Engineering Design Lecture 4 PDF

Engineering Design ET ZC413 Lecture - 4 BITS Pilani Dr. Glynn John Pilani Campus Mechanical Engineering  Customer need identification and Product Specifications Customer need identification...

Engineering Design ET ZC413 Lecture - 4 BITS Pilani Dr. Glynn John Pilani Campus Mechanical Engineering  Customer need identification and Product Specifications Customer need identification Gather Raw Data from Customers Choosing Customers The Art of Eliciting Customer Needs Data Documenting Interactions with Customers Interpret Raw Data in Terms of Customer Needs Organize the Needs into a Hierarchy Establish the Relative Importance of the Needs Reflect on the Results and the Process Benchmarking in General Competitive Performance Benchmarking Reverse Engineering or Product Dissection Quality Function Deployment The House of Quality Configurations Steps for Building a House of Quality Product Specifications 17 August 2024 2 Identifying Customer Needs 17 August 2024 ENGINEERING DESIGN 3 Goals Product Design DE ZG541 BITS 8/17/2024 4 Pilani Gather Raw Data from Customers 1. Interviews: One or more development team members discusses needs with a single customer. Interviews are usually conducted in the customer’s environment and typically last one to two hours. 2. Focus groups: A moderator facilitates a two-hour discussion with a group of 8 to 12 customers. Focus groups are typically conducted in a special room equipped with a two-way mirror allowing several members of the development team to observe the group. 3. Observing the product in use: Watching customers use an existing product or perform a task for which a new product is intended can reveal important details about customer needs. For example, a customer painting a house may use a screwdriver to open paint cans in addition to driving screws. Product Design DE ZG541 BITS 8/17/2024 5 Pilani Gather Raw Data from Customers 4. Customer complaints: These may be recorded by communications (by telephone, letter, or email) to a customer information department, service center or warranty department, or a return center at a larger retail outlet. Third party Internet websites can be another source of customer input on customer satisfaction with a product. 5. Warranty data: Product service centers and warranty departments are a rich and important source of data on the quality of an existing product. Statistics on warranty claims can pinpoint design defects. 8/17/2024 6 The Art of Eliciting Customer Needs Data When and why do you use this type of product? Walk us through a typical session using the product. What do you like about the existing products? What do you dislike about the existing products? What issues do you consider when purchasing the product? 8/17/2024 7 Documenting Interactions with Customers Audio recording Notes Video recording Still photography The final result of the data-gathering phase of the process is a set of raw data, usually in the form of customer statements but frequently supplemented by video recordings or photographs. 8/17/2024 8 Step 2: Interpret Raw Data in Terms of Customer Needs Product Design DE ZG541 BITS 8/17/2024 9 Pilani Step 3: Organize the Needs into a Hierarchy The result of steps 1 and 2 should be a list of 50 to 300 need statements. Such a large number of detailed needs is awkward to work with and difficult to summarize for use in subsequent development activities. The goal of step 3 is to organize these needs into a hierarchical list. The list will typically consist of a set of primary needs, each one of which will be further characterized by a set of secondary needs. In cases of very complex products, the secondary needs may be broken down into tertiary needs as well. 8/17/2024 10 Step 4: Establish the Relative Importance of the Needs The development team will have to make trade-offs and allocate resources in designing the product. A sense of the relative importance of the various needs is essential to making these trade-offs correctly 8/17/2024 11 Step 5: Reflect on the Results and the Process Have we interacted with all of the important types of customers in our target market? Are we able to see beyond needs related only to existing products in order to capture the latent needs of our target customers? Are there areas of inquiry we should pursue in follow-up interviews or surveys? Which of the customers we spoke to would be good participants in our ongoing development efforts? 8/17/2024 12 Translate to need statements 8/17/2024 13 Translate to need statements “See how the leather on the bottom of the bag is all scratched; it’s ugly.” “When I’m standing in line at the cashier trying to find my checkbook while balancing my bag on my knee, I feel like a stork.” “This bag is my life; if I lose it I’m in big trouble.” “There’s nothing worse than a banana that’s been squished by the edge of a textbook.” “I never use both straps on my knapsack; I just sling it over one shoulder.” 