Hi Ed,

I'm confused.  Is the supplier saying they can't build stuff with 4 mil
lines and spaces with a 20% tolerance or that it's a bad design rule in this
instance?

As with every board, line width & spacing depends on what is specified in
the customer's Master Design Package, part of the Procurement Documents.
Customer specifications always supercede any IPC document.  If the design
package says build it 'this way' then the fab can build it 'that way'.  I
thought minimum dimensions on lines & spacing depended on the current and
frequencies you're running (to avoid crosstalk).

Hans


~~~~~~~~
Hans M. Hinners
Materials (& Process!) Engineer
Warner Robins - Air Logistics Center/Avionics Production Division
Manufacturing Branch (LYPME)
380 Second Street, Suite 104    (Building 640)
Robins AFB, GA  31098-1638
912-926-1970 (Voice) 468 - 1970 (DSN)  912-926-7164 (Fax)
mailto:[log in to unmask]


> -----Original Message-----
> From: Brunker Ed [SMTP:[log in to unmask]]
> Sent: Wednesday, March 01, 2000 08:18
> To:   [log in to unmask]
> Subject:      [TN] IPC- 6012 CONDUCTOR WIDTH/ANNULAR RING
>
> With regard to conductor width 6012 states that the tolerance is 20%.
> Suppliers have responded that at 4 thou (mil) track and gap that this
> isn't
> a viable tolerance. Does IPC-6012 run out of steam at certain tracking
> densities?
> Minimum annular ring class three is 0.050mm (outer). Does this apply to
> blind via/multiple laminataion technology? Is there anyway to go beyond
> the
> "Tangent is acceptable" statements? If tangent is acceptable on sample,
> then
> there are bound to be breakouts on boards not checked.
> Regards
> Edward Brunker

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