I’m very puzzled in my acrylic adventures. I ran a few initial tests at 100% power and varying speeds. The best being 5mm p/s and 3 passes. All good and fairly happy. Carried on and tried cutting a key ring. Didn’t cut all the way through. So lowered speed to 4mm p/s and seemed ok. Now when I try either of these settings or I go totally off piste with numbers the top edge of the red acrylic is being melted. I can’t get my head around it !! Why did it work fine and now it’s ending up like this ? The physical scenario and material is the same. It does not matter wether I use air assist or not. Same results… can anyone suggest what the choof is going on please ? Many thanks
It is possible that too much heat accumulates in material, I have the same problems with very small objects or many changes of direction in a small area.
Are you using air assist? If not, and if you are using a laser diode, the lens may be dirty.
It’s just an idea based on what happened to me with the same problem.
Hiya ! Yes…. This may well be the main issue. I took it to bits and cleaned. It didn’t appear mucky as only cleaned it a couple days ago. But ! It seems to have made a lot of difference ! Definitely cutting cleaner.” On the top. But the sides are still not great and frosted. May just be the nature of the beast with diode ??? Thank you
From what I’ve read, I would say that if you were able to work (not long ago) well or reasonably well and now you can’t, I would say that the problem is a sum of small problems. Dirt on the lens, laser out of focus (as @jkwilborn mentioned), speed, power and even (eventually) wear and tear on the laser itself (if it has been working for many hours).
This defect on the edges seems to me to be too much heat absorbed by the material (as @bernd.dk mentioned)
If you don’t have air assist, this would be a priority to take into account. Start solving small issues one at a time to avoid making the same mistake over and over while trying to solve others. In the case of the dirty lens, I made the lens of my laser useless, precisely because I insisted while waiting for the air assist system to arrive.
I’m still pretty new to this but quickly learned that air assist is invaluable for keeping the shield lens clean. Yes, it helps cutting and workpiece cleanliness, but I’m approaching 100 working hours on my first laser and have yet to clean the shield lens. I inspect it regularly and it still looks pristine.
I recently added a second laser from a different company and it had a burned/pitted shield lens straight out of the box. I only noticed it because I was adding an air system to it before firing it the first time. I don’t know how long they test fired the module, but it couldn’t have been more than a minute or two unless they have a really unusual QC program (that completely overlooked lens condition pre and post test).
I tend to clean the whole unit on a weekly basis as i use it in a shop for lots of things. But first time I am trying acrylic. If definitly works better without the air assist with that. But as you are all mentioning it seems to deteriorate the lens quickly. Its been much better since cleaning. And I will be using the air assist all the time from now one. I will have to live with the frosty edges on red for now. All great answers and responses people. Thank You
It doesn’t take much air to keep the lens clean. If yours isn’t adjust flow, adding a needle valve is cheap and easy.
I added a flowmeter for for repeatability and educational purposes and find 3lpm (can just barely feel it at the nozzle) is sufficient for most things. I turn it up to about 7 for slate just because the sparks concern me. 7 seems to be about my minimum to knock down the sparks.
