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Thread: Newb questions...

  1. #1
    Join Date
    Aug 2007
    Location
    Indianapolis, IN
    Posts
    196

    Default Newb questions...

    I have a few questions about scanners (et al)

    What are the mirrors on the galvos made from typically?
    How are they bonded to the axle?
    Can they be replaced if they break?
    I've noticed that I'm getting a certain amount of transmission through my galvo mirrors - is this normal?
    What is amp/galvo tuning all about?

    This one is DT40Pro specific - I noticed that there are 2 inputs +/- on the amps. Currently I'm using only 1 - am I getting only half the range on output? Or are the two inputs an "either/or" thing?

    Finally, when does the squiggly pattern in front of your eyes fade?

    Thanks,
    Steve Newb.
    Last edited by shobley; 09-07-2007 at 07:14.

  2. #2
    Join Date
    Jun 2007
    Location
    northern maine.
    Posts
    329

    Default

    Quote Originally Posted by shobley View Post
    Finally, when does the squiggly pattern in front of your eyes fade?
    i can't tell from your post how you got enough exposure to give you eye symptoms,but it is a good idea to use the lowest power possible(if the laser is analog modulated.) for when you are aligning stuff.
    if you can't adjust your input voltage to the modulation circuit,then you can just use one or two d cells applied to the modulation leads to get 1.5v or 3v respectively.

    otherwise,get goggles to protect for the wavelength you are using.
    peace,
    wes

  3. #3
    Join Date
    Aug 2007
    Location
    Indianapolis, IN
    Posts
    196

    Default

    Thanks, I do use goggles - the squiggly pattern was from watching the animations...

    Steve

  4. #4
    Join Date
    Jun 2007
    Location
    northern maine.
    Posts
    329

    Default

    ah,very glad to hear that.
    i used to get that from video games before i gave them up.
    peace.

  5. #5
    Join Date
    Jan 2006
    Location
    Charleston, SC
    Posts
    2,147,488,218

    Cool

    Quote Originally Posted by shobley View Post
    What are the mirrors on the galvos made from typically?
    Normally they're dielectric mirrors, though some really cheap stepper-motor scanners might still use silvered mirrors.
    How are they bonded to the axle?
    The axle is slotted to accept the mirror, and a drop of expoxy holds it in place.
    Can they be replaced if they break?
    Yes. You can usually use a soldering iron to loosen the epoxy so you can get the mirror fragment out. Then you need to install the new mirror. Balance and alignment is crucial, however.
    I've noticed that I'm getting a certain amount of transmission through my galvo mirrors - is this normal?
    Yes. Up to 5% loss per mirror is normal, though most galvos have mirrors that only loose 1 or 2 percent.
    What is amp/galvo tuning all about?
    Adjusting the scanner amp to get maximum performance out of the galvos. It's as much an art as a science, but it makes a noticable difference. Tuning is specific to a galvo-amp pair.
    This one is DT40Pro specific - I noticed that there are 2 inputs +/- on the amps. Currently I'm using only 1 - am I getting only half the range on output? Or are the two inputs an "either/or" thing?
    You're using single ended input rather than differential input. (Differential would be using the + and the - input, with the center pins grounded.) As for the size, it depends on how the scanners were tuned at the factory. Your displayed image may only be half size, but you'd need to measure it to be sure.
    Finally, when does the squiggly pattern in front of your eyes fade?
    Normally as soon as you turn the laser off. If not, see your opthamologist pronto!

    Adam

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