On Wed, 07 Apr 2010 12:18:45 -0000, you wrote:
>I have used that method and it does work good - Just seems to be more hassle than doing a single double sided copper board. For critical alignments it could work better. I'm not sure it's really all that much more hassle - just a "mind frame" I got in.
I've done both. I find it easier to align two made boards than to
align two pieces of pulsar paper and expect them to keep alignment
during the runs through the laminator. I'll agree that the epoxy step
is a pain, but it isn't all that much of a problem.
I use the push pins to align the boards (untrimmed), then tape the
boards together on the outsides, preserving the alignment. Removing
the push pins and sandwiching the board between two pieces of marble
makes for a flat board. (cheap home store marble, remarkably flat).
The advantage is that if one layer does not etch well, you throw it
out and then make the single layer.
>
>I'll try it again. I do have some thin board material - it's double sided, but once it's etched it will be single sided then :)
>
You could use that for a ground layer, if you want, but that's just as
much hassle as a full layer, but not quite so critical in alignment
perhaps.
>I have though about trying a 3-layer board - maybe putting the ground plane (or power?) layer in the center.
Ground is typically better. The only ways I know would be to
1) more or less solid ground plane, donuts around pads to keep any
possible jumpers from shorting. Ground connections made from one
layer to ground plane only, or from one layer to ground/vcc only (if
you're doing a double sided inner layer).
Connections are made by large holes in upper layers and wire jumpers.
Not all that elegant, I think.
2) use eyelets. However, eyelets have to be done as follows:
a) probably a two layer board for the center plane, or one. Eyelet
needs correspondingly larger hole on the non-connected plane, so for a
top plane connected to ground, you have 1) pad on top, 2) no copper
area on facing layer to top plane, 3) ground plane on back of inner
layer, and 4) bottom layer.
This way, all ground connections go from top to ground plane, bottom
layer cannot connect to ground plane directly (unless using method #1
above), VCC connections can go from back of plane to second layer
only. That allows you to use eyelets to connect two layers. If your
eyelets are not long enough, you can't use them to connect the bottom
and top layers directly.
Haven't tried either method, though.
Harvey
>
>Ken H>
>
>--- In Homebrew_PCBs@yahoogroups.com, Harvey White <madyn@...> wrote:
>>
>> On Wed, 07 Apr 2010 02:20:19 -0000, you wrote:
>>
>> I have a supply of .023 board available, single sided.
>>
>> To make use of that, I put each side on a piece of board. I have four
>> or five alignment holes on each side. Each board will be drilled
>> through the alignment holes using a drill that matches a map push pin.
>> The stiffer the pin and fatter, the better. Small pins wobble,
>> allowing misalignment.
>>
>> Etch the boards as usual, do not combine the boards yet. Drill the
>> alignment holes after etching and plating.
>>
>> Combine the boards, top and bottom to check alignment. You may drill
>> a hole or two in a non critical location if you wish.
>>
>> I epoxy the boards together with slow epoxy. It gives me enough
>> working time and the ultimate setup and hold time are no different (24
>> hours).
>>
>> Shear boards to size, drill.
>>
>> Good enough alignment to use 0.023 drills for vias, with about .043
>> pads for good solder joints (stitched for high density boards), or use
>> eyelets as needed for lower density boards.
>>
>>
>> Works well for me.
>>
>> Harvey
>>
>>
>>
>>
>> >That sounds like a very good procedure - I just might try it. I usually drill a .021 hole in the corner mounting holes, with a tiny hole thru the same mounting hole in the paper, press a pin thru the paper and board holes to hold paper in alignment, start in laminator and as board gets started good, remove pins so the board can go on thru. "Most" of the time this works pretty good.
>> >
>> >Using as large a pad as possible, and not having a hole in the center of copper pad allows drilling all from one side. "IF" the other side isn't perfect, it is usually close enough to be in the pad on other side. Not perfect, but works.
>> >
>> >I think I'll try your method on next board.
>> >
>> >Ken H>
>> >
>> >
>> >--- In Homebrew_PCBs@yahoogroups.com, Alessio Sangalli <alesan@> wrote:
>> >>
>> >> Hi, what is your "technique" to properlu align double-face boards? I am
>> >> using toner transfer and a laminator. So far thge best method I've found is:
>> >>
>> >> 1) print out the two faces on special paper. Make some holes in
>> >> reference points, I use the mounting holes.
>> >> 2) put only one "face" in the laminator with the board and pass it a
>> >> couple of times until it is fully "attached".
>> >> 3) wait for it to cool down
>> >> 4) drill holes in the PCB using the holes in the paper as reference
>> >> 5) align the second face on the back and put it in the laminator, and
>> >> pass it several times
>> >>
>> >> 6) proceed with removal and etching etc
>> >>
>> >> Do you have any advice?
>> >> bye
>> >> as
>> >>
>> >
>> >
>> >
>> >
>> >------------------------------------
>> >
>> >Be sure to visit the group home and check for new Links, Files, and Photos:
>> >http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>> >
>> >
>> >
>>
>
>
>
>
>------------------------------------
>
>Be sure to visit the group home and check for new Links, Files, and Photos:
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