Poli Corrado. Design for Manufacturing: A Structured Approach

Elsevier Science & Technology Books, 2001. — 385 p. — ISBN: 0750673419.Design for Manufacturing: A Structured Approach is intended as a text for mechanical, industrial, and manufacturing engineering students at the junior level or higher, and as a continuing education text for manufacturing engineers and engineering design practitioners in industry. Unlike many books on design for manufacturing that provide only broad qualitative guidelines to designers, this book uses a combination of both qualitative and quantitative information to assist readers in making informed decisions concerning alternative competing designs.
The quantitative methods presented here inherently require considerably more attention to geometric detail, more than required by conceptual or even configuration design. If students are to do quantitative DFM (design for manufacturing) evaluations, they simply must take the time and trouble to learn to do them. Although engineering design can be considerably more abstract than DFM, the transition from the abstraction of engineering design to the concrete detail of DFM simply goes with the territory if one wants to perform quantitative DFM evaluations in a concurrent fashion. The part-coding systems that are the basis for some of the DFM methodologies may initially appear cumbersome (there are a lot of new terms to learn), but they are in fact easy to learn. The reward is not only the ability to estimate relative tooling and processing costs, but also a good sense of the design issues that drive part costs.
This book is based on material that first appeared in Engineering Design and Design for Manufacturing:A Structured Approach, a book I co-authored with John R. Dixon and published in 1995. Design for Manufacturing: A Structured Approach is an updated, revised, reorganized, and stand-alone version of the chapters in the earlier book that dealt primarily with design for manufacturing and materials and process selection. The greatest changes occur in the chapters dealing with stamping. The coding system originally used to estimate the number of active stations required to produce a stamped part has been dropped. Instead, a more accurate and user-friendly algorithm based on the concept of process planning and strip-layout development is used to determine the number of active stations required to produce the tooling for a stamped part.
Another change that has been made in this book occurs when estimating the total relative part cost, that is, the cost of the part relative to a reference part.
The original approach allowed the cost of the reference part to vary with production volume. This, in turn, often resulted in increases in the total relative cost of the designed part with increases in production volume. This counterintuitive result appeared to cause confusion among students. The approach used here, as suggested by Professor Larry Murch of the University of Massachusetts Amherst, is to fix the cost of the reference part to $1 and the production volume of the reference part to the production volume that results in a part cost of $1.00.
This approach, which results in an increase in relative part cost with increases in production volume, appears to be favored by students, and allows them to use the DFM systems to roughly estimate the production cost of a proposed design.
To assist students in better visualizing and understanding the many orthographic views that appear in the book, isometric views have also been included where it was deemed advantageous. Many new homework problems have also been added.
To help students better envisage and comprehend the rationale behind the DFM methodologies described here, a series of PowerPoint presentations has been developed, which are on a CD-ROM that is available for use by faculty in courses that require the use of this book. These presentations contain both video clips and quick-times movies of processes such as injection molding, stamping, die casting, forging, rolling, rod drawing, and aluminum extrusion.
Readers of this book may also be interested in visiting the design for manufacturing Web site hosted by the Mechanical and Industrial Engineering
Department at the University of Massachusetts Amherst.
Design for Manufacturing: A Structured Approach can be used to support a one-semester course in Design for Manufacturing (or Manufacturing for Design) at the level of the junior or senior year in college. Such a course could be taught independently of a design course, or the two courses could be taught simultaneously.
It is strongly recommended that this course include a design for manufacturing project. Although it is true that DFM can be taught without the use of a supplementary DFM project, my experience is that student interest in manufacturing and how parts are made increases significantly when a project is included.Manufacturing, design, and design for manufacturing.
Functional designed objects.
The product realization process.
Industrial (or product) design.
Engineering design.
Production design.
Scope of the book.Questions and problems.Tolerances, Mechanical Properties, Physical Properties A review.
Interchangeability of parts.
Tolerances.
Mechanical and physical properties.
Physical properties of materials.Questions and problems.
Polymer Processing.
The processes.
Materials used in polymer processing.
Injection molding.
Compression molding.
Transfer molding.
Extrusion.
Extrusion blow molding.
Other polymer processes.
Qualitative dfm guidelines for injection molding, compression molding, and transfer molding.Questions and problems.
Injection Molding: Relative Tooling Cost.Estimating relative tooling costs for injection-molded parts.
Determining relative tooling construction costs due to basic part complexity (cb).
Determining cs.
Determining c T.
