40W Chinese Laser not cutting quite right

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CJG71
Posts: 3
Joined: Wed May 10, 2017 4:50 pm

40W Chinese Laser not cutting quite right

Post by CJG71 »

Hi all...

I am new to laser cutting and I just bought a Chinese laser cutter, here is a link to the specific one that I bought.
https://www.amazon.com/gp/product/B06XP ... UTF8&psc=1

I got it all hooked up, installed the software etc. and everything seemed to be fine until I tried to engrave one of the example logos. It sort of engraved but just barely. Then I tried to cut with it and it would hardly leave a mark on the acrylic. Having done lots of research before purchasing this machine I am aware that they are not "plug and play" so I figured it was a common problem like mirror alignment etc. So I cleaned all the mirrors (cotton swabs and acetone) and the lens then I did an alignment of all the mirrors (quickly and as best as I could for the first time).

I got it to at least work better it will now cut 2mm clear acrylic but only at full (99.9%) power and set to a speed of 1 mm/s. I am planning to go home tonight and adjust the mirrors again to try to maybe dial it in a little better but I am wondering... Are the mirrors really the problem? Could it be the power supply is not working or something else? I don't have the equipment and I am a little nervous to go messing around inside this thing and with the laser but I am willing to give it a shot if anyone has any suggestions or might know what the problem is.

Also one other thing I would like to point out... I do not have the earthing ground hooked to anything. I did look at the wiring inside the control panel and coming off the 3 pin power plug are red, black and yellow wires. The yellow wires are also tied to the earthing pin so, being as I live in Texas I figured it should be adequately grounded off the 110 wall socket, but I could be wrong. If this is the problem I am in trouble because I live in the 3rd floor of an apartment complex and I really have no place to run a wire for the earthing ground. Also I noticed the laser beam on the outlet end is occasionally arching to the metal ring I'm not sure if its the anode or cathode, maybe this is the loss of power?

Any help or advice would be greatly appreciated!
vitaliy1981
Posts: 3
Joined: Fri Feb 17, 2017 10:25 am

Re: 40W Chinese Laser not cutting quite right

Post by vitaliy1981 »

I'm agree with you.You need to adjust the laser beam path.1mm/s for 40watt cut 2mm acrylic is slowly.
CJG71
Posts: 3
Joined: Wed May 10, 2017 4:50 pm

Re: 40W Chinese Laser not cutting quite right

Post by CJG71 »

So an update... I got home and meticulously adjusted the mirrors and got the path dead on bit it is still not cutting. The more I read and see the more I think it is the laser arcing internally to the cathode that is draining the power. Why me, from what I understand this is one of the worse problems to have but I still have not seen a really good solution. Some say water some say power supply, some say bad laser tube... Like I said I am an engineer but I am not an electrician and I am not comfortable with 15,000 volts. I think I might just return the machine although I have until June 8th to decide to return it... I do know it was arcing with or without distilled water so I think that can probably be ruled out.

Any suggestions? Can it be fixed? Is am I better of returning it?
TimM
Posts: 6
Joined: Thu May 11, 2017 9:36 pm

Re: 40W Chinese Laser not cutting quite right

Post by TimM »

Place a piece of paper over the first mirror, the one by the laser. I use sticky notes, which stick to the frame but do not gum up the mirror. Set the laser power to about 20 percent. Hit the Test button for a very short burst. It should burn a real hole in that paper (at least my 40-watt Chinese laser does!). If yours does not, there's a problem with the tube (beyond my pay grade).
CJG71
Posts: 3
Joined: Wed May 10, 2017 4:50 pm

Re: 40W Chinese Laser not cutting quite right

Post by CJG71 »

Thanks for the reply! I did try that actually and it caught the paper on fire... I did find there was a crack in the first mirror closest to the laser. The beam was actually being split in two... I rotated the mirror to get the crack to the bottom, realigned so the beam was missing the crack completely and it seemed to work a little better. After some messing with it I managed to get it to cut on 70% at around 5mm/s the funny thing is when I raise it to 90% it wont cut any faster. I'm going to try re-aligning everything one more time and fiddle with a few other things but if I cant get it working I'm just going to send it back.
TimM
Posts: 6
Joined: Thu May 11, 2017 9:36 pm

Re: 40W Chinese Laser not cutting quite right

Post by TimM »

>> I do not have the earthing ground hooked to anything. I did look at the wiring inside the control panel and coming off the 3 pin power plug are red, black and yellow wires. The yellow wires are also tied to the earthing pin so, being as I live in Texas I figured it should be adequately grounded off the 110 wall socket <<

I just noticed this. This is VERY DANGEROUS. A malfunction inside this cheap Chinese laser could put 15,000 volts on the metal chassis; instant death. If you home grounding is PERFECT at every connection from your machine to the earth rod, you are fine. But if there is even one bad connection (corrosion, poor wiring) that 15 KV will seek the easiest path to ground, such as a human body. And it's not just you in danger. Suppose the flaw is a few rooms over and someone in the last room before the flaw touches their grounded appliance and a true ground such as the plumbing. That person is dead.

Run a wire from the chassis ground to a true ground. I ran mine through the cellar to the ground rod where my breaker panel grounds.

Tim
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