Richard, Could it be the change of seasons? I believe humidity and temperature have an affect on several processes from the weaving operation, to impregnation at the laminator, to stack-up, and press. But, I don't have any hard data to prove it. Maybe the gremlin is Mother Nature in disguise. Glenn Pelkey Quality/Reliability Engineer Richard MacCutcheon <[log in to unmask]> Wrote: | | We seem to have developed a gremlin in our registration | dept. | A very large portion of scrap is attributed to NO Annular | Ring (<.002"). | | Over 90% of our product is 8-layer GIL with 2 and 7 as | ground planes. | Cores are .005 constructed of 1-106 and 1-2313. Prepreg | is 2313. | | Layer to layer misregistration is around .005" on average. | Artwork pad | sizes are .022" over the max acceptable hole size. | Tooling seems to be as | tight as ever but in the last few weeks we have had an | inordinate amount of | scrap due to NO Annular Ring. | | What is the best systematic approach to take in | identifying the problem(s)? | | Thanks for your time. | | Richard MacCutcheon |