Bottle Closure Sealing System Mark Nauman Andrew Seagraves Jeff Staniszewski Vincent Uathavikul Design Report

Background Berry PlasticsBerry Plastics -New child resistant timed-closure developed -Cap intended to seal without a liner Dome designed to flexDome designed to flex Initial FEAInitial FEA -Cap showed plastic deformation -Inadequate for sealing as is

Problem Definition To design a liner for their existing closureTo design a liner for their existing closure Constraints Process: Compression MoldingProcess: Compression Molding Material: Thermoplastic Elastomer (TPE)Material: Thermoplastic Elastomer (TPE) System Level Wants Create a seal for a liquidCreate a seal for a liquid Maintain seal for 1 yearMaintain seal for 1 year Minimize cost per unitMinimize cost per unit Achieve seal within tolerance rangeAchieve seal within tolerance range

Project Scope Project WantsProject Wants Create a waterproof sealCreate a waterproof seal -in a leak test -in an accelerated creep test At nominal dimensionsAt nominal dimensions Within tolerance rangeWithin tolerance range Minimize cost per unit byMinimize cost per unit by -Minimizing material costs -Minimizing tooling costs Project MetricsProject Metrics Performance in aPerformance in a -standard leak test -elevated temperature leak test Nominal bottles and capsNominal bottles and caps Max bottle with min capMax bottle with min cap Min bottle with max capMin bottle with max cap VolumeVolume Machining time of toolingMachining time of tooling

Terminology

Compression Molding

Initial Concepts Constant Thickness Variable Thickness Cutaway Concept

Comparative Leak Test Purpose Compares the sealing performance of Constant and Variable conceptsCompares the sealing performance of Constant and Variable conceptsSpecifics 6 Different Torques6 Different Torques -From 2 to 12 inch-pounds -3 samples per torque level -Constant volume of water + food coloring Results No leaks with any sample after 48 hoursNo leaks with any sample after 48 hoursConclusions Constant and Variable are equivalent in sealingConstant and Variable are equivalent in sealing

Comparative Cost Study At 50 million units… Cost / Unit Total Cost of Production Cutaway$0.0114$570,000 Constant$0.0126$630,000 Variable$0.0118$590,000 Assumptions Production: 50 Million parts/yrProduction: 50 Million parts/yr TPE bulk cost: $2 / poundTPE bulk cost: $2 / pound Cost of Machining Punches: $70/hrCost of Machining Punches: $70/hrResults Constant concept costsConstant concept costs -9.5% more than the Cutaway -6.3% more than the Variable At 50 million parts, material costs account for ~ 16% of the total costs and 50% of the controllable costsAt 50 million parts, material costs account for ~ 16% of the total costs and 50% of the controllable costs

Manufacturing Concerns Easier to seal off in the land area instead of ridgeEasier to seal off in the land area instead of ridge Variable and Cutaway concepts now virtually the sameVariable and Cutaway concepts now virtually the same Cap Sleeve Punch Ridge Liner

Concept Elimination Constant and Variable liners have the same sealing performanceConstant and Variable liners have the same sealing performance Variable liner will cost less than ConstantVariable liner will cost less than Constant Cutaway and Variable are the same because of manufacturingCutaway and Variable are the same because of manufacturing  Variable Concept will be prototyped be prototyped

Simple Model Cap Liner Bottle Select Section View

Instron Testing Linear Correlation found between Torque and Pressure can be used for FEA and also by Berry PlasticsLinear Correlation found between Torque and Pressure can be used for FEA and also by Berry Plastics

Finite Element Analysis Model of Cap, Liner and BottleModel of Cap, Liner and Bottle Force applied to contact areaForce applied to contact area Boundary Conditions Boundary Conditions - Cap sides are stationary - Cap sides are stationary - Bottle can move in y-direction - Bottle can move in y-direction

Finite Element Analysis Results A cap with no liner contained stresses above yield limitA cap with no liner contained stresses above yield limit A cap with a liner was close to yield limitA cap with a liner was close to yield limit

Validation of Test Design O-ring and compression liners compared with FEAO-ring and compression liners compared with FEA O-ring liner performs similar to actual design under same loadO-ring liner performs similar to actual design under same load -Within 8% on all stresses -Within 2% on all deflections O-ring is an accurate approximation geometryO-ring is an accurate approximation geometry

Standard Leak Test Procedure Bottles are sealed to predetermined range of torqueBottles are sealed to predetermined range of torque Opening torque immediately applied and measuredOpening torque immediately applied and measured Bottles are resealed and checked for leaking over 2 week timeBottles are resealed and checked for leaking over 2 week time Opening torque is applied and measuredOpening torque is applied and measuredResults No bottles leak in this timeNo bottles leak in this time Opening torque slightly lower after 2 weeksOpening torque slightly lower after 2 weeks D outer = 1.42” D inner = 1.06” Thickness =.04”

Elevated Temperature Test Used to simulate relaxation over timeUsed to simulate relaxation over time Sealed bottles are put in environmental chamberSealed bottles are put in environmental chamber -2 weeks at 100 °F ~ 2 months All bottles remained sealed over periodAll bottles remained sealed over period Relaxation curve made using existing dataRelaxation curve made using existing data -Immediate opening torque -Opening torque after 2 weeks -Opening torque after simulated 2 months -Match shape of current relaxation curves

Elevated Temperature Test Results 10 in lb may be inadequate to seal10 in lb may be inadequate to seal -Cap relaxes too much over the period Higher than 12 in lb will seal over timeHigher than 12 in lb will seal over time -Curves flatten out

Conclusions Testing ShowsTesting Shows -Prototype maintains short term waterproof seal Performance Metric of Standard Leak test satisfiedPerformance Metric of Standard Leak test satisfied -Waterproof seal intact after simulated 2 months Performance Metric of Elevated Temperature test satisfiedPerformance Metric of Elevated Temperature test satisfied FEA ShowsFEA Shows -Prototype design and actual design behave similar -Higher torques could cause plastic deformation Analysis ShowsAnalysis Shows -Seal would survive simulated year PrototypePrototype -Simulates the actual liner design to be implemented by Berry

Implementation Plan Test the cap for relaxation over a simulated yearTest the cap for relaxation over a simulated year Optimize liner thickness to reduce production costsOptimize liner thickness to reduce production costs Small scale production of punch for further physical and consumer testingSmall scale production of punch for further physical and consumer testing Large scale production of punch for commercial use of cap and linerLarge scale production of punch for commercial use of cap and liner

Questions Elevated Temperature FEA Stress Manufacturing Simple Model Instron Setup Tolerance Variation

Elevated Temperature Back to Questions

Stress

Liner Cap and Punch Cap Sleeve Punch Ridge Liner Back to Questions

Simple Model Cap Liner Bottle Select Section View Back to Questions

Instron Setup Back to Questions

Tolerance Variation Back to Questions