gEDA-user: Commercial CAD, land pattern generators report

[John Griessen <john@xxxxxxxxxxxxxx>]

I attended a trade show/info-mercial to do with printed circuit layout
and manufacture yesterday to meet some people to ask for
contract work and heard about Mentor CAD tools and overall trends
we should pay attention to in planning additions to gEDA tools.

A speaker named Tom Hausherr described how he had developed a 10000 part
library operating a layout service bureau, then sold the library as a business
for a while, then sold that business, and started designing software for
Mentor to auto-generate libraries, and lead creation the templates to
auto-generate from.  Mentor has made a tool that will generate variants of
a library of footprints to suit IPC or IEC or EIA standards with your preferences
of Most, nominal, Least, least, or user specified different from standards
amount of solder area for pads, courtyard extra manufacturing allowance,
preferences about assembly drawing layers, etc.  The tool also relates
package 3d shape to footprint per IPC or other standards rules so you can
change existing package data to create a new one with similar but different
shape quickly -- one view is a plan and elevation of a package, the other is
footprint and fill forms that change it via preferences that are relative to the
chosen land pattern standard.   They market this to freelance
layout folks as helping them with career mobility, and to big Co's as efficient.
Their next thing planned is to not even have the tool show a plan and elevation,
but import 3d DXF, (autocad interchange format),
data to filter through preferences and generate a land pattern.

Another thing I heard about is the trend to use metric units.  Tom H. has lots of
experience with doing boards, still does some and was helping with layout
of the Red Camera circuit board where they had customers wanting it bad
right after the design was simulated to work, but not laid out, so they tried autorouting
it and no go until they chose a grid based on 0.05mm spacings.  That spacing rule
combined with the predominant parts available today let the autorouter work best
on that board routing between 1000+ BGA pins among other circuit parts with ten routing layers.
PCB already handles 0.05mm spacings fairly well -- might have some rounding artifacts, but not ones
that will stop good autorouting that I know of.  I've not tried using the autorouter
or toporouter with more than 2 layers yet... Anyone?

The trend of asking for 3D DXF files from all the manufacturers is something
to ponder when anyone gets a coding urge.  From such data, ALL that is
needed to make a land pattern is extractable, including the website link
it comes from, and possibly other BOM data, and it is becoming a defacto standard
(which is the way all electronics standards have started).

John Griessen
--
Ecosensory   Austin TX

http://en.wikipedia.org/wiki/Red_Digital_Cinema_Camera_Company


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