ENGM 621: Statistical Process Control What is quality?

Meaning of Quality and Quality Improvement TM 720: Statistical Process Control Meaning of Quality and Quality Improvement Quality – one of most important consumer decision factors in selecting products and services Understanding / improving quality is key factor for success, growth, and competitive position Substantial return on investment comes from: Improved quality Successful implementation of quality techniques as overall business strategy (c) 2002-2006 D.H. Jensen & R.C. Wurl

TM 720: Statistical Process Control Dimensions of Quality Performance – Will the product do the intended job? Reliability – How often does the product fail? Durability - How long does the product last? Serviceability – How easy is it to repair the product? Aesthetics – What does the product look like? Features – What does the product do? Perceived quality – What is the reputation of the company or product? Conformance to standards – Is the product made exactly as the designer intended? (c) 2002-2006 D.H. Jensen & R.C. Wurl

Quality is a multifaceted entity. TM 720: Statistical Process Control Quality is a multifaceted entity. Traditional (OLD) definition of Quality: Fitness of use (i.e., products must meet requirements of those who use them.) (c) 2002-2006 D.H. Jensen & R.C. Wurl

Two Aspects of “Fitness for use” TM 720: Statistical Process Control Two Aspects of “Fitness for use” Quality of design – all products intentionally made in various grades of quality. (e.g., Autos differ with respect to size, options, speed, etc.) Quality of conformance – how well the product conforms to specifications. (e.g., If diameter of a drilled hole is within specifications then it has good quality.) (c) 2002-2006 D.H. Jensen & R.C. Wurl

What's Wrong with "Fitness for Use" Definition of Quality? TM 720: Statistical Process Control What's Wrong with "Fitness for Use" Definition of Quality? Unfortunately, quality as “Fitness for Use” has become associated with the "conformance to specifications" regardless of whether or not the product is fit for use by customer. Misconception: Quality can be dealt with solely in manufacturing - that is, by "gold plating" the product (c) 2002-2006 D.H. Jensen & R.C. Wurl

Modern Definition of Quality: TM 720: Statistical Process Control Modern Definition of Quality: Quality is inversely proportional to variability If variability of product decreases  quality of product increases Quality Improvement – Reduction of variability in processes and products Quality Engineering – Set of operational, managerial, and engineering activities that a company uses to ensure that quality characteristics of a product are at nominal levels (c) 2002-2006 D.H. Jensen & R.C. Wurl

Statistical Methods for Quality Improvement TM 720: Statistical Process Control Statistical Methods for Quality Improvement Relative Savings from a $1 investment in: Acceptance Sampling ($1) On-Line Process Control ($10) Off-Line Process Improvement ($100) (c) 2002-2006 D.H. Jensen & R.C. Wurl

Quality Design & Process Variation Lower Spec Limit Upper Spec Limit Acceptance Sampling 60 80 100 120 140 Statistical Process Control Experimental Design

TM 720: Statistical Process Control Acceptance Sampling Reduces bad product sent to consumer Dodge & Romig 1930s Sample from lot to determine acceptance More effective than 100% inspection No feedback, prevention or improvement (c) 2002-2006 D.H. Jensen & R.C. Wurl

On-Line Process Control TM 720: Statistical Process Control On-Line Process Control Monitoring of manufacturing process with control charts Shewhart 1920s Sample & stop process if necessary No improvement, but maintains current process quality level (c) 2002-2006 D.H. Jensen & R.C. Wurl

TM 720: Statistical Process Control Off-Line Improvement Designed experiments Taguchi & Classical Statistics 1980s If it's not broke, improve it! Continuous improvement of product designs and manufacturing processes (c) 2002-2006 D.H. Jensen & R.C. Wurl

Quality Myth: Higher Quality  Higher Cost TM 720: Statistical Process Control Quality Myth: Higher Quality  Higher Cost $ Defect Rate Quality Cost Total Cost Failure Cost 12/2/2018 ENGM 720: Statistical Process Control (c) 2002-2006 D.H. Jensen & R.C. Wurl

