Nailed it!
Cheers

Hi everyone,

I have recently added a new Aero extruder and have removed the inductive Z probe, I didn't use it for bed levelling as the surface is quite true.
I now have an issue where I can't home the bed anymore using the Z endstop microswitch. When I get to the Z level section in homeall I get a prompt for manual bed levelling. I have tried M558 P0 in the config file without success.
Any advice will be greatly appreciated.

config.g below

M111 S0 ; Debugging off
M555 P2 ; Set firmware compatibility to look like Marlin
M84 S30 ; Set idle timeout
M667 S1 ; Select CoreXY mode

; Endstops
M574 Y2 Z2 S0
M574 X1 S1 ; Define active low and unused microswitches
;M558 P4 I1 X0 Y0 Z0 H5 F240 T6000 ; Set Z probe type to switch, the axes for which it is used and the probe + travel speeds
;G31 P200 X38 Y0 Z0 ; Set Z probe trigger value, offset and trigger height
M557 X0:250 Y13:195 S20 ; Define mesh grid

; Drives
M569 P0 S0 ; Drive 0 goes backwards
M569 P1 S1 ; Drive 1 goes backwards
M569 P2 S1 ; Drive 2 goes forwards
M569 P3 S0 ; Drive 3 goes backwards
M569 P4 S0 ; Drive 4 goes backwards
M350 X32 Y32 Z32 E32 I1 ; Configure microstepping with interpolation

M92 X160 Y160 Z800 E1600 ; Set steps per mm
M201 X500 Y500 Z250 E250 ; Accelerations (mm/s^2)
M203 X6000 Y6000 Z200 E1500 ; Maximum speeds (mm/min)
M566 X800 Y800 Z30 E200 ; Maximum jerk speeds mm/minute
M208 X300 Y200 Z310 ; set axis maxima (adjust to suit your machine)
M208 X0 Y0 Z0 S1 ; set axis minima (adjust to make X=0 and Y=0 the edges of the bed)
M906 X800 Y800 Z1500 E1000 I30 ; Set motor currents (mA) and motor idle factor in per cent
G21 ; Work in millimetres
G90 ; Send absolute coordinates…
M83 ; ...but relative extruder moves

; 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 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 0
M305 P1 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 1
;M305 P2 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 2

; 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
;M563 P1 D1 H2 ; Define tool 1
;G10 P1 X18 Y0 Z0 ; Set tool 1 axis offsets
;G10 P1 R0 S0 ; Set initial tool 1 active and standby temperatures to 0C

; Network
M550 PD-Bot ; Set machine name
M551 P4Rahsc!2 ; Set password
M552 S1 ; Enable network and acquire dynamic address via DHCP

; Fans
M106 P0 S0.3 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P1 S1 I0 F500 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P2 S1 I0 F500 H-1 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned off

; Custom settings are not configured

; Miscellaneous

Solved!

I had changed the original H-Bar ends from a 4 wheel version to a 3 wheel version when building the D-Bot. The 3 wheel version moved well and there was no play at all. What I suspect happened was the H-Bar was twisting or flexing slightly as the belts applied force at either end.

Going back to the 4 wheel version solved the problem.

Thanks everyone for your help.

I've managed to smooth out the Z lines … mostly. I moved the Z lead screws further back which seemed to do the trick.
I'm now trying to eliminate the ringing, the strange thing is that no matter what I set Jerk and acceleration to, the ringing is unchanged.

I would like to clear the ringing so I can fix the remaining Z issues

Jerk at 500 Acceleration 1000

Jerk at 1500 Acceleration 3000

Jerk at 4000 Acceleration 10000

Thanks for that. The print in the photo above was done at 90% extrusion multiplier, I've tried 100% and 110% and the cube looks the same.

The only other issue I can think of, but it's a long shot, is that there is some pull on the hotend from the ptfe tubing. I've ordered a titan extruder and will try that out and see how it goes.

Thanks everyone for the comments to date, to clarify a few points. I am running 1.8 degree steppers with 200 steps per revolution, x32 (256 interpolation) microstepping. Before the comments above I was certain I was running M8 leadscrews (8mm per revolution) but now I'm not sure. I measured 1 revolution of travel with my callipers and it was around 8mm, I'm guessing if it was imperial it would be close to that too, the antibacklash nuts are these http://www.makerstore.com.au/product/anti-backlash-nut-block/ and the leadscrew travels through without snagging. I tried printing again with 0.12mm layer height and the results are pretty much the same; see below.

