Richard A. Wysk

Milling parameter optimization through a discrete variable transformation

Abstract Although milling is one of the most common chip metal removal processes, little has been done to aid in identifying the optimum operational conditions for milling processes. In this paper, a mathematical model for milling operations is developed and the five primary control variables identified. The model is then decomposed and an efficient optimization procedure developed for control variable identification.

An Integrated CAD/Automated Process Planning System

Abstract In this paper, the integration of an automated process-planning system with an interactive computer graphics system is presented. (The current system is capable of planning hole-making processes.) This paper discusses the graphics system, the generative automated process planning system, their interface and the possibility of interfacing with a larger CAD/CAM system. An example of planning a precision machined part is also presented.

A Dynamic Programming Approach to Machine Requirements Planning

Abstract This paper presents an approach to determining the optimum number of machines, and their operating rates, for each machine center in a serial-flow production system. Computational comparisons are given to solve this problem using dynamic programming and a standard mixed-integer programming package.

Alternative approaches to the machining parameter optimization problem

Abstract Several nonlinear programming techniques may be used in solving the machining parameter problem for optimal values of speed, feed, and depth of cut. These techniques vary widely in efficiency and ease of implementation. Five techniques are described and two, SUMT and an Exterior Penalty Function method, are compared through an example problem. The latter approach is found to be more efficient and accurate, as well as easier to use.

An economic model for the machining of cast parts

Abstract A procedure for selecting a casting/machining strategy is presented. The procedure emphasizes the casting/machining process sequence rather than the mathematics of optimization that generally characterizes research in this class of problems. By using information readily available in most machine shops, the technique is practical, easy to implement, and requires a minimal amount of computational effort to arrive at a good solution strategy.

Machining Parameter Optimization with Lot Size Considerations

Abstract The research literature on metal cutting contains numerous papers on optimizing machining parameters for maximum production rate or minimum production cost. Analyses presented in the literature, however, have been limited to conditions of “steady-state” manufacture (i.e., a large number of parts were to be produced). In todays metal cutting industry, over ninety percent of all parts are produced in lots of thirty or less. This implies that steady-state manufacturing may never be reached. This paper introduces lot size information into the selection of machine operating rates. A solution procedure is presented for the single decision variable (machine speed) case. An example problem is also presented to illustrate the gains that can be attained using lot size information.

Interfacing CAD and CAM—A study in hole design

Abstract Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) are modern tools for both the designer and manufacturing engineer. These two tools, however, are not usually integrated into one system. In this study, an effort has been made to connect design and manufacturing by interfacing them into a unified software system. Through this demonstrative CAD/CAM package, the designer interacts with a graphics terminal to enter hole design details; these, in turn, are sent to a generative automatic process planning routing which defines appropriate process plans. In addition, a cost estimate is given which provides the designer with a measure of the economic effectiveness of his design. In the future, it will be possible to interface such systems with part programming routines to obtain explicit machine control information. Such a system represents a significant step toward making totally automated manufacturing a reality.

A procedure to determine the least cost purchased-part planned lead-time for items controlled by an MRP system

Abstract In this paper a computer-simulation methodology is developed to investigate total inventory cost as a function of purchased-part planned lead-time practices in a Material Requirements Planning (MRP) system. The simulation model developed is a detailed model capable of simulating job-shop detail. An experimental design using the simulator and some typical cost variables was conducted. Several product structures and lead-time strategies were simulated in order to develop the minimum-cost purchase-part practice. These practices are described in the conclusions of this paper.

Optimizing machining parameters in a framework for adaptive computer control

Abstract This paper presents a simplified approach for determining optimum machining parameters. Sensitivity analysis using this approach is illustrated through an example problem and extended to demonstrate a framework for an adaptive control structure.

Simulation of adaptive controlled machining

Abstract This paper presents a basic digital simulation structure for adaptive controlled machining processes. The use of this approach to determine the feasibility of adaptive control is discussed and illustrated in the context of a turning operation.