I was given a 60w black/red KH7050 from a friend who is moving. I have done some preliminary tuning such as aligning the beam, leveling the cutting board and cleaning the mirrors and lense. I did some runs using 3mm mdf as well as stainless steel engraving with cermark.
I noticed the machine was unable to cut the mdf and engrave the steel even at low speeds (12mm/s) and high power (90%). After some inspection of the mirrors, I decided to replace them since they looked very old.
One of my questions is should I replace the tube? I noticed the manufacture date on the tube is 2015 so my assumption is it has seen some wear and tear, but the beam does appear to be firing.
I did a ramp test and I got a focal length of 1.5” which seems very high. I tried some more etching on stainless this morning with cermark at some recommended settings with no luck.
Any suggestions on getting it back up to par would be great.Laser beam
Standard question, what does a test shot on the M1 look like? 2015 is a long time for a CO2 laser tube but on the video it looks functional.
Do you know what kind of lens you have in the nozzle.
The 1.5 inch lens has something with a 38.1mm focal length, if I’m not mistaken and it fits with what you describe. But be aware that the correct measurement is from the lens and not from the end of the nozzle.
An aquarium pump is not sufficient for a 60 Watt laser, the risk of air bubbles and too high coolant temperature is too high, a few minutes without water or too high water temperature and the tube is worthless.
What does the beam look like on M1?
Yes that is correct. The 1.5" measurement I took was from the end of the nozzle to the work surface after doing a ramp test which I thought was large.
I agree the aquarium pump is undersized, but for the small jobs I’m testing with right now (~2min) I wouldn’t expect to see any performance issues that quickly.
Can you elaborate on the M1 and how to test this, I am very new to this.
This is how I start all alignments, that includes a check to the beam at m1. I cut my targets out of watercolor paper… easy to mark/view and a bit more ridged than regular paper so you can handle them easily.
A good tube, used within it’s specifications, should last about 10k hours. Or about 5 years in an 8 hour/day operation.
Looking at the results it doesn’t look too bad. I did a rough alignment and will test cutting some MDF tomorrow. Do you know any recommended settings?
I assume this is at the 45 deg angle of the mirror?
At 45 deg, I’d expect an elongation, but it looks like it’s not quite right… Lighter colored paper is preferred, but a better photo of that would be good also.
Yes I think my tube and mirror alignment is safe. I tried cutting some balsa wood laser night and the laser had a trail of fire following the path on the wood and did not cut through. I’m beginning to think that the lens may be an issue as a more concentrated and smaller focal point would likely cut through the wood and not leave such a wide burn mark.
That sounds like it is out of focus. If your laser is out of focus it will produce a wide kerf and will not burn through.
I read some of your previous posts and you said you did a rough alignment, that’s not good enough. The laser has to be correctly aligned or it will not function properly.
If I were having the same issues you are having I would check the alignment at the nozzle by placing a piece of masking tape over the hole and pulsing the laser. the burn should be centered in the nozzle hole. if it isn’t firing centered at the nozzle you have to correct the alignment.
2. I would check and make sure the laser was in focus. if your lens is a 2 1/2" lens you need to have the lens 2 1/2" above the work. work out the distance between the bottom of the lens and the end of the nozzle & subtract that distance from the focal length of your lens. that is the length of the space you need between the end of the nozzle and your work.
Your problem could very well be the lens but you will not know for sure until you get the laser correctly aligned and focused. I have had lenses that were absolutely destroyed that would still cut, but a brand new lens that isn’t properly focused will just make a mess.
Good luck, i hope you get your problems sorted out
Cheers,
Rob.
