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Thread: IPG YLP 0.5mJ 10 watt fiber laser test results

  1. #11
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    ... a razor blade is easier to penetrate than much other targets - when optimizing a newly developed disc-laser with max. 0.5J pulsing (avg. 3W CW), I did this regularly to find the optimal focus ... should be a focus diameter around 20 microns then, and penetrated the razor blade with a single pulse ;-)

    Viktor

  2. #12

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    0.5J in a 100ns pulse would be 5 megawatts. I think many materials would bow to that level of peak power. But only 6 pulses per second would make a hell of a dotted line if trying to cut :-)

    I really like this laser and the newness of it (just over 3 years old and little run time) but I am going to keep my eyes open for the 1mJ or 2mJ version if it ever comes up for a good price on fleabay and you guys are asleep or something.

  3. #13

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    Viktor, I found this paper which performed tests using your exact laser (maybe it was even used here):

    http://lasers.org.uk/paperstore/Cutting4.pdf

    Very interesting. They were cutting 0.1mm stainless with as little as 1 watt average power (but at a much lower rep rate than I can go).

    50mm achromatic lens.

  4. #14

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    On the subject of focusing lenses, what do you think about these V-coated 1064nm N-BK7 plano-convex lenses for experimenting?

    LA1540-YAG f = 15.0 mm, 1/2", N-BK7 Plano-Convex Lens, 532/1064 nm V-Coat $27.90
    LA1074-YAG f = 20.0 mm, 1/2", N-BK7 Plano-Convex Lens, 532/1064 nm V-Coat $27.60
    LA1304-YAG f = 40.0 mm, 1/2", N-BK7 Plano-Convex Lens, 532/1064 nm V-Coat $25.60

    on this page: http://www.thorlabs.us/newgrouppage9...tgroup_id=5383

    They also have fused silica v-coated plano-convex lenses but they are about $90+ each (which is still $100 cheaper than Edmund or Newport)

    15mm to 40mm FL gives me a pretty good range for playing with depth of field vs smallest spot.

    They have air spaced v-coated high power doublets, which would probably be the bees knees, but they are $525!

    How is N-BK7 vs fused silica? Would I even notice a difference?

    Edit: There are also broadband (1050nm to 1620nm reflectance less than 0.5% from each surface) coated cemented achromatic doublets that are reasonably priced.

    AC080-010-C f=10.0 mm, 8.0 mm Achromatic Doublet, ARC: 1050-1620 nm $45.00
    AC080-016-C f=16.0 mm, 8.0 mm Achromatic Doublet, ARC: 1050-1620 nm $45.00

    AC127-019-C f=19.0 mm, 1/2" Achromatic Doublet, ARC: 1050-1620 nm $67.00
    AC127-025-C f=25.0 mm, 1/2" Achromatic Doublet, ARC: 1050-1620 nm $67.00

    Or maybe the Best Form lenses which have a similar 1050nm to 1620nm coating
    LBF254-040-C N-BK7 Best Form Lens, 1", f = 40 mm, ARC: 1050-1620 nm $52.20
    http://www.thorlabs.us/newgrouppage9...tgroup_id=4876
    Last edited by Skyko; 07-20-2013 at 20:03.

  5. #15

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    This phd research paper has some excellent information around page 24 to 25 about singlet vs doublet for micromachining.

    http://research-archive.liv.ac.uk/12...295_part_1.pdf

    It looks like the doublet is very much superior for getting the most energy in the smallest spot.

    I think I would like to play with that Thor Labs cemented doublet, perhaps the 25mm FL 1/2 diameter. I am not sure if the 8mm diameter lens would fit my 6mm beam.

  6. #16
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    ... for the actual tests with the 9W-diode I'm using a single plastic lens with 9.6mm diameter and receive a focus of around 0.15mm in 20mm distance to the lens.

