Assignment 6: Detail Design

Problem 9.1:

Examine the detail drawing for a product designed by your team. Be sure you identify the actual shape, dimensions, and tolerances. What other information contained in the drawing?

 In a detailed drawing, there will be information about the dimensions and tolerances. Besides, there will be also information about the product such as name, date and also information about the designer and also whether the design was approved or not.

Assignment 5: Product Architecture of a Fingernail Clipper

Problem 8.2:

The standard fingernail clipper is an excellent illustration of the integral style of product architecture. The clipper system consists of four individual components: lever (A), pin (B), upper clipper arm (C) and lower clipper arm (D). Sketch a fingernail clipper, label its four components and describe the functionality provided by each component.

Figure 1

Total number of parts = 4

The standard nail clipper is a portable tool used for trimming fingernails and toenails. It can also be used for filing your nails and removing the dirt from behind your nails. The nail clipper consists of three main parts, which are:

1)  Lever

• It is connected to the base by the same bolt that connects the two main pieces of the base. The bolt is constructed to allow the leverage part to rotate 360 degrees about the bolt. When the piece is lifted forward and in, it parallels itself to the base (Figure 1). It can also be moved to a position 43 degrees at an angle to the base which allows the piece to compress the two sharp end pieces of the base.

2) Base

• It has two pieces consists of upper clipper arm and lower clipper arm connected to each other by a bolt at an angle of 5 degrees to each other. At the ends of these two pieces is the sharp part of the nail clipper that is used to cut the nail. These ends are shaped to fit around your fingernail or toenail.

3) File

• The file is connected to the base of the nail clipper by a circular shaft at the opposite end of the clipper. It can rotate about this shaft 360 degrees, which allows for easy access of the file. At the end of the file there is a sharp point which allows the user to remove dirt from behind the nails.

The three main parts of a nail clipper all work together to provide the necessary leverage to compress the sharp ends of the base. The nail clipper works to trim your nails when the lever is at an angle to the base of the clipper. When the lever is compressed with your nail underneath the cutter, that portion of your nail is removed.

Problem 8.3:

Design a new fingernail clipper with totally modular product architecture. Make a sketch and label the friction provided by each part. Compare the number of parts in this design with the original standard nail clipper.

Figure 2

Figure 3

Total number of parts = 3

This design consists of two main parts that used to provide necessary leverage

1)  Lever

• Flexible as it can be rotated 180° to open (Figure 2) or to close (Figure 3)
• Connected to the base by a side pin

2) Base

• Consists of two parts, lower clipper arm and upper clipper arm.
• Connected by a pin.
• Can be disassembled easily.
• At the end of the two pieces is the sharp part that used to cut the nail

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

Answer:

Pugh concept selection for a fast-food coffee cup. We have substituted a paper cup with a cardboard sleeve for concept (e) in the problem statement, since it is a more current concept.

	DESIGN CONCEPTS
Design requirements	Regular paper cup	Styro- foam cup	Rigid injection molded with handle	Double-wall biodegradable plastic	Paper cup with fold- out handle	Paper cup with cardboard sleeve
Temperature in the hand		+	+	+	+	+
Material environ- mental impact	D	-	-	+	s	S
Indenting force of cup wall	A	+	+	+	s	S
Porosity of cup wall	T	+	+	+	s	S
Manufacturing complexity	U	+	-	-	-	S
Ease of stacking the cups	M	+	-	s	-	S
Ease of use by customer		s	+	s	-	+
Temperature loss of coffee over time		+	-	+	s	S
Overall cost		s	-	-	-	-
∑+		6	4	5	1	2
∑-		1	5	2	4	1
∑s		2	0	2	4	6

This problem illustrates that the Pugh chart is an excellent tool for quick comparison of alternative concepts. However, the numerical values should be used with caution. A rigid summation of pluses and minuses should never be done. Based on the analysis, it shows that the Styrofoam coffee cup is superior to the paper cup (DATUM) and to all other proposed concepts but its one negative outweighs all other considerations. Since Styrofoam does not degrade in a landfill it is banned in many jurisdictions and strongly frowned upon in others. All concepts are superior to a paper cup in providing better thermal insulation so that the cup is not too hot in the hand. However, they are all more expensive than either a paper or Styrofoam cup. The biodegradable plastic cup would be the best solution but it is the most expensive concept. The most widely adopted solution appears to be a paper cup with a cardboard sleeve. While it does not provide as much thermal protection as the two designs with handles, it is cost effective and acceptable to most people.

It is important to emphasize to them that the chief benefit to using the Pugh Chart is the insight to the problem to be gained from deep group discussion. Often concepts with many minuses have the kernel of a winning idea when combined with other concepts.

Assignment 3: Morphological Chart

Problem 6.11:

Create a morphological chart for a mechanical pencil

Parts of a mechanical pencil

Morphological chart for a mechanical pencil