ABSTRACT
Quality should be built into the product very early in its design stage in a proactive manner than reacting to any defects that occur after the product is launched in the market This proactive approach is called “Creating Quality” (Kolarik, 1995) Thus, all product design teams should strive to create quality by designing the product that the customer would want The Systems Engineering (SE) process discussed earlier (see Chapters 1 and 2) clearly implements this approach
In the Quality Engineering and the Quality Management fields, there are following well-developed approaches to implement quality in products and processes: (1) Total Quality Management (TQM), (2) ISO 9000 Series Standards for organizations, (3) Criteria for Malcolm Baldridge Quality Award (performance criteria to evaluate organizations based on their quality-related accomplishments), (4) Six-Sigma Improvement Methodology (using DMAIC, ie, Define, Measure, Analyze, Improve, and Control approach), and (5) Design for Six Sigma (DFSS) (using IDOV, ie, Identify, Design, Optimize, and Verify approach) The above five approaches are complementary in their implementation in the sense that an organization seeking to improve quality can apply anyone or more of the approaches
The objectives of this chapter are to provide general background into the above quality initiatives and to discuss their importance in creating quality products
Quality is determined by the customers Therefore, there is no unique definition for quality The customer needs and customer perceptions of a product can vary widely And thus various definitions can be used to define quality Kolarik (1995) provides an excellent discussion on classical definitions of quality Some commonly referred definitions of quality and basic considerations in quality are given below
1 Quality is an inherent feature, a peculiar, identifying, or essential characteristic, a degree of excellence that constitutes the basic nature of a thing or one of its distinguishing attributes (Webster’s, 1980)
2 Quality is the totality of features and characteristics of a product or service that bear on its ability to satisfy stated or implied needs now and in the future (ANSI/ASQC, 1987)
3 Quality is customer satisfaction and loyalty Quality is customer focused (Gryna et al, 2007)
4 Quality is fitness for use, meeting and exceeding customer expectations (Juran and Godfrey, 1999)
5 Quality is conformance to requirements (clearly stated) (Crosby, 1979) 6 Quality should be aimed at the needs of the consumer, present and future
(Deming, 1986) 7 Quality (Q) = P/E = (Performance of the product)/(Expectations of the cus-
tomers about the product) 8 A widely quoted definition of product quality was provided by Garvin (1984,
1988) He suggested that the quality of a manufactured product should be based on the following eight dimensions:
a Performance: Product’s ability to perform its basic functions b Features: Product features that add to its usefulness, comfort, and
convenience c Reliability: Product’s ability to perform without failure over time d Conformance: Degree to which the product meets its applicable codes
(or regulations/standards) of state or community e Durability: The length of time the product will last before it is retired
from service f Serviceability: Ability to make repairs quickly and at reasonable costs g Aesthetics: The look, feel, and design/styling or appeal of the product h Perceived quality: The impression of quality created by the product in
the customer’s mind 9 Other dimensions of quality suggested in the literature are perfection, con-
sistency, eliminating waste, speed of delivery, compliance with policies and procedures, providing a good usable product, “Doing it right the first time,” delighting or pleasing the customers, and total customer service and satisfaction
A number of practitioners and researchers in the Quality Management field have provided useful insights into understanding quality-related issues and concepts Some important observations from the literature are provided below
1 Quality is a business issue It is no longer only the quality manager’s job Quality relates to everything in an organization-all individuals and all processes must be involved Quality demands specialized knowledge, training, and tools The TQM approach leads to successful organizations Organization must have a well-developed Quality Management System (QMS) and it must be followed by all in the organization (Kolarik, 1995; Gryna et al, 2007; ISO, 2012)
2 About 85% of poor quality is attributable to the system (management) and only 15% is attributed to the worker (Deming, 1986) Thus, the management must take an active role in creating quality
3 Understand the purpose of inspection Inspection is for improvement of processes and reduction of cost (Deming, 1986) (It is not just to scrap nonconforming parts)
4 Juran’s trilogy showed that (1) quality planning, (2) quality control, and (3) quality improvements are three interrelated processes in quality management (Gryna et al, 2007 Juran and Godfrey, 1999) First, the quality actions must be planned through understanding customer needs Second, the processes that produce products must be controlled to ensure that they deliver what is important to the customers And third, improvements must be made from the measurements (data) obtained during the quality control processes
5 The system for causing quality is prevention of defects, not appraisal The performance standard is zero defects Quality is free (Crosby, 1979)
6 Systems approach must be implemented to improve quality (Feigenbaum, 2004) Quality problems must be approached by studying the whole system; that is, all aspects of the system affecting the customer satisfaction must be studied
7 Product and process design should be immune to uncontrollable factors; that is, products should be designed by considering “robustness” (Performance of “Robust” products is not affected by factors that we cannot control) Quality must be designed into the product (Taguchi, 1986; Phadke, 1989)