Very Often: Higher Quality  Lower Cost TM 720: Statistical Process Control Very Often: Higher Quality  Lower Cost Gear Assembly Manufacturing Process $20 / part 75% Conform 100 parts (75 good parts) 25% Non-conforming: (10 scrap parts) (25 parts) Re-work Process $4 / part (15 good parts)   (c) 2002-2006 D.H. Jensen & R.C. Wurl

TM 720: Statistical Process Control Study finds excessive process variability responsible for high nonconformity rate New SQC procedure implemented NOW: manufacturing non-conformities = 5% SAVINGS: $22.89 – $20.53 = $2.36 / good part PRODUCTIVITY: 9% improvement   (c) 2002-2006 D.H. Jensen & R.C. Wurl

How Quality Engineering Makes a Company More Competitive TM 720: Statistical Process Control How Quality Engineering Makes a Company More Competitive Tactical less inspection less scrap and rework more capacity easier scheduling & shorter lead time less inventory less warranty cost Strategic more flexibility to make new products customer satisfaction easier to spot and solve problems employee involvement in continuous improvement (c) 2002-2006 D.H. Jensen & R.C. Wurl

Taguchi (1980) and Robust Design TM 720: Statistical Process Control Taguchi (1980) and Robust Design New Goal: consistently good performance in a variety of operating conditions Minimize variation in processes and products   Use Designed Experiments to achieve robustness (c) 2002-2006 D.H. Jensen & R.C. Wurl

Experimental Design SCI – solder bridges, solder gaps Squeegee over template has potential to leave too much or too little solder SD Cement Plant \ Strength of concrete dependent of quality/amounts of raw materials that go into the product

Taguchi's Example: Elasticity of Caramel TM 720: Statistical Process Control Taguchi's Example: Elasticity of Caramel Product X conforms to elasticity spec at 72o Product Y performs well in a wider variety of operating conditions – more robust! Elasticity Prod X Prod Y Spec 72o Temp (c) 2002-2006 D.H. Jensen & R.C. Wurl

Personal Example People operate more productively at a temp of 71 degrees 69-73 degrees probably can’t tell 65 degrees we go home 75 degrees we go home

Total Quality Management – TQM TM 720: Statistical Process Control Total Quality Management – TQM Although statistical techniques are critical for quality improvement: the management system must direct quality improvement philosophy and ensure its implementation in all aspects of business TQM must be implemented within a management system that is scientifically quality driven (c) 2002-2006 D.H. Jensen & R.C. Wurl

International Standards Organization ISO 9000 (1990s) TM 720: Statistical Process Control International Standards Organization ISO 9000 (1990s) An ISO 9000 certified company examined by a registered official has an effective management system, capable of consistent performance Examples: System in place to correctly identify customer needs Staff have correct versions of documentation Preferred suppliers selected; consistent communication system System to document and correct errors (c) 2002-2006 D.H. Jensen & R.C. Wurl

TM 720: Statistical Process Control Six Sigma - Motorola Six Sigma = 3.4 defects per million opportunities! Every employee must show bottom line results of quality project – finance, mail room, manufacturing, etc. identify problem; develop measurement; set goal; close gap Long term process – 5 years to fully implement 12/2/2018 ENGM 720: Statistical Process Control (c) 2002-2006 D.H. Jensen & R.C. Wurl

Malcolm Baldridge National Quality Award TM 720: Statistical Process Control Malcolm Baldridge National Quality Award Established by congress in 1987, for excellence in organizations Applicant receives intense investigation   NIST (National Institute of Standards and Technology) study shows Baldrige Award recipients outperformed the Standard & Poor’s 500 by nearly 2.5 to 1. (c) 2002-2006 D.H. Jensen & R.C. Wurl

TM 720: Statistical Process Control The Baldridge Award examines quality of organization in seven categories Leadership Information and Analysis Strategic Planning Human Resource Development and Management Process Management Business Results Customer Focus and Satisfaction (c) 2002-2006 D.H. Jensen & R.C. Wurl