I'm re-sending this posting since I've not received any replies! I sent this originally just before last weekend and perhaps since it was down the list many of you missed it! I sure would appreciate your comments. I know there is a lot of experience out there and I can't believe no one has any suggestions. Any and all comments would be appreciated.
Thank You,
Craig

We have recently been experiencing some issues Drilling the above material. We currently run chiploads in the 1.0 to 1.7 range drilling 1-2 high on Excellon Mark 6 ( air bearing) equipment. Retract Rate is between 500-800.
Drill/Spindle/Collet maintenance is current and run-out well within limits. Drill bits are all new and supplied by HAM. We have experience with Kemmer, International Carbide and a few others without seeing significant differences. We have performed numerous feed and speed studies ( including every conceivable combination of back-up and entry from various manufacturers) which have led to the above chiploads and retract rate. What we are seeing in our Cross-section Analysis are Glass Bundles and apart and separate from these Teflon fibers extending 2+ Mils into the hole. With subsequent Plating we experience nodule formation and reduction in hole size leading to Non-conformance to the Customers requirements. The  typical hole size range and tolerance were dealing with is 0.043-0.055 inches plus .003/ minus.001 inches. We are using an Advanced Plasma unit for Hole conditioning and have even gone to an Ammonium Bifluoride Glass Etch process to at least try to remove the Glass. We use Direct Metallization instead of Electroless.

Has anyone else being seeing these issues? And/Or do you have any recommendations? 
We also believe that there may be Lot to Lot or within lot variation. Our feedback from the Supplier was recommendations for Chiploads in the neighborhood of 5.0. This yielded raised burrs on the entry side of the material at all retract rates. 
Any feedback would be appreciated!
By the way we drill many other forms of Teflon here and have seen excellent results with the above Drilling Parameters and other mentioned processes.
Thanks,
Craig Ropp
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