Die Design Fundamentals. Vukota Boljanovic
2. In many figures a punch shank is shown because it is still in everyday use in many small stamping shops. However, according to the OSHA Standard 1910.217(7) it cannot be used for clamping the punch holder to the slide (ram) of a press, but can be used for aligning the die in the press. Slide (ram) mounting holes or another clamping system must be provided in the punch holder for fastening. The final chapter deals with presses and quick die-changing (QDC) systems.
The intent of this new edition is to provide students, instructors, and working professionals with graphically detailed assistance in understanding the underlying principles of designing single-station dies as well as small progressive dies of a type generally used once for short runs of parts manually cut from strip sheared from sheets.
For the first time, a dual (English and metric) system is included. New methods of producing blanks widely acknowledged within the industry, such as waterjet cutting and laser cutting are included, as well. The chapter 20 “Presses and Quick Die-Change Systems” has been considerably revised, with the addition of a new subtopic, “Quick Die-Change Systems.” To this third edition of the book has also been added a Glossary of the terms used.
In response to comments and suggestions by numerous reviewers, several major and minor changes have also been made throughout the text. A page-by-page comparison with the second edition will show that literally hundred of changes have been made for improved clarity and completeness.
It is hoped that by reading and studying this third edition of the book, students and other users will come to appreciate the vital nature of tool and die engineering as an academic subject that is as exciting, challenging, and as important as any other engineering and technology discipline.
The author of the third edition owes much to many people. I am grateful to my son Sasha for valuable contributions in the preparation of this edition. Finally, I wish to thank Em Turner Chitty for her competent proofreading of this new edition.
Vukota Boljanovic
Knoxville, Tennessee
INTRODUCTION TO DIE DESIGN
Die design, a large division of tool engineering, is a complex, fascinating subject. It is one of the most exacting of all the areas of the general field of tool designing.
How then shall we enter into the study of die design? Obviously, we shall have to begin cautiously, learning each principle thoroughly before proceeding to the next one. Otherwise it is quite likely that we should soon become hopelessly involved in the complexities of the subject and in the bewildering number and variety of principles that must be understood. What, then, is a die?
The word “die” is a very general one and it may be well to define its meaning as it will be used in this text. It is used in two distinct ways. When employed in a general sense, it means an entire press tool with all components taken together. When used in a more limited manner, it refers to that component which is machined to receive the blank, as differentiated from the component called the “punch,” which is its opposite member. The distinction will become clear as we proceed with the study.
The die designer originates designs of dies used to stamp and form parts from sheet metal, assemble parts together, and perform a variety of other operations.
In this introduction you will learn basic meanings and the names of various die components; then, operations that are performed in dies will be listed and illustrated. In other sections of the book, the design of dies and die components will be explained in a far more thorough manner, so that your understanding will be complete in every respect.
1.1.1 Part Drawing
To begin our study of the various components that make up a complete die, let us consider the drawing of the link illustrated in Figure 1.1. This part is to be blanked from steel strip and a die is to be designed for producing it in quantity. The first step in designing any die is to make a careful study of the part print because the information given on it provides many clues for solving the design problem.
Figure 1.1 A typical part drawing.
Figure 1.2 A complete die drawing.
1.1.2 Die Drawing
Figure 1.2 is a complete die drawing ready to be printed in blueprint form. To the uninitiated it might appear to be just a confusing maze of lines. Actually, however, each line represents important information that the die makers must have to build the die successfully. In illustrations to follow, we will remove the individual parts from this assembly and see how they appear both as three- and as two-view drawings, and as pictorial views, to help you to visualize their shapes. As you study further, keep coming back to this illustration to see how each component fits in. When you are through, you should have a good idea of how the various parts go together to make up a complete die.
1.1.3 Blueprints
After a die has been designed on tracing paper using traditional techniques or AutoCAD, blueprints are produced for use in the die shop where the dies are actually built by die makers. This is how a blueprint of a die drawing appears. From such prints, die makers build the die exactly as the designer designed it. The drawing must be complete with all required views, dimensions, notes, and specifications. If the die maker is obliged to ask numerous questions, the drawing was poorly done. Figure 1.3 shows a typical blueprint.
Figure 1.3 A typical blueprint.
1.1.4 Bill of Material
The bill of material (Figure 1.4) is filled in last. This gives required information and specifications for ordering standard parts and for cutting steel to the correct dimensions. This material is cut and assembled in the stock room, then placed in a pan, along with a print of the die drawing. When filled, the pan must contain everything the die maker will require for building the die, including all fasteners and the die set.
Figure 1.4 A typical bill of material.
Figure 1.5 A pictorial view of an entire die.
1.1.5 Die Assembly
Figure 1.5 is a pictorial view of the entire die as shown in Figure 1.2. The die pierces two holes at the first station, and then the part is blanked out