ASSIGNMENT 7

ASSIGNMENT 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 insulators, and the paper cups often get too hot for the hand. A design team is in search of a better disposable coffee cup. The designs to be evaluated are:

(A) a standard Styrofoam cup,
(B) a rigid injection-molded cup with a handle,
(C) a paper cup with a cardboard sleeve,
(D) a paper cup with a pull-out handle,
(E) a paper cup with a cellular wall.

These design concepts are to be evaluated with the Styrofoam 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 customer
9. Temperature loss of coffee over time
10. Estimated cost for manufacturing the cup in large quantities

Using your knowledge of fast-food coffee cups, use the Pugh concept selection method to select the most promising design.


ANSWER:

PHASE I

1. Choosing the criteria by which the concept will be evaluated

2. Formulate the decision matrix

3. Clarify the design concepts.

4. Choosing the datum concept.

5. Run the matrix

6. Complete the matrix entries.

7. Evaluate the ratings.

Based on the question, the first phase of Pugh Chart is done as shown in the table below.

SELECTED CRITERIA	DESIGN CRITERIA
	A	B	C	D	E
1. Temperature in the hand	D A T U M	+	+	+	+
2. Temperature of the outside of the cup		+	+	S	+
3. Material environmental impact		+	+	S	-
4. Indenting force of cup wall		+	-	S	+
5. Porosity of cup wall		-	+	S	-
6. Manufacturing complexity		+	S	-	-
7. Ease of stacking the cups		+	-	-	+
8. Ease of use by customer		-	S	-	S
9. Temperature loss of coffee over time		+	-	S	+
10. Estimated cost for manufacturing the cup in large       quantities		+	+	+	-
Number of Pluses (+)		8	5	2	5
Number of Minuses (-)		2	3	3	4
Standard / Same		0	2	5	1

Based on the ratings or the result of the first phase, design concept  D which is paper cup with pull-out handle is eliminated due to its poor rating on some of the important criteria which are in term of temperature and also the ease of using and keeping it. For the second phase, design B is selected as the datum as it has the least number of minuses.

PHASE II

8. Establish a new datum and rerun the matrix

9. Examine the selected concept for improvement opportunities

SELECTED CRITERIA	DESIGN CRITERIA
	B	C	E
1. Temperature in the hand	D A T U M	+	+
2. Temperature of the outside of the cup		-	-
3. Material environmental impact		S	-
4. Indenting force of cup wall		-	+
5. Porosity of cup wall		+	S
6. Manufacturing complexity		S	-
7. Ease of stacking the cups		+	S
8. Ease of use by customer		+	-
9. Temperature loss of coffee over time		+	+
10. Estimated cost for manufacturing the cup in large       quantities		+	-
Number of Pluses (+)		5	3
Number of Minuses (-)		2	5
Standard / Same		2	2

Based on the result of phase II, design concept C which is paper cup with cardboard sleeve is chosen as the best design concept due to its good rating when compared to the datum.