8/17/2024 14 Target Specifications Specifications spell out in precise, measurable detail what the product has to do. Product specifications do not tell the team how to address the customer needs, but they do represent an unambiguous agreement on what the team will attempt to achieve in order to satisfy the customer needs. Identify Establish Generate Select Test Set Plan Customer Target Product Product Product Final Downstream Needs Specifications Concepts Concepts Concepts Specifications Development Perform Economic Analysis Benchmark Competitive Products Build and Test Models and Prototypes 8/17/2024 15 When Are Specifications Established? For technology-intensive products, specifications are established at least twice. Immediately after identifying the customer needs, the team sets target specifications. These specifications represent the hopes and aspirations of the team, but they are established before the team knows what constraints the product technology will place on what can be achieved The team revisits the specifications while assessing the actual technological constraints and the expected production costs. To set the final specifications, the team must frequently make hard trade-offs among different desirable characteristics of the product. 8/17/2024 16 Establishing Target Specifications The target specifications are established after the customer needs have been identified but before product concepts have been generated and the most promising one(s) selected. Later these specifications will be refined based on the limitations of the product concept actually selected. 8/17/2024 17 Target Specifications The process of establishing the target specifications entails four steps: 1. Prepare the list of metrics. 2. Collect competitive benchmarking information. 3. Set ideal and marginally acceptable target values. 4. Reflect on the results and the process. 8/17/2024 18 Customer Requirements Physiological needs such as thirst, hunger, sleep, shelter, and exercise. These constitute the basic needs of the body, and until they are satisfied, they remain Maslow's Hierarchy of Needs the prime influence on the individual’s behavior. Safety and security needs, which include protection against danger, deprivation, and threat. When the bodily needs are satisfied, the safety and security needs become dominant. Social needs for love and esteem by others. These needs include belonging to groups, group identity, and social acceptance. Psychological needs for self-esteem and self-respect and for accomplishment and recognition. Self-fulfillment needs for the realization of one’s full potential through self-development, creativity, and self-expression. Image Source: https://www.simplypsychology.org/maslow.html 17 August 2024 ENGINEERING DESIGN 19 Differing Views of Customer Requirements Performance deals with what the design should do when it is completed and in operation. The time dimension includes all time aspects of the design. Currently, much effort is being given to reducing the PDP cycle time, also known as the time to market Cost pertains to all monetary aspects of the design. It is a paramount consideration of the design team. Quality: A good definition of quality for the design team is the totality of features and characteristics of a product or service that bear on its ability to satisfy stated or implied needs. Value: Value is the worth of a product or service. It can be expressed by the function provided divided by the cost, or the quality provided divided by the cost. 17 August 2024 ENGINEERING DESIGN 20 Basic dimensions of quality for a manufactured product These have become a standard list that design teams use as a guide for completeness of customer requirement data gathered in the PDP. Performance: The primary operating characteristics of a product. This dimension of quality can be expressed in measurable quantities, and therefore can be ranked objectively. Features: Those characteristics that supplement a product’s basic functions. Features are frequently used to customize or personalize a product to the customer’s taste. Reliability: The probability of a product failing or malfunctioning within a specified time period. Durability: A measure of the amount of use one gets from a product before it breaks down and replacement is preferable to continued repair. Durability is a measure of product life. Durability and reliability are closely related. Serviceability: Ease and time to repair after breakdown. Other issues are courtesy and competence of repair personnel and cost and ease of repair. Conformance: The degree to which a product’s design and operating characteristics meet both customer expectations and established standards. 