Process Engineering for manufacturing /

Our ly the ady

Contents

1 The Process Engineering Function

General Manufacturing Processes, 2. Organization Chart, 4. Product Engineering, 5. Process Engineering. 7. Glossary of Terms, 10. Com-munications, 11.

2 Preliminary Part Print Analysis

Problems Encountered in Reading and Interpreting Part Prints, 15. Establishing the General Characteristics of the Workpiece, 15. Auxiliary Methods for Visualizing the Part from the Print, 22. Determining the Principal Process, 23. Alternate Processes, 24. Functional Surfaces of the Workpiece, 25. Determining Areas Used for Processing. 26. Speci-fications, 28. Nature of the Work to be Performed, 29. Finishing and Identifying Operations, 32. Relating the Part to Assembly, 33.

3 Dimensional Analysis

Types of Dimensions, 43. Measuring the Geometry of Form, 44. Sur-face Quality and Its Measurement, 56. Baselines, 70. Direction of Specific Dimensions, 72. The Skeleton Part, 72.

4 Tolerance Analysis

1

Causes of Workpiece Variation, 80. Terms Used in Determining Work-piece Dimensions, 80. How Limits are Expressed, 81. How Tolerances are Expressed, 81. The Problem of Selective Assembly, 83. Tolerance Stacks, 84. Cost of Arbitrary Tolerance Selection, 90.

5 Tolerance Charts

14

42

Purpose and Utilization of Tolerance Charts, 98. Definitions and Sym-bols, 99. Rule for Adding and Subtracting Dimensions, 100. Estab-lishing a Tentative Operation Sequence, 101. Layout of the Tolerance Chart, 103. Converting Tolerances, 105. Figuring Stock Removal, 106. Developing the Tolerance Chart, 107. Balancing the Tolerance Chart, 117.

79

98

Y
Contents

Basic Factors in Machine Selection, 325, Cost Factors, 025. Design Factors, 326. Approaches to Selection Among Alternatives, 129. Cost Analysis of Proposals, 330. Comparatice Cost Analysis, 339. Com-parison by Break-even Principle, 340. Acquiring New Equipment by Leasing. 340.

12 Standard Equipment

Turning, 347. Drilling. 361. Milling. 373. Shaping, 389. Broach-ing, 399. Grinding, 413. Cutof, 435. Pressworking. 446. Pressure Molding. 461. Forming. 474. Assembly, 493. Heating, 512. Clean-ing and Surface Treatment, 525. Classification Systems, 551.

13 Special Equipment

Workpiece Handling Systems, 559. Integrated Equipment, 579. Unit-ized Equipment, 586. Controls, 602. Special Processes Equipment, 603. Rules for Automation, 605.

vil

346

558

14 Classification of Tooling

607

Sources of Tooling, 608. Tooling, 613. 617. Workpiece Holders, 652. Molds, 676. Patterns, 681. Core Boxes, 683. Dies, 686. Templates, 690. Gages, 690. Miscellaneous Supplies, 705. Tools, 615. Tool Holders,

15 The Process Picture

Process Symbols, 707. Process Picture Sheet, 710. Processing Dimen-sions, 713. Selection of Views, 714.

16 The Operation Routing

720

Routing Uses, 722. Routing Description, 728.

17 Orders and Requests

736

Engineering Release, 737. Engineering Change Notice, 739. Stand-ards, 741. Tool Orders, 742. Tool Revision Orders, 745. Request for Purchase Requisition, 746. Request for Engineering Change, 748. Machine Specifications, 751. Miscellaneous Paperwork, 753.

Index

707

755

Beyond the design stage, one of the most complex problems faced by the engineer is the development and coordination of plans for manufacturing products. Using essentially the only information available to him, the part print, he must create and follow through a properly sequenced series of operations to transpose materials into useful products. To supplement his plan, he must select the types of tooling and equipment needed to carry it out. He must at the same time be concerned with product qual-ity, quantity, and manufacturing economy. This function is called process engineering and should not be confused with tool design which performs the mechanical funetion of designing the tools which are used to carry out the process engineer's plan.

In our initial statement we used the word coordination. This, of course, requires getting together all those people directly concerned with the successful production of the product. We emphasize the need for close contact with the product designer, for it is from his part print the process engineer must work. As in a legal contract, there must be a meeting of the minds. Both the designer and process engineer must work toward the same objective: To produce a product which is acceptable to the customer. Errors and omissions on the part print are not entirely avoidable. Some information needed for manufacturing cannot conveni-ently be specified on the print. Manufacturing problems discovered early in the planning may prevent costly engineering and tooling changes later. Thus, the need for close cooperation between these two functions is vital. It is significant, then, that in writing those sections of the book which relate to tolerances, surface quality, and other areas of common interest, we have endeavored to maintain contact with our associates in product design. In the end, we have all gained a closer understanding of each other's problems.

We have combined a substantial number of years of experience as process engineers or under related titles with such organizations as Chevrolet and Buick Motor Divisions, North American Aviation, Howard Manufacturing Corporation, and others, with our years of teaching this subject at General Motors Institute in developing this book. Many tech-niques and principles were developed or acquired over the years and are included. Prior to this book, our processing course was taught with the

Ingeniería Industrial