5.56 mm Case Mouth Waterproofing Product Development For High-Speed Manufacturing NDIA Joint Services Small Arms Annual Symposium Kansas City, Missouri.

5.56 mm Case Mouth Waterproofing5.56 mm Case Mouth WaterproofingProduct Development ForProduct Development ForHigh-Speed ManufacturingHigh-Speed Manufacturing

NDIA Joint Services Small Arms Annual Symposium Kansas City, Missouri

May 14, 2003

Presented by:

Steve Hawk, Alliant Tech SystemsGreg Bubniak, U. S. Army TACOM-ARDEC

Team Members

Dr. Sheila HarperRandall BuskyKerry Bricker

May 14, 2003 2

• Not limited by geography

The Need For Waterproof Ammunition Is Critical

• End-users are divese

• Work focused on small caliber ammunition

May 14, 2003 3

Current Mouth Waterproofing: An Internal Application

May 14, 2003 4

Illustration of Mouth Waterproofing Challenge

BOATTAILBEARING SURFACEOGIVE

NECK LENGTH

SEATED BEARINGSURFACE

MAX LENGTHOF MOUTH

WATERPROOFING

BULLET SEATING DEPTH

% SEATED BEAING SURFACE TO NECK LENGTH

CAL .50M33, M17M8, M20

56%

7.62 mmM8064%

7.62 mmM62

163%

5.56 mmM19373%

5.56 mmM855171%

5.56 mmM856322%

May 14, 2003 5

Per

cent

Def

ectiv

e

y = 0.0002x + 0.0122

R2 = 0.724

0.00

2.00

4.00

6.00

8.00

10.00

12.00

0 50 100 150 200 250 300 350

.50 Cal5.56mmM855

5.56mmM856

5.56mmM193

7.62mmM62

7.62mmM80

Bullet Seating Depth Ratio

Cartridge Comparison/Waterproofing50-Cal, 7.62 mm, and 5.56mm

May 14, 2003 6

Problem Statement: Challenge is 1200 ppm Application Speed of SCAMP

May 14, 2003 7

Bullet

Case

DESIGN

MATERIAL

Mouth Waterproofing

Procedures

Tools Gages

Training

Equipment

PROCESSES

Material Preparation

Short Term Fault Tree Analysis of Design, Materials and Processes

May 14, 2003 8

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

Proposed Bullet Improvements:• Double Cannelure• Step on Tail End• Knurl MWP Slot• Knur-less

•Lower Lip•Boat Tail•Bulge•Wedge

CaseBullet

NoSignificant

Effect ofFlaredMouth

UndesiredSignificant

Effect ofCannelure

Depth

Two ExperimentsCannelure Depth

Flared MouthWaterproofing

Design Factors Did Not Improve Waterproofing Performance

May 14, 2003 9

BulletBurnishing

Carbo Wax Content inthe Case Wash

Mouth-waterproofingSealant Dry Time

Bullet BurnishTime

Case WashSealantApplication

• 4 hrs• 24 hrs• 96 hrs

• 5 min.• 30 min.

• 1000 cc• 2000 cc

Number of “leakers”increases with

Increasing dry time

Number of “leakers”increases with

increasing burnish time

Number of “leakers”increases with

decreasing concentration

Standard Operating Procedures were revised to cause improvementand reflect the most favorable condition.

Processes: Full Factorial Experiments Material Prep

May 14, 2003 10

Material: Case Mouth Waterproofing Sealant Characterization

Hernon 650 (water-based)

Hernon 650S (modified 650)

PSM-69 (PCBTF)

LCC277 (TCA raw cmpd)

PSM-1 (TCA Paint Shop Mix)

AnalyticalTechniques

• FTIR• GC/MS• LC/MS• GPC

Filmconstituents are:

asphalt, benzotriazole tall oil rosin

Gilsonite

Process Characterization

• Zahn Cup Viscosity• Slump/Sag• Tack• Dry Time

Filmthicknesses arecharacteristic of

viscosityresults

Safety &Environmental

• MSDSs• Websites• Literature

No(per State of MO)

non-ODC/non-VOCwith high evap rate

low viscosity

Wet Lab Methods

• Evaporation Rate• Surface Tension• Viscosity

• Brookfield• Cannon-Manning

Order ofmagnitude differencein viscosity between

as-supplied &as-used

May 14, 2003 11

Partially Soluble/Insoluble

• ethyoxydodecafluorohexane• dichloropentafluoropropane• nonafluoroisobutyl ether

• nonafluorobutyl ether• decafluoropentene• acids/alcohols

Rejection Criteria

Total of 26 solvent systems evaluated!

