Inconsistent Cuts in acrylic

Hi

Im trying to figure out an issue with inconsistent behaviour and im after some advice!

Im cutting a 400x600 sheet of acrylic, with lots of small shapes with cutouts if i cut one or two at t time i seem to get better results than if i cut a full sheet. I will get almost a random shapes that are not cut all the way thought, usually just some small dots that are all the way through.

If i cut the same shape on its own it seems ok.

Im using a omtech 100w autofocus CO2 laser. 3mm thick acrylic. Cutting at 18 mm/sec 47% power.

The ones that do cut work perfectly and ive tried using the same shapes that wont on there own and it cuts fine.

Thanks

Just a few questions, are you sure these are not items that have been welded back together? Can you explain why you use the values you do to cut 3mm acrylic?
It seems to me that you are using too much energy and or too slow speeds. Sometimes too much compressed air also irritates, especially with acrylics, the vapors cannot escape easily enough…

I cut a lot of 3mm acrylic with my 40W machine…

This is a vertical alignment tool (from Russ Sadler)…

You have 2.5 times the power I do and my cut settings are 13mm/s@80%… yours are 18mm/s@47%… you seem to be running too fast for the power you’re using…

I’d bump both power and speed… the only real use of a big machine (meaning power) is that it will cut thicker material… with acrylic the faster you can go, within reason, the better cut you will achieve. Use that 100W and increase the power…

If you use air assist, lower the pressure to just what it needs to keep the lens clean. High pressure seems to do more damage than low pressure when cutting acrylic.


This can also indicate an alignment problem… especially if the cut is different with the location on the laser bed…

You can singly cut out an object in the area of failure to ensure this… however I’d suggest you start at m1 and check the TEM state or mode of the tube and that the alignment is correct.

Good luck

:smile_cat:

…more or less the same machine as @jkwilborn , bought as 60 Watt but is probably a 50-55Watt machine.

I bought a 50W and it turned out to be about 40W… :face_with_spiral_eyes:

:smile_cat:

Now that you say it I remember, sorry. But surely you are as happy with your machine as I am with mine and four years earlier I was also very happy with my old K40.
Btw, do you have a lot of work for your new fiber laser?

I think the tube had it’s rating pushed… When cutting I ran it at 18mA, when it was placarded at 21mA as a maximum… If I ran it that way it would produce 44W according to the Mahoney meter.

It only lasted about 14 months… it went from working to out of TEM00 mode when I didn’t use it for 3 days… Can’t figure why, but it went south very quickly… While I was waiting for a replacement 40W from Cloud Ray, one of the CR versions… I had to realign it every couple of hours…

Yes, I’m happy, but I didn’t know much about them or what to expect … so it could have been worse and I’d never have know in time to do anything about it… I really like my little dpssl lasers very much, but getting good ventilation without a cabinet can be problematic…


The fiber is great and very illusive… It’s a lot more to handle than the co2… speed/power is complicated by frequency/q-pule width… not to mention working with metal instead of natural materials… Metal is a lot more expensive…

I’ve been using the fiber on images using LBT100 spray, but I’m working with the TiO2 to get something useful… I’ve gotten a good one, but many have failed my quality test…

After that I’ll probably work on the color game… I have a Martin the Martian I’d like to do in stainless and I haven’t got the colors where I want them… More difficult than expected and it varies with different types of stainless and it’s thickness…

Not to mention a change when you go to a different lens…

But I’m satisfied, even though OMTech could have been a lot more transparent on what they are shipping me and what they advertise…

:smile_cat:

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