IDEMI

Press Tools

• 1. Tool Design Methods
• 2.Drafting And Design Techniques In Tool Drawing
• 3.Presses And Equipments For Sheet Metal Dies
• 4.Die Cutting Structure 
• 5.Die Design
  
• 6.Scrap- Strip layout For Blanking
• 7.Bending, Forming And Drawing Dies
• 8.Progressive Dies
• 9.Fine Blanking
• 10 Materials Used For Die Parts

Tool Design is a specialized phase of tool engineering. Tool-design functions may be performed by a tool engineer in addition to his other duties in manufacturing, or they may be performed by a tool-design specialist who devotes his entire working time to tool design.

The word “tooling” refers to the hardware necessary to produce a particular product. A considerable amount of tooling is the result of work performed by the tool designer. Tooling, as viewed by the tool designer, consists of a vast array of cutting devices, jigs, fixtures, dies, gauges, etc. used in normal production. The type of production will determine to a large extent the type of tooling. The most common classification of types of tooling is as follows:

1)    Cutting tools, such as drills, reamers, milling cutters, broaches, and taps

2)    Jigs and fixtures of guiding the tool and holding the work piece

3)    Gauges and measuring instruments

4)    Sheet-metal press working dies for all types of sheet-metal fabrication

5)    Dies for plastic molding, die casting, permanent molding, and investment casting

6)    Forging dies for hot and cold forging, upsetting, extrusion and cold finishing.

 The tool designer is commonly a specialist in one or perhaps two of the above types of tooling. For example, a designer of injection molds for plastics usually has little to do with the design of metal-cutting tools. On the other hand, a designer of cutting tools should be knowledgeable in jig and fixture design because of the close relationship between cutting tools and jigs and fixtures.

The basic task of the tool designer is to provide drawings of a tool or set of tools to produce the work piece. He will be provided with a blueprint of the work piece to be manufactured, the name and specifications of the machine to produce the work piece, and the number of work pieces required. If large numbers of work pieces are needed, an expensive tool may be justified.  If only a few work pieces are needed, the tool must be inexpensive. In all cases, the tool must be made as economically as possible for the required service. The tool should be easy and safe to operate; it should also look practical and attractive, but it certainly should not have unnecessary elaborate trimmings or needless complexity. The latter point is very important, since even experienced designers sometimes let their enthusiasm for fine mechanisms lead them to develop excellent tools that are not practical from the standpoint of cost. Of course, striving to obtain economy may be overdone, and unsatisfactory tools produced. It is a question of good judgment based on experience. In order to complete his task the tool designer may have to produce a complete set of drawings showing (1) an assembly drawing, (2) one or more subassemblies, if the design is complex, (3) a detail drawing of each part, (4) a complete list of parts needed to make the tool.  These are handed to the toolmakers, whose task it is to make the tools.

The tool designer must know manufacturing procedures. He must be able to visualize exactly how the work piece is to be made. He should be competent to judge the merits of different methods. For example, the tool designer should be able to determine whether work piece A should be made on a shaper or a milling machine or whether piece B should be a stamping or die-casting. The product design in the engineering department will also have a share in making decisions relative to the advantages of a particular stamping to a corresponding die casting. In large concerns the tool engineer rather than the tool designer may settle this point, but, nevertheless, the tool designer must understand all this thoroughly to do his job well.

The tool designer must have knowledge of standards and procedures. The greatest economy can be affected where standard parts (screws, bushings, handles, clamps, and so on) can be worked into new tools. Since they are made in large numbers, standard parts can be manufactured at a lower cost than special jobs. Further more, standard parts can be salvaged from obsolete tools and used again.

Knowledge of procedures is important in modern organizations. This includes methods used by the plant in manufacturing, in trucking or conveying stock or parts from one department to another, in inspecting material and products, in drafting, in releasing blueprints and stock lists, and in filling tracings and prints. All this is largely a matter of experience, but it forms an important part of the assets of a good tool designer.

In addition, a tool designer must be inventive and original. He must be able to incorporate his ideas in design layouts. In come of his work, especially as a junior designer, he may be able to follow older designs, making only slight modifications in order to meet new requirements. But as he is given more responsibility, the tool designer generally finds that while his background of experience is invaluable, he is more and more required to develop original tools. In his work he should always be ready to try out new ideas and also ready to abandon them once he sees that they will not work. Flexibility of mind is important. No designer should be set in his ways. Designs can always be improved; so suggestions from others should be welcome. It is sometimes unpleasant to redesign a tool after many hours of drawing, but the tool designer exists only to produce the best design under the conditions imposed. Time spent on redrawing will, in the end, cost less than the waste created by an unsatisfactory tool. The beginner should remember that his eraser is not given to him solely to remedy mistakes. It is to be used freely in reforming structures that could be found unsatisfactory only after they were drawn to scale.

The tool designer must understand how tools perform their function. For this he needs a good background in mechanics and mathematics. He should also know the physical properties of materials used in making tools. These are mostly steel, but since there are now a large variety of alloy steels, each with its won individual properties, this subject is a comprehensive one.

A mastery of drafting techniques is as essential to the tool designer as ability to read and write. His ideas are valueless unless they can be expressed in a manner that toolmakers can understand. This means adherence to the standard graphical language understood by all technical men. But the tool designer has to do much more than convey ideas.  He must convey information in exact terms. All drawings must be clear, complete, exact, and easily understood and must be a genuine help to the toolmaker. The designer cannot rely on verbal instructions or on the previous experience of the toolmakers.  Instructions like “Make it like the one you made last time but with two more bushings” lead to trouble and confusion.  Such remarks are impossible in large organizations or where the tools are made by outside jobbing shops.

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