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5.56 mm Case Mouth Waterproofing Product Development For High-Speed Manufacturing

5.56 mm Case Mouth Waterproofing Product Development For High-Speed Manufacturing. Presented by: Steve Hawk, Alliant Tech Systems Greg Bubniak, U. S. Army TACOM-ARDEC. Team Members Dr. Sheila Harper Randall Busky Kerry Bricker. NDIA Joint Services Small Arms Annual Symposium

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5.56 mm Case Mouth Waterproofing Product Development For High-Speed Manufacturing

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  1. 5.56 mm Case Mouth Waterproofing Product Development For High-Speed Manufacturing Presented by: Steve Hawk, Alliant Tech Systems Greg Bubniak, U. S. Army TACOM-ARDEC Team Members Dr. Sheila Harper Randall Busky Kerry Bricker NDIA Joint Services Small Arms Annual Symposium Kansas City, Missouri May 14, 2003

  2. Not limited by geography • End-users are divese • Work focused on small caliber ammunition The Need For Waterproof Ammunition Is Critical

  3. Current Mouth Waterproofing: An Internal Application

  4. BOATTAIL BEARING SURFACE NECK LENGTH OGIVE SEATED BEARING SURFACE MAX LENGTH OF MOUTH WATERPROOFING BULLET SEATING DEPTH % SEATED BEAING SURFACE TO NECK LENGTH CAL .50 M33, M17 M8, M20 56% 7.62 mm M80 64% 7.62 mm M62 163% 5.56 mm M193 73% 5.56 mm M855 171% 5.56 mm M856 322% Illustration of Mouth Waterproofing Challenge

  5. Cartridge Comparison/Waterproofing 50-Cal, 7.62 mm, and 5.56mm 12.00 5.56mm M856 10.00 8.00 y = 0.0002x + 0.0122 Percent Defective 6.00 2 R = 0.724 5.56mm 7.62mm M193 M62 4.00 .50 Cal 5.56mm M855 2.00 7.62mm M80 0.00 0 50 100 150 200 250 300 350 Bullet Seating Depth Ratio

  6. Problem Statement: Challenge is 1200 ppm Application Speed of SCAMP

  7. Equipment Procedures Bullet MATERIAL DESIGN Mouth Waterproofing Material Preparation Training Case Gages Tools PROCESSES Short Term Fault Tree Analysis of Design, Materials and Processes

  8. Bullet Case • Proposed Bullet Improvements: • Double Cannelure • Step on Tail End • Knurl MWP Slot • Knur-less • Lower Lip • Boat Tail • Bulge • Wedge Two Experiments Cannelure Depth Flared Mouth Waterproofing Design Factors Did Not Improve Waterproofing Performance Design Factors: Full Factorial Experiments • Proposed Case Improvements: • Chamfer Mouth/Flare Mouth/Base Bulge • Crimp Loading Method/Double Crimp • Bullet-Case Dimensional Relations • Reverse Taper Mouth/Taper Mouth • Surface Condition of Contact Area UndesiredSignificant Effect of Cannelure Depth No Significant Effect of Flared Mouth

  9. Bullet Burnishing Case Wash Sealant Application • 4 hrs • 24 hrs • 96 hrs • 5 min. • 30 min. • 1000 cc • 2000 cc Standard Operating Procedures were revised to cause improvement and reflect the most favorable condition. Processes: Full Factorial Experiments Material Prep Mouth-waterproofing Sealant Dry Time Bullet Burnish Time Carbo Wax Content in the Case Wash Number of “leakers” increases with Increasing dry time Number of “leakers” increases with increasing burnish time Number of “leakers” increases with decreasing concentration

