I have been using LightBurn successfully on my xTool D1 with the original 10 Watt diode laser head (actually two 5 W lasers acting together). As per the xTool D1 User Manual, I downloaded and imported the configuration file xTool-D1-V2.lbdev. The xTool User Manual specifically said to not use LightBurn’s Find My Laser capability for this.
I just replaced the original head with the new xTool 20 Watt diode laser head (two 10 Watt lasers), but how does LightBurn know this? Are changes to the Device Settings needed? I presume Find My Laser is still off limits.
No changes should be needed. It doesn’t know (or care) if you have a 2mW or 2kW laser. This is why power is handled via a percentage.
Lightburn only needs to talk to the controller, which you have been doing. It should work ok. I don’t know what the xTool-D1-V2.lbdev actually changed, these usually just hold configuration data of the device.
You can always set it up via manual configuration. I’d think there wouldn’t be any change with connecting.
Hey, thanks for the reply. I’m new to lasers, and I’ve always been confused about laser power settings. From what you say, I presume the firmware automatically queries the laser head to determine its max power, and then sets the working power by applying the percentage from Lightburn to that max power. I see the “Spindle Speed” is set to S=1000, which seems to mean the granularity of the max power setting that’s possible, like 12.5% is a power that’s 125/1000 of the max power. Do I have that right?
The controller just tells the machine what to do. The laser itself is controlled by a pulse width modulated signal (pwm). It has no need to know how powerful it is.
With a 100watt laser, I get 50 watts at 50% power. A 1 watt laser gives me 1/2 watt at 50% power. There controller doesn’t need to know or care. It just generates the proper pwm to drive the laser.
Might as well know now, that there is no ‘power’ control on a laser. When it lases, it lases at 100% power. What you get for ‘power’ control is power/time. At 50% power it will lase @ 100% for 50% of the time… average power over time is then 50% …
Sure does. The controller board in the xTool uses an ESP32, and I have many projects under my belt using that microcontroller and others. PWM is a fundamental capability built in to microcontrollers for controlling motor speed, servo positions, LED brightness, etc. I looked at the GRBL source code and realized that the firmware just sends a PWM signal to it’s target device and doesn’t care what’s at the end of that. Could be a spindle motor or a laser. I haven’t seen a cogent paragraph that plainly states what’s going on with laser power, in my limited quest for learning about them. Just a short well written paragraph would suffice.
Seems your question is predicated on the notion that power specification results in an absolute power level. But that’s not the end-to-end behavior. Power is specifying percent of max output. So if the laser module is capable of outputting more or less, the controller is oblivious to that. It only knows that it asked for 100% power or 50% power, or whatever. The laser module simply responds in kind to providing the % of max, with no regard to absolute output. A comparison would be like “full” throttle on a go-kart vs an F1 car… You’re going 100% on both but the output will be dramatically different.
I just saw something that seemed to indicate that the 20W module is a 24V unit. I believe the original 10W module ran on 12V. You may want to confirm.
Do you have a separate power supply going to the laser module? If not, you’ll likely need one. I’m not aware if the controller on the D1 is 24V tolerant and how power to the steppers is managed so something to look out for.
Thanks all for your helpful replies. Amazing that I haven’t come across the information you provided in this thread anywhere else, and I’ve looked at a number of beginner tutorials.
I now tweak laser power/speed by focusing on delivered energy per mm, calculated as Percent*Max-Laser-Power/Head-Speed. Units are Joules/mm if you use Speed in mm/sec, Power in Watts (and percent is divided by 100%). I also have used Speed in mm/min, yeilding units of Watt-Min/mm. Sort of a nicer number for typical diode lasers. To respond to a number of your comments…
(1) Yes, my 20 Watt laser has a separate power supply, but my 10 Watt just runs off the controller board. I haven’t measured the voltages of either.
(2) Thanks for the schematic. Confirms that lasers are different animals than spindles.
