Docstoc

5.56 mm Case Mouth Waterproofing

Document Sample
5.56 mm Case Mouth Waterproofing Powered By Docstoc
					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
               The Need For Waterproof Ammunition Is
                              Critical
                                    • Not limited by geography


                                    • End-users are divese


                                    • Work focused on small
                                      caliber ammunition




May 14, 2003                                                     2
               Current Mouth Waterproofing: An Internal
                             Application




May 14, 2003                                              3
               Illustration of Mouth Waterproofing
                             Challenge
                                                                      BOATTAIL
                                                                          BEARING SURFACE
                                      NECK LENGTH
                                                                         OGIVE




                                     MAX LENGTH                          SEATED BEARING
                                      OF MOUTH                              SURFACE
                                    WATERPROOFING

                                    BULLET SEATING DEPTH
                             % SEATED BEAING SURFACE TO NECK LENGTH




               CAL .50    7.62 mm     7.62 mm     5.56 mm     5.56 mm       5.56 mm
               M33, M17     M80         M62         M193        M855          M856
               M8, M20      64%         163%        73%         171%          322%
                 56%


May 14, 2003                                                                                4
                              Cartridge Comparison/Waterproofing
                                  50-Cal, 7.62 mm, and 5.56mm
                                   12.00
                                                                                                    5.56mm
                                                                                                    M856
                                   10.00
               Percent Defective




                                   8.00

                                                                                         y = 0.0002x + 0.0122
                                   6.00                                                         2
                                                                                               R = 0.724
                                                         5.56mm           7.62mm
                                   4.00                  M193             M62
                                               .50 Cal
                                                                           5.56mm
                                   2.00                                    M855
                                                          7.62mm
                                                          M80
                                   0.00
                                           0        50     100      150      200         250        300      350

                                                            Bullet Seating Depth Ratio



May 14, 2003                                                                                                       5
               Problem Statement: Challenge is 1200
                 ppm Application Speed of SCAMP




May 14, 2003                                          6
               Short Term Fault Tree Analysis of Design,
                       Materials and Processes


           Equipment                                     Procedures


                               Bullet
                                             MATERIAL

                              DESIGN            Mouth
    Training                                 Waterproofing        Material
                                                                Preparation
                               Case




                Gages                                   Tools



                                 PROCESSES
May 14, 2003                                                                  7
          Design Factors: Full Factorial Experiments


                      Bullet                                          Case

         Proposed Bullet Improvements:                Proposed Case Improvements:
         • Double Cannelure •Lower Lip                • Chamfer Mouth/Flare Mouth/Base Bulge
         • Step on Tail End  •Boat Tail               • Crimp Loading Method/Double Crimp
         • Knurl MWP Slot    •Bulge                   • Bullet-Case Dimensional Relations
         • Knur-less         •Wedge                   • Reverse Taper Mouth/Taper Mouth
                                                      • Surface Condition of Contact Area

                   Undesired                                            No
                   Significant             Two Experiments          Significant
                    Effect of             Cannelure Depth            Effect of
                   Cannelure               Flared Mouth               Flared
                     Depth                 Waterproofing              Mouth




               Design Factors Did Not Improve Waterproofing Performance

May 14, 2003                                                                                   8
        Processes: Full Factorial Experiments Material Prep


                Sealant                    Bullet
                                                                    Case Wash
               Application               Burnishing


          Mouth-waterproofing           Bullet Burnish          Carbo Wax Content in
           Sealant Dry Time                  Time                  the Case Wash
                  • 4 hrs
                                           • 5 min.                   • 1000 cc
                  • 24 hrs
                                           • 30 min.                  • 2000 cc
                  • 96 hrs


          Number of “leakers”         Number of “leakers”       Number of “leakers”
            increases with               increases with            increases with
          Increasing dry time       increasing burnish time   decreasing concentration



               Standard Operating Procedures were revised to cause improvement
                           and reflect the most favorable condition.
May 14, 2003                                                                             9
           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                Wet Lab              Process                  Safety &
       Techniques                 Methods           Characterization          Environmental

   • FTIR                    • Evaporation Rate     • Zahn Cup Viscosity     • MSDSs
   • GC/MS                   • Surface Tension      • Slump/Sag              • Websites
   • LC/MS                   • Viscosity            • Tack                   • Literature
   • GPC                        • Brookfield        • Dry Time
                                • Cannon-Manning



             Film                                           Film
     constituents are:                                thicknesses are
   asphalt, benzotriazole           Order of          characteristic of              No
        tall oil rosin       magnitude difference         viscosity           (per State of MO)
         Gilsonite           in viscosity between          results           non-ODC/non-VOC
                                 as-supplied &                               with high evap rate
                                    as-used                                     low viscosity


May 14, 2003                                                                                       10
                                        Solubility Trials




                                                              Partially Soluble/
                        Soluble                                   Insoluble


                                                  • ethyoxydodecafluorohexane • nonafluorobutyl ether
                                                  • dichloropentafluoropropane • decafluoropentene
                                                  • nonafluoroisobutyl ether   • acids/alcohols

             High                    Low
                                                                Elimination by
          Evaporation             Evaporation
                                                            chemical similarity to
             Rate                    Rate
                                                            “rejected” candidates.
                              • Re-Entry Plus 4        Nine additional solvent systems
                              • PCBTF                              rejected

     Low            High                                    Elimination on the basis
    Toxicity       Toxicity                                       of polarity.
   Absolve VG                                         Two additional solvent systems
                        TCE
      (NPB)                                                      rejected
   Class II ODC
                   Total of 26 solvent systems evaluated!
May 14, 2003                                                                                            11
                     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)