I have the same result printing from either Cura or S3D.

How can I tell if the leadscrews are imperial?

2 lead screws either side of the X axis with anti-backlash nuts. I've coupled the lead screws with a belt but it's made no difference. I have a 6mm aluminum plate with a silicone heater underneath and a PEI sheet on top.

Thanks for the reply. It was one of the first things I checked and I can't see any play anywhere, to be sure I changed the hotend mount and it made no difference. I've also checked the nozzle and heater block.

I assumed it was not mechanical because the lines are so consistent on all 4 sides and through each layer.

Hi everyone and thanks in advance for your help. I’m having some issues with Z lines that I can’t get rid of. Please see attached photos. I can see someone else on this forum has had similar problems, but I don't think this one is related.

The printer works well in every other way, the X,Y,Z sizes of the test cube are spot on, it’s printed in ABS which exacerbates the Z lines; it looks better on PLA however they are still noticeable. I’ve tried many combinations of temperatures, speeds, acceleration and jerk, in fact I now have so many I could probably build a house with these cubes.

Printer settings are as follows:
Corexy (D-Bot) with 2 Z motors on either side of the X axis.
0.09 layer height
0.4mm nozzle
0.48 extrusion width
240 deg C (Verbatim filament). Have tried 220 deg to 255 deg with no appreciable change in Z lines.
55 mm/S print speed
Bowden setup with 3.6 mm retraction.
Slicer is S3D and have tried Cura as a comparrison

CONFIG FILE

; Configuration file for Duet WiFi (firmware version 1.18.1)
; executed by the firmware on start-up

; General preferences
M111 S0 ; Debugging off
M555 P2 ; Set firmware compatibility to look like Marlin
M84 S30 ; Set idle timeout
M667 S1 ; Select CoreXY mode

; Endstops
M574 X1 Y2 Z0 S0 ; Define active low and unused microswitches
M558 P4 I1 X0 Y0 Z1 H5 F240 T6000 ; Set Z probe type to switch, the axes for which it is used and the probe + travel speeds
G31 P100 X35 Y0 Z0 ; Set Z probe trigger value, offset and trigger height
M557 X15:285 Y15:185 S20 ; Define mesh grid

; Drives
M569 P0 S0 ; Drive 0 goes backwards
M569 P1 S0 ; Drive 1 goes backwards
M569 P2 S1 ; Drive 2 goes forwards
M569 P3 S0 ; Drive 3 goes backwards
M569 P4 S0 ; Drive 4 goes backwards
M350 X32 Y32 Z32 E32:32 I1 ; Configure microstepping with interpolation

M92 X161 Y161 Z800 E280:280 ; Set steps per mm
M201 X3000 Y3000 Z12 E400 ; Accelerations (mm/s^2)
M203 X15000 Y15000 Z300 E1500 ; Maximum speeds (mm/min)
M566 X1200 Y1200 Z24 E300 ; Maximum jerk speeds mm/minute
M208 X300 Y200 Z310 ; set axis maxima (adjust to suit your machine)
M208 X0 Y0 Z0 S1 ; set axis minima (adjust to make X=0 and Y=0 the edges of the bed)
M906 X1000 Y1000 Z1000 E900:900 I30 ; Set motor currents (mA) and motor idle factor in per cent
G21 ; Work in millimetres
G90 ; Send absolute coordinates…
M83 ; ...but relative extruder moves

; 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 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 0
M305 P1 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 1
M305 P2 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 2

; 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
M563 P1 D1 H2 ; Define tool 1
G10 P1 X18 Y0 Z0 ; Set tool 1 axis offsets
G10 P1 R0 S0 ; Set initial tool 1 active and standby temperatures to 0C

; Network
M550 PD-Bot ; Set machine name
M551 PT! ; Set password
M552 P0.0.0.0 S1 ; Enable network and acquire dynamic address via DHCP

; Fans
M106 P0 S0.3 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P1 S1 I0 F500 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P2 S1 I0 F500 H-1 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned off

; Custom settings are not configured

; Miscellaneous
;T0 ; Select first tool

Now I'm a little confused. Should selecting a temperature either in the active or standby drop-downs turn the heater on and heat to the selected temperature? Or have I misunderstood? The bed turns on and heats to the selected temperature in the active temperature dropdown.
Thanks