Seven Quality Tools [Statistical Process Control]. by S.OliverNesaRaj Assistant professor School of Mechanical Engineering SRM University.
Seven Quality Tools[Statistical Process Control] by S.OliverNesaRaj Assistant professor School of Mechanical Engineering SRM University
Quality managementrefers to systematic policies, methods, and procedures used to ensure that goods and services are produced with appropriate levels of quality to meet the needs of customers. Organizations today integrate quality principles into their management systems using tools such as Total Quality Management (TQM), Six Sigma, and Lean Operating Systems, Quality circle, Zero defect, Kaizen Poka Yoke etc., . Quality management
A Brief History of Quality Management Historical uses of quality management include the precision involved in building of Egyptian pyramids, interchangeable parts during Industrial Revolution, and statistical tools used for quality control during World War II. Dr. Joseph Juran and Dr. W. Edwards Deming were pioneers in the field (more later on these two quality gurus). The Japanese integrated quality ideas and methods throughout their organizations and developed a culture of continuous improvement.
Understanding Quality Quality can be a confusing concept, partly because people view quality in relation to differing criteria based on their individual roles in the value chain, such as: perfection, delighting or pleasing the customer, eliminating waste, doing it right the first time, and/or consistency.
Factors Affecting Quality: • Market compulsions, Product complexities • Money, Men Machines • Shop floor point of delivery • Responsible Management • Information systems • Motivation Techniques
W. Edwards Deming • Focus on bringing about improvements in product and service quality by reducing uncertainty and variability in goods and services designand associated processes (the beginning of his ideas in 1920s and 1930s). • Higher quality leads to higher productivity and lower costs. • “14 Points” management philosophy. • Deming Cycle – Plan, Do, Study, and Act.
W. Edwards Deming 14 Points Point 1:Create a Vision and Demonstrate Commitment Point 2:Learn the Philosophy Point 3:Understand Inspection Point 4:Stop Making Decisions Purely on the Basis of Cost Point 5:Improve Constantly and Forever Point 6: Institute Training Point 7:Institute Leadership
W. Edwards Deming 14 Points….. Point 8:Drive Out Fear Point 9: Optimize the Efforts of Teams Point 10: Eliminate Exhortations Point 11: Eliminate Numerical Quotas Point 12:Remove Barriers to Pride in Work Point 13: Encourage Education and Self- Improvement Point 14:Take Action
What is quality ? • Fitness for the purpose - Joseph M Juran • Suitability for use by the customer • Goods that do not come back, but customers that do come back • The totality of features and other characteristics of a product or service that bear on its ability to satisfy stated or implied needs. [As per ISO 8402 - 1986]
Product Quality Functionality Reliability [mean time between failure] Usability Maintainability [mean time to repair] Efficiency Portability [Ability to transferred from one environment to another] Service Quality Quality of customer service Quality of service design Quality of delivery Additional Attributes… Timeliness Aesthetics [ appearance] Regulatory Requirements Requirements of Society Conformance to Standards DIMENSIONS OF QUALITYThe dimensions of quality are nothing, but the various features of a product or service.
Quality control • The operational techniques and activities employed to achieve and maintain the quality of a product, process or service. • It involves Monitoring activity • It finds out and eliminates the causes of quality problems • Juran gives 3 steps of QC : • Evaluation actual operating performance • Compare actual performance to goals • Act on the difference Quality assurance • Quality assurance, refers to planned and systematic production processes that provide confidence in a product's suitability for its intended purpose
Total Quality Management (TQM) [Company Wide Quality Control (CWQC)] • It is a process which involves the whole organization, every department ,every activity, every single person at every level in the production of quality products. • Responsibility….(As per TQM) • Design department • Purchase department • Machine operators • Inspection department • Marketing service department
key factors for the success of TQM • “Fit for purpose" (the product should be suitable for the intended purpose) and “Right first time" (mistakes should be eliminated). • Use statistical process charts & control charts • For variation in quality, the route cause must be found out • Don’t fight with person – but fight for the issue • Ensure total involvement of all the employees. • Look for continuous improvement in the major contributing factors of TQM.
Total Quality Management (TQM)….. • European Construction Institute (1993) recommends the following objectives to achieve TQM in construction: • C – Commitment by top management • O – Organization and structure for total quality management • N- Normal financial control • S – Supplier relationships • T – Training, education and safety awareness
Total Quality Management (TQM) ….. • R – Relationships with customers • U – understanding and commitment by employees • C – Communications • T – Teamwork • I – Independent certification to ISO 9000 • O – Objective measurement • N – Natural use of tools and techniques
Total Quality Management (TQM) Customers will seek out the highest quality product. Improved quality that exceeds customer expectations will generate more revenues that exceed the cost of quality. Therefore, quality is “free”.
