Epilog Fusion fiber imprint changes location in relation to focal distance?? why?

[Edward Ike Brown]

Hello there, been a bit but I figure I'd post here before I bug Table Mountain.

(Fusion M2 100/50 Watt laser) I etched steel this morning via Fiber source, lowered the focus and repeated the file (touched nothing), and the anneal print was off about 1.5-2mm to the left of the original print. This was done with a fiber only 5" lens, I did the same thing with the included 3" dual lens and macro photo showed no change (although the increased focal distance of the 5" could magnify the problem and I might not be seeing the change with the 3").

This is first time I've ever seen this happen, I've seen double prints with older machines with loose belts but I can consistently make this happen, the more I move the focus closer to the table the more the imprint prints to the left.

Any help with this would be greatly appreciated - We also just had another lens sent to us (the 5" in question), I'm honestly hoping its a pre alignment issue, no time to align optics right now with Holiday rushs.

Thanks in advance!

E

[Edward Ike Brown]

After engraving some more I noticed as I run the focus back and forth, about 3 inches from the table, you can see the diode pointer going left to right.

Again, recently we did get a replacement lens, just the lens, used the same "carriage" as before. I am starting to wonder if the lens isn't properly seated, or if this is just a property of this 5" lens, OR a alignment issue. Most of which I can't do at the moment.

Hopefully this info helps describe my problem better

[Scott Shepherd]

Sounds like the head isn't square with the table. Pretty common. They don't do much alignment on that since most people never need to move the head up or down on the same item.

Run a precision square against the head, from the table and you will see. Or, put a piece of paper down, run the head close to the table, mark with a pencil where the red dot is and then run the table down a couple inches and mark where the red dot is. It probably won't match.

[Edward Ike Brown]

Thanks for the reply, I'm guessing I'll need to figure out how to correct it. I engrave repeat jobs alot, adjusting focus as I need to so it needs to be addressed. It just didn't seem noticable at all before I replaced the focal lens, and as well with the stock 3" lens, I can back in out just fine.

I just did an AR lower, had to mark it with pencil, I can run the focus +2"/-2" and the red pointer travels over a quarter inch left and right, pretty crazy. I understand changing focus isn't normal but after every pass essentially the focus is changing due to the material being ablated away, soft metals especially.

By any chance do you know the procedure to squaring the table up? or does a standard optic calibration do the trick? I would have to guess the last 2 steps when you adjust the head

Again thanks!

[Scott Shepherd]

It's likely not the table, it's the head tilted at an angle. You can check that by measuring the distance between the table and the bottom of the X-Axis bar at all 4 corners. It should be the same. That'll tell you that the table is parallel to the sliding assembly. If that's the same, and not more than .030" of an inch out, then it's your head. It's been a long time since I've seen a Fusion in person so I can't say exactly how it would be done, but there should be some screws that hold the head to the assembly that the belts end up clamping to. You'd loosen those and rotate it until it's square. You should be able to take a precision square and stand it on the table and butt the edge standing up against the head assembly. That should get it really close. I doubt they even check that at the factory because to them, it doesn't really matter. To you, in your case, it does.

Just my guess at all it.

[Kev Williams]

Assuming I read your "...and as well with the stock 3" lens, I can back in out just fine." to mean it STILL 'backs out fine' currently; not past-tense, some simple troubleshooting:

IF- moving the focus distance worked ok with the old lens-
AND- now it's NOT okay with the replacement lens-
AND- the 3" lens still works okay-
THEN- Occam's Razor says: the problem is the replacement lens, it's the only common denominator...

so as to the lens, it could be a faulty grind, could be it's not squarely installed in its holder, could be there's something burnt onto the lens that's reflecting the beam...

BUT- if the 3" lens is now doing the same thing as the new lens... Never mind. ;)