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Thread: Black v Gray Cermark, whuuuUUTT?

  1. #1

    Black v Gray Cermark, whuuuUUTT?

    OK, so for going on 5 years I've had issues with my 80w RECI-Chinese Triumph producing grayish rather than blackish Cermark results. My Gravograph 40w LS900 and the 30w GCC Explorer both give me stellar black results. Both have Synrad lasers in 'em...

    I just bought a new (to me) Gravograph 35w LS100, which tested at 45 watts.

    So it's been much to my chagrin that this new laser is giving me the same exact results as my Triumph rather than my other 2 Western machines!

    One difference: Coherent laser this machine, Synrad's the other two.

    Since I can't have two machines that don't do stainless, I decide to run some tests at varying power levels, to see if too much power is an issue...

    And something really weird and unexpected just happened:

    First, here's the test pieces:
    lt1.jpg
    lt2.jpg
    lt3.jpg
    first, the two "laser test"s in the middle were done long ago with the LS900 for reasons I forget
    The top line tesT(s) were done with the LS100, between 90 and 60% power, same speeds, not much change, but--
    In pic one shot straight-on, the top line is noticeably grayer compared to all the others.
    The bottom 2 pics show how it gets worse as the plate is angled-- ICK!!

    BUT, the tesT's in the very middle, they're nice and black! At all angles! Perfect!
    but, how it happened was the weird and unexpected part because--
    -- that line is engraved with the same exact settings as the top line!

    I made one tiny change, what was it?

    (and I'm very much hoping it works for the Triumph!)
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  2. #2
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  3. #3
    Nope, both versions in sharp focus... but you're in the ballpark

    And, I'm testing the Triumph, I'm hoping...
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  4. #4
    Join Date
    Aug 2006
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    Suwanee, GA
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    top to bottom vs bottom to top
    I have done so much with so little for so long, that I can do almost anything with practically nothing...

    Trotec Speedy 400 80 watt 8/2015
    G. Weike LF-30, 30 watt galvo fiber - 1/2016
    G. Weike LF-30, 30 watt galvo fiber - 3/2015
    Fargo HDP5000 Card printer


  5. #5
    Lens size (focal length of the lens)?
    Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
    Printers : Mimaki UJF-6042 UV Flatbed Printer , HP Designjet L26500 61" Wide Format Latex Printer, Summa S140-T 48" Vinyl Plotter
    Router : ShopBot 48" x 96" CNC Router Rotary Engravers : (2) Xenetech XOT 16 x 25 Rotary Engravers

    Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.

  6. #6
    Ok--

    what I did: Swapped the lens from the LS900 to the LS100. That's it... !

    To test the results I put the LS100 lens in the 900, and I got gray engraving -- Definitely the lens!

    And late last night I put the Explorer's lens in the Triumph, and lo and behold, for the first time ever, the Triumph produced nice black outlines on one of my big SS operator panels! Holy crap!!

    I'm elated! Now, I knew there was a difference between $18 lenses and $300 lenses, but I had no idea just a lens change would make such a night & day difference with Cermark! I've tried probably 10 different Chinese lenses the Triumph, different 1.5", 2", 2.5", 3" and 4"ers, and a couple of 1.75" GaAs lenses, never gotten black Cermark with any of them. Likewise, I've used a couple of the Chinese lenses on the LS900, and they worked great, but I wasn't doing stainless. Just found this out by accident!

    So I'll be asking my rep why the LS100 lens acts like a cheap lens? It's flawless to look at and engraves everything else beautifully, but maybe it's been replaced?

    Final question then, if I spring for a couple of $300 lenses, how will I know they'll be the ones I need?
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  7. #7
    Quote Originally Posted by Kev Williams View Post
    Ok--

    what I did: Swapped the lens from the LS900 to the LS100. That's it... !

    To test the results I put the LS100 lens in the 900, and I got gray engraving -- Definitely the lens!

    And late last night I put the Explorer's lens in the Triumph, and lo and behold, for the first time ever, the Triumph produced nice black outlines on one of my big SS operator panels! Holy crap!!

    I'm elated! Now, I knew there was a difference between $18 lenses and $300 lenses, but I had no idea just a lens change would make such a night & day difference with Cermark! I've tried probably 10 different Chinese lenses the Triumph, different 1.5", 2", 2.5", 3" and 4"ers, and a couple of 1.75" GaAs lenses, never gotten black Cermark with any of them. Likewise, I've used a couple of the Chinese lenses on the LS900, and they worked great, but I wasn't doing stainless. Just found this out by accident!

    So I'll be asking my rep why the LS100 lens acts like a cheap lens? It's flawless to look at and engraves everything else beautifully, but maybe it's been replaced?

