Laser Is Not Engraving Consistently, Help!

[patrickonb]

Hello all,

I built a DIY laser cutter a couple of years ago, and have finally gotten around to getting it running over the last couple of weeks. I also own a K40 machine, and it works very well, pretty happy with it so far. BUT, I've noticed something over the last couple of days on my DIY machine that is not happening with my K40 machine. I can cut/engrave the same parts on the K40 and the DIY machine, but the DIY machine seems inconsistent with it's engraving.

While watching the laser tube during operation, I can see the laser beam pulsing/flickering while it's working. This also makes the parts being engraved have an inconsistent texture as well. My DIY machine uses a 60 watt laser tube I purchased off of eBay about 3 years ago when I first started the project. The laser power supply is a 60 watt power supply I purchased from Light Object, and it's all hooked up to an AWC708C Lite controller. The power supply I have from Light Object looks just like the 20W~45W PWM CO2 Laser Power Supply, but is a 60W supply. For some reason, they no longer offer this type of supply.

Do you think there is something going on with my power supply, causing this inconsistent laser beam power? Everything about my DIY is great except this one problem, and I would like to know how to get this corrected. Could it be the laser tube itself?

Any insight, questions, suggestions would be greatly appreciated.

Thanks,
Patrick

[AMTLaser]

Could it be you are trying to engrave at too low of a power setting on the DIY laser? The 60watt tube will differ somewhat on the low end compared to the k40 setup. Do you have a mA meter on your DIY machine? That would also help with your troubleshooting some. My understanding is most tubes do age, even just sitting on the shelf.

[patrickonb]

Thanks for the reply,

No, I do not have a mA meter on the system at this point. I guess I didn't know that running a tube at a low setting could cause inconsistencies in the burn. I do have another K40 35 watt tube sitting around form another machine, I suppose I could set that up on the DIY machine if all else fails, and see if that makes any difference.

BUT, getting back to the lower settings on the higher watt tube, how would I compensate for something like that? Run it faster on a higher setting, and see if that helps with the inconsistencies?

Thanks for any help,
Patrick

[Tech_Marco]

Yes, run faster to offset higher power burned. How fast did you run? For engraving, we usually set speed to 550mm/s to 600mm/s. In the future, we will increase the speed to 700mm/s-759mm/s once we switched to "closed loop" motor

BTW, a tube idle for 3 yrs could turn into bad due to gas leaking. That being said, you used it or not the laser power will drop 5-8% every year.

Marco

[patrickonb]

OK thanks. Sad news, $300+ down the drain. Oh well, live and learn.