  10. Material: Case Mouth Waterproofing Sealant Characterization Hernon 650 (water-based) LCC277 (TCA raw cmpd) Hernon 650S (modified 650) PSM-1 (TCA Paint Shop Mix) PSM-69 (PCBTF) Analytical Techniques Wet Lab Methods Process Characterization Safety & Environmental • FTIR • GC/MS • LC/MS • GPC • Evaporation Rate • Surface Tension • Viscosity • Brookfield • Cannon-Manning • Zahn Cup Viscosity • Slump/Sag • Tack • Dry Time • MSDSs • Websites • Literature Film constituents are: asphalt, benzotriazole tall oil rosin Gilsonite Film thicknesses are characteristic of viscosity results No (per State of MO) non-ODC/non-VOC with high evap rate low viscosity Order of magnitude difference in viscosity between as-supplied & as-used

  11. Solubility Trials Desired Outcome Rejection Criteria Partially Soluble/ Insoluble Soluble Accepted Rejected • ethyoxydodecafluorohexane • dichloropentafluoropropane • nonafluoroisobutyl ether • nonafluorobutyl ether • decafluoropentene • acids/alcohols Low Evaporation Rate High Evaporation Rate Elimination by chemical similarity to “rejected” candidates. • Re-Entry Plus 4 • PCBTF Nine additional solvent systems rejected Elimination on the basis of polarity. Low Toxicity High Toxicity Two additional solvent systems rejected Absolve VG (NPB) Class II ODC TCE Total of 26 solvent systems evaluated!

  12. Characterize the existing mouth waterproofing solution (PSM-1) with respect to solvent selection criteria Isolate the effects of TCA solvent grade Vapor degreasing grade TCA (Dow) Regular solvent grade TCA (PPG) Solubility Evaporation Rate Viscosity Surface Tension No detectable differences • Dow: 1.27 mg/sec • PPG: 1.32 mg/sec • Dow: 2.8cps • PPG: 2.9cps • Dow: 27.15 dyne/cm • PPG: 27.05 dyne/cm Define boundary conditions for materials and processes Identify function of components Develop profile as a function of volume fraction Baseline to PSM-1 processing characteristics

  13. Define boundary conditions for materials and processes Identify function of components Develop profile as a function of volume fraction Baseline to PSM-1 processing characteristics Volume fraction of TCA in PSM 1 = 0.75

  14. Identify Factors Establish Control Levels • EtAc Content • NPB Content • DBP Content • Oil Content Two-Level Three-Level • DBP Content • Oil Content Solvent Ratio Develop Full-Factorial Matrix Run DOE Establish “measures” for determining significant effects • Evaporation Rate • Surface Tension • Adhesion Tests • Viscosity • Slump/Sag • Prepare 12 unique formulations • Test all runs in identical manner • Collect “measures” • No variables confounded • 12 unique process runs Build a Design of Experiment (DOE) to determine significant effects using laboratory bench top tests.

  15. Statistically evaluate the results of the “benchtop” DOE to determine those factors which cause significant effects Measures Exhibiting Significant Effects Measures Exhibiting No Effects Total of 12 Total of 17 Compare values of critical process parameters for PSM-1 to the “measures” collected for all DOE runs

  16. Optimize/Tailor Case Mouth Waterproofing Formulation Identify conditions which most closely match PSM-1 processing characteristics Formulate Raw Compound Formulate Paint Shop Mix Perform Process Trials

  17. Results of Process Trials • No new machine settings required • Leaker rates not greater than TCA No other quality problems introduced!

  18. Long Term Prospective Technologies In-Joint Application Exterior Applied Coatings Using Capillary Action Anaerobic Using Lacquers

  19. First Article Testing Bench Top Testing Pilot Plant Testing Document/ Report Results IPT Group Identified “Musts” IPT Group Identified “Wants” Generate ECP “Go/No-Go” Tests For Characteristics Perform QFD Test For Characteristics Capital Expenditures/ Installation Choose Technology and/or Vendors Rank And Choose Materials First Article Production Kepner-Tregoe Decision Focus Goal: Zero Defects

  20. Summary • Waterproofing Presents Challenges • Short-Term Solution: N-Propyl Bromide and Asphalt • Long-Term Solution: Solventless

  21. Questions and Comments

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