I am looking to maximize my marking area and am wondering if this is possible before I start messing with settings. Is it possible to use the full circular marking area of the laser. For example, a 300x300 lens should yield a 424mm diameter circular working area. I have a couple longer parts that I’d like to mark in a single pass.
Not sure if this is as easy as setting the larger working area at 424x424 or if I risk damaging my system. Or does the EZCad control board prevent using the full area anyway.
When calibrating lens with the 9 point utility, LB has a maximize work area feature. I haven’t tried it but another member reported using it with success Please report back if you give it a try.
I finally got a chance to test this and it kind of works but kind of doesn’t The working area got larger, but the scale accuracy got worse. If I draw and mark a 12in x 12in square it is dead on. 10x10 is slightly undersized, and 5x5 even more so. Is this behavior expected? I have my settings below in case something stands out.
As a bonus, I was hoping to use the Field > Angle setting to square up my laser output with a custom base. To fit in our existing enclosure, this angle would need to be set to 50 degrees. When I make this setting scale seems to be affected and parts can get cutoff. I’d be happy with any thoughts here as well. Obviously building a new safety enclosure is the best bet, but was hoping it could be done via a setting for the time being.
Interesting I never get skew other then 1.000 on any of my 3 lenses with the 9 point correction, did you measure corner to corner and manually adjust or did the correction give you that?
To answer your question, no, not expected. Assuming you are using the 300x300, 12x12 is oversized by a little but the other sizes should be spot on.
What percentage did you use for your calibration?
How did you figure this? You can’t get a 424mm circle in a square that is only 300mm on each side.
To use it, it has to be focused and the area coverage is limited. Most of these lenses have a set angle they work with. Mostly +/-28 deg, although I’ve see a few with up to around +/-30 deg. I think coverage is limited by lens length at which point you get distortion from the lens.
This is the defined area of coverage. If you shrink it, you change the how the lens in corrected. You can only do this by a lens change. The surface speed of the laser or scan rate has to take into account the head height or lens focal length for a corrected value. Unlike a gantry where this is fixed, the galvo has to move at a different rate depending on the lens length.
As far as I know, there’s no way to configure a longer lens to have a smaller coverage area.
I understood the OP differently, sounds like he calibrated to max size and then just burned and measured the smaller squares as a back check, didn’t re-calibrate or shrink.
If that’s the case, I also think the “Maximize working area” gives him a larger square then 300x300 (12"x12" test square, 13.86" x13.86" maximum field) but causes a little distortion with the 5"x5" and 10" x 10" test squares. I don’t use the “Maximize working area” feature (except when I first noticed it and experimented with it a little bit) and my test squares burn to pretty tight tolerances.
I thought I heard rumors there was going to be a 16 point correction that would improve corrections on lenses with non linear errors, like what the OP describes.
To solve all of field problem we are must use full field galvo correction. Its a better way for compensation of all lens distortion. Seacad use multipoint correction but with linear interpolation. Ezcad 3 use interpolation with smooth function.
You get 424 as the square is inside the circle, not outside. If you use a circle inside the square, then you are minimizing your working area, not maximizing.
And Albroswift is correct, I was using the 12x12, 10x10, and 5x5 as burn tests to verify the resulting accuracy. I was not changing the field of view. Apologies as this was explained poorly on my part.
I think the 12x12 is a bad test case. Just because it shows when framing and marks doesn’t mean I should trust it. A 12x1 would be a safe bet as it fits within the 13.86" circle that the maximize checkbox returned for a value.
Perhaps the reason the maximize function returns a width of 13.86" is taking into account what jkwilborn is saying about the scan angle, but that would mean we start to get defects as we approach the 11.81" (300mm) limits that touch the edge of that circle. Ideally we would be able to rotate that square within the circle and get the same results at any angle. Thus maximizing the output.
I think you have it right, but proof is in the pudding. After the 9 point correction there is a scale feature for fine tuning, might try it at 8x8 or 9x9, and then try back checking larger and smaller squares. With my 300x300 lens fine tuning scale at 290x290 gave me really good results all the way down to 100x100, 50x50 but every lens is different.
