Homebrew PCBs

It is easy to edit gerber files with target layout software, so if you
like a particular pattern i can get it out for you. You could use the
free test version, but since it is size limited that might be a
problem with the large gerber file.

ST

On Tue, Mar 25, 2008 at 5:33 AM, Mike Schoenborn <rtfm@...> wrote:
> At 12:47 PM 3/24/2008 -0400, you wrote:
>
> >... and would like to be able to measure trace widths, etc
> >wthout reinventing the wheel.
>
> Has anyone looked into "IPC-9251"?
>
> http://dcchapters.ipc.org/html/downloads.htm
>
> ---------------------------------------------------------------
> [from the web page...]
>
> IPC-9251
> Test Vehicles for Evaluating Fine Line Capability
>
> Conductor Analysis Technologies, Inc. and E. I. DuPont Company
> developed test patterns for evaluating fine line capabilities, and
> IPC has been provided permission to distribute the data to the
> industry. The effort has been coordinated by the Etch and Strip
> Subcommittee (4-15) of the Fabrication Processes Committee (4-10)
> of IPC and is now being made available to industry for free. You will
> be asked to complete a short information form before downloading.
>
> Download IPC-9251 (.zipped file)
> [ http://dcchapters.ipc.org/html/9251form.htm ]
>
> ---------------------------------------------------------------
> [from the pdf included in the downloaded zip...]
>
> The files are named IPC221.ZIP and IPC441.ZIP. Both designs are 18- by
> 24-inch with 352 one-inch-square modules arranged in 16 rows and 22
> columns. IPC221.ZIP has multi-pitch modules with 2-, 3-, 4-, and 5-mil
> lines separated by 2-, 3-, and 4-mil spaces, respectively; IPC441.ZIP
> has multi-pitch modules with 4-, 5-, 6-, and 7-mil lines separated by
> 4-, 5-, and 6-mil spaces, respectively. Each design contains an aperture
> list and a "README" file that describes the pattern, and provides
> recommended processing procedures.
>
> The IPC441 design is useful to evaluate process uniformity, while the
> IPC221 design is intended for evaluating narrow lines and spaces. Both
> patterns may be inspected optically or tested electrically. Precision
> electrical resistance measurements from the patterns can provide
> conductor and space defect density, and conductor width and height
> uniformity.
>
> ---------------------------------------------------------------
>
> The idea is to  run off a batch of  these boards then send them (along
> with some number of $US) to a testing service who will evaluate them and
> return a report of their quality.  If you're making boards for sale to
> NASA/ESA/CSA/JSA, such a report might come in handy.
>
> bad: they're Gerber files
> good: "... tested electrically" (check out the patterns)
> bad: "...18- by 24-inch"
> good: "...one-inch-square modules"
>
> I believe one of the 1" module patterns would be worthwhile for
> evaluating the work done here; the idea of using precise resistance
> measurements to qualify a board is intriguing.
>
> I wanted to extract one of the modules from the huge design, but by the
> time I found a workable Gerber viewer and sorted out aperature issues, I
> had lost my ambition to hand-edit/awk the files.   Recreating the
> patterns programmatically is left as an exercise for javag^H^H^H^H^H the
> student.
>
> I thought I first heard about IPC-9251 in one of the Riston spec sheets,
> but can't find the reference right now.  If I can find the time I'll
> contact CAT/IPC/DuPont to see how they would feel about allowing a copy
> of their files here for our reference.
>
> Mike
>
>
>
>
> ------------------------------------
>
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