Figure: Design Evaluation and Partner Selection Approach
Consider an agile manufacturing firm that forms partnerships with other manufacturers as necessary to produce mechanical or electromechanical products quickly in response to market opportunities. The firm and its partners share data electronically about product designs and manufacturing capabilities and have established policies for forming virtual enterprises. In this environment the firm decides to design and manufacture a new product. From the product requirements, the designer synthesizes a new design and seeks feedback on the cost, quality, and lead time necessary to manufacture this design in a virtual enterprise composed of the firm and its partners.
Figure 
provides an overview of the system's functionality.
Using the CAD system,
the designer first stores the design under consideration in
an integrated product model that
defines the complete geometry and topology of the product shape,
the manufacturing features of the product, and the electrical
components and attributes of the product.
This database uses the data definitions of STEP, the international
Standard for the Exchange of Product Data (ISO 10303 [19]),
and thus supports the free exchange of data between the firm
and its partners.
The designer has two methods for design evaluation:
design retrieval (variant design critiquing)
and high-level process planning (generative design critiquing).
Both methods require more abstract product information
than that in the STEP-based product model.
Group Technology (GT) codes are used for searching
for similar products, and more detailed data about
the GT code attributes are used for detailed sorting of
similar products and for high-level process planning.
These detailed data form the Object-Oriented Group
Technology (OOGT) information, which is created from
the STEP-based product model by
the system's Automated OOGT Processor (as
shown in Figure ).
In the design retrieval step (OOGT Search and Sort), the designer exploits the concise nature of the GT codes to search quickly for similar products in the product databases of candidate partners. The designer uses the additional data in the OOGT information of the similar products to calculate more accurate similarity measures and to sort the list of similar products. The information about the designs, process plans, and performance of the similar products (if any) is valuable in estimating the cost and lead time performance of the new product design, and the similar products indicate the existence and performance of partners that can manufacture the product. The design of cost-effective, high-quality similar products may also suggest useful changes to the current product design.
If no adequate information is obtained from the variant design evaluation, the designer performs high-level process planning in two steps. The first step (Feasibility Assessment) generates feasible manufacturing alternatives. The system uses generic data about manufacturing processes and specific information about the process capabilities of the candidate partners to construct plant-specific process plans and identify features of the design that are infeasible with respect to generic or partner-specific process capabilities. These process plans specify the sequence of manufacturing operations, the candidate partners who could perform these operations, and the design attributes to be realized at each operation. (The process plans do not describe the tooling, fixtures, or other specific manufacturing instructions necessary for actual production.) In addition, this step identifies for the designer those attributes that critically affect the design feasibility. The second step (Manufacturability Assessment) also uses both generic data about manufacturing processes and specific performance measures about the processes of the candidate partners to evaluate each feasible process and partner combination with respect to cost, quality, and lead time. In addition, this step identifies for the designer those attributes that contribute to the design cost, quality, and lead time.
Once the design evaluation is complete, the system allows the designer to sort the alternative high-level process plans on selected criteria, identify the partners that form the most desirable plan, and receive feedback on the plan's expected cost, quality, and lead time.