Gina

Wiring for the LH XY motor and Duet board connected to XY and Z wiring.

A couple of photos of wiring.  First is the Z motor wiring under the base of the box and second the RH XY motor wiring.

Now if only I can solve the XY drive problem.  Maybe try the 60mm long NEMA17s though the 48mm ones I'm using worked fine in my Giant printer.

Tried increasing motor currents to 2A (they're rated at 2.5A) and now have some X movement albeit with much "grumbling"!

Next test...  Swapped the 48mm NEMA17s for 60mm ones with current set to 1A (rating 1.2A), r4eversed the drive for the RH motor and the X and Y drives are now working fine ?  Some noise on slewing but considering they're mounted on a gert big sounding board, that's not surprising.  That's with a slewing rate of 100mm/s in X or Y.

PROBLEM SOLVED!!  PHEW!!

Connected the Z drive and been testing - tremendous improvement over the 60mm NEMA17s.  3 times the speed, smooth and much quieter.  The NEMA23s are a great success

Just connected the NEMA23 Z motors to an 8 way flat cable rated at 4A per wire, soldered and heatshrink sleeved.  Then 8 connector female parts crimped on followed by insertion into two 4 pin housings.  This wiring business is tedious!!

Think I'll sleep on the XY problem and work on the wiring and installation of PSU, Duet board, etc.  I have the NEMA23s screwed onto the box and now have to extend the wires and add connectors to plug into the Duet board.  Since I need new wiring anyway I think I might as well run it where I want it straight off.

OK...  I've removed the Duet board (previously in the Titan printer) and substituted the one from my Giant printer and the result is just the same.  And yes, I have double checked that I didn't get confused and put the same board back - the config.g file shows the printer as "GinaRep Giant".  I changed the other to "GinaRep Concorde".

Incidentally, the Giant had the same arrangement of CoreXY with the right hand motor upside down.  I haven't touched the config.g since the Giant was working (though not very well).

To confirm my findings earlier, I've re-enabled CoreXY and both motors are working fine but again both X and Y controls drive the carriage in the Y direction - no X movement whatsoever!  I'm running out of things to try...  I do have the Duet WiFi board from the Giant printer I could try I guess.

15 minutes ago, jarl72 said:

Hello Gina,

I'm following your thread with a lot of interest, since I have been planning a similar build for some time.

One question, though: did you leave some built-in "give" to avoid over-constraining your axes? The difference in coefficients of expsinsion between the AL components and the wood frame (in particular given the size) can create some "interesting" issues there.

I doubt differential expansion will have much affect but there is a bit of stretch in the timing belts.

Sorry Dave - got my left and right mixed up again!!  I've had that problem all my life!!  You are right for RH above read LH!  Sorry for the confusion.

Tried disabling CoreXY so that i could test the motors individually.  There is a problem with the RH motor (Drive 0) or X motion. The Y control moves the X carriage diagonally as expected.  That would indicate a RH motor problem yet that motor works with CoreXY mode.  I have confirmed that everything moved freely by hand.

Another test - swapped motor leads over and it's still the same physical motor that is at fault.

Put the connectors back as they were viz. LH to  Drive 0 and RH to Drive 1 and reversed Drive 1.  Now X moves +Y and Y moves -Y so that's reversed the motions but still no X motion - only Y.  This is daft!!

Yes, agreed the RH motor will be reversed.  Can't flip th connector on the Duet board as these connectors are polarised,  OTOH it's easy enough to reverse the motor in the config.g file via the web interlace.

NEMA23s have arrived.  Here's a photo comparing the 60mm long NEMA17 (on 3D printed mounting plate) with the NEMA23.

Swapped motors and got a similar result except both X and Y drove the Y positively.  The NEMA23 Z motors are out for delivery and the couplers have arrived.

Having fixed a broken wire in one of the connectors I now have both XY motors connected and all X and Y belts attached and tensioned ready to go.  Got a funny though!  Y movement works normally but X give -Y movement with no X movement.  Clearly I must have something wrong in config.g.

; Configuration file for Duet WiFi (firmware version 1.20 or newer)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool on Wed Jan 31 2018 10:30:18 GMT+0000 (GMT)

; General preferences
M111 S0                                  ; Debugging off
G21                                      ; Work in millimetres
G90                                      ; Send absolute coordinates...
M83                                      ; ...but relative extruder moves
M555 P1                                  ; Set firmware compatibility to look like RepRapFirmare
; Automatic saving after power loss is not enabled
M667 S1                                  ; switch to CoreXY mode *** Gina added
M208 X0 Y0 Z0 S1                         ; Set axis minima
M208 X400 Y400 Z350 S0                   ; Set axis maxima

; Endstops
M574 X1 Y1 S0                            ; Set active low endstops
M574 Z1 S2                               ; Set endstops controlled by probe
M558 P4 H7 F600 T6000 I1                 ; Set Z probe type to unmodulated and the dive height + speeds
G31 P500 X20 Y0 Z2.2                     ; Set Z probe trigger value, offset and trigger height
M557 X50:350 Y50:350 S300                ; Define mesh grid