17 August 2024 ENGINEERING DESIGN 21 Kano Diagram 17 August 2024 ENGINEERING DESIGN 22 Benchmarking in General Benchmarking is a process for measuring a company’s operations against the best practices of companies both inside and outside of their industry. The more common sources of resistance to benchmarking are as follows: Fear of being perceived as copiers. Fear of yielding competitive advantages if information is traded or shared. Arrogance. A company may feel that there is nothing useful to be learned by looking outside of the organization, or it may feel that it is the benchmark. Impatience. Companies that engage in an improvement program often want to begin making changes immediately. 17 August 2024 ENGINEERING DESIGN 23 Competitive Performance Benchmarking Competitive performance benchmarking involves testing a company’s product against the best-in-class that can be found in the current marketplace. Determine features, functions, and any other factors that are the most important to end user satisfaction. Determine features and functions that are important to the technical success of the product. Determine the functions that markedly increase the costs of the product. Determine the features and functions that differentiate the product from its competitors. Determine which functions have the greatest potential for improvement. Establish metrics by which the most important functions or features can be quantified and evaluated. Evaluate the product and its competing products using performance testing. Generate a benchmarking report summarizing all information learned about the product, data collected, and conclusions about competitors. 17 August 2024 ENGINEERING DESIGN 24 Reverse Engineering or Product Dissection Reverse engineering is another name for product dissection. Product dissection entails the dismantling of a product to determine the selection and arrangement of component parts and gain insight about how the product is made. The “teardown” of a product is often a part of product benchmarking, but without the intent of copying the design. Steps Discover the operational requirements of the product. Examine how the product performs its functions. Determine the relationships between component parts of the product. Determine the manufacturing and assembly processes used to produce the product. 17 August 2024 ENGINEERING DESIGN 25 Quality Function Deployment There are many techniques used to generate engineering specifications. One of the best and currently most popular is called Quality Function Deployment (QFD). What is good about the QFD method is that it is organized to develop the major pieces of information necessary to understanding the problem: Hearing the voice of the customers Developing the specifications or goals for the product Finding out how the specifications measure the customers’ desires Determining how well the competition meets the goals Developing numerical targets to work toward Product Design DE ZG541 BITS 8/17/2024 26 Pilani Quality Function Deployment The QFD method was developed in Japan in the mid-1970s and introduced in the United States in the late 1980s. Using this method, Toyota was able to reduce the costs of bringing a new car model to market by over 60% and to decrease the time required for its development by one-third. 8/17/2024 27 Importance of QFD No matter how well the design team thinks it understands a problem, it should employ the QFD method for all original design or redesign projects. In the process, the team will learn what it does not know about the problem. The customers’ requirements must be translated into measurable design targets for identified critical parameters. You cannot design a car door that is “easy to open” when you do not know the meaning of “easy.” Is easiness measured by force, time, or what? If force is a critical parameter, then is “easy” 20 N or 40 N? The answer must be known before much time and resources are invested in the design effort. 8/17/2024 28  Importance of QFD The QFD method can be applied to the entire problem and any sub-problem. It is important to first worry about what needs to be designed and, only after that is understood, to worry about how the design will look and work. Our cognitive capabilities generally lead us to try to assimilate the customers’ functional requirements (what is to be designed) in terms of form (how it will look); these images then become our favored designs and we get locked onto them. The QFD procedure helps overcome this cognitive limitation. 8/17/2024 29  Importance of QFD This method takes time to complete. In some design projects, about one-third of the total project time is spent on this activity. Ford spends 3–12 months developing the QFD for a new feature. Experimental evidence has shown that designers who spend time here end up with better products and do not use any more total time when compared to others who do a superficial job here. Time spent here saves time later. Not only does the technique help in understanding the problem, it also helps set the foundation for concept generation. 