Total Quality Management (TQM) W. Edwards Deming proposed that improving quality reduces cost and improves profitability. Quality can be and should be improved continuously. Revenues Max Profit Cost Max Quality
What is QCProblem Solving ? “Problem solving, the isolation and analysis of a problem and the development of a permanent solution, is an integral part of the quality-improvement process”. Not hit or miss, but objective and systematic Not directed at symptoms, but rather at root causes
Problem Solving Process Symptom Recognition Fact Finding Problem Identification Follow Up Idea Generation Solution Development Plan Implementation
All Managers Need Problem Solving Skills 80% of problems are external to QC organizations Quality problems transcend individual functions Companies need multi-discipline problem solving approach Management involvement and commitment is crucial
Problem Solving Skills for Managers Understand and utilize a systematic problem solving process Ask the right questions Present information clearly and unambiguously Make judgments based on information
Kaizen: Implementation • The Deming cycle: Originally developed by Walter Shewart, but renamed in 1950s because Deming promoted it extensively.
Kaizen: Implementation • Plan– Study the current system; identifying problems; testing theories of causes; and developing solutions. • Do – Plan is implemented on a trial basis. Data collected and documented. • Study– Determine whether the trial plan is working correctly by evaluating the results. • Act– Improvements are standardized and final plan is implemented.
10 Problem Solving Steps Recognize Problem Continuous improvement Form quality improvement teams Ensure performance ACT Define Problem Evaluate Solution Analyze Problem STUDY PLAN Determine Possible Causes DO Identify Possible Solutions Implement Solution
Plan: study current situationDo: implement plan on trial basisStudy: determine if trial is working correctlyAct: standardize improvements
Process Analysis Method UNDERSTAND SELECT ANALYZE ADOPT PLAN CHECK DO
PDSA and QC Tools Brainstorming Pareto analysis ACT ACT PLAN PLAN Why-Why diagram Run charts Cause and effect diagram STUDY STUDY DO DO Control charts Histograms Scatter diagrams Check sheets Control charts Scatter diagrams Check sheets Pareto charts Run charts
BrainstormingBrainstorming to encourage creative thinking and generation of ideas Purpose - generate a list of problems opportunities ideas Success requires no criticism no arguing no negativism no evaluation Problems for“Why-Why” discussion • Construct a “Why-why” diagram • List problem statement • Ask why 5 times; record responses
Chapter 15 Quality Management • Cost of Quality Measurements • Thecost of qualityrefers to the costs associated with avoiding poor quality or those incurred as a result of poor quality. • Prevention costsare those expended to keep nonconforming goods and services from being made and reaching the customer. • Appraisal costsare those expended on ascertaining quality levels through measurement and analysis of data to detect and correct problems.
Chapter 15 Quality Management • Cost of Quality Measurements • Internal-failure costsarecosts incurred as a result of unsatisfactory quality that is found before delivery of good or service to the customer. • External-failure costsare incurred after poor-quality goods or services reach the customer.
Statistical Process Control • The objective of process control is to control the quality of the processes and ensure that the deliverables are produced as planned • The aim of statistics based process controls to produce products and services with quality consistently. The application of statistics to quality control hasenabled quick analysis and control of quality in all types of businesses. STATISTICS : Collection,Organization,Analysis,Interpretation and Presentation of data.
Ishikawa’s Basic Tools of Quality Kaoru Ishikawa developed seven basic visual tools of quality so that the average person could analyze and interpret data. These tools have been used worldwide by companies, managers of all levels and employees
The 7 Quality Tools are Problem Solving Tools which can • Help to identify and prioritise problems quickly and more effectively. • Assist the decision making process. • Provide simple but powerful tools for use in continuous improvement activity. • Provide a vehicle for communicating problems and resolutions throughout the business. • Provide a way of extracting information from the data collected.
Why do we need the 7 QC tools? TQM is data driven: data are impersonal; opinions are not. Experience is gained quickest by collecting and analyzing data. The 7 QC tools provide common methods of analysis to help problem solving teams operate effectively.