    Maybe 3 years ago I've tested something similar with a glass lens, comparing a 5W-diode with the fiberlaser - the cut from the diode was around 0.2mm wide (thick cuts @2W), from the fiberlaser around 0.04mm (thin cuts @<1W with 2mm spacing) ... but could be better, when finer tuned ...

    Viktor
    Attached Thumbnails Attached Thumbnails IR-2Wdiode-1Wfiber.jpg  


  7. #17

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    Some small update:

    I turned a copper nozzle, or at least an artist's conception of what a nozzle might look like since I really have not a clue. I drilled a 0.045" hole for the beam exit and tapered the inside and outside. I found a old section of tube in my junk box to press fit the nozzle into, and also a section with a hose input.

    I also bought a set of (non-stainless) feeler gauges to get some different thickness than the 0.009" standard razor blades.

    Mounting up the 0.005" thick feeler gauge, I set the 75% argon/25% CO2 gas feed to 30 PSI. I then cut some rectangles that are 0.02" wide by 0.03" high. I tried feedrates of 0.6 IPM, 1 IPM and 2 IPM. The 2 IPM actually seemed to leave the best cut. I have not tried faster yet.

    There is still some brownish/red smudge around the cuts and some dross on the top and bottom side, but definitely less than when I was running with no nozzle or gas. These tests are all with a cheapy plano convex single lens of about 30mm FL. I will be getting the hopefully much better achromat doublet from Thorlabs this Monday.

    The pictures show the rectangles cut out next to a 0805 resistor for a sense of scale. There were three pieces but I sneezed and one went flying somewhere. The last pic is the very comical setup I have for this on my Shizuoka cnc bedmill. Imagine a 7000 pound cnc mill being used to cut out a square that is 0.02" by 0.03" by 0.005"! I do plan on building a xyz stage out of some NSK linear robot modules very soon. Always being safe, I am in a closed room wearing OD10+ goggles and not staring at the beam. Until this gets into a closed box system I am being extra cautious.

    I would like to try some variables to see if I can get an even better cut. I did all of these at 20khz rep rate....perhaps going to 40khz or even higher might improve things. Suggestions?

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    Last edited by Skyko; 07-26-2013 at 16:39.

  8. #18
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    ... the 'magic numbers' are highly depending on your machine - when you'll hit some resonancies, the cut can get 'wavy'.

    But I'll recommend going faster with higher rep-rates, powers and gas pressure ...

    Viktor

  9. #19

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    Quote Originally Posted by VDX View Post
    ... the 'magic numbers' are highly depending on your machine - when you'll hit some resonancies, the cut can get 'wavy'.

    But I'll recommend going faster with higher rep-rates, powers and gas pressure ...

    Viktor
    I tried going faster and it does produce a cleaner looking cut that goes all the way through (I only tried up to 10 IPM though). I also tried upping the frequency to 50khz 80khz then max 100khz and perhaps it makes a little bit cleaner cut.

    The problem is the cut is filled with melted steel or slag or something and I have to press pretty hard to snap the part out. I think my nozzle design is somewhat of a fail....I went too big with the hole at 0.045" It does protect the lens...there is enough pressure for that, but it does not have the umph to blow the vaporized/melted steel out of the very narrow kerf (maybe 20um right now with this lens, soon to be even smaller) through the thickness of the steel (about 117um). I have tried up to 80psi of the argon/co2 mix...it gets better, with much less brown smudge and dross on the top, but the cut is still filled up with molten metal on the top and bottom side.

    I re-read one of the papers I linked and they used a nozzle hole of 0.5mm which is about 0.020" This is way way smaller than my 0.045" hole. Back to the lathe :-)

  10. #20
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    Quote Originally Posted by Skyko View Post
    Some small update:

    I lathed a copper nozzle,
    turned! Turned! TURNED! Lathed is not a work. A lathe is a machine, turning is what you do on a lathe.

    But otherwise, pretty cool!

    -Jerry

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