8/17/2024 30 QFD – House of Quality Product Design DE ZG541 BITS 8/17/2024 31 Pilani QFD House of Quality Interrelationships Customer importance How to satisfy ratings customer needs assessment Competitive What the Relationship customer matrix needs Target values Weighted rating Technical evaluation 8/17/2024 STEP 1: IDENTIFY THE CUSTOMERS: WHO ARE THEY? For most design situations, there is more than one customer; for many products, the most important customers are the consumers, the people who will buy the product and who will tell other consumers about its quality (or lack thereof). Sometimes the purchaser of the product is not the same as its user (e.g., gym equipment, school desks, and office desks) 8/17/2024 33 STEP 2: DETERMINE THE CUSTOMERS’ REQUIREMENTS: WHAT DO THE CUSTOMERS WANT? The consumers want a product that works as it should, lasts a long time, is easy to maintain, looks attractive, incorporates the latest technology, and has many features. Typically, the production customer wants a product that is easy to produce (both manufacture and assemble), uses available resources (human skills, equipment, and raw materials), uses standard parts and methods, uses existing facilities, and produces a minimum of scraps and rejected parts. Typically, the marketing/sales customer wants a product that meets consumers’ requirements; is easy to package, store, and transport; is attractive; and is suitable for display. 8/17/2024 34 STEP 3: DETERMINE RELATIVE IMPORTANCE OF THE REQUIREMENTS: WHO VERSUS WHAT The next step in the QFD technique is evaluating the importance of each of the customers’ requirements. This is accomplished by generating a weighting factor for each requirement and entering it in the QFD diagram. The weighting will give an idea of how much effort, time, and money to invest in achieving each requirement. Two questions are addressed here: (1) to whom is the requirement important? and (2) how is a measure of importance developed for this diverse group of requirements? 8/17/2024 35 STEP 4: IDENTIFY AND EVALUATE THE COMPETITION: HOW SATISFIED ARE THE CUSTOMERS NOW? The goal here is to determine how the customer perceives the competition’s ability to meet each of the requirements. Even though you may be working with a totally new design, there is competition, or at least products that come close to filling the same need that your product does. The purpose for studying existing products is twofold: first, it creates an awareness of what already exists (the “now”), and second, it reveals opportunities to improve on what already exists. In some companies, this process is called competition benchmarking and is a major aspect of understanding a design problem. 8/17/2024 36 STEP 5: GENERATE ENGINEERING SPECIFICATIONS: HOW WILL THE CUSTOMERS’ REQUIREMENTS BE MET? The goal here is to develop a set of engineering specifications from the customers’ requirements. These specifications are the restatement of the design problem in terms of parameters that can be measured and have target values. Without such information the engineers cannot know if the system being developed will satisfy the customers. Engineering specifications consist of parameters of interest and targets for parameters. 8/17/2024 37 STEP 6: RELATE CUSTOMERS’ REQUIREMENTS TO ENGINEERING SPECIFICATIONS: HOW TO MEASURE WHAT? To complete this step, we fill in the center portion of the house of quality. This relationship matrix is completed in parallel to Step 5, and it yields additional knowledge. Each cell of the form represents how an engineering specification Product Design DE ZG541 BITS 8/17/2024 38 Pilani STEP 7: SET ENGINEERING SPECIFICATION TARGETS AND IMPORTANCE: HOW MUCH IS GOOD ENOUGH? In this step we fill in the basement of the house of quality. Here we set the targets and establish how important it is to meet each of them. There are three parts to this effort, calculate the specification importance, measure how well the competition meets the specification, and develop targets for your effort. 8/17/2024 39 STEP 8: IDENTIFY RELATIONSHIPS BETWEEN ENGINEERING SPECIFICATIONS: HOW ARE THE HOWS DEPENDENT ON EACH OTHER? Engineering specifications may be dependent on each other. It is best to realize these dependencies early in the design process. Thus, the roof is added to show that as you work to meet one specification, you may be having a positive or negative affect on others. 8/17/2024 40 8/17/2024 41 8/17/2024 42 Thank You References: ▪ George E. Dieter, Linda C. Schmidt, "Engineering Design", 6/e (Indian Edition), McGraw Hill Education (India) Pvt. Ltd., New Delhi, 2021. ▪ David G. Ullman, “The Mechanical Design Process”, McGraw-Hill Inc., Singapore, 1992 ▪ Kevin Otto and Kristin Wood, “Product Design: Techniques in Reverse Engineering and New Product Development”, 1/e, Pearson Education, New Delhi, 2004. ▪ N. J. M. Roozenburg, J. Eekels, Roozenburg N. F. M., “Product Design: Fundamentals and Methods”, John Wiley and Sons, 1995 17 August 2024 43