lecture 01-29-09 - From Needs to Design Specifications OR...

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Unformatted text preview: From Needs to Design Specifications OR From Understanding the needs to concept development Karthik Ramani QFD History • First developed by Yoji Akao and applied in Mitsubishi Kobe Shipyard in 1970’s • It was popularized later by Clausing [1988] (paper in your reading) Karthik Ramani © 2009 2 Functional Decomposition Karthik Ramani © 2009 3 Otto and Wood, page 180 Karthik Ramani © 2009 4 Function relationship to Concepts • • • • • Karthik Ramani © 2009 5 Structure or form (components and architecture), follows function A concept is an idea that is sufficiently well developed to evaluate the physical principles that govern its behavior Concepts on development to the product (should) meet the targets set Important customer requirements are related to the functional performance desired in the product Functional decomposition and constraint variation allow concept generation and combination Structural Decomposition Karthik Ramani © 2009 6 Function Structure Mapping Karthik Ramani © 2009 7 QFD Dimensions • It supports and documents benchmarking and customer needs analysis • Consensus building activity on what the product should do and how it will perform • It aligns different disciplinary subsystems • Addresses the increasing separation between producers-consumers and between units of a company • Establish engineering requirements – – – – – Surrogate for qualitative requirements Clear customer needs to requirements map Document benchmarking data Establish target value for engineering requirements Check for conflicts Karthik Ramani © 2009 8 Basic Correlation Matrix (Qualitative Requirements) Objectives DIRECTIONS HOW Functional Requirements IMPORTANCE RATING Must/Should Could: VOC AND RATINGS CUSTOMER TARGETS RELATIONSHIP MATRIX HOQ WHAT Customer Requirements TARGETS/CONSTRAINTS How Much Karthik Ramani © 2009 9 Needs Karthik Ramani © 2009 10 Mapping Function-Structure Value Analysis Graph What How I (EM) How II KJ (Affinity Matrix) Karthik Ramani © 2009 11 Value Analysis Graph What How I (EM) How II Function Decomposition Engineering Metrics: Measurable Product Characteristics Karthik Ramani © 2009 12 CR’s vs. EM’s of QFD Value Analysis Graph What How I (EM) How II Relationship between what and how Karthik Ramani © 2009 13 CR: Benchmarking How important is lightweight? Compare it to the competition! Karthik Ramani © 2009 14 Roof of HOQ ? ? Karthik Ramani © 2009 15 QFD! Prioritizing product requirements • Why it is important to establish priorities of product requirements? Because “value” is not just performance delivered. • It is performance delivered at a given price (target cost is covered later) for products that are driven by cost constraints. • Critical tradeoffs must be made regarding functions and features to arrive at the optimum level of product development design concept • QFD is a simple, easy to use decision and prioritization tool that can be applied intelligently at the beginning of a product development projects (evolving and new needs) Karthik Ramani © 2009 16 Karthik Ramani © 2009 17 The first-level application of Lean QFD is to convert customer benefits into prioritized functions. The example of a cell-phone product is used to illustrate "Function" Lean QFD how the tool works.- Figure 7 Key Customer Benefits Function Priority No. B) Lightweight / Easty to Use A) Mobile/ 24Hr. Comm C) Large Service Area 1 0 5 3 0 3 1 1 0 1 0 Possible Functions that Could Deliver Desired Benefits 1.5 5 0 0 5 0 0 0 0 0 0 Weighting Factors for Key Benefits Customer Ranking of Functions 17.5 5 7 15.5 9 3 1 0 7 0 1 5 4 2 3 6 7 4 - 18 2 1) Wirelss Transmit/Receive 5 2) Fits into Shirt Pocket 0 3) Audible/Silent "Ring" 2 4) Long Distance Reception 4 5) Usable at Night 3 6) Voice and Data Capability 1 7) Color Display 0 8) Games 0 9) Text Messaging 3 Karthik 10) Digital Camera Ramani © 2009 0 A) Mobile/ 24 HR Comm B) Lightweigh t Easy to Use C ) Large Service Area Time-to-Market 1 0 0 6 -1.5 -3 0 0 -3 0 0 Selected Requirements 0 0 0 3.5 Weighting Factors For Key Benefits 2 1 1.5 2 Possible Performance Requirements or Design Tradeoffs 1) Type of Cell-Phone Chip Used Option 1 – 1st Generation 0 2 3 1 3 -5 1 2 -1 0 0 0 Option 2 – 2nd Generation Option 3 – 3rd Generation 2) Power Utilization Option 1 – Low Option 2 - Moderate 3) Communications Standard Option 1 – GMT Option 2 - CDMA 0 1 3 -1 0 0 0 0 0 -2 2 -2 0 0 0 0 Karthik Ramani © 2009 Unit Manufacturing Cost The second-level of Function First-Priority Lean QFD - Requirements Figure 8 Wireless Transmit / Receive Key Customer Benefits 19 Conclusions • • QFD is a tested and powerful tool to ensure product is “designed” to requirements QFD although is effective in the first and to some extent in the second HOQ’s, its further use in later stages is not well established Underlying design model work and further methods are necessary It is usable in many projects in product definition stages Karthik Ramani © 2009 20 • • ...
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