Questions about plastic Molding

Discussion in 'The Projects Forum' started by Sonoma_Dog, Jun 3, 2009.

  1. Sonoma_Dog

    Thread Starter Active Member

    Jul 24, 2008
    I know that it has nothing to do with electronic circuits, but I am sure someone in this forum have ton of experience in making plastic. I am currently designing a programmable light signs. I have all the electronic circuit and concepts of what the final product going to look like. But I don’t have much knowledge in mechanical, just downloaded AutoCAD and playing with it for a bit last night.
    I guess my question is…
    Where and what company can turn my autocad design file into a actual molding?
    Where can I get the plastic manufacture once I got the mold?
    How much do they cost, for both molding and manufacturing. (the design will not be too big or complex, probably 7”x4” )

    Oh and one last question about electronic…..
    Is it not safe to operate light sign at 48v DC in a long run?
    Because I have seen most of the sign out in the market is running off 12v DC.
    And what are the benefits of running LEDs off a 12V DC? it will actually dissipate more power in the resistors, right?

    Thanks in advance
  2. Bernard


    Aug 7, 2008
    Is it cast, formed,or machined? Can you describe the sign a little more? Length of run,"long" not to informative; For 100 ft, go with 48V if there are around 12 LED's in series, better check the circuit and see what V is appropriate & use it, adjust wire size to load & loss.
  3. KL7AJ

    AAC Fanatic!

    Nov 4, 2008

    Are we ever living in a wonderful age! Plastic prototyping outfits like this:

    are abundant...and very reasonably priced.

    Best wishes. Let's know how your masterpiece turns out!

  4. Sonoma_Dog

    Thread Starter Active Member

    Jul 24, 2008
  5. Duane P Wetick

    Senior Member

    Apr 23, 2009
    Most signs that use LED's are multiplexed, that is, turned on and off rapidly by pulsing a voltage to them. Since they respond rapidly, with little or no turn-on or off time, an array of them can be used to form a message or a picture or anything under the sun, actually. The voltage source can be anything as long as each LED receives the necessary V & I to get LIT at its interval in time. There are 2 levels normally used, daytime and night. Less power is needed at night. Modern cars have LED arrays for rear tail lights and some high end cars actually make the LED's glow brighter in response to the braking pedal pressure.

    Cheers and I wish you success! DPW