Using the part coding system to determine cb, Cs, And ct.
Total relative tooling construction cost.
Relative mold material cost.
Multiple cavity molds.
Example lmRELATIVE Tooling cost for a simple part.
Example 2--relative tooling cost for a complex part.
Worksheet for relative tooling cost.Questions and problems.
Appendix 4.A Notes for Figures 4.1 and 4.19, and Tables 4.1 and 4.2.
Appendix 4.B Worksheet for Relative Tooling Costs--injection Molding.
Injection Molding: Total Relative Part Cost.
Injection-molded part costs.
Determining total relative cycle time (t,) For injection-molded parts - overview.
Determining the basic part type: the first digit.
Itioning partitionable parts.
Non-partitionable parts.
Other features needed to determine the first digit.
Wall thickness--the second digit.
Inserts and internal threads--the third digit.
Surface requirements and tolerancesmTHE Fourth and fifth digits.
Using the coding system--overview.
Effect of materials on relative cycle time.
Example 5.1 Indetermination of relative cycle time for a partitionable part.
Example 5.2--DETERMINATION Of relative cycle time for a partitionable part.
Example 5.3INDETERMINATION Of relative cycle time for a non-partitionable part.
Relative processing cost.
Relative material cost.
Total relative part cost.
Example 5.4--DETERMINATION Of the total relative part cost.
Worksheet for relative processing cost and total relative part cost.Questions and problems.
Appendix 5.A Notes for Figure 5.2 and Tables 5.3 and 5.4.
Appendix 5.B Worksheet for Relative Processing Cost and Total Relative Cost.
Metal Casting Processes.Sand casting.
Investment casting.
Die casting.
Other casting processes.
Qualitative dfm guidelines for casting.Questions and problems.
Die Casting: Total Relative Part Cost.
Die cast part costsmOVERVIEW.
Relative tooling cost.
Example 7.1IRELATIVE Tooling cost for a die-cast part.
Worksheet for relative tooling cost.
Processing costs - overview.
Production yield and effective cycle time.
Surface finish.
Tolerances.
Example 7.2INDETERMINATION Of relative cycle time for a partitionable part.
Total relative part cost.
Example 7.3--DETERMINATION Of the total relative part cost.
Worksheet for relative processing cost and total relative part cost.Questions and problems.
Sheet-Metal Forming.The stamping process.
Stretch forming.
Spinning.
Stamping dies.
Stamping presses.
Process planning.
Design for manufacturing guidelines for stamped parts.Questions and problems.
Stamping: Relative Tooling Cost.Estimating the relative cost of stamped parts.
Die construction costs.
Determination of the number of active stations for shearing and local features.
Example 1reNUMBER Of active stations for a flat part.
Determination of the number of active stations for wipe forming and side-action features.
The number of bend stages.
Example 2reNUMBER Of active stations for a bent part.
Relative die construction costs.
Example 3--relative die construction cost for a flat part.
Example 4--relative die construction cost for a bent part.
Effects of part material and sheet thickness on die construction costs.
Relative die material cost for progressive dies.
Example 5--relative tooling cost.
Example 6-relative tooling cost.
Worksheet for relative tooling costmSTAMPING.Questions and problems.
Stamping: Total Relative Part Cost.Relative processing cost, ce.
Determining press tonnage, fp.
Press selection.
Determining the relative cycle time.
Example 1 -relative processing cost for a part.
Example 2-relative processing cost for a part.
Relative material cost.
Total relative part cost.
Example 3-total relative part cost for a part.
Worksheet for relative processing cost-stamping.Questions and problems.
Other Metal Shaping Processes.
I introduction.
Metals and processes.
Forging.
Aluminum extrusion.
Machining.Questions and problems.
Assembly.
Assembly processes.
Qualitative guidelines on design for assembly (dfa).
Total assembly cost.
Summary of dfa guidelines.
Reducing part count by combining several parts into one.Questions and problems.
Selecting Materials and Processes for Special Purpose Parts.Two approaches--a brief overview.
A hierarchical organization of material alternatives--tables 13.1 To 13.4.
Application issues in selecting materials.
Cost.
Information in selecting processesmTABLES 13.5 To 13.7.
Examples.
Injection molding versus die casting.
Injection molding versus stamping.Questions and problems.
Appendix 1 3.A Some Properties of Selected Materials.
Communications.Written communications.
Research reports.
Business technical reports.
Hybrid technical reports.
Oral reports.
Graphical communications.Questions and problems.
Nomenclature.
Index.