“You don’t inspect quality into a product: You have to build it in.” Discuss the implications of this statement.
Answer. The saying, "You don't inspect quality into a product, you have to build it in!" emphasizes the shift in emphasis from inspection to prevention
Investing in prevention can be economic. A typical factory invests 20 to 25 percent of its operating budget in finding and fixing mistakes. One fourth of all workers fix things that are not done right. These are appraisal and internal failure cost. On the other hand, if quality standards are enforced as the item is being built, appraisal, internal and external failure costs will decrease while prevention costs will increase. The rule of thumb is that for every dollar spent in prevention, ten dollars are saved in failure and appraisal costs.
What is quality? This is a multifaceted question, difficult to address in the abstract. It is easier to understand quality by considering its evolution in leading companies. In the United States and Europe, quality control of one sort or another has been part of manufacturing for more than a hundred years, and the use of various quality concepts has come and gone and come again.
By contrast, in Japan quality control was not significant until after World War II. In Japan as in the United States, however, the spectrum of quality practices ranges from none at all to the leading edge, where progress has been rapid and uniform.
At the beginning of this evolutionary process, quality of any kind is not noticed or measured. Goods are produced and shipped. If customers want to send something back, they do so –en of the story.
Quality in product development began with attempts to inspect quality into products or services either in the process domain (scrap and rework), the design domain (verification tests and durability failures) or the customer domain (warranty costs and complaints). The evolution of quality involved a significant mind-set transition from reacting to inspection events to utilizing process patterns in engineering and manufacturing to build quality into the product. Recent developments in quality engineering involve the use of structural tools to lay the proper foundation for good design and enable the process-level methods to work better. Six Sigma is used to react to or fix unwanted events in the customer, design or process domains. DFSS is used to prevent problems by building quality into the design process across domains at the pattern level of thinking. Use of new structural tools such as TRIZ (a Russian acronym for “theory of inventive problem solving”) and axiomatic design provide a foundation for future enhancement of Six Sigma methodologies.
Model of Product Development
The process of design involves understanding what you want to achieve and then selecting a strategy that achieves that intent. The creation of great products or services involves selecting strategies associated with four primary activities or domains: customer domain, functional domain, physical domain and process domain. The customer domain consists of customer attributes—a characterization of needs, wants or delights that define a successful product or service from a customer perspective. The functional domain consists of functional requirements—a characterization of design goals or what the product or service must achieve to meet customer attributes from the viewpoint of the designer. The physical domain consists of design parameters—the collection of physical characteristics or activities that are selected to meet functional goals. The process domain consists of process variables—the collection of process characteristics or resources that create the design parameters.
The development of products or services is highly iterative and involves selecting elements in each domain and mapping these elements from one domain to another. The better the mapping between these domains, the better the design.
The History and Evolution of Quality
The early history of quality in product development was based upon event thinking in the various design domains. After World War II, the primary way of assuring quality to customers was inspection after the process domain. Parts were produced, and then these parts were checked to see if they were good enough to ship. If the parts were not good, then an event occurred, resulting in rework or scrap and problem solving.
Popular and Powerful Methods
In subsequent years, about 120 different quality tools and methods have been created at the pattern level for designers to manage product development process trends, making inspection events a nonevent. Some of the most popular and powerful methods are SPC and QFD, include: failure mode and effects analysis (FMEA) for both the product and process domains, Genichi Taguchi's methods of parameter design (for the product and process domains) and tolerance design (for the product domain), design for assembly (DFA) and design for manufacturing (DFM), which improve the mapping from the product to the process domain, and system engineering, value analysis (VA) and value engineering (VE) in the functional domain.
The transition from event thinking to pattern thinking is the transition from find and fix to prevent. In the words of Henry Wadsworth Longfellow, “It takes less time to do a thing right than it does to explain why you did it wrong.” So then why not do it right the first time? The payoff in warranty savings, customer satisfaction and productivity more than offset the relatively modest investment in longer-term thinking.
The transition from event thinking to pattern thinking is also the transition from Six Sigma to Design for Six Sigma (DFSS). Companies that rely on event thinking and utilize Six Sigma realize that about 80% of the problems they are fixing (and the money they are saving) are determined by design. DFSS is a rigorous approach to designing products and services from the very beginning to ensure that they meet customer expectations. DFSS is an integration of all the prevent quality tools across the pattern level domains. Use of DFSS results in sigma levels between 5 and 6. Further improvement requires implementation of structural thinking tools. The role of DFSS is to build quality into the design by implementing prevent thinking and tools in the product development process. DFSS is, in fact, an integration of prevent methods at the pattern level across all four domains.
