Oh, ok I understand. Need to overthinking it again. Than you for you warning.

They do it in Fusion 360, but only for turning the laser off 8-( :
But this is easy to fix with a custom Postprocessor.

G0 S255 M4

G0 S50 M4

G1 S0

also in Fusion change is quite low as you can only define one power setting per action.

Other tools like laserweb use the S parameter in a much more aggressive way for laser raster (grbl):

G1 X0.10 Y0.10 S0.0000
X0.20 S57.4706
X0.40 S57.8562
X0.60 S58.2353

for smoothieware it uses a value between 0 und 1.0 for S :

G1 X0.10 Y0.10 S0.0000
X0.20 S0.5765
X0.40 S0.5739

If the IN pin allows you to control the laser power right down to zero, then I suggest you feed the Duet PWM output pin (the one you specified in the M452 command) into that pin. You could use a separate GPIO pin to do on/off switching at the start and end of a job too if you like.

Alternatively, if the cutting speed is slow you could wires it as you have done for Smoothie but reduce the PWM frequency.

Please note, RepRapFirmware does not yet adjust the PWM during acceleration and deceleration the way Smoothieware does. I plan to implement that before the 2.02 release. However, I'd like to get some feedback on the current implementation first, so that I know it is basically doing the right thing before I make any changes.

See https://reprap.org/wiki/Duet_pinout

@snowcrash said in Laser PWM Module V1:

@keyz182 said in Laser PWM Module V1:

The projects is linked here on EasyEDA.

Excellent project & write-up, @keyz182! Thanks for sharing 🙂

Could you please provide more info (& pics) regarding the laser you're using with this module? (I might give it a go myself and haven't worked with lasers before so any pointer would be helpful).

This is the laser I'm using. It appears to be using the same control board as the Eleksmaker laser modules that are all over Aliexpress and similar.

They're pretty simple boards, they take GND, +12V and PWM. They have a button on them, when off, the laser is on, but in very low power, so good for lining up parts, focusing, and I generally leave the switch in this position when not in use. When on, the laser is in PWM mode where it's intensity is PWM controlled, from off up to full power.

If you're getting one, be sure to check that it's a PWM laser, and buy safety glasses! I also got some transparent safety acrylic that filters out the lasers wavelength which I'm going to try to either enclose, or somehow shield the laser with for extra safety.

And perhaps say a bit more about what you're using the laser for? is it for etching/cutting acrylic and the like or something totally different?

I only have a 2.5w module, so plenty of etching, but limited in cutting - card, paper, thin/light wood, very thin opaque acrylic (or a lot of passes - ~16 passes at 3mm/s on some 3mm thick stuff I tried yesterday). Also remember that this is a visible light wavelength laser, so if you can see through it, the laser will "see" through it too (unless, as mentioned above, it filters that particular wavelength).

I'm trying/failing to get into leather work (wallets, belts and the like), so hoping to use the laser to cut templates and etch logos/designs/etc.

After changing the tool offset, you should always do a travel move to the desired starting position before you do either an extruding move or a move with a spindle or a laser turned on. This is because RRF applies the tool offset to future commanded positions. It doesn't apply it to the current position and move the head immediately because the coordinates of the current position are quite often unreachable in the new coordinate system.

@resam said in Laser/ CNC Support in RRF - gCode Semantics:

@dc42 said in Laser/ CNC Support in RRF - gCode Semantics:

This is what I am thinking of implementing:

Add an extra parameter letter to G1 commands with the same meaning as S currently has. Possibly H, because S1 or H1 indicates a Homing move. This letter would be supported in all modes.

When M452 is used to set the machine to Laser mode, if the M452 command includes the S parameter then the meaning of S in G1 commands changes to laser power.

For G0 commands, the laser power will always be zero and any S parameter will be ignored.

A G1 command with no S parameter will be executed with the laser power set according to the most recent M3 command.

The number that follows the S parameter in the M452 command is the S value in G1 commands that corresponds to full power.

Comments?

@dc42 any progress on this? I didn't see anything about this in the 2.0RC's - is it going to make it, or do you target this for a possible future 2.1 release?

Firmware 2.0 is for the switch to RTOS and for bug fixes, so major enhancements like the laser support will have to wait for 2.01.