Hi Kathy,

Did a little surfing to see if I could find some images similar to yours. Didn't find any, but did find some interesting sites that >may< be relevent.

First one is a link about glass compression. This happens when the laminate is compressed with fast heat-up rates. Said to possibly be a cause for drilling problems including delamination. Go to:

http://www.arlonmed.com/applications/compres.htm

Next is a link from a manufacturer of entry and back up materials. They make a backup material called "SlickBack" (pretty catchy name huh?). There's some good SEM images there of hole wall quality using their material vs standard materials...

http://www.lcoa.com/pages/slickback_mg.htm

The last link has standard guidelines for feed and speed rates used for different laminates, hole sizes, stack heights, how many hits a tungsten carbide bit should take before replacing, etc. Good reference page.

http://www.holders.co.uk/kennametal_overview.htm

As "murphy" always has it, you don't find out about these problems until AFTER you build the assemblies huh? Same logic always goes for misloaded components, it's NEVER the 1-per, it's always the 50-per...such is our life (GRIN)

-Steve Gregory-


I have a few assemblies that a customer had asked me to look at and I noticed an oddity around the vias.  It looks like there is delamination around the vias.  Steve was kind enough to post these photo's on his web page for all to view.  I need to know if this is delamination or just haloing. I saw an issue like this a long time ago (15 years ago) and at that time we scrapped them because we didn't know what the issue was caused by.  Some at that time thought the drill bit for that size was either pushed to fast through the material causing a slight delanmination or the drill bit was dull. 

I appreciate any assistance or thoughts on the issue.  I have already suggested that a cross section may have to be completed.

http://www.stevezeva.homestead.com

Thanks in advance.

Kathy