Circle settings

[chad shoemaker]

Hey guys, I have a 30w fiber laser and my circles are not coming out correctly. I believe the parameters are in the Galvo 1 and Galvo 2 settings. Does anyone know.of a way to adjust the settings or is there a correct parameter setting for a perfect circle.
Thanks in advance

[Kev Williams]

It's that dreaded time where you need to spend an hour or so aligning the laser-- In the F3 params menu is where it's all done. You need to re-shape the laser's output AND align the red LED to the laser's cut.

The summary version:

how big is your working area? whatever it is, lets say 150mm, you need to find or make a square that's about 20mm less, or 130mm in this example... Thin, and light colored is best. It doesn't have to be exactly square, but you DO need good 90° angles if possible. You'll need to accurately measure it, down to .01mm or .001" inch if possible

Once you have your square, best is to place it on a black background, doesn't matter what, paper, whatever. Tape the two together, set aside.

NEXT- find something to test engrave, 4" x 4" -ish, 2" at least. White is good. Draw a SQUARE box in EzCad that fits on the text piece, SQUARE is best. Lets say 80x80mm.

put the test piece on the table, focus, then red-light it so it's close to the lens center, then tape or clamp it so it doesn't move. Set your speed at 1500 and power at ZERO, then run an outline pass.
-if it didn't mark, add 10% power and run until it does mark.

NEXT, redlight what you just engraved. Now is when you adjust the red-light to match the engraving in the F3 menu- to start, you click on the "other" tab, then 'red light pointer'- here you'll find offset X and Y, and size scale X and Y... tweak the offset X numbers to get the red light's X centered up with the vertical box sides you engraved, likewise, adjust the Y offset to align the horizontal top and bottom sides. Size scale moves from 1:1 up or down, adjust these to match the size of the redlight to the engraving...

Get the red box to match the engraving as close as possible, use a magnifying glass if need be-

When done, measure the engraved box for exact height and width. Let say it measured 79.44mm on the X and 80.22mm on the Y- In the main F3 menu in the Galvo1 and Galvo2 section, note the 'scale' sections. Also note ABOVE which galvo = X. On the right side of the 'scale' is a box with 2 >> in it, click on whichever is your X galvo- you'll get 2 boxes, 'desired marking size' and 'actual mark size'- in this case desired is 80mm, and actual is 79.44... enter those, and the program will calculate the adjustment. Repeat for the Y galvo. When done, repeat the engrave test, and re-measure. You'll likely have to tweak, and you can use your own numbers to fine-tune.

When you get it to actually engrave an 80x80 square, you're close.

NOW, draw a rectangle or square that exactly matches your test square in EZcad, center it and redlight it. Fetch your white-ish test square and dark backing place (anchor) them to your table as square and centered as possible to the red lighted square... In a perfect world the redlight will exactly match the square piece, but pretty sure it won't. You'll find either, or a combination of, angled or curved sides that don't match the square. In the F3 menu, the 'shapes' is where you correct for these problems. From here it's trial and error, which means, make some big adjustments one way or another to see what the adjustment does, this gives you a baseline on how to counteract it :) WRITE DOWN previous measurements, it helps. Once you get the ENGRAVED square right, tweak the redlight to fit the engraving perfectly... when done, squares will be square, circles will be round, and at the right size :)

have fun --