@jimakron said in Trouble firing 45 watt TTL Laser on "output6_buff" PMW:

We are NOT ABLE to fire the laser using the 'output6.buff" pin on the Duet 3 mini 5+when we wire to the IN pin on the MYJG5W.
The ... 'IN' pin is a analog 0-5vdc analog PMW signal.

M452 C"!out6" R255 S0 F3000 ; enable Laser mode, on out6 (F3000)

Have you got a link to the manual for the Cloudray MYJG50W PSU? The product page is quite vague, https://www.cloudraylaser.com/products/cloudray-50w-co2-myjg-series-power-supply-black-shell-myjg-50w

As far as I can tell 'H' and 'L' are on/off (L being H inverted) inputs. The 'IN' pin is said to support "input 0V to 5V analog signal, can also input PWM signal" (there's no such thing as an "analog PWM" signal). By 'analog signal', it means a signal of 0 to 5V, usually controlled by a potentiometer. The Mini 5+ output6.buff doesn't supply an analogue signal, only a 5V PWM signal.

I can't find any information on the PWM frequency that the Cloudray MYJG50W accepts, but it's possible that F3000 in the M452 command is too high. The firmware default is 500Hz (F500), have you tied that?

Ian

@Macwolf ok then. so you just need to connect the "L" connection to the duet. You will need to connect a ground connection, like on PSU type 2, to your power supply powering your duet

@aytact There's a few ways to do this, including defining a fake extruder, and moving that while firing the laser. However, I think the easiest way is to redefine the laser pin to an unused pin, then define the laser pin as a normal output pin, and then turn the laser on and off with M42. Then reverse the process to set it back to laser control. eg:

; macro for firing laser stationary M452 C"e1heat" R255 F100 S1 ; Set initial laser mode in config.g M452 C"fan2" R255 F100 S1 ; Set unused pin as dummy laser pin M950 P2 C"e1heat" Q100 ; Create output using laser pin M42 P2 S2 ; Fire laser at low power (range 0.0-1.0 or >1.0-255) G4 S1 ; Time for the laser to fire M42 P2 S0 ; Turn off laser M950 P2 C"nil" ; Clear pin M452 C"e1heat" R255 F100 S1 ; set laser pin

The advantage of this method is that the coordinate systems are maintained as it stays in laser mode, the laser can be fired without moving (so position doesn't change), and the laser can be fired for a specified amount of time at a specified power.

There is a Github issue to fix this with M3, but generally the workarounds seem to be sufficient, so M3 is not made more complicated.

Ian

@rabbit not that I'm aware of. You'd have to regenerate the file with a higher/lower power set

@jay_s_uk i had tried that previous but just added it again with no luck.

@rhys161 You most likely need to invert the output, by putting a ! in front of the pin name (the example for M452 shows this), ie

M452 C"!exp.heater6" R255 F200

Ian

@droftarts Im using 3.5.3

Ill test it when im home and let you know.

Thank you

@FHesse I think the simplest solution for now is to set up a macro that does this:

use M451 to switch out of laser mode to free up the laser control pin use M950 to configure the laser pin as GpOut pin use M42 to set the desired PWM on that pin use M291 to prompt the user to press OK when focusing is complete use M42 to turn off the laser use M950 to deconfigure the GpOut port use M452 to reselect laser mode.

@FlashPackets I don't think the M3 and M5 commands will be doing anything, as you are using M452 S0 (non-sticky mode). If you want to use them, see https://docs.duet3d.com/en/User_manual/Reference/Gcodes#m3-spindle-on-clockwise

Ian

@hauschka I asked @dc42 about supporting lasers and spindles on expansion boards. He said:

Supporting lasers/spindles on expansion boards would not be impossible but would raise a few implementation issues.

I think it just hasn't been requested before, so currently there's no reason to spend the time implementing it. If you want, raise a feature request on Github https://github.com/Duet3D/RepRapFirmware/issues/new/choose so at least it's on the great big list of things to do!

