60W/JPT-MOPA with a rotary and 110mm lens. Annealing on stainless. Have a regular customer that provides me with a stainless cylinder that I am annealing their logo onto. Have done this successfully numerous times. However, recently I find it is in focus just fine on the first half of the logo; when it gets to the “back half” of the logo, it starts to engrave, i.e. focus is too close. If I am watching closely I can shift the focus up and not ruin the product. Anyone else experience this? Thoughts on the issue here - cylinder is round so that is not the issue.
I found a problem with a rotary that we found by mounting a dial indicator on the table and rotating a piece of acrylic. It warbled about 0.30mm on the end. Once the dial indicator was there, you could see it.
Dissassembly of the rotary showed a piece of metal from the machine shop in between the mount face and the chuck itself. This caused a slight wobble.
Is this an F110 or a 110mm square coverage?
Focus is very critical, as I’m sure you are aware…
Most of these are probably not applicable… so lets look at it differently…
If the machine works for 1/2 the image then goes out of focus … the distance between the lens (or glavo head) and work piece has to change in order to go out of focus…
The basic operation indicates something loose… What can change in 1/2 a turn ? … I’m thinking on this one.
It must be something related to the hardware, since there is no software control for changing the Z position taking it out of focus.
Unless you have a stepped Z axes that changes or the Z thumb lock that isn’t firm… there’s really no way to do this, except mechanically…
Thanks for the reply Jack. Sorry, I wasn’t more clear on the lens - F110. Overall, not really a size issue with lens or image. This USED to do just fine; but, has only recently changed, i.e. in the last 2 months. I did have some hardware issues, i.e. a new galvo head; but, the problem started before that. I don’t believe it is software either other than Lightburn updates were applied in last few months. And agreed - do not believe it to be Z axis moving. So…I will try to see if I can see a change while it rotates. Same rotary however. I have made over 100 of these successfully up until a few months ago. I continue to ponder…
The only way I can imagine this happening is there being a change in distance. As you know, the shorter the lens the more critical the focus.
The only way it can go out of focus is by a mechanical movement…
Lens tight?
Hi Jack - yes, the lens is tight. As I said, I even had a head swap in the last 2 weeks (was strange that the original went bad; but, it did). I may change to my 200mm lens to try - just didn’t really want to go through the testing to find the sweet spot. The only other thing I can think of personally is the cylinder goes out of round due to the chuck. I am gripping this piece on the inside - perhaps that is elongating it some. BUT, that confuses me as it ALWAYS happens on the back half of the file. There are 725 steps in the file, and it always happens are 450. Thanks for pondering this with me.
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