Cutting with my 50W CO2 laser

[ajacks0n]

Hi folks,

New user here, picked up a used Chinese 50W CO2 laser cutter a few weeks ago and doing lots of research and getting the hang of designing some pieces and settings for cutting/engraving etc.

One thing I've noticed is that while I can cut through 3mm MDF relatively easily at 80% power, 20mm/s with about 3 passes, I can't seem to easily cut through 6mm MDF. I've tried increasing the power, slowing the speed, doing more passes etc. Too much power and too little speed ends up burning the wood. I've found that at 90-100% power at 20mm/s I can cut through the 6mm MDF but it takes anywhere from 25-30 passes... :-O

I've checked the laser alignment up to the final mirror on top of the cutting head and it's fine. I can't work out how to get the lens off the cutting head so unable to check that the raw laser beam is coming down exactly perpendicular.

Am I missing something here or should the laser cutter be able to cut through 6-8mm without too much fuss? Could the laser tube be on the way out?

Any tips or advice would be appreciated.

Cheers,
AJ

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[Blackened]

How do you clean the lens if you can't get it off the head? Just wondering if a dirty lens is contributing to your issues.

[robertk925]

Do you have an ammeter (amp meter) on the machine? On my 50W blue and white Chinese eBay laser, 65% power equals about 20mA, which is the maximum (maybe even a little above) for the tube. Higher powers will eventually damage the tube and paradoxically often create less cutting power.

The very tip of the laser head should unscrew off, which will reveal the lens.

I would highly recommend searching for "SarbarMultimedia" on YouTube. Russ owns the same laser and has done a lot of experiments (and made a lot of helpful test fixtures) to better understand and fine-tune the machine.

[Dean448]

I have a 50 (actual power might be around 35) and would not be able to make it through 6mm mdf. Will cut 3mm but only at high power and slow speeds.
Keep in mind that if your using a 50mm focal lens you are focused at the top. 6mm down and your out of focus.
If desperate take your second pass with z up 3mm. Or index the work, mirror the part and cut it on the back side.
No guarantee

If this were 6mm solid wood you would have no issues


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[ajacks0n]

Thanks robertk925 and Dean448 for your considered responses.

Do you have an ammeter (amp meter) on the machine? On my 50W blue and white Chinese eBay laser, 65% power equals about 20mA, which is the maximum (maybe even a little above) for the tube. Higher powers will eventually damage the tube and paradoxically often create less cutting power.

The very tip of the laser head should unscrew off, which will reveal the lens.

I would highly recommend searching for "SarbarMultimedia" on YouTube. Russ owns the same laser and has done a lot of experiments (and made a lot of helpful test fixtures) to better understand and fine-tune the machine.

I’ve got a similar blue and white Chinese unit. I don’t have an ammeter but I might try lowering the power to 65% and comparing the results. I thought as much about the very tip of the cutting head screwing off but it’s quite firmly screwed on, and there are a couple of attachments fitted near the tip which I think are the air blower and the red led pointer - wasn’t sure how to take them off and didn’t want to damage them. Cheers for the tip on YouTube, I’ve subscribed to his channel and will keep learning.

I have a 50 (actual power might be around 35) and would not be able to make it through 6mm mdf. Will cut 3mm but only at high power and slow speeds.
Keep in mind that if your using a 50mm focal lens you are focused at the top. 6mm down and your out of focus.
If desperate take your second pass with z up 3mm. Or index the work, mirror the part and cut it on the back side.
No guarantee

If this were 6mm solid wood you would have no issues

Since posting my question I’ve been doing some more research and I have it on my list of things to do to measure the exact focal point/length and see how much cutting depth I’m working with - I got this from one of the videos from user “makestuffnow!” on YouTube. I might also make a ‘zero’ guide for the X and Y axis, and an inlay so that I can reasonably accurately flip materials for cutting on the reverse. The same guy on YouTube shows that technique in one of his vids.

Thanks again.



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