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Thread: Warm Up Time and Cool down Time to prevent damage??

  1. #1
    Join Date
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    Default Warm Up Time and Cool down Time to prevent damage??

    I got this question becouse I dont want to damage my laser...
    On many web pages they say 2-20 minutes Warm up time ..

    Why is that ??

    To prevent from damage?
    To get a more stabile output with max power?
    Warm it up before I can use TTL mode on it ?

    This is a question I not have getted any good answer on...

    What do you do when you "warm up" the DPSS ?
    Do you run the laser on constant white output for 10min with the door closed ??


    And what about cool down time?
    Viasho told me to TURN down the power before I turn off laser on button..
    That will give the chrystal longer life-time...

    So I wonder...
    When I use the laser..
    I cannot use TTL mode if not been ON 15min ?
    And "can" I use TTL if the laser should not be turn OFF directly ?


    hmm..
    thanx

  2. #2
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    Default

    Hey Liteglow,

    It's a good question.
    I think warm up time specified on the datasheets is the time between the power on and the max output / stability. It is often specified at 10min, but in reality it is less...

    But now, can it be better to let the laser warm up before using modulation? It's not impossible, especially if you modulate slowly (you can see the beam turning off and on).

    But for my laser projector, if the ambiant temperature is too cold, I HAVE to let the green laser warm up without blanking for ~5min, if I don't do this, the power is 1/10 the nominal power and the mode is TEM01.
    So, I close the shutter, and I run a show without blanking

    (edit : lol it's my 100th post on this forum (only), a good reason to open a beer )

  3. #3
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    Congratulations on your century
    I agree that the warm up time is the time for the laser to reach optimum power.
    The diode needs to stabalise and the tec does too.

    Jim

  4. #4
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    Riverside, CA
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    Default

    From what I've gathered in general, if a dpss for whatever reason is not stable, you may see the following effects until it stabilizes:

    1) divergence may be poor, meaning your "dot" will be larger than when it stabilizes.
    2) the laser may not operate in TEM00, meaning you see extra dots horizontally or vertically, or circles around your central dot.
    3) the brightness may be off from what you expect.

    TTL on/off mode should work regardless. If you have any of the issues listed above, you will see them while the laser is TTL on, until it stabilizes. Running TTL during the stabilization period should not damage your laser. If it does, it's really poorly built, and I'd return it, but that's just my opinion.
    Last edited by ajohnson30; 03-07-2007 at 00:37.

  5. #5
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    Question

    How do you warm up your lasers? When I turn mine on, by a power strip all at one time, they all stay off until the DAC is told to turn them on. If I unplug the DAC from the computer they'll comeon sometimes but not always. I can unplug the blanking line for my blue and green and they will come on, but the maxymod needs the voltage there or it will not come on. I do notice when I first run a frame the red always looks brighter for the first 5 or so minutes. I figure it doesn't need any warm up time. kcar's magic touch or something.

    I could always just run a white dot for ten minutes, but is that really needed? For my laser's health?
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

  6. #6
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    like sayd last.. is it needed ?

    I think I feel better if I let the laser get "warm" before I start to use them hardcore on full speed blanking..
    I guess it`s my feeling from drive cars..
    I ALWAYS drive the first 10-15 min of my car very slowly..
    But after the engine is HOT it`s full throttle on my VTEC


    But.. the other problem if I leave the blue ON constant for 5min it get more stabile.. but constant ON for 10 min and it will turn off becouse of to much heat :P (have happend somethimes, but it get on after 5sec)


    well thanx for ansvers...

    I did recive my 1Watt from Viasho today !!!
    PEAK power measured 1470mW !!!!!!
    I`m very pleased with the help from Viasho...
    Think I will write a new post about it.. but i`m very busy this days..

    I did measure the laser with my power meeter, but at 999mW it start make alarm about to high power nice..


    THANX to Viasho for GREAT support and that they did replace my diode
    Cheers... thank you Nono

  7. #7
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    How did you read 1470?

    Jim

  8. #8
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    Quote Originally Posted by liteglow View Post
    I guess it`s my feeling from drive cars..
    I ALWAYS drive the first 10-15 min of my car very slowly..
    But after the engine is HOT it`s full throttle on my VTEC
    Lol, exactly like me VTEC forever but only after warm up (I have the civic Type-R 200cv)

    But for sure it's less important for a laser, there isn't mechanical contraints as much as in a motor

  9. #9

    Wink my arguments

    Hello , thanks very much for filip's goodness. It's my pleasure to say something about the filip's question. I hope filip use the laser after warming up the laser , just for the application and effect of output power. When open laser fresh, some lasers(not all the lasers) beam mode is TEM01, not TEM00, but after warming up , the beam turn into TEM00 Mode, and the power will be stable.

    About turning off laser after turning down the current (power), I think it is good step , though the current isnot as high as high power electrical appliance,if turn off the laser directly just as pull out the electrical wire.Sometimes it willnot work abnormity , because in the power driver all have the equipment design to protect it from damage of break suddenly.So I trully hope if time is enough , why not add the easy step?

    Thanks very much for filip's understanding !I hope to make friends with all of you , not the business relationship.

  10. #10
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    Lightbulb

    I'd like to bring this one up again... just to answer my question about how to warm your lasers up.

    At SELEM I found out a good way to measure you laser output in Pangolin is to use the abstract generator using only the white loop that is used when the generator is first opened. If you decrease the size to zero you are actually getting a white dot with no blanking, i.e. all your lasers at full power.

    When I turn my projector on, I do this for 5 or 10 minutes so all 3 lasers are warmed up at full power... Then I light a match with them just to make sure...

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