Page 324 - Design for Six Sigma a Roadmap for Product Development

294 Chapter Nine

TABLE 9.1 Design Parameters

1 Weight of moving object 21 Power
2 Weight of nonmoving object 22 Waster of energy
3 Length of moving object 23 Waster of substance
4 Length of nonmoving object 24 Loss of information
5 Area of moving object 25 Waster of time
6 Area of nonmoving object 26 Amount of substance
7 Volume of moving object 27 Reliability
8 Volume of nonmoving object 28 Accuracy of measurement
9 Speed 29 Accuracy of manufacturing
10 Force 30 Harmful factors acting on object
11 Tension, pressure 31 Harmful side effects
12 Shape 32 Manufacturablity
13 Stability of object 33 Convenience of use
14 Strength 34 Repairability
15 Durability of moving object 35 Adaptability
16 Durability of nonmoving object 36 Complexity of device
17 Temperature 37 Complexity of control
18 Brightness 38 Level of automation
19 Energy spent by moving object 39 Productivity
20 Energy spent by nonmoving object

improved drastically and system performance will be raised to a whole
new level. TRIZ developed many tools for elimination of technical con-
tradiction. These tools are discussed in Sec. 9.5.
Physical contradiction. A physical contradiction is a situation in which a
subject or an object has to be in two mutually exclusive physical states.
A physical contradiction has the typical pattern: “To perform function
F , the element must have property P, but to perform function F ,it
2
1
must have property P, or the opposite of P.” For example, an automo-
bile has to be light in weight (P) to have high fuel economy ( F ), but it
1
also has to be heavy in weight ( P) in order to be stable in driving (F ).
2
Example 9.3 When an electrotechnical wire is manufactured, it passes
through a liquid enamel and then through a die which removes excess
enamel and sizes the wire. The die must be hot to ensure reliable calibra-
tion. If the wire feed is interrupted for several minutes or more, the enamel
in the hot die bakes and firmly grips the wire. The process must then be
halted to cut the wire and clean the die.
Physical contradiction. The die should be both hot, for operation, and cold,
to avoid baking the enamel.

In many cases a technical contradiction can also be formulated as a
physical contradiction. Conventional design philosophy is based on
compromise (trade-off). If a tool or object must be both hot and cold,
it is usually made neither too hot nor too cold. Contrary to this
approach, TRIZ offers several methods to overcome physical contra-
dictions completely. These methods are discussed in Sec. 9.4.