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Explore examples of failures such as technician error leading to a patient's death and the Thalidomide disaster. Understand the importance of designing for failure, safety considerations like sprinkler systems, and product convenience like easily opened packaging. Learn about product life issues, field service reports, warranty analysis, and product testing methods.
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Chapter 22 Miscellaneous Issues
Learning From Failure • Technicians in an ambulance taking a heart attack victim to a hospital lost use of their heart machine every time they attempted to use their radio transmitter. (Unshielded RF interference) The patient died. • Thalidomide was sold in Europe in the late 1950s, causing over 8,000 births of malformed children. The drug had not been tested adequately prior to market release.
Design for Failure • Should consider and plan for failure • For safety and convenience
Safety Considerations • Sprinkler Systems – the increase in temperature due to a fire causes melting of a metal plug and the opening of a sprinkler or gas quenching system to put out the fire • In the event of a power failure, a lead shield drops in front of a cobalt therapy delivery unit
Design for Convenience • Postage Stamps – sheets of postage stamps typically contain individual stamps separated by perforations. A slightly skilled user can easily separate out an individual stamp by causing failure along the perforations. • Scoring of a surface to enhance breakage is a common way to ensure easily opened bags of coffee and pop-top cans of various designs
Product Life Issues • Necessary to determine how a product is performing during actual use • Analysis of field service reports • Failure analysis of failed units • Warranty analysis
Analysis of Field Service Reports (FSR) • Type of Product • Serial # • Date of Service Activity • Symptom of the problem • Diagnosis • List of parts replaced • Labor hours required • Service representative
Data Analysis • Determine most significant problem information & trend causes • Pareto Analysis – a histogram of problems • Graphical Plots • Determine what pt in life cycle • Determine efficiency of manufacturing process • Useful for analyzing warranty costs
Failure Analysis of Field Units • Focus on cause of problem based on symptom • Fault- tree analysis
Warranty Analysis • Warranty cost as a % of sales • Warranty cost per unit • Installation cost per unit • % of shipped units experiencing problems
Product Testing Issues • HALT Testing – may indicate problems early in testing that would take some time to occur in the field. • More severe parameters • Misuse of product (type & severity testing)