Quality theories Quality management Lecture 3.

Theory: coherent group of propositions used as principles pf explanation for a class of phenomena What: elements How: direction of relationship Why: connection between them Who-where-when: boundaries, when the relationship is true 1. phenomena Quality improvement Improved worker morale +

2 ways of estabilish theories Induction: Collect dataanalyzeproposition Deducion: Propose a model Collect dataTest theory

History of quality management Early 1920Scientific management (Taylor, Gilbreth) 1920sStatistical process control (Shewart) 1930sAcceptance sampling (Dodge, Roming) 1940sMilitary standards introduced 1950sQuality management in Japan (Deming, Juran) 1960sTaguchi method, and quality tools 1970sQuality becomes strategic (USA) 1980sIntroduction of LEAN, TQM, Baldrige Award 1990sReengineering, Six Sigma 2000sSupply chain management, improvement of supplier development, LEAN, Six sigma become popular, contingency theory

Quality and taylorism Basics of taylorism –The whole process is divided into short steps (division of labor) –It is not the worker who determine the process/movements -specialist do that (task management) –Workers are selected and trained for work –Standard movements and tools, detailed instructions (standardization) Quality effects: –Product and process design were separated from the repair of product –Workers were not responsible for repairing of product –Quality control department was established to control the product at the end of the process –The responsibility for quality were spread over in the company

Deming Not just worker but managers have the responsibility for establishing quality –Workers are responsible for special problems –Managers are responsible for the whole system (proper methods, equipments, motivation system etc.) Quality improvement must be divided between the two level

Juran Quality problems are rooting in insufficient and ineffective planning for quality In traditional way: –Planning determine the tools for producing goods –20% of the operating process is waste, it is planned into the product or process –Instead of quality improvement they only do quality control Juran trilogy –Planning –Control –Improvement

Ishikawa Democratizing statistics: everyone is responsible for statistical analyzes, total involvement of the operating employees in improving quality Basic 7 tools of quality –Process map – flow chart, step of process –Check sheet – to collect errors for analyzes –Histogram – graphic representation of data –Scatter Diagrams – examine the relationship between variables (what cause the problem) –Control Chart – is the process stable or not –Cause-and-effect (Ishikawa) diagram – find all reason of the problem, directed tool for find all causes –Pareto Chart – prioritize causes, determine problems must be focused on

Feigenbaum Father of Total Quality Control (TQC) the entire organization should be involved in quality improvement The quality is poor –If the product is designed incorrectly (engineering) –If the product is released in the wrong market –If the customer relationship is not proper. (marketing) 3 steps of improvement 4 deadly diseases

Crosby Crosby’s four theorem –Quality is the conformance to the requirements of customers. The whole system must be developed according to this approach. –The main goal is zero- defect. Do the right product at the first time. –Thus the applied method for quality assurance is prevention not control. –Quality can be a source of profit. Quality costs must be evaluated, and on the basis of these costs, corrective actions should take place.

Taguchi Quality definitions: quality is measured in terms of loss to society if the service not performed as expected. Quality Loss Function (QLF): any deviation from target value results in loss to society Robust Design: products should be designed to be defect-free –Concept design (technology and process choices) –Parameter design (select parameters which have an effect on quality – amount of training, heights of a paper) –Tolerance design (deals with decrease variation in order to fulfill the specification limits – use a higher-grade materials)

Contingency theory There are no schemes, firms do not have to use only one quality approach Successful firms adopt aspects of each approach that help them improve, understand them, and apply them creatively. It depends on the situation which approach is the best.

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