Fiber Settings - Almost Rocket Science

[Tim Bateson]

The thread title may be a bit of a stretch, but there really isn't any reliable sources for Fiber settings. They are complex and sometimes not very intuitive, often the opposite of what one would think to be obvious. Finding reliable Fiber settings are the extreme opposite CO2 settings which are comparatively elementary, with a ton of sources for such settings. Not only does Fiber have more settings than CO2, they are not at all definitive. I am continually modifying and making variants of past saved settings. For example I have 3 different saved settings for Chrome. Different Chrome marks differently. Same is true for SS, Sterling Silver and Aluminum. ... Don't even get me started on the variants for plastics. grrr

[Gary Hair]

I think rocket science would be easier than this...
I have an 8 x 8 grid that I used for color testing on 304 stainless. The constants were .01mm hatch @ 45 and 135 degrees, and 80 frequency. The variables were speed, 50-225, and power, 10-31. In those 64 squares there are at least half that are black, or at least a suitable shade that resembles black, and the rest are bluish (25 or so), yellowish (4 or 5) and redish (2 or 3), with bluish being the majority. What does this tell me? I have no less than 32 different combinations of speed and power to get a black mark. You could spend your entire lifetime experimenting and still not cover every possible combination.

It would be nice to create a macro that would go through an array of settings to save the time of manually entering them and testing. I would gladly have a bunch of 5" squares of stainless cut up just to sacrifice them for testing settings. As it is now, I use what I found to work and tweak it periodically as I discover some improvement.

If you consider the following:
Speed - 1-10,000 in increments of 1
Power - 1 -100 in increments of 1
Frequency - 30 - 80 in increments of 1
Then throw in:
Hatch - type, angle, number, spacing
Focus - in or out of focus (and how far out)

And do this for EVERY material known to man... "oh no, I've gone cross-eyed" (bonus points if you know this movie quote)

[Kev Williams]

I posted the below in another thread just 3 days ago, I think it's relevant, and rather than link to it, I did the lazy thing and just copied and pasted it here! :D
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If there's one absolute I've found with my fiber, it's that nothing is absolute.

Examples-- depending on a few speed, power and focus changes, I've found I can get a great black mark on stainless no matter what frequency I choose. The other day I 'wobbled' a nice black mark onto some 20 gauge flat 304 SS, so I used the same settings to mark a customers SS coffee to-go mugs. I literally fried the stainless- the blue/brown discoloration extended nearly 1/8" beyond the engraving. This was ONE pass at 50% power, 1500 speed (wobble slows that down dramatically), .01 wobble spacing both ways, and 100k frequency, on the rotary. This is the result after scrotchbrighting the thing. This came out totally different than my flat sample. Material thickness would be one reason, and possibly they're 2 different grades of SS...
http://www.sawmillcreek.org/attachment.php?attachmentid=345805&d=1476548956&thumb=1 (http://www.sawmillcreek.org/attachment.php?attachmentid=345805&d=1476548956)
These mugs were for practice thankfully ;) -- the obvious rotation seams, this underscore the need for testing and tweaking your rotary. In this case, the diameter I entered needs adjustment as the sections are spaced too far apart. I believe this means I need to enter a larger number as the working diameter, this would make the actual rotation move slightly less, closing that gap....

back to frequency, EZcad has a 'visual aid', that shows the relationship between the laser's firing frequency and the speed you're running. I've found this to be fairly important actually, because for the most part (not absolute!), when you find a frequency/speed ratio that works for a particular situation, you can work with the ratio's to save engraving time.

This is the visual aid. First up, 1500 speed and 40kz frequency, this is popular for anodized aluminum...
http://www.sawmillcreek.org/attachment.php?attachmentid=345802&d=1476548330&thumb=1 (http://www.sawmillcreek.org/attachment.php?attachmentid=345802&d=1476548330)
This aid assumes a beam diameter of .05mm, and shows each spot the laser fires. The overlap is the important part, this is a good 'chewing' pattern...

Now, double the speed to 3000 and the frequency to 80kz-- you have the exact same spacing pattern...
http://www.sawmillcreek.org/attachment.php?attachmentid=345803&d=1476548339&thumb=1 (http://www.sawmillcreek.org/attachment.php?attachmentid=345803&d=1476548339)
This means you can double the speed and get the same results! Or can you?
To a point, I've found this to be true. However, the beam is spending half the time in any one place, so there's power loss. Also, laser start/stop times come into play, and can create other differences. But depending on what you're engraving, you may well be able to save some time.

Another benefit, is the visual shows you can't increase speed AND frequency to get a totally different result. 3000 speed and 80kz likely won't anneal or 'light' engrave much better than 1500/40kz...

So, change one or the other, then check the results...
This is the fire pattern at 500 speed and 80kz-
http://www.sawmillcreek.org/attachment.php?attachmentid=345804&d=1476548351&thumb=1 (http://www.sawmillcreek.org/attachment.php?attachmentid=345804&d=1476548351)
This is likely a good annealing pattern, but will likely require some experimenting with power and focus. Doubling up to 1000/160kz would produce the same pattern, but may produce totally different results...

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and to add to this a bit-- Yesterday I engraved some key chain things, a cylinder made to look like an essential oils vial, about 1-1/2" tall and 3/4" diameter, pretty sure it was chrome plated. These things had a very narrow frequency "window"; at 800 speed and 100 power, at 100khZ they would only faintly mark- at 60khZ they marked ok-ish. At 50khz the burn was good but almost too much, going beyond bright silver and touching yellow-ish. 40khZ was burning in too much, but following it with a 55khZ burn brightened it right up.

Almost everything is a crap shoot! --except anodized, that's pretty forgiving!

Don't know how any of you do plastics, I don't even try!

[matthew knott]

Don't get an SPI laser then , frequency from 0.1 to 1000khz, & 40 differnt pulse shapes to add to the mix , millions of posiblities

[Kev Williams]

Oh, but I'd LOVE all those possibilities! :D