Assignment 4: Pugh Concept Selection Method

Problem 7.5

In the search for more environmentally friendly design, paper cups have replaced Styrofoam cups in most fast food restaurants. These cups are less effective insulation, and the paper cup often gets too hot for the hand. A design team is in search of a better disposable coffee cup. The design evaluated is: (a) a standard Styrofoam cup. (b) A rapid injection mold cup with a handle (c) a paper cup with a cardboard sleeve. (d) A paper cup with a pull out cup and, (e)a paper cup with a cellular wall. These design concepts are to be evaluated with the Styrofoam as the datum.

The engineering characteristics on which the cups are evaluated are:

1. Temperature in the hand

2. Temperature of the outside of the cup

3. Material environmental impact

4. Indenting force of cup wall

5. Porosity of cup wall

6. Manufacturing complicity

•  The Pugh Concept was developed by Stuart Pugh who was a professor and head of the design division at the University of Strathclyde in Glasgow.
• —  It is also called a variety of names including Pugh method, Pugh analysis, decision matrix method, etc.
• —  As a decision making model, it is obviously used to choose between a list of alternatives.
•   The most important criteria in the decision are chosen, and the alternatives are compared using these criteria.
• —  There are variations and how to use the criteria and we will look at those later on.
•   The competing ideas are then compared to a standard datum
•  selected for its typicality in the product category, and are evaluated as being better than, equal to, or inferior to the datum
• — on the key dimensions that will contribute to product success.
•  The group proceeds to eliminate weaker ideas, but also attempts to cull the advantages of each concept and incorporate it into the remaining ones before discarding it.
•   In this way, the ‘winning’ concept incorporates many of the best ideas of all of the other concepts.”

First Pugh chart

Second Pugh chart

Conclusion

• —Pugh Chart Selection Method is very important in product design development as the time it takes a development team to analyze the scores and weighting factors is usually much shorter and cheaper compared to deploying the wrong solution to a project.
•  Based on the second pugh chart, design B is chosen because it has greater score than the other design.

Advantages of pugh chart

•  Finding a “best” design
• — Prevents a team from “falling in love”
• — With a flawed design or one not meeting
• — All design constraints or objectives
• Communication tool; builds consensus