Amy J. C. Trappey

The integration of modular fixture database, fixturing knowledge base and 3-D fixture planning interface

Abstract The objective of this project is to present a computer aided fixturing system (CAFS), which integrates modular fixture database, fixture positions knowledge base and 3-D graphic display interface. The system will automatically select and layout the fixture elements to secure a workpiece through an interactive progress. This work can be sub-divided into three tasks. The first task is to build a modular fixture element database. The second task is to determine true positions of modular fixture elements given a set of fixture points, called fixture configuration. The third task is to provide a 3-D graphic interface to display and refine the fixture plan interactively. The system will be developed on the platform of a solid modeler, I-DEAS. Using this platform, the user can graphically rearrange fixture elements to refine the fixture plan.

Global logistic management for overseas production using a bulk purchase 4PL model

In order to improve the quality of the components supplied by key suppliers and delivered to the final assembly sites overseas efficiently and timely, a new logistics business model and assessment analysis are proposed using services provided by fourth-party logistics (4PL) companies. In the research, a Petri Net process modeling approach is adopted to construct the model and identify the current bottlenecks discovered in the as-is (existing) logistic processes. According to the benefits of the proposed e-logistics information system and its to-be process improvement, total operating time and total operating costs can be reduced 41% and 21% respectively. The global logistics information platform is built to enhance the logistics management efficiency of manufacturers with multinational operations for improving their global competitiveness.

Planning Product Assortment Using Portfolio Optimization

The task of planning product assortments using portfolio optimization is developed and applied to a case in apparel manufacturing and distribution. The planning process begins with the retail buyer, the key individual in the organization that selects merchandise for resale to the consumer. In order to maximize the profit and minimize the risk of the merchandise investment, the retail buyer must simultaneously consider many different factors that impact the merchandise mix decision. A merchandise planning model is developed for the retail buyer based on the concept of stock portfolio theory. The investment returns and risks are considered to determine the product assortment. A retrospective statistical test is conducted to verify the goodness of the product assortment portfolio model. The methodology, developed for a large Midwest retailer, can be extended to a wide variety of cases in manufacturing, especially cases involving the production of consumer products.

A sequential block approach to the design of a cost estimation system

Abstract The estimation of costs is a vital concern of every manufacturing firm. Many economic and financial decisions are arrived at using some form of cost estimation. To assist in the estimation process, companies have produced computer software specifically designed for cost estimation. A common characteritic of many cost estimating software are their narrowly focused estimation capabilities. This refers to the software being designed to estimate costs for specific process or a specific set of processes. Since different companies estimate costs using different inputs and estimation techniques. flexibility in a cost estimation software design is essential. However, if a cost estimation syste is not designed properly too much flexibility can reduce the effectiveness of the system. This paper discusses a sequential block approach to the design of a computerized cost estimation system. The system constructs cost estimates by defining each step of the production as a block for a specific product. Then the sequence of blocks are linked as a tree structure to represent the whole production processes. The design of the syste is illustrated using the estimation of the manufacturing cost of a typical plate/fin type automotive evaporator.

AN INTEGRATED SYSTEM SHELL CONCEPT FOR COMPUTER AIDED DESIGN AND PLANNING

An integrated system shell called MetaDesigner, which deals with computer integrated product design and manufacturing planning, is developed by using various types of Al techniques. The object-oriented programming technique is applied to represent the information, including data and knowledge, and to implement various reasoning processes. A hierarchical structure is used to manage the processes of design ideation and manufacturing planning. Ultimately, it is the structure that the search process follows to find the instances of design and planning solutions. The system also provides interactive and system guided knowledge acquisition, classification, and retrieval to increase the intelligence of the hybrid expert systems developed in MetaDesigner.

Using Optimization Model to Control Workpiece Rigidity and Deformation in Workholding to Achieve Precision Machining

The basic criterion in precision machining is to machine a workpiece that satisfies dimensional accuracies and low tolerance variations. Precise machining demands the work-piece to be rigidly fixed, which in turn requires high clamping forces. The clamping forces, as well as cutting forces, result in deformation of the workpiece. This deformation of the work-piece hinders the final goal of the machinist, which is to machine within low dimensional and geometric tolerance band-widths.