    Final question then, if I spring for a couple of $300 lenses, how will I know they'll be the ones I need?
    You don't need to spring for $300 lenses. Go to ii-vi and you can call them. Tell them the diameter and the thickness and they'll match it to what they sell. They supply lenses and mirrors to everyone in the business. I think my first (and only) lens I bought from them was about $125. I think it was $145 or something and they had a first time buyer discount so it ended up being $125. Top notch company, very good people, very smart.
    Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
    Printers : Mimaki UJF-6042 UV Flatbed Printer , HP Designjet L26500 61" Wide Format Latex Printer, Summa S140-T 48" Vinyl Plotter
    Router : ShopBot 48" x 96" CNC Router Rotary Engravers : (2) Xenetech XOT 16 x 25 Rotary Engravers

    Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.

  8. #8
    +1 on ii-vi
    Mike Null

    St. Louis Laser, Inc.

    Trotec Speedy 300, 80 watt
    Woodworking shop CLTT and Laser Sublimation
    Evolis Card Printer
    CorelDraw X5

  9. #9
    Amazing to read about the differences...Thanks for the story, Kev.
    But we use ii-vi here also.
    Best wishes,
    Ian



    ULS M-300, 55w made 2002 with rotary. Goldenlaser 130 watt, 1300x700 made 2011.
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  10. #10
    Then I'll have to give them a try, I can see where they'll need to special-make any lenses I'd want, none of their in-stock lenses are even close to what fits a typical laser engraver...

    funny thing, I've only bought lenses for the Triumph, all of my western machines, including the 21 year old ULS are on the original lenses...
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  11. #11
    Join Date
    Aug 2006
    Location
    Suwanee, GA
    Posts
    3,620
    Quote Originally Posted by Kev Williams View Post
    Then I'll have to give them a try, I can see where they'll need to special-make any lenses I'd want, none of their in-stock lenses are even close to what fits a typical laser engraver...

    funny thing, I've only bought lenses for the Triumph, all of my western machines, including the 21 year old ULS are on the original lenses...
    They stock every size you could possibly need Kev. I know the GCC takes .75" and the one you have in the laser, or at least had in the laser, was a stock lens from II-VI. Check eBay there are a lot there - 19.05mm is close enough to fit, at least in the GCC anyway.
    I have done so much with so little for so long, that I can do almost anything with practically nothing...

    Trotec Speedy 400 80 watt 8/2015
    G. Weike LF-30, 30 watt galvo fiber - 1/2016
    G. Weike LF-30, 30 watt galvo fiber - 3/2015
    Fargo HDP5000 Card printer


  12. #12
    If that lens is a ii-vi then I'm sold -- it's a hair under 3/4", maybe .71 as that comes to 18mm... a 3/4" does fit in the holder okay, I've used a 1.5 in it a couple times...

    Their website's size listing's don't show anything close to laser-engraver size, at least this page doesn't, goes from 1/2" dia. straight to 1", and then nothing but bigger!
    iivi.jpg

    --going to hit ebay..
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  13. #13
    Quote Originally Posted by Kev Williams View Post
    If that lens is a ii-vi then I'm sold -- it's a hair under 3/4", maybe .71 as that comes to 18mm... a 3/4" does fit in the holder okay, I've used a 1.5 in it a couple times...

    Their website's size listing's don't show anything close to laser-engraver size, at least this page doesn't, goes from 1/2" dia. straight to 1", and then nothing but bigger!
    iivi.jpg

    --going to hit ebay..
    Kev, just call them. They are a huge company with a huge inventory. Just call them with the use and dimensions and they should be able to match your needs.
    Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
    Printers : Mimaki UJF-6042 UV Flatbed Printer , HP Designjet L26500 61" Wide Format Latex Printer, Summa S140-T 48" Vinyl Plotter
    Router : ShopBot 48" x 96" CNC Router Rotary Engravers : (2) Xenetech XOT 16 x 25 Rotary Engravers

    Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.

  14. #14
    Join Date
    Aug 2006
    Location
    Suwanee, GA
    Posts
    3,620
    Those are meniscus lenses and you want Plano convex.

    Quote Originally Posted by Kev Williams View Post
    If that lens is a ii-vi then I'm sold -- it's a hair under 3/4", maybe .71 as that comes to 18mm... a 3/4" does fit in the holder okay, I've used a 1.5 in it a couple times...

    Their website's size listing's don't show anything close to laser-engraver size, at least this page doesn't, goes from 1/2" dia. straight to 1", and then nothing but bigger!
    iivi.jpg

    --going to hit ebay..
    I have done so much with so little for so long, that I can do almost anything with practically nothing...

    Trotec Speedy 400 80 watt 8/2015
    G. Weike LF-30, 30 watt galvo fiber - 1/2016
    G. Weike LF-30, 30 watt galvo fiber - 3/2015
    Fargo HDP5000 Card printer


  15. #15
    The part number I have for a 3/4" diameter, .080" thick, 2" focal length lens is 488614.
    Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
    Printers : Mimaki UJF-6042 UV Flatbed Printer , HP Designjet L26500 61" Wide Format Latex Printer, Summa S140-T 48" Vinyl Plotter
    Router : ShopBot 48" x 96" CNC Router Rotary Engravers : (2) Xenetech XOT 16 x 25 Rotary Engravers

    Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.

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