After reading "Sandia installation uncovers fiber issues" (see Industry Spotlight, June 1996, page 71), we would like to clarify a misinterpretation pertaining to hand-polishing and flat-tipped connectors. The statement on page 72, "properly executed hand-polishing was found to produce exceptional and consistent results, although only for flat-tipped connectors," is not correct. In our report pertaining to Sandia`s installation, which included only domed zirconia-ceramic ferrules in ST-type connectors, we state that "both hand-polishing and machine-polishing are capable of producing consistent high-quality connectors in the field."
During the recabling process at Sandia, a small quantity of flat-tipped connectors were unintentionally installed. They did not meet our acceptance criteria. Rather than cutting off the connectors, we attempted to reshape the ferrules into dome-tipped ferrules, using both hand and machine processes. The polishing machines produced the most consistent doming results. The reshaped dome-tipped connectors were then polished by hand and machine, and all yielded superior performance characteristics.
We do not recommend attempting field-doming for small quantities as we did at Sandia. The investment in engineering, installing and retesting time and materials to reshape flat-tipped ferrules will never be justified, as it is a once- in-a-lifetime challenge.
One final correction: Jon`s last name is Eberhart (not Eberhard).
Roger Adams, RCDD LAN Specialist
Sandia National Laboratories