IPC-A-600F and IPC-6012A have the same requirements for these features.
Table 3-5 of the 6012A may be less verbose But it says the same thing. For
Class 3, when the drilled through hole is plated (supported) an external ring
shall not be less than 0.002". Measured from the inside of the hole to the
outside of the remaining ring. If the drilled hole is not plated (unsupported)
then an external ring shall not be less than 0.0059". In any event some further
reduction, not more than 20% due to pits, dents, nicks and the like,
is acceptable.
The
internal rings have different requirements. They are described in Clause 3.4.2
in the 6012A and Clause 3.3.1 of the IPC-A-600F. For Class 3, one mil min.
measured as shown in Figure 3-1.
Fellow TechNetters,
The QUESTION is for
clarification on HOLE BREAKOUT;
IPC-A-660F sec. 2.10.1.2 - 2.10.4 refers to
Annular rings Supported and Unsupported.
What is the DIFFERENCE
between the two categories. Does this apply to internal annular
for hole breakout?
Is there another guideline which is
more straight forward?
Victor,