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Managing Quality and Time to Create Value. Chapter 7. How much quality is enough?. Total quality management (TQM) Continuous improvement toward perfection Assumes customers seek high quality and will pay for it Return on quality (ROQ) Tradeoff between costs and benefits of quality
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How much quality is enough? • Total quality management (TQM) • Continuous improvement toward perfection • Assumes customers seek high quality and will pay for it • Return on quality (ROQ) • Tradeoff between costs and benefits of quality • Maximize profit instead of quality
Costs of quality • Prevention costs • Cost incurred to prevent a problem • Design, process improvement, training, etc. • Appraisal costs • Cost incurred to identify problems • Inspection, testing, evaluations, etc.
Costs of quality • Internal failure costs • Costs incurred to correct problems while still in the company’s control • Rework, scrap, retesting, delays, etc. • External failure costs • Costs incurred to correct problems after the problem leaves the company’s control • Warranty repairs, replacement, recalls, lawsuits, damage to reputation, lost sales, etc.
Costs of quality • In theory: • Spending on prevention reduces appraisal and failure costs • Spending on appraisal reduces external failure costs • ROQ is maximized where combined cost is minimized
Tracking quality • Indicators • Frequency distributions • Run chart • Control chart • Diagnostics • Scatter diagrams • Cause and effect diagrams/flowcharts • Pareto charts
Time matters • Time is the one resource you cannot buy • Speed is a competitive advantage • Product/service development time • Customer response time • Receipt of order to delivery • Production cycle time • Start to completion of production process
Time/efficiency measures • Productivity • Outputs / inputs • Cycle time • Total processing time / good output produced • Throughput efficiency • Value-added time / Total processing time
Measuring capacity Theoretical (rated) capacity -- Planned downtime = Practical capacity -- Capacity used to meet demand = Excess capacity
Time-based ABC • Simpler version of traditional ABC • Time used as driver base • Calculation of driver rate Cost of capacity to provide service Time available to complete service • Cost = time required * driver rate
Just-in-time systems • Traditional “push” system • Results in mismatch between supply and demand • Excess inventory or lost sales
Just-in-time systems • JIT “pull” system • Better match between supply and demand • Less inventory • Possibly slower response
Just-in-time systems • Requirements of JIT • Flexible capacity and workforce • Smooth production flow • Short cycle times and processing times • Reliable suppliers • Commitment to quality