Team Cleanweld, University of Idaho: Ken Bean, David Hewitt, Tess Howell, Nathan Jerred, Erik Shallman

Advisor: Dr. David Drown

May 1, 2009

Client Project Introduction• Prior Analysis and Scope

Objectives Stored Gas Inflator Wash Process Spectrometry and Microscopy Methods and Results Recommendations

Autoliv Inc. • A worldwide leader in automotive safety• Products include seatbelts, airbags, child

restraints, etc.• Products used by all major auto

manufacturers• Based in Brigham City, Utah

Stored Gas Airbag Inflator• Three-Step Cleaning Cycle

“Leakers” • Represent loss of product

Autoliv’s Prior Analysis• Inflators are leaking due to failing laser welds• Failures not caused by welding parameters• Failure possibly due to surface contamination

from the wash process Scope of Research• Focus on burst disk laser welds• Includes a study of weld surfaces and wash

process

Determine the effects of wash and rinse compositions on laser-weld failure• Identify surface contaminants present on

inflators• Explore existing failures to determine leak

rates• Examine the laser weld using optical

microscopy• Analyze the composition of the wash

detergent and rinse solutions• Recommend strategies to reduce weld

failures and operational costs

The Initiator The Diffuser

The Body

Inconel™ Disk

JenFab Drum Washer

Wash Rinse 1 Rinse 2 Dry

Wash Rinse + RP

Part Flow

SendSend ReturnReturn

Tap Water + RPWash Solution

HMS confirmed inflators were leaking Sniffer wand confirmed leaks from

initiator burst disks only

Part ID HMS Leak Rate

MAS VXA EF BET 7.78 E -04

NXG VXA EK EBM Too large to measure

NXG VXA EK ETW 5.73 E -06

NXC VX9 EK E1B Too large to measure

FCP VXA EX CHE Too large to measure

Two inflators tested: “As received” – taken directly off Autoliv’s

wash process assembly line“Clean” – washed in the lab with acetone

and ethanol Identified surface residue with EDS

analysis Compared the cleanliness of the

inflators

“As Received” “Clean”

Laser weld with Porosity Laser weld without porosity

Inductively Coupled Plasma (ICP)• Provides the elemental composition of the

solutions pH• Enable us to compare the basicity of the solutions

with their respective leaker data and draw important conclusion

Potassium Ion Selective Electrode (ISE)• Converts the activity of a specific ion dissolved in a

solution into an electrical potential which can be measured

Conductivity• In solution, current flows by ion transport.

Therefore, an increasing ion concentration in the solution will result in higher conductivity values

Further research suggestedCurrent data is inconclusive

Solution Monitoring MethodsConductivity and K-ISE viable methods

Counter Current Wash Modifications

Tap Water + RP

Waste WaterWash solutionDirty Rinse

JenFab Drum Washer

Autoliv Inc.Mark Bunker

Dr. David Drown Dr. Yanko Kranov Dr. Karl Rink Dr. Daniel Choi Branden Poulsen

Thank you for your attention.