Peter, a "supported hole" is one that is "plated through" with a metallic
material, usually copper followed by tin/lead or such. An unsupported hole
is one that contains no plating or other metallic material.
Usually supported holes (plated-through-holes [PTH]) have connecting
circuitry on both sides of the board, where as, unsupported holes may have
one connecting circuit or even none.
I hope that clarifies it for you.
IPC-A-610C figures 6-4 and 6-27 show examples of plated through (supported)
holes.
Figures 5-11 and 5-13 show examples of non-plated though (unsupported)
holes.

Ron Dieselberg
Trainer/Auditor
CMC ELECTRONICS
CINCINNATI
[log in to unmask]

                -----Original Message-----
                From:   Peter Lee [mailto:[log in to unmask]]
                Sent:   Tuesday, June 25, 2002 15:22 PM
                To:     [log in to unmask]
                Subject:        [TN] Definition of Suported/ unsupported
hole

                Technet,

                Can anyone explain the difference between a supported
                and unsupported hole on PCB?

                I am reading a section on IPC-A-600 RevF and section
                2.10.3/4 specify difference acceptance criteria
                according to the hole type.

                Rgds,
                Peter


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