I'd love to get some advice from you guys.
I'm using the new Duet 3 Motherboard 6HC + RPi (DSF Version: 3.1.1, RepRapFirmware for Duet 3 MB6HC 3.1.1 (2020-05-19b2)) and built my own laser using an SPT 100W red dot tube and an Cloudray 100W power supply. It moves, it lazes, but not consistently. I spent many nights troubleshooting and would love to get your input on the following problem:
When i start a lazing job, initially the power is very high, but looses lots of power over the next 4-5cm - it finishes the job with this very low power (probably only about 20% of the acutal set power) - it sometimes doesn't even activate the laser anymore (which means less than about 5-6mA). During all this i get normal amperage readings (17mA for S0.5 = 50% PWM), which confuses me.
Today i disconnected the power supply from the Duet 3 and controlled power via a potentiometer - no power loss here (I'm very happy about this - thought i killed the tube!). Below you'll find two test jobs i just lazed.
Image: Left - 15mA via Potentiometer, Right - 17mA via TTL
All this tells me I must be doing something wrong controlling the lasers power input via TTL:
- I connected the 5V rail of the power supply to the "IN" port - which should give full power if activated via TTL.
- I attach the ground-cable from the duets "out9" (the somewhat dedicated laser output port) to TTL_High "H" on the power supply and ground from the out9-port to ground on the power supply.
- I'm overriding the waterpump-alarm on the power supply with a simple switch.
This is my config.g:
; General preferences
G90 ; send absolute coordinates...
M550 P"Duet 3" ; set printer name
; Drives
M569 P0.0 S1 ; physical drive 0.0 goes forwards
M569 P0.1 S1 ; physical drive 0.1 goes forwards
M569 P0.2 S0 ; physical drive 0.2 goes backwards
M569 P0.4 S1 ; physical drive 0.4 goes forwards
M584 X0.0 Y0.1:0.4 Z0.2 ; set drive mapping
M350 X16 Y16 Z16 I1 ; configure microstepping without interpolation
M92 X53.33 Y53.33 Z3820.00 ; set steps per mm
M566 X100.00 Y100.00 Z50.00 ; set maximum instantaneous speed changes (mm/min)
M203 X20000.00 Y20000.00 Z500.00 ; set maximum speeds (mm/min)
M201 X1000.00 Y1000.00 Z20.00 ; set accelerations (mm/s^2)
M906 X1650 Y1650 Z1650 I30 ; set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout
; Axis Limits
M208 X0 Y0 Z0 S1 ; set axis minima
M208 X1358 Y878 Z240 S0 ; set axis maxima
; Use Endstops
M574 X2 S1 P"!io0.in"
M574 Y1 S1 P"!io1.in+!io4.in"
M574 Z2 S1 P"!io2.in"
; Laser
M452 C"out9" R1 S1 Q20000
I think this should be all the information needed. I'm happy to provide more if I missed something.
Thanks for your help
- I only noticed this because my z-movement is slow. If i set the speed of movement buttons to 500 - all movements fire.