Gina

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.

Although a lifetime computer programmer I found I couldn't get my head round OpenSCAD.

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 :-

TEC efficiency varies enormously with make. But a very common mistake is to use a more powerful TEC than required - this just reduces efficiency.

Slic3r and other slicers can scale an STL file to make a bigger or smaller print but I don't think there's much else you can do. Some CAD softwares can import STL files but I haven't yet found one that works properly.

Very smart

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

I print directly on glass and rarely have a problem as long as the glass is scrupulously clean.

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?

Different colours of the same type and brand can need different settings I've found.

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.

As I understand it, it's UV light that causes cataracts.

I was planning to use two of the stepper motors in series for the Z drive though wonder if the phase resistance and inductance may be a bit high for series use on 24v. I also have some other motors a bit smaller (48mm v 60mm long) but lower resistance/inductance. Wantai 42BYGHW811 These are rated at 2.5A and the Duet will handle up to 2.4A so no lack of power. I'd appreciate advice as to which motors would be best for the Z motors.

Recovered PSU, SSR for mains voltage bed heater, Duet WiFi, extruder and hotend, three stepper motors type JK42HS60-1206 (see bottom line below) and various other bits.

Titan is no more R.I.P. Titan you served me well and now your parts are going on into a new body where they will continue to serve. Yes, I have dismantled my Titan printer. Didn't take long...