; Drives
M569 P0 S0                               ; Drive 0 goes backwards
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 I1                 ; Configure microstepping with interpolation
M92 X80 Y80 Z3200 E418.5                ; Set steps per mm                                   ******************* 80 microsteps/mm XY and 3200 microsteps/mm Z for Concorde ************************
M566 X900 Y900 Z12 E120                  ; Set maximum instantaneous speed changes (mm/min)
M203 X6000 Y6000 Z150 E1200             ; Set maximum speeds (mm/min)                              ******************* mm/minute Z for Concorde ************************
M201 X500 Y500 Z25 E250                 ; Set accelerations (mm/s^2)                              ******************* Z acceleration 1/10 for Concorde ************************
M906 X500 Y500 Z1200 E1000 I30          ; Set motor currents (mA) and motor idle factor in per cent1010  ******************* 100omA Z for Concorde ************************
M84 S30                                  ; Set idle timeout

; Heaters
M305 P0 T100000 B3950 C7.060000e-8 R4700 ; Set thermistor + ADC parameters for heater 0
M143 H0 S150                             ; Set temperature limit for heater 0 to 150C
M305 P1 T100000 B4725 C7.060000e-8 R4700 ; Set thermistor + ADC parameters for heater 1
M143 H1 S350                             ; Set temperature limit for heater 1 to 300C

; 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
M550 PGinaRep Concorde                   ; Set machine name
M552 S1                                  ; Enable network
M586 P0 S1                               ; Enable HTTP
M586 P1 S0                               ; Disable FTP
M586 P2 S0                               ; Disable Telnet

; 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 H1 T45                ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P2 S1 I0 F500 H1 T45                ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on

; Custom settings are not configured

Now for the XY calibration.  The motor pulleys have 20 teeth and the belt is 2mm tooth spacing so one revolution is 40mm.  200 whole steps therefore gives 40mm thus steps/mm = 200/40 or 200x16/40 microsteps per mm = 80.

Now have the X carriage assembled and installed on the X rail.  Also run both timing belts and secured to X carriage, connected XY motors to control board and been testing.  Y direction moves very smoothly but something is stopping the X movement.  Evidently the X carriage is no longer moving freely along the X rail so I have an investigation to do.  I've found the Z rods are slightly too long and catch on the Y carriages so will need to shorten them.  I shall wait until I have the NEMA23 motors though (due to arrive tomorrow) as the shafts may be different lengths, the couplers may be different and the mountings are definitely different.

Later... Found the X carriage problem and fixed it - one of the belt clamps touching the rail.

I'm going for it!  I not only want accurate drives but I want to be able to move the bed reasonably quickly so I will give NEMA23s a try.  Never used these bigger stepper motors before but read that they are much more efficient than NEMA17s (even long ones).  NEMA23s are easier to mount too - no messing with tiny M3 screws that have to be just the right length.  The idea of the Concorde printer is to go for the best without too much overkill.

Quoting the Duet2 documentation :-

Quote

Use Nema 23 motors if you cannot get sufficient torque from long Nema 17 motors.

Maybe I should go for NEMA23s instead.  Why "spoil the ship for a ha'p'orth of tar"?  It does seem that NEMA17s are underpowered for Z drive at a reasonable speed using threaded rods.  OK I know that for printing the Z speed is minuscule but it's nice to be able to move the print bed out of the way reasonably quickly to change filament or move the print down away from the nozzle after printing.

Matching shaft couplers :- 8x6.35mm Motor Shaft Coupler for 3D printer, Flexible 8mm to 6.35mm Z Axes, CNC

Repaired the couplings by squeezing them together in a vice and remounted the Z motors to ensure accurate alignment.  Sort of working but the maximum Z rate I can get is 200mm/min which is pretty darn slow (two minutes for the full Z range).  And even at that speed the motors are noisy - not that that bothers me much.  I may try the other motors but I would have thought 60mm NEMA17 stepper motors running at 1.2A should be able to do better.  I don't know why I should be having trouble with threaded rod Z drive when everyone else seems fine!!  Am I missing something?

I using two of these Flexible Shaft Couplings but it looks like they're not strong enough as they've failed   OTOH there shouldn't be that much torque required to turn the rods.

Of course the Z calibration is far from right having changed from gears and string for the Z drive (this is the Duet board from the Titan).

Threaded rods are single start so one revolution = 1mm Z feed.  So we need 200x16 microstrps per mm. ie. 3200.

Connected a mains cable to the PSU and tried moving the Z.  LHS wasn't too bad but the RHS didn't have enough drive power and the motor skipped steps intermittently.  So I need to see if I can adjust things.  Motors were quite noisy.

Mounted the 60mm steppers to the base and connected up the threaded rods.  Plugged into Duet board so Z drive is ready to go when I get power on the Duet control board.