From the analysis of the relationship of the correlating parts and the correlated plates, we can see that two conditions must be met in order to achieve the correlated structure design of holes on plates:

1. The size of the hole(s) on the correlated part(s) will be determined by the correlating part(s).

2. When location of the correlating parts ismoved or the size of the correlating parts is edited, so too do the holes on the correlated plates.

Hence, we establish a descriptive model that views the correlating parts as controller. The relationship model of associated holes is defined as follows: Class associated holes:

Correlating part (one part or a functional assemble) Location points for the correlating part Correlated plates (one or a group of parts) Corresponding library features of holes (one or a group)

3 Construction process for correlated hole design system for progressive die

Parameterized die design takes changeable sizes of die structure as parameters and then changes the die structure

sizes by means of a relationship formula for the parameters so as to fulfill the design objectives. But in the relevant hole design process for progressive die, some portions of the die structure, such as guides, punches, dies, lifters, and supporting plates, may be rather different in shape, so it is impossible to meet the design requirements by simply changing the structure size alone. Therefore, in this document, various structures of the main parts of a progressive die are partitioned into functional features, and the same functions are categorized into a single identical functional module. The resulting structural chart of the functional modules for holes on plates for progressive dies is shown in Fig. 13. The standard punches, for example, are classified into three types: circular, rectangular, and irregular. The configuration for parts and assembly are adopted to express multiple kinds of parts and components. The library feature technology is used to accomplish the hole structure in accordance with the design criteria and design standards. 3.1 Application of library feature

Library feature is modeled by using the function provided by SolidWorks software. The function let the user define customized feature by composing a group of simple feature

with user-defined parameters. By extracting the feature parameters and establishing template files, user can achieve variable design for parts and assemblies. So users can quickly and easily build their own library features which can be loaded when needed. The user-defined library features are regarded as a simple feature like other features provided by SolidWorks software. When the library features is added onto the design part, they can also be parameterized in shape and location which enlarge the scope of the feature-based modeling module and simplified the modeling process effectively.

During the progressive die design procedure in Solid- Works software environment, different kinds of holes usually are modeled by employing the “cut-extrude” or “hole wizard” function. For some complex holes, e.g., composite hole, repetitive use of “cut-extrude”, or “hole wizard” functions with various parameters are needed. Because there are a lot of holes on the plates and some holes are often reused, it is very convenient to establish hole feature library with various structures which can be loaded by program. As a result, the efficiency of the design is improved to a large extent.

The characteristics of library feature are:

1. Flexibility, the production is simple and convenient 2. The size and the structure can be self-definition 3. Positioned by setting the reference point

4. The same structure with different sizes can be produced by multiple configurations

Select hook screw hole as an example. The modeling processes and applications for library feature are as follows: 1. Set up a desired folder for saving user-defined features in the design library directory.

2. Draw a sketch point coincidence with the origin point, name the sketch as “locating sketch”, then model the hole structure by employing the feature of “cutextrude”, “hole”, “hole wizard”, and so on.

3. Select one or a group of features and drag them to desired folder and name the library feature with a file extension “.sldlfp”.

4. If the hole has multiple group of parameters, multiple configurations will be set up.

5. When the defined library feature is loaded on a plate, the locating point on the plate is indicated and the configuration is also selected (Figs. 9, 10, and 11).