           No detectable            • Dow: 1.27 mg/sec     • Dow: 2.8cps        • Dow: 27.15 dyne/cm
            differences             • PPG: 1.32 mg/sec     • PPG: 2.9cps        • PPG: 27.05 dyne/cm

                        Define boundary conditions for materials and processes




                                               Develop profile                  Baseline to
               Identify function
                                               as a function of               PSM-1 processing
                of components
                                               volume fraction                 characteristics


May 14, 2003                                                                                           12
                    Define boundary conditions for materials and processes




                                               Develop profile                      Baseline to
           Identify function
                                               as a function of                   PSM-1 processing
            of components
                                               volume fraction                     characteristics


                         14
                                                                             B Dow TCA
                                                                      H
                                                                             J   PPG TCA
                         11
                                                                      J
                                                                      B      H NPB
                                                  H
                                                        H H
                                                  J     B B
                                                          J
                                        H H
                                          B       B     J
                          8
                                        B J
                                        J
                               J
                               B
                               H

                          5
                                                                            Volume fraction of TCA
                                                                                in PSM 1 = 0.75
                          2
                               0       0.25     0.50      0.75       1.00
                                   Volume Fraction of Parent Solvent

May 14, 2003                                                                                         13
                                 Build a Design of Experiment (DOE)
                                to determine significant effects using
                                     laboratory bench top tests.


                   Identify Factors                  Establish Control Levels

                   • EtAc Content
                   • NPB Content
                   • DBP Content
                   • Oil Content                   Two-Level             Three-Level

                                         • DBP Content
                                         • Oil Content           Solvent Ratio


                                                                                   Develop
                                           Establish “measures” for
               Run DOE                                                           Full-Factorial
                                         determining significant effects
                                                                                     Matrix
   • Prepare 12 unique formulations        •Evaporation Rate   • Viscosity        • No variables confounded
   • Test all runs in identical manner     •Surface Tension    • Slump/Sag        • 12 unique process runs
   • Collect “measures”                    •Adhesion Tests



May 14, 2003                                                                                              14
                            Statistically evaluate the results of the
                             “benchtop” DOE to determine those
                            factors which cause significant effects



               Measures Exhibiting                              Measures Exhibiting
                Significant Effects                                 No Effects

       Total of                                                                Total of
         12                Compare values of critical process parameters         17
                                  for PSM-1 to the “measures”
                                    collected for all DOE runs

                                        Evaporation Rate     Surface
                                        (mass change in      Tension       Viscosity
                       Solution          grams per sec)     (dyne/cm)        (cps)
                  PSM-1 with Dow TCA       1.272 x 10 -3       27.2          2.8
                  PSM-1 with PPG TCA       1.321 x 10 -3       27.1           2.9
                     DOE Run #5            1.350 x 10 -3       27.2           3.0
                     DOE Run #6            1.386 x 10 -3       26.9           2.9
                     DOE Run #7            1.408 x 10 -3       26.8           2.9
                     DOE Run #8            1.342 x 10 -3       26.4           2.9
May 14, 2003                                                                              15
               Optimize/Tailor Case Mouth Waterproofing Formulation


                   Identify conditions which most closely match PSM-1
                                processing characteristics

                                                      Old                     New
                                               TCA (Vf = 0.63)    Abzol VG (Vf = 0.63)
               Formulate Raw Compound          Asphalt 255        Asphalt 255
                                               Gilsonite          Gilsonite
                                               Rosin              Rosin
                                               Benzotriazole      Benzotriazole


                                                        Old                         New
                                             (Solids Content = 16%)      (Solids Content =22%)
                                               Raw Compound              Raw Compound
               Formulate Paint Shop Mix        Ethyl Acetate             Ethyl Acetate
                                               TCA                       Mineral Oil
                                               Mineral Oil               DBP
                                               DBP




                               Perform Process Trials


May 14, 2003                                                                                     16
                    Results of Process Trials

               • No new machine settings
                 required
               • Leaker rates not greater than
                 TCA
                       Percent Defective Due to “Leakers”*
                                     PSM-1 Solvent Type
                  Bullet               TCA                   Abzol
                  Type      (Ops Leak Rate Nov/Dec 02)        VG
                  M855                  5.90                 1.20
                  M856                  9.20                 6.20
                *Acceptable Quality Level (AQL) is 4%.

               No other quality problems introduced!
May 14, 2003                                                         17
           Long Term Prospective Technologies

               In-Joint Application   Exterior Applied Coatings




           Using Capillary Action         Using Lacquers
                Anaerobic



May 14, 2003                                                      18
                       Kepner-Tregoe Decision Focus
                Bench Top            Pilot Plant      First Article
                 Testing              Testing            Testing

                 IPT Group           IPT Group
                                                       Document/
                  Identified          Identified
                                                      Report Results
                   “Musts”             “Wants”

                “Go/No-Go”         Perform QFD
                 Tests For           Test For         Generate ECP
               Characteristics     Characteristics

                   Choose            Rank And            Capital
                 Technology           Choose          Expenditures/
               and/or Vendors        Materials         Installation


                                                       First Article
                                 Goal: Zero Defects    Production


May 14, 2003                                                           19
                           Summary

         • Waterproofing Presents Challenges

         • Short-Term Solution: N-Propyl Bromide and
           Asphalt

         • Long-Term Solution: Solventless




May 14, 2003                                           20
               Questions and Comments




May 14, 2003                            21

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:125
posted:5/9/2010
language:English
pages:21