Having Trouble with Engraving

[Brent Ramsay-Boyd]

After much tinkering I finally got my engraving to an acceptable level, but alas it seems it was not meant to be. I was engraving some awards on clear acrylic (plexiglass) and everything seemed to be going smoothly. I did notice that i was needing more power for each subsequent award and so I decided it was time to clean the optics. I did so exactly as I have done before, and set the laser up to continue working.

That is when the problems started. The laser seemed to be engraving a double image. I found a short term fix by changing the engraving from swing to unilateral, just so I could finish the order. I engraved three more awards, and then everything went downhill fast. The machine has not been touch, but it went from engraving a nice smooth finish to engraving different depths on each pass leaving a terribly rough finish which you can see in the first image. Since then I have not managed to get my engraving right.

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In the second image you can see the double engraving on the test block in the top left corner, and in the lettering you can see how the laser seems to engrave deeper towards the center leaving a bowlike shape rather than a uniformly engraved surface. In the last picture you can see how the edges of the engraving are not straight but rather wavy.

With my limited experience I am not sure what the problem/problems are. I am hoping there are some members who have had similar issues and have some suggestions for me.

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I have a 1300x 900, 80W Shenhui machine.

Regards

Brent

[Bill George]

I would start by checking your mirrors and tube to see if anything has worked loose. After that you can find the post I made on finding a lot of loose, ready to fall out wire connections on the controller and both power supplies. Check with the power off and use a small screwdriver or whatever needed to tighten. I would start with the optics and mounts first.

[Keith Colson]

If your belt is loose then you will get a double image. Also my ULS has a "tuning" value which adjusts the engrave to match the play in the belt. Two more things to look into.

cheers
Keith

[Mayo Pardo]

If the wobbly vertical lines only started after cleaning your optics, double check that the lens is secure and not able to move. Also make sure there is nothing caught in the air cone if your laser has one. I have found tiny bits of paper in mine after cutting some note cards.

[Art Swander]

I am not sure what machine you are using, but I would first look at my optics closely, and make sure that they are actually clean, and don't have something either sticking on them, or there is not a scratch on them, that could be causing the double engraving. Make sure everything is properly tightened up in the machine as far as optic mounting screws and such. Check your entire beam path, and everything that is in the path. That is the most likely cause of the ghosting. You may also want to check electrical connections and such, but not convinced here that is the issue. Belt tension can also cause this. Good luck with everything.

[Dale Weber]

I have seen this exact issue when the beam is not aligned properly, and it glances off the wall of the air purge nozzle. It can also happen if any of the mirrors or lens are scratched or loosing the coating. Look at them carefully with a very bright flashlight. You will be able to see defects that you cant see in normal light. Especially on the lens.