# the pugh method[1]

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The Pugh Method of Creative Concept EvaluationUSE THE ENGINEERS MINDSET

Problem Solving ProcessData Collection, Analysis PROBLEM DEFINITION

Related TaskGoals, Objectives Customer/Market Analysis, Design Criteria CONCEPTUAL DESIGNS Engineering, Cost Analyses Tolerances PROCESS PLANNING OPTIMIZED DESIGNS Design Review Go/No Go Decision BEST DESIGN Detail Drawings PROTOTYPE

Brainstorming IDEA GENERATION Pugh Method IDEA EVALUATION IDEA JUDGMENT IMPLEMENTATION

Steps and Documentation in Engineering DesignDESIGN STEPARTIST + ENGINEER PROD. EXPLORER + DETECTIVE + JUDGE

DOCUMENTATIONDP1 Project concept statement DP2 Table of design constraints DP3 Customer survey DP4 Table of design objectives DP 5 Design problem analysis and statement DP6 Project plan, design proposal DP7 Pugh matrix, design concept descriptions, drawings DP8 Progress report, BOM, analyses DP9 Production specs, drawings DP10 Prototype test plan DP11 Design evaluation results report DP12 Final project report and team evaluation/presentations

1.

Identify the forces driving the design 2. Identify design constraints 3. Identify user needs 4. Define the objectives or design specifications 5. Analyze the design problem and its context 6. Plan the design process 7. Develop concepts and select best alternatives 8. Complete system level design 9. Complete the detailed design 10. Test effectiveness of design 11. Review design at each stage 12. Iterate, refine, optimize design and communicate the results

What Is the Pugh Method?It is a creative design idea or concept evaluation technique that uses criteria derived from the voice of the customer in an advantage-disadvantage matrix. Each concept is evaluated against a datum using a three-way evaluation scheme. EVALUATION SCALE + S means substantially better means clearly worse (or flawed) means more or less the same

Additional Features1. 2. A best conventional design can be used as datum against which the new designs are compared. While the team completes the evaluation matrix, it generates new ideas and thus adds new concepts to the matrix. This process is repeated several times over days (for students) or weeks/months (in industry), until a superior concept emerges that cannot be overturned since all negatives (flaws) have been removed.

3.

Benefits of the Pugh Method1. Discussions reveal arbitrary criteria. Team members gain insight into the problem and clearly understand the criteria which become better defined. The discussion also leads to creative leaps between different concepts and idea synthesis, as flaws are attacked together and the team experiences synergy. The team develops consensus about the best solution. The resulting new concepts are better than the original ideas. No flaws are overlooked; engineering changes are eliminated, and invulnerable products are developed that will succeed in the marketplace. The method results in cost savings.

2.

3. 4.

5.

The Pugh Method Phase I1. 2. 3. 4. 5. 6. The design teams brainstorm and rank a list of 15 to 20 evaluation criteria (based on customer needs). The design teams develop imaginative concepts. The matrix is prepared on a large wallboard, and the best existing product is chosen as benchmark/datum. Each teams design concept is discussed and evaluated against the list of criteria and the datum. The ratings are evaluated. The design teams work to strengthen the positives and removed the negatives through synthesis and new ideas; these concepts are added to the matrix which is rerun for one or more rounds, with the strongest concept chosen as the datum each time.

The Pugh Method Phase II1. Over a period of time, the teams further develop their best concepts, run analyses, and research missing information. The designs/concepts are now engineered or developed to more detail. Weaker designs/ideas are dropped (after their good points have been judged for use elsewhere). The matrix and concept improvement process are iterated until a winning concept emerges. All team members understand why this solution is bestall good points have been strengthened and all negatives overcome.

2. 3.

OUTCOME: Everyone is committed to the best or optimized design which is now ready for development into a commercial product.

Cost Impact of Decisions

85% Committed Manufacturing Cost

CONCEPT

PROTOTYPE

PRODUCTION

Design Cycle Phase

Influence on Product Cost (Car Example)PRODUCT COST30% Overhead

INFLUENCE ON COST5% 5% 20%

15%

Labor

Materials 50%

70%

Design

5%

Comparison of Engineering Changes US and JapanNumber of Engineering Changes Processed US COMPANY JAPANESE COMPANY

Job #1

2004 Edward Lumsdaine

-24

-18

-12

-6

0

6

Months

Kitchen Lighting Example 2004 Monika Lumsdaine

I.D. #,Rating

Table 1 Existing Kitchen Lighting Fixtures Type Fixture Location

Switching

A 4, 20 watt 2-ft fluorescent, triangular Under wall cabinets individual B 4, 40 watt 4-ft fluorescent tube C 2, 75 watt Aluminum spotlight D 1, 20 watt 2-ft fluorescent tube On top of cabinets 5 ft above sink Under microwave 3-way switch individual Plug-in cord

