Manufacturing Engineering Processes, Second Edition

Leo Alting

• Publisher: CRC Press
• Year: 2020
• Print ISBN: 9780824791292
• eBook ISBN: 9781000148251
• Topic: Technology & Engineering
• Subtopic: Industrial Engineering
• Index: Technology & Engineering

Responding to the need for an integrated approach in manufacturing engineering oriented toward practical problem solving, this updated second edition describes a process morphology based on fundamental elements that can be applied to all manufacturing methods - providing a framework for classifying processes into major families with a common theoretical foundation. This work presents time-saving summaries of the various processing methods in data sheet form - permitting quick surveys for the production of specific components.;Delineating the actual level of computer applications in manufacturing, this work: creates the basis for synthesizing process development, tool and die design, and the design of production machinery; details the product life-cycle approach in manufacturing, emphasizing environmental, occupational health and resource impact consequences; introduces process planning and scheduling as an important part of industrial manufacturing; contains a completely revised and expanded section on ceramics and composites; furnishes new information on welding arc formation and maintenance; addresses the issue of industrial safety; and discusses progress in non-conventional processes such as laser processing, layer manufacturing, electrical discharge, electron beam, abrasive jet, ultrasonic and eltrochemical machining.;Revealing how manufacturing methods are adapted in industry practices, this work is intended for use by students of manufacturing engineering, industrial engineering and engineering design; and also for use as a self-study guide by manufacturing, mechanical, materials, industrial and design engineers.

1
A Morphological Process Model

1.1 INTRODUCTION

In industrial production, many different processes or manufacturing methods are used. To be able to select the technically and economically best manufacturing sequence for a given product, it is necessary to have a broad, fundamental knowledge of the possibilities and limitations of the various manufacturing pro cesses, including the work materials used and the geometries, surface finishes, and tolerances required.

In this first chapter the individual processes are not considered in detail, but a coherent picture of the common structure on which all processes are based is introduced. By defining and considering the elements in this structure, a sys tematic understanding of materials processing is obtained, which is based on a general engineering background and allows an evaluation of the possibilities and limitations of the different processes. This approach has a broad, general appli cation since it reflects invariant relations, methods, or principles, but in the con text of this book it will be related only to those processes characteristic of the manufacturing industry.

1.2 BASIC STRUCTURE OF MANUFACTURING PROCESSES

The term process can in general be defined as a change in the properties of an object, including geometry, hardness, state, information content (form data), and so on. To produce any change in property, three essential agents must be available: (l) material, (2) energy, and (3) information. Depending on the main purpose of the process, it is either a material process, an energy process, or an information process. In the following sections, only material processes will be considered, especially those producing geometrical changes or changes in ma terial properties, or both (1). This does not, however, imply a limitation of the general principles.

1.2.1 General Process Model

The general process model can be illustrated as shown in Fig. 1.1. The model shows that a material process can be described by the associated flow system: material flow, energy flow, and information flow.

Material flow can be divided into three main types, as shown in Fig. 1.2:

1.Through flow, corresponding to mass-conserving processes

2.Diverging flow, corresponding to mass-reducing processes

3.Converging flow, corresponding to assembly or joining processes

Mass-conserving processes (dM = 0) can be characterized as follows:

•The mass of the initial work materials is equal to (or nearly equal to) the mass of the final work material, which means, when referring to geomet rical changes, that the material is manipulated to change its shape.

Mass-reducing processes (dM < 0) can be characterized as follows:

•The geometry of the final component can be circumscribed by the initial material geometry, which means that a shape change is brought about by the removal of material.

FIGURE 1.1 The general process model. Here i designates inputs and o outputs.

FIGURE 1.2 The three main types of material flow: (a) mass-conserving processes (dM = 0); (b) mass-reducing processes (dM < 0); (c) assembly or mass-increasing pro cesses (dM > 0). Here M means mass of material, i input, and o output. The numbers 1 and 2 refer to the number of material elements.

Assembly or joining processes (sometimes expressed as dM > 0) can be char acterized as follows:

•The final geometry is obtained by assembling or joining components so that the mass of the final geometry is approximately equal to the sum of the masses of the components which are manufactured by one or both of the previous methods.

These three types of material flow have been related to the work material but, depending on the process, auxiliary flow of material may be necessary, such as lubricants, cooling fluids, and filler material. Most processes aiming at a change in material properties without a change in geometry are mass-conserving processes.

The energy flow associated with the process can be characterized as energy supply, energy transmission to the workpiece, and removal or loss of energy.

Information flow includes what might be termed shape and property infor mation. A certain geometry for a certain material can be characterized as the shape information for the material. In a geometry-changing process, shape change information is impressed on the material so that the final shape infor mation is equal to the sum of the initial shape information and the shape-change information impressed by the process. The shape-change information is created by an interaction between a tool or die (with a certain contour content) and a pattern of movement for the work material and the tool or die. This means that a geometry-changing process is characterized by a material flow on which, by means of an energy flow, the shape-change information corresponding to the information flow is impressed.

Impressing a change in geometry on a material can be carried out in one or more steps, which means that

Io=Ii+ΔIp1+ΔIp2+…+ΔIpn(1.1)

where I_o is the desired geometry, I_i the initial shape information of the material, and I_pn the shape-change information for a single process. The number of pro cesses necessary is determined partly for technical and partly for economical reasons.

Similarly, the property information flow, for example, hardness, strength, and so on, involves the sum of the properties of the initial material and the changes in properties produced by the various processes.

The proper inte...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Foreword
• Preface to the Second Edition
• Preface to the First Edition
• Table of Contents
• 1 A Morphological Process Model
• 2 Properties of Engineering Materials
• 3 Engineering Materials
• 4 Basic Theory of Metalworking
• 5 Classification of the Manufacturing Processes
• 6 Solid Materials: Mass-Conserving Processes
• 7 Solid Materials: Mass-Reducing Processes
• 8 Solid Materials: Joining Processes
• 9 Granular Materials Powder Metallurgy
• 10 Liquid Materials: Casting Processes
• 11 Plastics and Plastic Processing
• 12 Nontraditional Manufacturing Processes
• 13 Manufacturing Systems
• 14 Cleaner Manufacturing
• 15 Notes on Industrial Safety
• References
• Problems
• Answers to Selected Problems
• Appendix: Unit Conversions
• Index