11 ES1050 – Introductory Engineering Design and Innovation Studio Introduction to Design Process Customers’ Needs Product Design Specifications Sept. 23, 2009 Prof. Paul Kurowski

2 WHAT versus HOW First, designers need to know WHAT the customer wants Then, designers need to determine HOW to meet the customer requirements

3 WHAT THE CUSTOMER WANTS? Customer requirements: 1. Must be discriminatory 2. Must be measurable 3. Must be orthogonal (no overlapping of requirements) 4. Must be universal (applicable to all alternatives under consideration) 5. Must be external to problem (not impose design choices)

4 1. Customer requirements must be discriminatory Requirements must reveal the differences between alternatives to help distinguish one from the other during an evaluation. If you say that a bicycle should be suitable for riders whose body mass is between 20kg and 200kg, this requirements is useless. It does not allow for discrimination between people.

5 2. Customer requirements must be measurable There must exist an objective method to measure if the requirement has been satisfied. For example a questionnaire can be used to find to what extend the requirement has been satisfied 1. The product does not meet the requirement at all. 2. The product meets the requirement slightly. 3. The product meets the requirement somewhat. 4. The product meets the requirement mostly. 5. The product fulfills the requirement completely.

6 3. Customer requirement must be orthogonal The requirements must not overlap. Each requirement should identify a unique feature of the alternative. There should be no overlapping of requirements. This is often difficult because overlapping is so hard to identify. For example, in the initial list of criteria for choosing a new product, a company proposed two criteria: Product must give smooth ride over rough roads Product should reduce shocks from bumps What is wrong?

7 4. Must be universal A universal requirement characterizes an important attribute of all the proposed alternatives. If only some of the alternatives have the feature measured by the requirement, then it is not universal and either the issue is not well defined or some of the alternatives have features not consistent with the issue being addressed. For example in the initial list of criteria for choosing a transportation system, it was stated: The new system must use the existing network of re-fuelling stations What is wrong?

8 5. Must be external to problem; must not impose design choices For example in the initial list of criteria for a new bicycle it was stated: The new bicycle must have an aluminum frame What is wrong?

9 A customer requirement for an All Terrain Vehicle has been defined as: “Must have a chain drive” What is wrong with this definition? AIs not discriminatory BIs not measurable CIs not orthogonal (specifies overlapping requirements) D Is not universal (not applicable to all alternatives under consideration) EIs not external to problem (imposes design choices)

10 As marketing requested it As sales ordered it As engineering designed it As production manufactured it As plant installed it What the customer really wanted ! DIFFERENT PERSPECTIVES OF THE SAME PROBLEM

11 Customer Requirements: WHAT? BBQ lighter Examples of customer requirements Lights up a BBQ Easy to use Lightweight Stylish Reliable Affordable Customer Requirements are qualitative

12 Product Design Specifications: HOW? Product Design Specifications describe features and characteristics present in the product. Product Design Specifications are quantitative, must be measurable in numbers with clearly specified units.

13 Product Design Specifications: HOW BBQ lighter Selected product design specifications Length 20 cm Weight 0.1N Flame length 30mm Works 200 times on one load 0.2N force required to release the trigger

14 Engineering design specifications Engineering requirements Design requirements Functional requirements Objectives and constraints Technical requirements Technical specifications Other names for engineering design specifications include:

15 Boat trailer – in class exercise

16 Kano Diagram of Customer Satisfaction Basic features  Must be present, expected Performance features  The more there is the happier the customer Excitement features  Exciting, new, unexpected features Over time, excitement features become basic features Play

17 How can we classify product design specifications and what is their importance in satisfying customers’ requirements? Not all customers’ requirements can be met 100%, some are mutually exclusive so a compromise must be found. How to satisfy customers? Product Design Specifications:

18 Understanding the Customer

19 Quality Function Deployment * (QFD) is a technique developed in Japan during the mid-1970's for better understanding the design problem, in particular of customer needs. * Deployment: the distribution of forces in preparation for battle or work

20 Quality Function Deployment (QFD) General Comments: No matter how well the design team thinks it understands a problem, it should employ the QFD technique for all design projects, because in the process the team will learn what it doesn't know about the problem. The customer's requirements must be translated into measurable design targets before a large amount of time and resources are invested in the design effort. It is important to first consider what needs to be designed and, only after that is fully understood, to worry about how the design will look and work.