8 The degree of match between the “true” and “substitute” quality characteristics ultimately determines customer satisfaction (Ishikawa, 1985) A measure (variable) used to evaluate quality (labeled as “substitute” quality characteristic by Ishikawa) must be selected carefully to ensure that it is truly related to the customer’s perception of quality
Many possible measures (variables) can be used to measure product quality and its attributes Since the ultimate evaluator of product quality is the customer, most measures of quality are subjective (ie, they are based on the judgments or ratings made by the customers based on their exposure/experience with the product) Objective measures based on measurements of certain physical characteristics of products (such as dimensions, temperature, air flow, surface finish or roughness, compressibility, and power consumption) can also be used if such measures can be related to the perception of quality or customer satisfaction (Such measures are used as the “substitute” quality characteristics [Ishikawa, 1985]; see point 8 in the earlier list)
Some commonly used measures of quality of automotive products are as follows:
1 Percentage of customers satisfied 2 Number of defects observed by the customers per vehicle 3 Number of things gone wrong (TGWs) per 100 vehicles sold
4 Number of things gone right (TGRs) per 100 vehicles sold 5 Number of products returned for repair 6 Ratings on customer satisfaction or how well they liked or disliked the
product (eg, using a 10-point scale, where 10 = liked very much and 1 = disliked very much)
The counts of TGW and TGR can be obtained from customer feedbacks from mail surveys, dealer received complaints, repair/warranty data, and market research clinics, where owners provided face-to-face feedback on “what they liked or disliked” about the product and “what didn’t work well”
Other product quality measures that are used are based on measurements of physical product characteristics, product functions, and product performance under various specified operating conditions Some examples of physical measures used are (1) values of engineering parameters, for example, use of a CMM (coordinate measurement machines) to measure critical dimensions of parts, (2) performance measures that can be measured by test equipment (eg, use of engine dynamometers to measure engine output torque vs speed relationships), and (3) recordings using sensors and/or video equipment (eg, strength measurements, sound/noise measurements, temperature measurements, fluid flow and velocity measurements, and deceleration levels of human dummies in vehicle crash tests)
Cost-based measures of quality are also used in the industry They are based on the following four types of quality-related costs: (1) prevention costs (eg, design reviews, training, and analyses), (2) appraisal costs (eg, inspection, testing, and auditing), (3) internal failure costs (eg, scrap, rework, and repair related costs when the product is in the manufacturer’s facilities), and (4) external failure costs (eg, returned products, handling customer complaints, and re-inspection/repair related costs when the product is used by the customers) (see Chapter 8 and Campanella [1990])
Other performance measures of quality of an organization can be based on (1) ISO 9001 certification (quality can be inferred based on whether the product producing organization is certified or not), (2) findings during quality audits, and (3) scores on the Baldridge award criteria (NIST, 2013) (Note: ISO 9000 standards and Baldridge award criteria are covered in a later section of this chapter)
Customer satisfaction with a product is dependent on provision of various features related to different attributes of the product Figure 91 presents three figures to explain the relationship of the product features to customer satisfaction The abscissa of the figures represent how a desired product attribute is achieved in terms of percent achieved The ordinate of the figures represents customer satisfaction in terms of percentage of customers satisfied
Certain features are “basic” The customer expects these features to be standard (ie, always available in the product) These are considered as “unspoken wants” Absence of such basic features will dissatisfy the customers However, provision of these features will not increase percentage of satisfied customers beyond some level (eg 50%; see Figure 91a) However, customers like and want more of certain
other types of features Thus, number of such features should be increased to improve customer satisfaction These are shown in Figure 91b as the “ satisfiers” And the third types of features are the ones that create impressions of “Wow’ because the customers have never expected or seen such features in such a product and they are excited and delighted to have these features These features are shown in the bottom of Figure 91c
These three types of features described above are the three basic components of the Kano Model of Quality Kano, a Japanese quality researcher, conceptualized that customer satisfaction is affected by three types of product features, namely: (1) the removal of the “dissatisfiers” (ie, providing the “unspoken wants,” otherwise dissatisfaction arises if the product does not provide what the customer expects), (2) increasing “satisfiers” (giving more of these features increases satisfaction with the product), and (3) adding “delighters” (that create “Wows” when present but do not cause dissatisfaction if not incorporated in the product) (Yang and El-Haik, 2003)
A careful study of all the three types of product features (either available in the market currently or new features that could be developed by studying new design and technological trends) and their incorporation in the product are essential to enhance product quality and customer satisfaction These three types of features should be considered during the early stages of product development and should be included during the development of the product attribute requirements
