I agree that this condition does not pass any 
IPC class, or any other specification that I 
am aware of.  Work with your supplier to 
resolve the issue.

It doesn't appear that the designed annular 
ring is very large.  What is the diameter of 
the via pad and also that of the finished 
hole (or drilled hole)?  

Annular ring = (pad dia. - drill dia.) / 2

The annular ring should be about .006" to .008" to
be manufacturable by most fabricators.  (.012" to
.016" difference in diameters)  If the annular ring
gets below .004" your supplier base will be limited as
will the cost of the board due to yield.

[log in to unmask]


"Dill, Norm J" <[log in to unmask]> Wrote:
| 
| 
| Eugenio,
|       I totally agree.  Your picture shows a basic 
| registration error.  If 
| you haven't already, work directly with your 
| supplier on this.  Regardless 
| of the source of the error, they should have 
| caught it and let you know.  If 
| the error is all theirs, they should be more than 
| willing to replace the 
| boards as well as provide you with written 
| corrective action detailing the 
| root cause of the error and the process changes 
| put in place to eliminate it 
| in the future.  If this is a problem for them, I 
| would look for another 
| supplier ASAP.
|       Depending on the root cause and the layouts 
| of your designs, internal 
| spacing requirements may be violated as well 
| because of the shift in the 
| hole locations.
| 
|      Norm Dill
| 
|  ----------
| From: TechNet-request
| To: ebini
| Cc: TechNet
| Subject: Re: Hole breakout - request for 
| opinions/assistance
| Date: Wednesday, May 08, 1996 8:17AM
| 
| I would not use those boards.  We specify 
| IPC-A-600 (rev E) - Class 2.  I
| just browsed the section, it looks like the bitmap 
| you sent fails all three
| classes.  If your vendor can't solve the problem, 
| I would start looking for
| a new vendor.  We use three different vendors, I 
| know that all three would
| be extremely embarrassed - and would take the 
| boards back no questions 
| asked.
| 
| At 12:44 5/8/96, [log in to unmask] wrote:
| >
| >     We are an Australian manufacturer of 
| electronic Telecommunications and 
| 
| >     Automated Fare Collection equipment. We use 
| PCBs manufactured both
| >     within Australia and overseas, specifying in 
| all cases manufacture to
| >     IPC-RB-276 standard.
| >
| >     We have recently discovered among our 
| incoming goods widespread
| >     incidence of annular ring breakout on the 
| via holes of numerous
| >     multi-layer boards. It appears to be the 
| result of incorrect
| >     registration during manufacture. The 
| attached file contains an image
| >     (in Windows Paintbrush Bitmap format) of a 
| typical example on a
| >     finished product.
| >
| >     We are not overly concerned about the 90deg. 
| and 180deg. hole breakout 
| 
| >     cases, but greatly worried by the 
| conductor/annular ring junction
| >     cases. The functional tests of our finished 
| products using these
| >     boards show no malfunctions, but we are very 
| suspicious about the
| >     long-term reliability aspects. This is 
| particularly so with those
| >     finished boards whose design service 
| environment is 60degC (140degF)
| >     and >80% humidity.
| >
| >     We would be very grateful for opinions 
| and/or assistance from people
| >     with past experience of such a problem and 
| first-hand knowledge of the 
| 
| >     long-term reliability implications.
| >
| >
| >     Thanks in advance for your help.
| >
| >     Eugenio Bini
| >     Mechanical Components Engineer
| >
| >     ERG Telecommunications Ltd.
| >     247 Balcatta Rd.
| >     Balcatta WA 6021
| >     Australia
| >     Tel.: +61-9-2731174
| >     Fax.: +61-9-2731173
| >     Email: [log in to unmask]
| >
| >The following is an attached File item from 
| cc:Mail.  It contains
| >eight bit information which had to be encoded to 
| insure successful trans-
| >mission through various mail systems.  To decode 
| the file use the UUDECODE
| >program.
| >--------------------------------- Cut Here 
|  ---------------------------------
| >
| >Attachment Converted: C:\EUDORA\ATTACH\pcb1.bmp
| >
| >
| >
| 
|  -Pat-
| 
|  -------------
| Patrick McGuine
| Nicolet Instrument
| [log in to unmask]
| (608) 276-6334
|