Goals of SPC • Collection of data of performance of products and service deliverables • Finding out variations • Analyzing through brain storming and determining the causes and eliminating the causes • Improving performance of processes continuously
Process improvement: Kaizen • Every employee strives for improvement. Top management views improvement as part of strategy and supports it. • Middle management can implement top management’s improvement goals by establishing, maintaining, and upgrading operating standards. • Workers can engage through suggestions, small group activity. • Middle management can help create conducive environment for improvement by improving cooperation amongst departments, and by making employees conscious of their responsibilities for improvement. • Supervisors can direct their attention more on improvement than supervision, which will facilitate communication.
Process management • Planning and administrating the activities necessary to achieve high quality in business processes; and also identifying opportunities for improving quality and operational performance – ultimately, customer satisfaction. • Process simplification reduces opportunities for errors and rework. • Processes are of two types – value-added processes and support processes. • Value-added processes – those essential for running the business and achieving and maintaining competitive advantage. (Design process, Production/Delivery process)
Process management • Support processes – Those that are important to an organization’s value-creation processes, employees and daily operations. • Value creation processes are driven by external customer needs while support processes are driven by internal needs. • To apply the techniques of process management, a process must be repeatable and measurable. • Process owners are responsible for process performance and should have authority to manage the process. Owners could range from high-level executive to workers who run a cell. • Assigning owners ensures accountability.
Process control • Control is the activity of ensuring the conformance to the requirements and taking corrective action when necessary. • Two reasons for controlling the process • Process control methods are the basis of effective daily management of processes. • Long-term improvements can not be made to a process unless the process is first brought under control. • Short-term corrective action should be taken by the process owners. Long-term remedial action should be the responsibility of the management.
Process control Effective quality control systems include • Documented procedures for all key processes • A clear understanding of the appropriate equipment and working environment • Methods of monitoring and controlling critical quality characteristics • Approval processes for equipment • Criteria for workmanship: written standards, samples etc. • Maintenance activities
Process improvement • Customer loyalty is driven by delivered value. • Delivered value is created by business processes. • Sustained success in competitive markets require a business to continuously improve delivered value. • To continuously improve value creation ability, a business must continuously improve its value creation processes. • Continuous process improvement is an old management concept dating back to 1895. However, those approaches were mainly productivity related. • More recently (1951) Toyota implemented Just-In-Time which relies on zero defects and hence continuous improvement!
Process improvement: Kaizen • Japanese for gradual and orderly continuous improvement over a long period of time with minimum financial investment, and with participation by everyone in the organization. • Improvement in all areas of business serves to enhance quality of the firm. • Three things required for successful kaizen program: operating practices, total involvement, and training. • Operating practices expose opportunities for improvement. JIT reveals waste and inefficiency as well as poor quality.
Kaizen: Implementation Juran’s breakthrough sequence: • Proof of the need • Project identification • Organization for breakthrough – two paths identified: symptom to cause (diagnostic) and cause to remedy (remedial) paths. • Diagnostic journey • Remedial journey • Holding the gains.
The Seven QC Tools(Process improvement tools) • Histograms • Control Charts & Run Charts • Check sheets • Pareto Charts • Cause and Effect Diagrams • Scatter Diagrams • Process Flow Charts
Histograms A graphical display of the frequency distribution of attributes. Defects Lead Indicators of Quality Variation indicates poor quality. To measure variation, there are several tools that can be used: Histograms Run Charts Control Charts
Cause-and-Effect Diagrams Cause-and-Effect Diagrams Scatter Diagrams Process Flow Charts Pareto Charts Diagnostic Information While Lead indicators tell that there IS a problem, Diagnostic tools help to determine WHAT the problem is. While lead indicators tell that there IS a problem, diagnostic tools help determine WHAT the problem is.
The “Seven QC Tools” • Flowcharts: process mapping to identify the sequence of activities or flow of materials/ information in a process. • Run Charts and Control Charts: a run chartis a line graph with data plotted over time; control chartsinclude control limits. • Checksheets: simple tools for data collection, ensure completeness. • Histograms:graphically represent frequency of values within a specified group.
The “Seven QC Tools”….. 5. Pareto Diagrams: separate the vital few from the trivial many causes; provide direction for selecting projects for improvement. Pareto analysis to separate the major causes of the problems form the minor ones 6. Cause-and-Effect Diagrams: represent chain of relationships; often called a fishbone diagram. To identify potential causes of a problem 7. Scatter Diagrams: graphical component of regression analysis. Often used to point out relationship between variables. Statistical correlation analysis used to interpret scatter diagrams
Histograms • Histograms are powerful tools for elementary analysis of data that contain variations. • A histogram is a diagram which represents the class interval and frequency in the form of a rectangle. • There will be as many adjoining rectangles as there are class intervals.