[Lietuva]

Hello,

We have Chinese Laser CO2 cutting engraving machine 50W. After replacing new tube and beam alignment we started cutting plywood. Why there is double line (seen at once) when cutting in top of working area and there is no problem with cutting in the bottom of working area. We cut same object.

[Tweakie]

You need to re-do your beam alignment.
It looks like you have a reflection off part of the structure.

[Lietuva]

Thank You! We will try to do this and come back with answer!

[Lietuva]

Hello, it is OK with cutting now, thank You! BUT still remains the problem with engraving small or thin objects, texts. If we engrave big objects then engraving quality is ok enough, but if small - only some marks is seen on plywood. Can somebody help?

[gfacer2]

I have a slight similar issue (and have had it of and on for ages - but I rarely try to engrave).

Try this - remove the nose cone and see if that fixes the issue. If it does, a part of the beam is hitting the cone and bouncing off. You can either leave the cone off if needed, ream out the hole, use a cone that is closer to the lens etc.

If it is not fixed it might be a scratch on a mirror or something like that or even a bad pattern to the beam. Basically something that creates a second light path. You can try replacing or even just swapping the mirrors (as it would likely not be an issue at the same place in another mirror holder).

Good luck,

[KH0UJ]

misalignment on the laser beam, recalibrate all mirrors (XYZ) sometimes when the door slams the alignment on the mirrors are changed, tube replacement mirrors sometimes changed, to cut the story short master how to align the mirrors on your unit, it works like a charm

[Sockles]

Yeah I was gonna say what Gfacer2 mentioned. The beam might be hitting the inside edge of the nozzle tube. Does this same problem happen everywhere around your table?

[grawley]

There may be an internal fracture in the focus lens. If you have a spare, may be worth swapping to test. If no spare, then with a magnifying glass, and turning at angles under light, you may be able to see the fracture as the light will reflect off it.

[Lietuva]

Dear all,

Thank You for Your answers. We will try to do what you suggested and come back with the feedback. But still it is strange why then everything is good with cutting but there are problems only with scanning (engraving).

[Blackened]

There may be an internal fracture in the focus lens. If you have a spare, may be worth swapping to test. If no spare, then with a magnifying glass, and turning at angles under light, you may be able to see the fracture as the light will reflect off it.

You can also check for certain invisible lens defects with 2 polarising filters. You can use the 2 separate eye pieces from a pair of 3D glasses. Make a sandwich of the polariser, lens, polariser. Then look through all 3 towards a strong light source. If you can't see through at all, turn one of the polarisers 90 degrees. This can uncover certain lens defects that are otherwise invisible.

Any damage you can see with this method should appear as a clouded/darker area.

[fixtureman1]

It could be a loose mirror