Steps / MM low on Railcore II

[ddunn]

Created a Railcore II setup using 1.8 degree stepper motors for x and y axis the steps/mm are currently set to 108 with 1/16 microstepping which seems extremely low i am wondering if i have something set up wrong in my configuration or if anyone has any ideas.

; Configuration file for the Iron Gold
; Communication and general
M111 S0 ; Debug off
M550 InsertCoolName ; Machine name and Netbios name (can be anything you like)
;*** Wifi Networking
M552 S1 ; Enable WiFi
M555 P2 ; Set output to look like Marlin
M575 P1 B57600 S1 ; Comms parameters for PanelDue

G21 ; Work in millimetres
G90 ; Send absolute coordinates...
M83 ; ...but relative extruder moves

M564 H0 ; Allow movement without homing
M669 K1 ; CoreXY mode

; Axis and motor configuration
M584 X8 Y9 Z5:6:7 C1 E0:3:4:2 ; Map Z to drivers 5, 6, 7. Define unused drivers 2,4,0 and 3 as extruder
M569 P0 S0 ; Drive 0 goes forwards Unused
M569 P1 S1 ; Drive 1 goes forwards Coupler
M569 P2 S1 ; Drive 2 goes backwards Unused
M569 P3 S0 ; Drive 3 goes forwards Extruder
M569 P4 S1 ; Drive 4 goes backwards Unused
M569 P5 S0 ; Drive 5 goes forwards Front Left Z
M569 P6 S0 ; Drive 6 goes forwards Rear Left Z
M569 P7 S0 ; Drive 7 goes forwards Right Z
M569 P8 S0 ; Drive 8 goes forwards X stepper (Rear)
M569 P9 S0 ; Drive 9 goes backwards Y Stepper (Front)

;Stall Detection - Used for homing
M915 C S5 F0 H200 ; Coupler
M915 X Y S5 F0 H400 ; X / Y Axes

;Leadscrew locations
M671 X-53.9:-51.75:313.9 Y30.7:284.9:157 S25 ;Front left, Rear Left, Right S7.5 is the max correction - measure your own offsets, to the bolt for the yoke of each leadscrew

M350 C8 I0
M350 X16 Y16 Z16 E16 I1 ; set 16x microstepping for axes& extruder, with interpolation
M574 X1 Y1 S3 ; Set X / Y endstop stall detection
M906 X1400 Y1400 Z1000 C400 E800 I60 ; Set motor currents (mA)
M201 X3000 Y3000 Z100 C400 E1500 ; Accelerations (mm/s^2)
M203 X24000 Y24000 Z900 C5000 E3600 ; Maximum speeds (mm/min)
M566 X1000 Y1000 Z100 C2 E1500 ; Maximum jerk speeds mm/minute
M208 X-42:340 Y-20:310 Z-0.5:700 C0:260 ; set axis maxima and high homing switch positions (adjust to suit your machine)
M92 X108 Y108 Z1600 C100 E409 ; steps/mm

; Fans
M950 F0 C"fan0" ;RRF3 define fan0
M950 F1 C"fan1" ;RRF3 define fan1
M950 F2 C"fan2" ;RRF3 define fan2
M106 P0 H-1 ; disable thermostatic mode for fan 0
M106 P1 H-1 ; disable thermostatic mode for fan 1
M106 P2 H-1
M106 P0 S0 ; turn off fans
M106 P1 S0
M106 P2 S0

; Tool definitions
M563 P0 D0 H1 ; Define tool 0
G10 P0 X0 Y0 Z-4.75 ; Tool offsets for tool 0
G10 P0 S0 R0 ; Set tool 0 operating and standby temperatures

; Thermistors
M308 S0 P"bedtemp" Y"thermistor" A"bed_heat" T100000 B3950 R4700 H0 L0 ;RRF3 Bed thermistor, connected to bedtemp on Duet2
M950 H0 C"bedheat" T0 ;RRF3 define Bed heater is on bedheat
M140 H0 ; map heated bed to heater 0
M143 H0 S120 ; set temperature limit for heater 0 to 120C

;If you have a Slice Engineering thermistor, comment out the next line
M308 S1 P"e0temp" Y"thermistor" A"e0_heat" T100000 B4725 R4700 C7.06e-8 H0 L0 ;RRF3 duet3 e3d
M950 H1 C"e0heat" T1 ;RRF3 define Hotend heater is on e0heat
M143 H1 S300 ; set temperature limit for heater 1 to 300C

M307 H0 A240.3 C608.7 D8.2 S1.00 V24.1 B0 ; Bed Heaters
M307 H1 A270.7 C90.4 D6.7 B0 S1.0 ;Heater 1 model
M570 S360 ; Hot end may be a little slow to heat up so allow it 180 seconds
M143 S285

; Z probe and compensation definition
M558 P8 C"^zprobe.in" X0 Y0 Z1 H5 F100 T3000 ; Z probe is an IR probe and is not used for homing any axes
G31 X0 Y0 Z0 P500 ; Set the zprobe height and threshold (put your own values here)

T-1 ; select no hot end

[Phaedrux]

How did you arrive at 108?

What size pulleys on the motors?

15 tooth pulleys?

xy_steps_per_mm = (motor_steps_per_rev ∗ driver_microstep) / (belt_pitch ∗ pulley_number_of_teeth)

[ddunn]

I had 200 then I ran a 10mm move and measured and it was at ~19 (can’t remember caliper number) so I did the math.

[Phaedrux]

@Phaedrux said in Steps / MM low on Railcore II:

xy_steps_per_mm = (motor_steps_per_rev ∗ driver_microstep) / (belt_pitch ∗ pulley_number_of_teeth)

I'd stick to the formula for what the steps per mm should be. If it's off after that, there is likely something mechanical wrong with the build.

[JamesM]

100 steps/mm for x & y should be right with 1.8* steppers. It would be 200 steps/mm if you had used 0.9* steppers.

[o_lampe]

Just out off curiosity, what's the purpose of the C-axis? (coupler)
I'd guess it's related to the 3 Z-motors/bed leveling, but I can't find the answer in your config.g

[droftarts]

@o_lampe he’s got 4 extruders, so I guess it’s a tool changing machine, and the C axis controls the tool locking mechanism.

Ian

[ddunn]

@droftarts Correct there are currently 3 hot ends that i have ready to go on when i finally get everything up and running with a 4th planned for future expansion. For this to be achieved the C is the tool changer motor.