First time using the Laser on the Lowrider2.
Always wear Laser safety glasses and take precautions when using a laser.
This was done with the NEJE 2020 20W 450nm laser module head kit, run by the Arduino Uno and CNC Shield 3.0
Turned out better than expected, since I didn’t have clue what I was doing., 
Awesome! Great work!
How do u focus the laser and know that the focus is correct?
You adjust it by setting the power to 5% or so. Then you either adjust the focusing beam or the distance from the workpiece until the beam is a little dot on the top of the workpiece. I usually over focus until it starts to get big and then go back a little again.
Cool!
Do u ever feel unsafe even with the glasses? Can u trust the glasses shipped from Aliexpress with the laser module?
I wouldn’t look into the beam, but they should be fine. It’s not like you would be trying to cut something reflective with a diode laser. The beam shouldn’t be culminated by the time it gets to your face.
i would say for safety always go overboard. i use OD 6+ glasses, i don’t know what is included with your kit. if your interested here is a website on how to determine the best safety glasses for your laser:
https://www.phillips-safety.com/2016/07/how-to-calculate-optical-density-for-laser-safety-glasses-for-maximum-protection/
keep in mind the the 20W rating you posted is input power, not output power. you probably have about 5W optical output power. (i know the 30W input lasers usually produce about 7-8W. so saying 5W is just a gues based on that.)
I had one on my lowrider and I miss it so much I’m building another cnc to sling it around, lol. Once you measure the offsets, you can use the laser to mark your board before or after you cut it with the router. Not something I needed a lot, but when I did…it was sure handy.
No I’m pretty confident with the glasses.
Oooh - says the green aliens in the Pizza Palace toy game - I like this idea!!! I assume one must do a “tool change” so you can remove the route bit and focus in the laser then un-pause to keep going.
Definitely want to set it up as a different toolpath. When I was set up that way, I actually used lightburn for the laser work. As long as the endstops are good, it’s ALL good.
Been using lasergrbl. Works great. It’s a separate toolpath.
Nah. Setup the controller to be able to turn the spindle on/off.
Just need to set the offset on the laser to the router bit.