TQM is defined as both a philosophy and a set of guiding principles that represent the foundation of a continuously improving organization The purpose of the TQM is to provide quality products and/or services to its customers Quality products, in turn, will increase the organization’s productivity and lower its costs (Besterfield et al, 2003)
The guiding principles of the TQM involve the following steps:
1 Continuously improving organization 2 Application of quantitative methods (covered in Chapter 14) 3 Application of human resource and training 4 Improving all processes within an organization 5 Exceeding customer needs now and in the future
The TQM is also based on the following six basic concepts:
1 Committed and involved management 2 Unwavering focus on customers 3 Effective involvement and utilization of the entire workforce 4 Continuous improvement of all business and production processes 5 Treating suppliers as partners 6 Establishing performance measures for processes
The letter “T” in the TQM stands for “Total” which means that everyone in the organization, all functions, and all processes must be subject to application of quality principles such as (1) continuously improving all operations performed in the organization, (2) customer focus in all operations performed by all in the organization, and (3) application of quality methods in improving all processes The second letter “Q” stands for quality that means “customer satisfaction” Thus, everyone in the organization must understand their roles in how to satisfy their customers and strive continuously to improve customer satisfaction The third letter “M” in the TQM stands for management, which means that quality must be actively managed as a business process by collecting data on the performance of all of their processes, applying quality tools, and monitoring all processes to improve customer satisfaction continuously
The ISO 9000 is a series of Quality Standards developed by the International Organization for Standards (ISO) to facilitate international trade by establishing common set of standards The standards identify the key elements of quality system and require that organizations develop a quality system and follow the system to improve quality of their products and services
The quality system comprised of all the organization’s policies, procedures, plans, resources, processes, and delineation of responsibility and authority, all deliberately aimed at achieving product or service quality levels consistent with customer satisfaction and the organization’s objectives When these policies, procedures, plans, and others are taken together, they define how the organization works, and how quality is managed (Goetsch and Stanley, 1998)
Organizations find that they have to achieve the ISO 9000 certification to meet both domestic and international competition The revised ISO 9000:2000, 9001:2008, and 9004:2009 documents define the eight-quality management principles on which the QMS standards of the series are based (ISO, 2012) These principles can be used by senior management as a framework to guide their organizations toward improved performance
Brief descriptions of the eight principles as provided by ISO (2012) are presented:
1 Customer focus: Organizations depend on their customers and therefore should understand current and future customer needs, should meet customer requirements, and strive to exceed customer expectations
2 Leadership: Leaders establish unity of purpose and direction of the organization They should create and maintain the internal environment in which people can become fully involved in achieving the organization’s objectives
3 Involvement of people: People at all levels are the essence of an organization and their full involvement enables their abilities to be used for the organization’s benefit
4 Process approach: A desired result is achieved more efficiently when activities and related resources are managed as a process
5 System approach to management: Identifying, understanding, and managing interrelated processes as a system contributes to the organization’s effectiveness and efficiency in achieving its objectives
6 Continual improvement: Continual improvement of the organization’s overall performance should be a permanent objective of the organization
7 Factual approach to decision making: Effective decisions are based on the analysis of data and information
8 Mutually beneficial supplier relationships: An organization and its suppliers are interdependent and a mutually beneficial relationship enhances the ability of both to create value
Malcolm Baldrige award is administered by the National Institute of Standards and Technology (NIST) of the US Department of Commerce and given annually by the President of the United States to small and large businesses in manufacturing and service, and to education and healthcare organizations that apply and are judged to be outstanding in the following seven areas: (1) leadership; (2) strategic planning; (3) customer focus; (4) measurements, analysis, and knowledge management; (5) workforce focus; (6) process management; and (7) results (NIST, 2013)
The criteria are used by thousands of organizations of all kinds for self-assessment and training and as a tool to develop performance and business processes Many organizations have found that using the criteria results in better employee relations, higher productivity, greater customer satisfaction, increased market share, and improved profitability
The purpose of the award is to help improve quality and productivity of the US businesses and industries by: (1) stimulating American companies to improve quality and productivity, (2) recognizing the achievements of those companies that improve the quality of their goods and services and providing them as examples to others, (3) establishing guidelines and criteria that can be used by business, industrial, governmental, and other organizations in evaluating their own quality improvement efforts, and (4) providing specific guidance for other American organizations that wish to learn how to manage for high quality by making available detailed information on how winning organizations were able to change their cultures and achieve eminence (NIST, 2013)
