Then you exceed the guidelines in the IPC standard. It is probably an optical anomaly.

From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Wednesday, March 08, 2017 10:49 AM
To: [log in to unmask]; Stadem, Richard D.
Cc: [log in to unmask]
Subject: RE: PWB Laminate Swelling

Dell - Internal Use - Confidential
  I use 6, 3 and 1 micron Microcrystalline Diamond Suspension slurry and then 0.05 micron polishing suspension.

Victor,

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Wednesday, March 8, 2017 10:40 AM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: [TN] PWB Laminate Swelling

It DOES smear and appear to be expanded at the cut level, but if properly bonded beforehand the subsequent sanding operations with very fine medium should get you past that artifact.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask]<mailto:[log in to unmask]>
Sent: Wednesday, March 08, 2017 10:22 AM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: [TN] PWB Laminate Swelling

Fellow TechNetters:

   Does PWB laminae swell during the cross sectioning process on an encapsulated mount?   During a 100x Optical inspection of the glass weave cloth I get a blur image.   I get a sharp image of the glass cloth in the SEM.   I can even count the individual rods and measure their diameters.

Victor,