Extrusion Multiplier: 1.05
Extrusion width: 0.5mm

Here are some of the most recent calibration prints. I did a pair of XYZ calibration cubes one in front of the other on the build plate. In the below picture, the left hand cube was printed at the same time as the right, and it was positioned directly in front of the right.

All of the below is Hatchbox PETG, 240c hotend, 70c bed

You can see the top looks under extruded, but I also have blobs at the very end of the print on the top. I've been trying to control that with coasting and retraction, but not sure I'm getting anywhere.

If anyone has any thoughts on the below, would love to hear them.



The thing I'm trying to figure out is that the "X" face prints differently for the front cube (left) than it does for the back cube (right)




To date, I've been adjusting coasting distance, extrusion multiplier, and extrusion speed. Here are the main S3D Settings:





The config.g for my DuetWiFi is below:

; Configuration file for Duet WiFi (firmware version 1.17)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool on Sun Oct 22 2017 14:48:43 GMT-0500 (Central Standard Time)

; General preferences
M111 S0 ; Debugging off
G21 ; Work in millimetres
G90 ; Send absolute coordinates...
M83 ; ...but relative extruder moves
M555 P2 ; Set firmware compatibility to look like Marlin

M667 S1 ; Select CoreXY mode
M208 X0 Y0 Z0 S1 ; Set axis minima
M208 X296.5 Y295 Z298 S0 ; Set axis maxima

; Endstops
M574 X1 Y2 Z1 S0 ; Define active low and unused microswitches
M558 P0 X0 Y0 Z0 H5 F120 T6000 ; Set Z probe type to switch, the axes for which it is used and the probe + travel speeds
G31 P600 X0 Y0 Z2.5 ; Set Z probe trigger value, offset and trigger height
M557 X15:265 Y15:265 S20 ; Define mesh grid

; Drives
M569 P0 S1 ; Drive 0 goes forwards
M569 P1 S1 ; Drive 1 goes forwards
M569 P2 S1 ; Drive 2 goes forwards
M569 P3 S1 ; Drive 3 goes forwards
M350 X16 Y16 Z16 E16 I0 ; Configure microstepping without interpolation
M92 X100 Y100 Z1600 E400.97 ; Set steps per mm (estimate for Titan Extruder)

;2017-11-28 - Jerk / Speed mods
; Extruder Jerk - from 129 to 1500
; Set Extruder Max speed from 1740 to 3600
; Set Extruder acceleration from 259 to 1000
M566 X900 Y900 Z12 E1500 ; Set maximum instantaneous speed changes (mm/min)
M203 X900000 Y900000 Z300 E3600 ; Set maximum speeds (mm/min)
M201 X1500 Y1500 Z250 E1000 ; Set accelerations (mm/s^2)

M906 X1200 Y1200 Z1200 E1600 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout

; Heaters
M143 S260 ; Set maximum heater temperature to 260C
M301 H0 S1.00 P10 I0.1 D200 T0.4 W180 B30 ; Use PID on bed heater (may require further tuning)
M305 P0 T100000 B3950 C0 R4700 ; Set thermistor + ADC parameters for heater 0
M305 P1 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 1

; Tools
M563 P0 D0 H1 ; Define tool 0
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

; Network
M552 S1 ; Enable networks
M586 P0 S1 ; Enable HTTP
M586 P1 S1 ; Enable FTP
M586 P2 S0 ; Disable Telnet

; Fans
M106 P0 S1 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P1 S1 I0 F500 H0:1 T45 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P2 S1 I0 F500 H0:1 T45 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on

; Custom settings
;Endstop set to Active Low
;Geometry refined (X, Y, Z max)
;Z home trigger height at z axis = 0.1
;Motor milliamps = 1200
; Selected preset thermistor coefficient (e3D)
; Extruder - 137.25 steps / mm (calcuated)
; X and Y motor steps / mm set to 100 (calculated)
; Z steps / mm = 1600, set Extruder fan to 100%
; M501 to load override params
; Keenovo Bed parameters - P0 T100000 B3950 C0 R4700

;Enable Pressure Advance
M572 D0 S0.1

; Miscellaneous
M501 ; Load saved parameters from non-volatile memory
T0 ; Select first tool

Edited 1 time(s). Last edit at 12/02/2017 02:25PM by webdad.

I think you are printing to fast. I print PETG with 35-45mm/s on my printers.
My D-Bot is 300x200 only, but I was able to reduce Bowdentube length to ~350mm. See my vid.
With a shorter Bowdentube, you'll be able to reduce retraction length. 6mm is a lot. Make sure you retract as fast as possible.

Thanks for the link and the input. I switched over to PLA to try printing that (since I started with PETG) and the PLA prints are coming out near perfect with mostly just temp modifications. I don't have a great deal of experience with PETG, since my Original PRUSA I3 MK1 tends to wear out PTFE tubes when printing that due to temp. After looking at the test prints, I was thinking that the print speeds might be too high.

Your bowden set up is wild! I'll definitely have to get some more experience before considering that.

I'm going to make a note to drop my print speeds and look at retraction speed when I go back to PETG in the next few days.

Gotta get some Christmas presents cranking on the printer.

Thanks again.