autofocus for my fiber

[Rodne Gold]

My Fiber did not come with a focussing mechanism... We had to determine optimum focus and make an acrylic focus gauge whiuch is a pain
So I got one of my old machines , where we dont use the red pointer and snaffled the diodfe and the mounting system from it
I mounted it as you can see , just below the galvo head and set it dso the 2 dots coincide or in this case are in line , at optimum focus...So all I do now is raise or lower my table and I can see exactly where its in focus rather than slip the perspex guage in (which tends to be rather fiddly)
Not exactly AUTO focus , but better than no focus at all :)


Here are some pics

https://fbcdn-photos-c-a.akamaihd.net/hphotos-ak-xft1/v/t1.0-0/s480x480/13690756_601143960066209_7173335828583427288_n.jpg ?oh=1661c7cb248b95f23cd3b30382a5047a&oe=58254103&__gda__=1479514897_36f17a0493657a7b975bf52803aacc4 8

https://scontent-ams3-1.xx.fbcdn.net/t31.0-8/13701030_601143956732876_3485421527266500958_o.jpg


https://scontent-ams3-1.xx.fbcdn.net/t31.0-8/13732050_601143953399543_8080671407086104429_o.jpg

[Kev Williams]

Mine came with the 2-LED focus, and I think I'd rather have a piece of plastic to focus!
--all in what I'm used to I guess, that's how I focus all my machines, a 1/4" thick piece of Sintra, different lengths for different lenses, and different ones for out-of-focus-slightly use.

Since the stationary LED isn't exactly stationary, I have no idea how well my fiber is in focus, haven't done anything resembling a ramp test yet.

[Gary Hair]

Both of mine came with the second led as well. Like Kev, I use a plastic focus tool instead. Some materials are impossible to see the light and others are reflective and I'd rather not have the beam reflecting back into my eyes!

[Gary Hair]

Since the stationary LED isn't exactly stationary, I have no idea how well my fiber is in focus, haven't done anything resembling a ramp test yet.

I was told to laser a small square or circle continuously and raise and lower the head until you see the brightest flash. On mine that measured 297mm to the bottom ring on the lens. One caveat - work quickly while the laser is firing for two reasons - 1. The metal will get hot fairly quickly. 2. If you take too long the laser will cut into the metal deep enough to make your measurement off a bit. Do it a few times to make sure you have it right and to eliminate the depth of cut being an issue.

[Kev Williams]

How about a really tight spiral for testing? I've been considering a ramp test at 1% power too for fun.

I did find out 1% power WILL mark an anodized pocket knife, didn't think it would ;)

[Gary Hair]

How about a really tight spiral for testing? I've been considering a ramp test at 1% power too for fun.

I did find out 1% power WILL mark an anodized pocket knife, didn't think it would ;)

The object you use doesn't matter, you just need to be able to see the flash and adjust the height. It's amazing how little power you need to mark ano, and how much speed you can use as well! With 100% power you can pretty much max out the speed and still get a mark - it won't be pretty, but it will mark!

[Kev Williams]

I was showing my 'time' customer the thing today- they're always having me do factory-repro engraving on watch backs, which I've always done via diamond.
I did some quick text outlining on an old watch back- 1mm high 'Testing the fiber'- it engraved faster than you can say 'fibertest', and while the burn wasn't perfect (my first time with brass) the lettering came out amazingly sharp and clear, every bit as nice as you'd expect .250" high lettering from a metal C02, and this is only .040"... The holes in the "e"s can't be much more than .010" tall, if that. The accuracy is amazing...

http://www.engraver1.com/erase2/watchbacktest.jpg

[John Kleiber]

I've never used a spacer to set focus on my fiber. Instead I have a little spreadsheet that I enter the items height to be marked.

341088

The PART HEIGHT in green is all I need enter. I populate the EZCAD 2 fields from the new calculations from the PART HEIGHT input.

[Kev Williams]

That's cool-- but would never work for me! Or Rod either I believe, as our machines have the lens and box connected as a unit, with a simple hand operated scissor-clamp for focusing. And I've already found these machines were built with a 100mm lens in mind. My 160mm lens only gives me about 2" of up-travel on the table before it's too close to the lens, so some MacGyver-ing is in order for many jobs! Last night I propped the machine up on a couple of pieces of 2x12 to get it high enough to focus on some bracelets I had to hold in a clamp- Monday I had to engrave the ends of some 20" tall aluminum boxes- I had the scissor table on a milk crate and the box on the table so I could raise/lower it. When close I semi-secured the box against the edge of the table with ratchet straps. I used to engrave these boxes with my pantograph, holding them much the same way, but the pantograph is gone...

This morning I'm cutting up 2x4's to span across the wood table legs to act as a backstop for these boxes and other items so I can hold them in place better. I'm also needing to buy or fab up a rolling table for the machine, so I can just roll the machine from side to side, which would be easier than moving clamped parts side to side...

Fun stuff! :D