[sdiy] DIY PCBs

[The Old Crow]

On Wed, 25 Jul 2001, Jim Patchell wrote:

>     Using CAD is almost mandatory these days to get a PCB made.  For
> two sided PCB's, the minimum is probably:
>
>     Top Layer Gerber Plot
>     Bottom Layer Gerber Plot
>     Top and Bottom Solder mask (assumes thru hole only, they will be the
> same) opt.
>     Top Legend (opt).
>
>     Axelon (sp?) drill file
>     Tool Table
>     Fab Drawing (this can be in gerber format as well)
>     Aperature List (for gerber files).
>
>     Gerber files are a common file that is used to generate the film used to
> manufacture the boards.  All PCB cad programs can generate these files.
>     Drill files are very important.  Without the drill file, the costs will
> go up astronomically.


  To add my two cents:

  When a place issues a quote, there are typically two prices: NRE and
unit cost.  The NREs (non-refundable engineering) are for photoplotting,
tool wheel setup, and the creation of the recipe program the lab will use
to produce the boards, and this cost is a one-time charge.  The unit cost
is for a given PC board, and is determined by the X-Y dimension, the
number of holes and the number of boards requested.

  A local place I use frequently charges about $195 for NREs and between
$2.00 and $10.00 per board, depending on size/holes.  Double-sided vs.
single sided and omitting the silkscreen, etc. don't make it any cheaper,
so I do most things as 2 or more layers with silkscreened legend.

  For a typical board of 4"x3" with 100 holes, 100 boards would cost me
about $600.00 for the first batch, and $400 per 100 for subsequent
batches.

  (Jim, btw it is "Exellon", named for the first manufacturer of a CNC
drill table, IIRC. ;)

Crow

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