Empirical Determination of the Manufacturing Processes Which Affect EFP Liner Performance

Abstract

Abstract This paper addresses a recent test series in which an L-8 Taguchi array was used to investigate the effect of various manufacturing factors on the formation of a high-performance aerostable flared explosively formed penetrator (EFP) and its subsequent effect on target. The purpose of the experiment was to develop a method of manufacturing liner blanks that would reduce variances in EFP performance. The factors investigated were: 1. Initial anneal of the material 2. Amount of work in the material prior to the initial anneal 3. Amount of material removed from the diameter of the material prior to forging 4. Forging temperature 5. Forging rate 6. Liner annealing temperature 7. Material lot number The analysis was done using 14 quality characteristics. These were: 1. EFP rod length 2. EFP necking ratio 3. Orthogonality of the flare to the rod 4. Circularity of the EFP flare 5. Sweep angle of the flare with respect to the rod 6. Flight angle 7. Entry hole diameter 8. Throat hole diameter 9. Exit hole diameter 10. Spall diameter 11. Spall volume 12. Impact accuracy 13. Overall shape (beauty) of the EFP 14. Variability between duplicates The analysis was done as a blind experiment in that the persons who were ranking the individual trials were not told what the factor levels were for the individual trial. The results of the rankings were combined and a process was chosen. This process was then used to form the verification units that confirmed the experimental results.