Solubility Trials

Elimination bychemical similarity to“rejected” candidates.

Nine additional solvent systems rejected

Elimination on the basisof polarity.

Two additional solvent systemsrejected

Desired Outcome

Soluble

Accepted Rejected

Absolve VG (NPB)

Class II ODC

TCE

LowToxicity

HighToxicity

HighEvaporation

Rate

• Re-Entry Plus 4• PCBTF

LowEvaporation

Rate

May 14, 2003 12

Characterize the existing mouth waterproofing solution(PSM-1) with respect to solvent selection criteria

Isolate the effects of TCA solvent grade

Solubility Surface

TensionViscosityEvaporation

Rate

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

Vapor degreasing grade TCA (Dow)

Regular solvent grade TCA (PPG)

Develop profile as a function ofvolume fraction

Identify functionof components

Baseline toPSM-1 processing

characteristics

Define boundary conditions for materials and processes

May 14, 2003 13

B

BB B

B B

B

JJ J

JJ

J

J

H

H H

HH H

H

2

5

8

11

14

0 0.25 0.50 0.75 1.00

Volume Fraction of Parent Solvent

B Dow TCA

J PPG TCA

H NPB

Volume fraction of TCA in PSM 1 = 0.75

Develop profile as a function ofvolume fraction

Define boundary conditions for materials and processes

Identify functionof components

Baseline toPSM-1 processing

characteristics

May 14, 2003 14

Build a Design of Experiment (DOE)to determine significant effects using

laboratory bench top tests.

Identify Factors

• EtAc Content

• NPB Content• DBP Content• Oil Content

Establish Control Levels

Two-Level Three-Level

• DBP Content• Oil Content Solvent Ratio

Establish “measures” fordetermining significant effects

• Viscosity• Slump/Sag

•Evaporation Rate•Surface Tension•Adhesion Tests

Run DOE

• Prepare 12 unique formulations• Test all runs in identical manner• Collect “measures”

DevelopFull-Factorial

Matrix

• No variables confounded• 12 unique process runs

May 14, 2003 15

Solution

Evaporation Rate (mass change in grams per sec)

Surface Tension

(dyne/cm) Viscosity

(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

Measures ExhibitingSignificant Effects

Statistically evaluate the results of the“benchtop” DOE to determine those

factors which cause significant effects

Total of 12 Compare values of critical process parameters

for PSM-1 to the “measures”collected for all DOE runs

Measures ExhibitingNo Effects

Total of 17

May 14, 2003 16

Perform Process Trials

Optimize/Tailor Case Mouth Waterproofing Formulation

Identify conditions which most closely match PSM-1processing characteristics

Formulate Raw Compound

Old New TCA (Vf = 0.63) Abzol VG (Vf = 0.63) Asphalt 255 Asphalt 255 Gilsonite Gilsonite Rosin Rosin Benzotriazole Benzotriazole

Formulate Paint Shop Mix

Old (Solids Content = 16%)

New (Solids Content =22%)

Raw Compound Raw Compound Ethyl Acetate Ethyl Acetate TCA Mineral Oil Mineral Oil DBP DBP

May 14, 2003 17

Results of Process Trials

• No new machine settings required

• Leaker rates not greater than TCA

No other quality problems introduced!

Percent Defective Due to “Leakers”*

PSM-1 Solvent Type

Bullet Type

TCA (Ops Leak Rate Nov/Dec 02)

Abzol VG

M855 5.90 1.20

M856 9.20 6.20

*Acceptable Quality Level (AQL) is 4%.

May 14, 2003 18

Using Capillary Action Anaerobic

Exterior Applied CoatingsIn-Joint Application

Using Lacquers

Long Term Prospective Technologies

May 14, 2003 19

Kepner-Tregoe Decision Focus

Pilot PlantTesting

First Article Testing

Document/Report Results

Generate ECP

CapitalExpenditures/

Installation

First ArticleProductionGoal: Zero Defects

Bench Top Testing

ChooseTechnology

and/or Vendors

“Go/No-Go”Tests For

Characteristics

IPT Group Identified“Musts”

IPT GroupIdentified“Wants”

Perform QFD Test For

Characteristics

Rank And ChooseMaterials

May 14, 2003 20

• Waterproofing Presents Challenges

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

• Long-Term Solution: Solventless

Summary

May 14, 2003 21

Questions and Comments