Problem Set 4
EMA 4714 - Materials Selection and Failure Analysis
Due Monday, February 11, 2008 – 8:30AM
Dieter Exercise 5.12
In the search for more environmentally friendly design, paper cups have replaced Styrofoam
cups in some fast-food restaurants. These cups are not as good insulators, and the paper cups
often get too hot for the hand. A design team is in search of a better disposal coffee cup. The
designs to be evaluated are:
[a] the current paper cup
[b] a standard Styrofoam cup
[c]] a rigid injection-molded cup with a handle
[d] a double-wall disposable plastic cup
[e] a paper cup with a pull-out handle
[f] a paper cup with a cellular wall.
These design concepts are to be evaluated with the current paper cup 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 complexity
7. Ease of stacking the cups
8. Ease of use by the customer
9. Temperature loss of coffee over time
Using your knowledge of fast-food coffee cups, use the Pugh concept selection method to select
the most promising design.
