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Nd:Yag Laser Etching System

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LAN_403

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Thu Jun 29 2006, 05:02AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Last year it was a tesla coil and coilgun for summer projects... But anyone can make those, this year it is time to up the anti to a laser etching/cutting/obliterating/bleaching/etc system...

It will consist one big huge assembly.... The laser head is going to be the SSY-1 Q-switched Nd:Yag laser here. I am going to build a little zvs flyback driver to give the 1kv to charge the cap, and a small PIC to give overtemp protection, control the pump energy serially (or manually) and generally make the laser a device that a computer can talk to. The laser will be mounted vertically pointing down at the medium being blasted at, mounted on a couple of optical stages for positioning... The head is going to be mounted on a manual micrometer stage to give fine focus control, and the work will be on a little jack to allow for big thick stuff to be done. After that it is going to be a 2-axis system, made of 2 2.5" optical stages. Moving these stages will be 2 Newport 850F linear actuators. Each of these actuators will be connected to a newport PCM2000-C2 controller, which will be on a GPIB buss (or a serial one if I can't get the gpib working, the first step will be to get a cable). This will give me about +/- 0.3 uM (ie .0000003M) accuracy

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Overall the design will be limited to a work area of about 2" square... And by how long I am willing to wait for the piece to come out... I hear that the flash tube can handle about 10W continuous power, so if I run 10J shots (well above the lasing threshold, but well below what it would have been run in range finder service) I can go 1shot/second. 10J shots put a hole about a .5mm pit in Al, so I will probably set the spacing at .5mm... So I will get an amazing speed of 1"/minute... I am unsure as to how fast I will end up going, but I expect it to be s-l-o-w... But that isn't a problem since it will be all computer controlled so I can start a run in the morning and come back home 10hrs later and get the piece with like 30k little pits in it

If I wanted to obliterate the whole thing I would need about an hour... Unless of course I do a better job of focusing it, I bet I could get some pretty small spots if I need them...

What I have so far...

The controller for them actuators... That readout is reading in inches. Yes, you can control it in .00001" increments

But since it only reads to the tenthousanth of inch you have to kind of guess where it is for that last sig fig

I need another female db25 connector to make the correct adapter for the second actuator, so that channel says not connected for now.

The overall setup... It is in a closet so I can close the door during operation so I don't need to wear my yag goggles all of the time. I will probably end up clearing off the next shelf and putting the computer responsible for all of the controlling up there, and run a vga extension cable outside for remote monitoring. I added that camera as kind of an afterthought, (heck, I have 3 of them, why not put one to use

) but since it has a pretty good magnification on the lens it will help me get the spot size down where I want it. But unless I mount it on the moving part of the system I won't be able to use it to monitor the process.
peter

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Sun Oct 01 2006, 07:02AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Update!

I have the motion controller stages done, and a simple vi written in labview to control them

(extra points to anyone that guesses my desktop background)

So I can dial in .00001" forward, click run, and it moves .000010" forward.

I will eventually write a program that allows me to upload a monochrome bitmap, and it will fire a hole for every black pixel, but that will be a little while.

I also have made some progress on the laser.

The first laser I was using had too much power, the smallest holes I could do were about .01" in diameter, so I want making much use of my 50nm (yes. 1/10 a wavelength of red light) precision. But that head has its uses, like making my own miniature mountain ranges

(1pixel~.005" looking at the top of a dip ic)

But I had another laser head that had chipped optics, which gave lower output power. So I was happy,

That is looking at a piece of black anodised aluminum, with a small oval of the anodising vaporized off, and a piece of 32awg enameled wire.

I REALLY wanted to write my name or 4hv or something with my new spots, but that head had some type of electrical short in it, so that whenever I fired it reset the motion controller and I had to renter all of the info about the actuators

So I switched the head with another one, that had a terrible beam shape (big oval mess) but at least a decent spot size, and did my best at creating a letter...

H was chosen becuase it was mostly vertical lines, which was good since the spot was really tall (the middle bar is one shot tall)...

So that is officially the first computer controlled image printed by the system! Well I used a computer to control the stages, and the firing was done at about 1shot/second automatically (as soon as the cap charged it fired). I didn't touch anything but the mouse, so I consider it computer controlled

Right now I am working on a computer controlled controller for the laser head (it is going to be a pretty complex beast), and getting a head to give the decent spot size I want. I assure you that by the end of the year I will have some much better shots (the same spot size as is the first one, hopefully with a round spot, and more complex designs).

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Sun Feb 25 2007, 05:40AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

I am sorry that I haven't updated this thread, but shortly after making that H I was cursed (or blessed, depending on how you look at it) by some very cheap 808nm laser diode bars, and making my dpss laserr sucked me dry. Later, I lost the hardrive that had the VI I had written and the pics I took, so I am more or less at where I started

With college coming up (man, time sure flies) I have officially decided to dump the project to make room for the mk2.1 of my rocket gps tracking system, my diode/flashlamp pumped lasers, some computers, possibly a few tesla coils, and hopefully some PIC programming. At least for the next few years

So, don't hold your breath for the finished product.

ConKbot of Doom

Sun Feb 25 2007, 01:50PM

Registered Member #509 Joined: Sat Feb 10 2007, 07:02AM
Location:
Posts: 329

The cost of this may be a bit much for you, but if you want an easy interface to a GPIB bus to your computer, sparkfun sells a premade GPIB <--> USB adaptor.

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Sun Feb 25 2007, 05:18PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

I already have a real PCI-GPIB card from NI, which works great.

Thanks for the suggestion tho

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