Problem BriefingA large Pullman-type kitchen in a 1940s house is quite dark at night, worst at the sink and chopping board located in front of the window. The cherry paneled ceiling has an average height of almost 11 ft and is traversed by a 14 in. x 6 in. wood-laminate beam supporting the flat roof above. All walls, countertops and metal wall cabinets are beige; the vinyl floor has a brownish brick pattern. Bottom cabinets are brick-red. The fluorescent tubes lying on top of the cabinets, as well as the spotlights, are ugly, look cheap, and are hard to clean. None of the lighting fixtures give adequate light for their tasks.

Table 2 Pugh Evaluation Round 1: Kitchen Lighting Concepts

1 Track Lighting

Install an 8-ft long track with 4 movable spots (50 watt each, black) to match existing track light in adjacent living room. Plug into outlet over cabinet near sink. Replace the two spotlights over the sink with new, nicer-looking, and more efficient practical lamps. Replace the fluorescent tubes with a lighted strip along the top of all wall cabinets. Install two 4-ft fluorescent fixtures with efficient diffusers at 8-ft level (from chains, with wood surrounds) to replace the over-the-cabinet tubes; wire to main switch. Option explored with supplier. Install two hanging halogen down lights; wire to main switch; match chrome style of under-cabinet triangular fixtures. Option explored with supplier. Paint walls white; install white vinyl flooring; install new white countertop; paint cherry panels in ceiling while.

3 Over-Cabinet Strip Lighting

4 Fluorescent Hanging Fixtures

5 Halogen Fixtures

6 Brighter Surfaces

Table 3 Pugh Method Round 1 Kitchen Lighting Concept Evaluation # Criteria 1 Adequate sink task lighting 2 Other countertop lighting 3 General lighting 4 Light to ceiling 5 Energy efficient 6 Easy to clean 7 Easy bulb replacement 8 Allow deletion of tubes 9 Matching adjacent room fixture 10 Attractive high-tech look 11 Low installation labor cost 12 Low materials cost TOTAL POSITIVES (+) TOTAL NEGATIVES () D A T U M Now 1 S S + + + + 4 6 2 + S S S + S S + + + 5 2 3 S + S + + + 4 6 4 + + + + S S + 5 5 5 + + + + + + + 7 5 6 + + + S S S 3 6

Table 4 Pugh Evaluation Round 2: New or Improved Lighting Concepts

5 Halogen Fixtures

Install two hanging halogen down lights; wire to main switch; match chrome style of under-cabinet fixtures. Install a black 8-ft long, 2-circuit track with 3 movable cans (150 watt incandescent bulbs or fluorescent bulb option) and one 2-ft fluorescent, 40 watt movable parabolic louvered diffuser to match living room track light. Mount to bottom of beam; connect to main switches with conduit along beam edge. Replace two spotlights over the sink with black cans matching the track lights of Option #7. Use fluorescent bulbs. Replace the fluorescent tubes with a rope light along the top of all wall cabinets. Install two 4-ft fluorescent fixtures with efficient diffusers at 8-ft level (sleek high-tech design); hang from ceiling, centered between counters. Install two hanging halogen down lights; wire to main switch; match style of dining room chandelier, if possible.

7 Fluorescent Track Lighting

9 Over-Cabinet Strip Lighting

10 Fluorescent Hanging Fixtures

11 Halogen Fixtures

Table 5 Pugh Method Round 2 Kitchen Lighting Concept Evaluation# Criteria 1 Adequate sink task light 2 Countertop lighting (window wall) 3 Countertop lighting (stove wall) 4 Ceiling illumination 5 Low-energy night lighting 6 Low glare 7 Flexible (direction, additions, lumens) 8 Easy bulb replacement 9 Energy efficient 10 Easy to clean 11 Preserves view of ceiling/open space 12 Allows deletion of B tubes 13 Matching adjacent room lamp styles 14 Attractive to future owners 15 Low labor cost 16 Low materials cost TOTAL POSITIVES (+) TOTAL NEGATIVES () 5 7 S + + S S + + 8 + + S + + + S S S + + + + + 10 2 9 + + + + + S + 6 9 10 S S S S S + S S S S S + 2 4 11 S S S S S S S S S S S S + S S S 1 0

D A T U M

S S S S + + + S 6 2

Table 6 Pugh Evaluation Round 3: New or Improved Lighting Concepts