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Thread: Pin registration system preferences

  1. #11

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    Re: Pin registration system preferences

    Quote Originally Posted by interneg View Post
    It's an abrasive jet, the spray is not good for coated optical surfaces.
    The glass surface is protected with any adhesive plastic layer, no problem. The CNC is very precise, and holes and dimensions are well in place, single thing is that the cut is not exactly perpendicular to the surface because of effects in the jet, some advanced machines inclinate a bit the jet to perfectly compensate that angle while the head is moving in any direction.

    Waterjets have an operation cost of (perhaps) around $200 per hour, but that job would be cut in less than one minute, so most of what would be invoiced is machine preparation cost and bureaucracy.

  2. #12
    Greg Davis's Avatar
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    Re: Pin registration system preferences

    I have the manual, what is your question?

  3. #13
    Drew Wiley
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    Re: Pin registration system preferences

    Waterjet would not be realistic. Micro-laser is hypothetically possible, but would be a specialty service, probably pricey for a one-off. Condit offered a thick anti-Newton glass that was soft and drillable, making That's been unavailable for about 30 yrs now. Later AN glass is quite hard and brittle; so is coated optical glass. But coated glass doesn't do it for me; I still get rings.

  4. #14

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    Re: Pin registration system preferences

    Quote Originally Posted by Drew Wiley View Post
    Waterjet would not be realistic.
    Drew, it's beyond realistic: it's real.

    How can you say "not realistic"? You can even make a butterfly: https://www.youtube.com/watch?v=1TEhYy4AcfM

    Why "not realistic"?

    _____


    Single thing is that you should use very flat glass, if not you get rings (those you mention) way easier. The glass used to make mirrors is very flat, but glass sold to make windows it may not be well flat.

  5. #15

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    Re: Pin registration system preferences

    Quote Originally Posted by Greg Davis View Post
    I have the manual, what is your question?
    Does it specify whether the bench/ wall models have a different (narrower) spacer casting between the neg stage and the column runner compared to the floor standing model?


    Quote Originally Posted by Drew Wiley View Post
    Waterjet would not be realistic. Micro-laser is hypothetically possible, but would be a specialty service, probably pricey for a one-off. Condit offered a thick anti-Newton glass that was soft and drillable, making That's been unavailable for about 30 yrs now. Later AN glass is quite hard and brittle; so is coated optical glass. But coated glass doesn't do it for me; I still get rings.
    I'll possibly ask Kienzle - they supply glass for the various Leitz Focomat II enlargers that use quite a thick piece of glass in their carriers. I'd be interested to know what the minimum quantity needed to get a suitable glass made would be - mainly because I suspect Condit made use of a suitable product already on the market rather than having the glass completely custom made.

  6. #16
    Drew Wiley
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    Re: Pin registration system preferences

    Condit used an AN Belgian glass unavailable for a long time now. Isn't made, period. But if you can work with plain glass, ordinary 1/4" thick float glass works fine. But don't use anything tempered - too tricky to drill precisely. There are plenty of sources for flat optical glass if you want to go that route. As usual, Pere is making sheer guesses.

  7. #17

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    Re: Pin registration system preferences

    Quote Originally Posted by Drew Wiley View Post
    As usual, Pere is making sheer guesses.
    Drew, LOL what sheer guesses? Please point what sheer guess.

    My dry plate coating glass platform was cut with a waterjet.

    Minimum hole diameter with a waterjet is usually 1mm, with 0.1mm precision, registration precision is not influenced by that precision, this is not a guess, but a fact. Of course tempered glass is not suitable for cutting.
    Last edited by Pere Casals; 17-Oct-2019 at 07:17.

  8. #18
    Drew Wiley
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    Re: Pin registration system preferences

    Yes, you could dimensionally size glass using waterjet. But any glass shop anywhere can do the same thing with common equipment. I can do it in my personal shop with even tempered glass. I wouldn't trust just anyone to size optical glass. But you refute your own premise when you state 0.1mm hypothetical precision - that's like a shotgun where you need a sniper rifle; in other words, not nearly precise enough. Enlarge things a bit, and even unsharp masking misalignment becomes a visual distraction, not to mention the far more demanding applications for punch and register gear like color separations. And in sequential film operations, errors become cumulative.

  9. #19

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    Re: Pin registration system preferences

    Quote Originally Posted by Drew Wiley View Post
    your own premise when you state 0.1mm hypothetical precision - that's like a shotgun where you need a sniper rifle; in other words, not nearly precise enough. Enlarge things a bit, and even unsharp masking misalignment becomes a visual distraction,
    Drew, register precision does not depend on the holes in the top glass, but on the holes in the film/mask, aren't you aware ?

    Imagine that the holes in the top AN glass are 2mm larger than the pins, no problem !!! what keeps negative-mask alignment are the holes in the film/mask and the pins.

    ____

    Now let me explain how to DIY make a Top Quality ANR glass:

    https://www.youtube.com/watch?v=XZ8FP0vJGMU

    You need this (amazon):

    Click image for larger version. 

Name:	71jfqU6cqWL._SL1200_.jpg 
Views:	10 
Size:	62.0 KB 
ID:	196629

    You protect one side of the glass with any adhesive plastic, then you dilute the "etching cream" with plain water until it works at some 1/10 of the speed shown in the video, so it would take 100min instead 10min to do the same.

    You submerge your glass in the soup until etching suits your taste. Done !!!

    You may submerge as many glasses you want until you are tired...


    Safety sheet says that it contains:

    BARIUM SULFATE 0.0 - 6.0% 7727-43-7
    SULFURIC ACID 0.0 - 9.0% 7664-93-91
    SODIUM BIFLUORIDE 7.0 - 12.0% 1333-83-1
    AMMONIUM BIFLUORIDE 21.0 - 27.0% 1341-49-7

  10. #20
    Drew Wiley
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    Re: Pin registration system preferences

    What kind of gibberish is that, Pere? All the spacing has to precisely align regardless - punch, pin glass, pins on carrier, if a registered carrier is involved. Go tell an automotive machine shop that you don't care if the cylinder holes and the pistons are precisely matched or not. But you apparently thought I was talking about a top glass. NO. I recommend and use AN glass on BOTH sides of the carrier sandwich. Pin registered bottom glass was once a standard offering by Condit; and there was a logical reason for that. But Contact frame glass itself also needs to be drilled, and is ideally thick AN glass. But since that's no longer available, one can substitute a thin sheet of mylar, frosted both sides, between the slick frame glass and the negative in the contact frame. That trick obviously won't work when enlarging. I wonder how much of these "done" snake oil projects you've ever actually undertaken. Somewhere around zero, it seems. There's more to an effective Anti-Newton surface than simple etching. If you don't do it just right, you'll get a pattern showing on the mask or interneg or whatever. But you just posted a product designed for essentially frosting glass. All glass etching is based on hydrofluoric acid. Even if that worked, you'd have to polish it up quite a bit to make it fully clear again.

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