VARIABLES AFFECTING THE OUTPUT OFLOW BRISANCE PERCUSSION PRIMERS

摘要

Dry-loaded, low brisance percussion primers used in man-rated aircrew escapesystem components have historically shown a tendency towards high variability inoutput. Such primers are somewhat pyrotechnic in performance and achieve theirlow brisance by minimizing the primary explosives in their chemical formulations. Thespecific primer addressed in this study (designated as the PVU-12/A) contains only28% primary explosives. In contrast, primers used in ammunition typically contain40-60% primary explosives.The output of low brisance primers can vary from a relatively quiet, but rapid, burn, toa relatively violent, loud, and energetic deflagration. Because current qualityacceptance procedures for percussion primer sensitivity and reliability testing arebased on traditional "output sound" (the goo-go criteria), there can be occasionaldifficulty during testing in determining whether a lower output primer actuallyfunctioned or not. Because of the criticality of their intended application and theirlower audible output, standard small arms testing procedures may not be fullyappropriate for these specialty output primers.In order better to understand the performance of such primers, to improve theirconsistency, and to evaluate alternate testing techniques, a Design of Experiments(DOE) study was performed based on a six variable, sixteen run, Taguchi matrix.This approach allowed determining the effect on primer output of various processingand formulation changes while keeping the number of test samples at a reasonablelevel. Factors investigated included the age of the primary explosives, mixprocessing variations, primary explosive level, binder level, and changes in theloading processes and tooling design.Also addressed in the study was an evaluation of potentially better methods fordetermining primer output. The current qualitative method, which relies solely on thejudgement and hearing of the test operator, has long been recognized as being toosubjective and does not use the best available technology to determine theacceptability of such critical man-rated components.