Low Power Laser No Matter What I Do

[Novus]

I just inherited a 40W machine from a buddy of mine. I know it worked before he shipped it to me (he cut stuff for me) but now I can't get it to cut through 1/8" MDF without doing at least 5 passes.

I aligned the mirrors well, I think.
Everything is clean.
The focus looks good.
Max power in LaserCAD is 99%
Power for jobs (10mm square test) and laser "light" button is 53% (16.5mA, approx.)
I calibrated the Amp-meter
I've triple checked the wiring
The chiller is always between 68-70F
Water flow is great (4.5 gallons of distilled).

Not sure what else to look at.

It was shipped across the country but the pack job was very good.

If any of you have any ideas I'd be grateful to hear them! Thanks!

[Novus]

With a little better focus I've gotten it down to 2 passes, but I'm still only doing a deep engrave at 16.5 mA. Are there software tweaks that might help?

[DonL]

What is the focal length of the lense? for cutting, you want a longer focal length to maintain a deeper cut. Also, do you have PPI enabled? If so, try disabling it.

To cut you need to go slow also, so what is your speed at what power setting?

For me to cut 1/4 inch MDF with a 35 watt I need 5mm/s at 90% Power and a 1.5" Focal length lense.

[Novus]

What is the focal length of the lense? for cutting, you want a longer focal length to maintain a deeper cut. Also, do you have PPI enabled? If so, try disabling it.

To cut you need to go slow also, so what is your speed at what power setting?

For me to cut 1/4 inch MDF with a 35 watt I need 5mm/s at 90% Power and a 1.5" Focal length lense.

Thanks for responding, DonL!

If I were to guess on the focal length I would say 5cm (1.9"). PPI was not enabled so I'm going to try with it enabled instead. I understand that PPI pulses the tube at higher currents. Can that hurt the tube over time?

[Novus]

So with PPI enabled at 600 (best setting so far), layer power at 100%, speed at 3mm/sec, machine max power 100%, and between 13mA and 16mA showing at the meter I still need two passes to get close to cutting through the material. With PPI enabled the edges are much cleaner but I still can't punch through 1/8" MDF.

Would it be worthwhile to cut open the silicone at the anode/cathode and check the connections? Could a bad connection leach off power? I wrapped the wire around the post and then sealed with silicone and a piece of surgical tubing.

I have spade connectors on the cathode between the meter and the laser driver. Is that bad practice?

Could I have gotten a bad tube from LightObject?

Is there a recommended settings document/file for LaserCAD?

[Novus]

I'm almost through the MDF. I can poke the 10mm square out the back of the material after one pass but the cut only goes about 98% through. PPI is up to 1800. Running 100% @ 3mm/s.

I'm pretty sure I'm missing something in LaserCAD. Is there a set up procedure anywhere?

[DonL]

Not sure about the tube but if it came from LightObject it is probably OK, Check your mirrors are real clean and focus is in center of mirrors and lens Also, 1.9 " is an odd focal length, It is usually 1" for small lasering, stamp making, fine engraving, 1.5" for normal engraving, 2" for cutting (58mm) 5.8 CM

If you are cutting at 50mm not 58mm you are out of focus...

[Novus]

OK, I've been messing with focus and used the recommended length and re-set the mirrors for the 6th time. I've bought a new LightObject laser driver and tube. Nothing seems to work.

So far, less than impressed with this cutter and the support.

I'm pretty sure there are some settings that just aren't correct but I don't see much in the way of help on that issue. Are there standard settings for this machine? Is there a file I can download? What are the parameters you use on the parameters pages?

[Novus]

This is what I have for my set up...







These are the LaserCAD settings...











No idea why some of these photos are rotated. Any help would be greatly appreciated.

[Tech_Marco]

What happen when you increase power from 12% to 40% on min_power setting?

Marco

[Tech_Marco]

43% on the Max power seem a little bit low in your case
I thinl you may want to raise it to 60 or 65% but limited current Not over 16mA

Marco

[Novus]

Hi Marco,

Thanks for responding!

I have the Max Power of the MFR parameters set to 98%. The cut power is 43% because that yields about 16mA on the meter. I can't go over that without maybe damaging the tube, right? Or, should I do that the other way around... Set the MFR parameters to 43% to cap out the power and then have the cut power at like 99%?

Regarding Min Power, what should it be set at? Should the band be that tight? For example, 43% max would have a corresponding 40% min?

[Novus]

increased min power to 40% but no change. I can still only cut about 1/3 of the way through 3mm MDF.

[Tech_Marco]

Are you sure mirrors and lens is cleaned?
Double check the alignment and the focus point.
What kind of focus lens do you have?

I can't think of anything else. We tested the tube before shipped. So, unless the tube is suffered damage, otherwise I wil opt it out from the trouble shooting list. Btw, how did you connect the laser tube?



Marco

[Novus]

That's the thing... I know it worked before it shipped because jgecik (that's his name on your forums) cut stuff for me. I basically took the entire thing apart when it arrived, rewired it, cleaned everything, and mounted everything. Now I've paid for a new tube and a new laser driver and it still won't work correctly.



That's a picture of the lens box that came with the machine. the FL looks "non-standard." But, I don't know if that is actually the box for the lens I'm using because I got this whole machine and all the associated stuff as one lump delivery with the lens installed and with this box containing a mirror instead of a lens. This is what I did regarding Focal Length: I unscrewed the retainer for the lens and measured its depth, which is 7mm from convex surface of the lens to the other end of the aperture. Based on the suggested FL from earlier in the post (from DonL, I think) I used a 58mm length (if I remember correctly) subtracted 7mm and made a 51mm focus gauge. It seems to be the correct FL but not according to this box.

I've done most of the suggestions you guys have had several times, too. I get a nice round beam out of the laser and all of the alignments look good.

I'll try the low-power FL search technique I read elsewhere, again...