冲压模具英文文献.docxVIP

Forming DiesForming dies, often considered in the same class with bending dies, are classified as tools that form or bend the blank along a curved axis instead of a straight axis. There is very little stretching or compressing of the material. The internal movement or the plastic flow of the material is localized and has little or no effect on the total area or thickness of the material. The operations classified as forming are bending, drawing, embossing, curling, beading, twisting, spinning, and hole flanging. A large percentage of stampings used in the manufacturing of products require some forming operations. Some are simple forms that require tools of low cast and conventional design. Others may have complicated forms, which require dies that produce multiple forms in one stroke of the press. Some stampings may be of such nature that several dies must be used to produce the shapes and forms required. A first consideration in analyzing a stamping is to select the class of die to perform the work. Next to be considered is the number of stampings required, and this will govern the amount of money that should be spent in the design and building of the tools. Stampings of simple channels in limited production can be made on a die classed as a solid form die. It would be classified under channel forming dies. Others-the block and pad type-are also channel forming dies. Such operations as curling, flanging, and embossing as well as channeling employ pressure pads. A forming die may be designed in many ways and produce the same results; at this point the cost of the tool, safety of operation, and also the repairing and reworking must be considered. The tool that is cheapest and of the simplest design may not always be best because it may not produce the stamping to the drawing specifications. Where limited production is required, and a liberal tolerance is allowed in a stamping, a solid form die can be used. Drawing Dies Drawing is a process of changing a flat, pre