Ian

@eponra if they are 2209s you should be running them in UART mode so change the jumpers
f7f563aa-e319-4fa9-9936-05d1039b549f-image.png

Even better solution: I hooked up the power wires for my laser to the bed heater output and made that a GPIO that I then turn on and off via gCode.

@infiniteloop I got it works as you described. Thank you!!!

Some detail for future reference.

Duet [PANEL DUE 5V_EXT] ==(orange)== Relay [JD-VCC]
Duet [PANEL DUE 3.3V_EXT] ==(green)== Relay [VCC]
Duet [PANEL DUE GND] ==(black)== Relay [GND]
Duet [out3-] ==(yellow)== Relay [IN1]
Duet [out4-] ==(blue)== Relay [IN2]
Duet [out5-] ==(brown)== Relay [IN3]

6673708b-eca8-40a8-8cd6-cf670a5a3606-image.png

83db91cc-387c-4398-8765-8e66b75b386f-image.png

config.g

; Laser mode M452 C"out6" R255 F200 ; Enable Laser mode, on out6, with max intensity being 255, and a PWM frequency of 200 ; FAN-as-IO setup M950 P0 C"out3" ; Red Laser M950 P1 C"out4" ; Laser Enable M950 P2 C"out5" ; placeholder

No strange behavior during power on nor power lost. Everything looks good.

Note: the board next to relay is isolated PWN to 0-10V converter, in case someone wondering.

@SanderLPFRG in the following I will assume that the engraving was done using back and forth scanning in the X direction, so adjust axis names appropriately if not.

Measure the X offset between adjacent lines in that engraving. Then try jogging the X axis back and forth a distance smaller than that and see if the tool head moves as expected.

Alternatively: construct a GCode file to engrave a short line in the Y direction, then move X a short distance (less than or equal to the offset), then engrave another short Y line, then move X back to the original position and engrave another Y line. Check that the X offset of the middle Y line from the outer two Y lines is the correct amount.

Another possibility is that the tool head is rotating about the Y axis as the belt or leadscrew pulls/pushes it first one way and then the other way. Such a rotation will affect the X position of the laser spot on the workpiece.

@shenbiand4 I found a thread about your motor on lightburn-forum.
The only confusing info about a replacement motor was the required shaft diameter.
Make sure, you measure your motors shaft, before you buy. NEMA23 steppers can be found with 5 ,6, 8, 10mm shaft and also 1/4 or 3/8 inch shaft.
If you pick the wrong one, you'll have to look for the right pulley for your belt.
All other requirements are pretty common, like 1.8 degree, 4-wire, 2.8A and 56mm motor length as you've already noted. Can't go wrong there.

The Oyo motors you've linked are almost identical, except for the D-shaft and wire length. I'd go for D-shaft, if I had to choose.

@WingedDonkey when you power up, expansion header pin 8 should be at 3.3V. It should go to 0V when you command the laser to turn on. If you are using the recommended connection then the output of the 74HCT02 should be 0V at power up and 5V when you command the laser on at full PWM.

HTH David

@dc42 Hello. The Beta 3.5.0 with segments of 0.02 is sufficient for my aplication at the moment.
We build this custom laser printer cut brain implants and the programs are quite long - 10's of thousands arcs connected together. Usually takes 3 days to cut one batch. During these last 6 motnhs we come up with a series of methods to minimize the offset in position from the first features cut to the last ones. We figured out there is no more mechanical possibilities for this offset to be happening. We even added temperature control on the whole printer.

I believe there may be some rounding going on in the system. We also notice this offset is larger on y axis.0002.png

Do you believe we could benefit from adding encoders to the Nema17 stepper motors?
by the way we use 1600steps/mm
Thanks

@Dizzwold See https://docs.duet3d.com/User_manual/Machine_configuration/Configuration_laser
This needs a little updating (on my to-do list!) but is good guide to get started.

Raster clustering, which speeds up raster engraving, is supported in RRF 3.5.0-beta3 and later. Lightburn supports this, I don't know if other laser gcode generation software does. RRF also supports G2 and G3 arcs in laser mode, though Lightburn doesn't!.

Ian