1.2 SOFTWARE IMPLEMENTATION

The software that was written for this thesis has been developed in a modular structure. All of the functions are isolated whenever possible. For example the Boolean algebra representation is stored in one C++ class, while the Boolean algebra manipulation subroutines refers to that class. The sets that the equations refer to are stored in yet another class. This hierarchy continues up, and beyond the planning level.

All software was written in a portable style, and it can be compiled and run under UNIX and MS-DOS at the present time (Excluding the MetCAPP component that is only available on the UNIX platform). To accommodate the wide variety of platforms, the software utilizes dynamic memory allocation. For the test cases the memory usage grew anywhere from less than 100 Kilobytes to over 200 Kilobytes for the examples in this thesis. The base memory usage is about 200 Kilobytes for the executable programs. Computation time also varied between 1 to 30 seconds on both the UNIX and MS-DOS platforms.

When this software is actually used in an industrial setting it will probably require about 50 rules for a small job shop, and hundreds of rules for large corporations. At present the relationship is hard to evaluate, and will remain so until an industrial implementation is tried.

To date the entire planning process is automatic. In the best of cases this is ideal, but for industrial use, it would be advisable to allow human direction, and verification for all plan steps. This would require the addition of an extensive user interface that does not exist at the present time.

The design files were all created by hand. Eventually the designs should be obtained as the output from a CAD system. Even more useful would be a CAD and CAPP system that would share a common database, and not need to encode the design in ASCII format for transfer between software. This tight coupling would allow realtime interaction between CAD and CAPP. The same can also be said about an interface to Scheduling.

The rule files are constructed by hand, and would have to be produced by a skilled Knowledge Engineer. At present this will lead to difficulties in locating personnel capable of developing the rule set. Eventually other methods and techniques could be developed to simplify the collection of new rules.

The final product of BCAPP is a design file that has been expanded to include process information. This format has benefits for replanning, and also referring back to the original design after process planning. At present I have provided a simple utility to convert this file into a set of Operation Sheets, and provide some operation planning using MetCAPP. Eventually this should be replaced by specific planning modules for the specific manufacturing technologies.