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Re: [Homebrew_PCBs] Re: Heating Idea for Toner Transfer Method

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  • Stefan Trethan
    ... Hi In some dark corner i should have a iron press, maybe i try that.. to the press ideas: PCBs are not compeltely flat ask the milling guys. If you have a
    Message 1 of 40 , Jan 1, 2004
      On Thu, 01 Jan 2004 03:33:46 -0000, mikezcnc <marabu@...> wrote:

      > Stefan,
      >
      > Thank you for such an extensive description of your process. You nailed
      > my problems: lousy printer, one iron only and the rest. I clean my board
      > with acetone (to remove leftovers and I have always plenty of those,
      > don't ask why...), then water with dishwasher soap, tehn sandpaper 600,
      > then brillo pad with detergent. Then all is well flushed with water.
      >
      > Your process is interesting, but it takes s much time toand full
      > attention. I am for the idea of Ron Peopeil: set it and forget it. Which
      > brings me to another idea: chicken grill, just kidding. I agree with your
      > supposition that higher temperature is more forgiving than lower and that
      > two high pressure is not good for narrow traces.
      >
      > I ahve one of those $2 grills for hamburgers but their footpriny is just
      > too small.
      >
      > The problem with iron is that I suspect that temperature is not evenly
      > distributeed and therefore it must be set higher to compensate for the
      > uneveness. However, that higher (than neccessary temperature -
      > someone mentioned 130 being needed for fusing..) causes problems in areas
      > with widened lines due to pressure. In other words the correct pressure
      > and slightly higher temperature in one area becomes correct pressure and
      > incorrect temperature in another, due to a temperature gradient within a
      > PCB. My next trial will be a Singer iron press that I picked up from a
      > garage sale 2 summers ago for this convenient moment of being able to
      > laminate PCBs... Right now I am baking that PCB in an oven after I
      > finished pizza and New Year's ham... Mike
      >
      >

      Hi

      In some dark corner i should have a iron press, maybe i try that..

      to the press ideas:

      PCBs are not compeltely flat ask the milling guys.
      If you have a flat plate (heated and press it against the pcb
      i doubt you get a even distribution of the pressure.


      you would need a flexible plate with flexible backing, which again leaves
      you
      with much harder pressed edges.


      I can only speak from experience, my iron seems to be flat, but if i only
      press it on flat (without moving around with the curved edge)
      there are always areas that don't adhere.


      I will measure for you the distribution of the heat in an iron.
      But i strongly suspect that there is no more than 2° difference.
      (in a solid aluminium iron, not stainless steel sheetmetal coated bottom)


      I don't really experience your problems, i get fairly good results
      in a wide pressure range (and i suspect also in a wide temp. range)

      Stefan
    • Alan King
      ... Yes induction works fine in copper. Copper plates work quite well for magnetic braking etc. Take a medium sized NIB magnet that s a close fit, and drop
      Message 40 of 40 , Jan 30, 2004
        Stefan Trethan wrote:
        > But how does it work then? with the stainless pots?
        > I took a really strong magnet minutes ago and there was no force at all
        > with the stainless
        > pots. the bottom is very thick on some, but still no force at all.


        Yes induction works fine in copper. Copper plates work quite well for
        magnetic braking etc. Take a medium sized NIB magnet that's a close fit, and
        drop it down a thick walled copper or aluminum pipe and note how slowly it
        falls. Something like iron that takes a weak field will probably be more
        efficient at heating up but that won't stop copper from working as well just not
        as fast.

        I think the thinness of the copper will be the real problem, much of the
        field may not be going through the copper. Really depends on frequency and a
        few other factors, go high and it should become RF type heating if you can pump
        it out.

        I don't really see any advantage over a normal iron or other heater with it
        though.

        I have been looking at a flat pan or griddle type system. A low (for cooking
        anyway) even heat, hold the paper and board above it to preheat the board, then
        lower and press firmly into the surface to make the transfer. Should be notably
        superior to either an iron or roll laminator. But I've got about ten other
        projects ahead of it, and an iron works fine for the boards I make so this one
        is low priority for me.

        Alan
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