Six Sigma is a systematic methodology for creating sustained improvements to sixsigma levels in important production and other repetitive processes The “Six Sigma” term also refers to a philosophy, goal, and/or methodology utilized to drive out waste and improve the quality, cost, and time performance of any business DFSS is a systematic methodology to design products and processes that will meet customer expectations at a six-sigma level (Creveling et al, 2003; Yang and El-Haik, 2003) The steps and tools used in the six-sigma methodologies are provided in Tables 122 and 123; and quality tools used in the six-sigma applications are described in details in Chapter 14
The six-sigma philosophy is used to reduce the defect rates to very low levels, particularly at or above the six-sigma level To achieve six-sigma level, defect rate is equivalent to reducing the variability of each product (or service) parameter (ie, critical to customer satisfaction) such that its 12 standard deviation (±6σ) tolerance will be smaller than its customer acceptance region (ie, the difference between the upper and lower specification levels of the product parameter) This requirement along with a ±15σ range of allowance on the location of mean value (μ) of the parameter maintains the defect rate below 34 defects per million opportunities This is equivalent to meeting the product parameter acceptance level at 99999660% Such a high level of quality (ie, very low-level defect rates) are particularly important for developing complex products that have many entities (systems, subsystems, and components), many product attributes, many attribute requirements, and many production operations This issue is further discussed in Chapter 16 and illustrated in Table 161 by considering combinations of different levels of reliability and number of entities or production steps
DFSS is a systematic methodology to design products and processes that should meet customer expectations at the six-sigma level The four phases in the DFSS approach can be remembered by the acronym IDOV The phases involve (1) Identify requirements, (2) Design using inventive approaches, (3) Optimize the design, and (4) Verify the design The approaches and methods used in the four phases of the approach are described in Table 123
The phase I of this approach typically involves identification of requirements by (1) forming a cross-functional design team, (2) determining customer expectations (eg, by application of QFD; see Chapter 13), and (3) determining product functionality based on customer requirements, technological capabilities, and economic realities
The phase II of the approach involves creating a design by (1) generating design alternatives, (2) focusing on product and process performance issues and variability factors that affect variables that are critical to quality (CTQ), and (3) evaluating design alternatives
Phase III involves optimizing the design by seeking to minimize the impact of variations in production (eg tolerances of critical product dimensions and tolerance stack-up when parts are assembled) and uses (ie, when the product is used by a variety of users in different usage situations and environmental conditions) and thus, creating a “robust” design (Phadke, 1989) (see Chapter 14 for Taguchi’s concepts)
And phase IV involves verifying the design by particular attention to variables that are CTQ by use of various evaluation methods (see Chapter 6) It should be noted that the above process has many similarities with the systems engineering process described in Chapter 2
The tools used to analyze problems in the quality-related fields can be grouped in the following three categories:
1 Seven traditional or basic quality tools (eg, cause and effect diagram, check sheet, histogram, scatter diagram, stratification, Pareto chart, and control charts) These traditional tools are used primarily in reactive mode
(ie, after the product or its entities are produced) to improve their quality They are mostly quantitative in nature; that is, they handle quantitative data Their format allows visualization of quality issues/problems They are used primarily on the shop floor Any of the tools can be used with any other tools
2 Seven new quality tools (ie, relations diagram, affinity diagram, tree diagram, matrix diagram, matrix data, arrow chart, and process decision program chart) These tools are mainly used in proactive manner (to create quality during the early stages of product development) They are used primarily for planning and by management (for brainstorming) They are qualitative in nature and more effective when used by multifunctional teams They are also visual, that is, they help in visualizing problems, issues, and relationships Any of the tools can be used with any other tools
3 Other product/process development tools include Benchmarking, quality function deployment (QFD), Pugh diagram, failure modes and effects analysis (FMEA), fault tree analysis (FTA), reliability analyses, experiment design, computer-aided design, computer-aided engineering, prototyping, computer-assisted process planning, computer-assisted manufacturing, and so forth
The above quality tools are described in Chapter 14 Other tools (eg, QFD, FMEA, FTA, and reliability analysis) are covered in Chapters 13 and 16
This chapter provided an overview on the definitions of quality, concepts considered in quality, and three major approaches used to improve quality, namely, Total Quality Management, ISO 9000 Certification, and Six-Sigma Methodologies Product quality is a very important area Measurement of perception of quality is a difficult area because quality is subjective and the customers can differ widely on what constitutes quality However, customer-based quality measures are useful in improving customer satisfaction Many currently used measures of quality were reviewed The Kano model of quality helps understand how the product features can be categorized into unspoken wants, satisfiers, and delighters and their relationship to customer satisfaction Many useful tools used in the quality area are presented in Chapter 14
