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ComputerAided_Design_Engineering_amp_Manufactur.pdf

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FIGURE 7.8 The staging and the strip layout for the manufacture of the part shown in Figure 7.2. (a) The st<strong>amp</strong>ing<br />

operations selected at the various stations, (b) the strip layout.<br />

such components and subassemblies are the piercing, notching, and blanking punches, pilots,<br />

and bending punch subassemblies.<br />

b. Components whose descriptions are deduced by reasoning about their geometrical and topological<br />

relationship with reference to the standard components described above— The punch plate is such<br />

a component. Its size and topological description will depend on the tools it supports.<br />

The schema for the description of some of the die components will be detailed later. The relationship<br />

between the component abstraction and the product hierarchy is illustrated in Figure 7.11. Functions<br />

and rules to derive the respective values of the slots of the objects in the product hierarchy can be<br />

implemented in the following manner:<br />

• Functions and rules that do not require the resolution of conflicts will be stored as monitors in<br />

the respective slots of the object in the component abstraction and will be executed when an<br />

object is created in the product hierarchy. For ex<strong>amp</strong>le, the function to calculate the screw size<br />

will be stored as a ‘‘when needed’’ monitor in the size slot of the screw object representation in<br />

the component abstraction. When a new screw needs to be added to the die assembly, the monitor<br />

will be fired to calculate its size.<br />

• Rules that require the resolution of conflicts will be represented as rules external to the object.<br />

Additional rules may be implemented to help resolve conflicts. For ex<strong>amp</strong>le, the locations of the

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