Although stamping dies vary in structural design and complexity-and are composed of a wide variety of parts-they are invariably divided into an upper die and a lower die. The upper die is typically secured to the press slide via a die shank and moves vertically along the press guide rails in unison with the slide, while the lower die is fixed to the press bolster (or work table). The classification and functions of the components that make up a stamping die are as follows:
Working Parts
These parts come into direct contact with the stamping material, applying pressure to execute the stamping operation. Working parts include punches, dies (female dies), and punch-die combinations (often referred to as forming parts); they are the most critical components of the stamping die.
Locating Parts
These parts establish the correct position of the material or workpiece within the die, ensuring the stamped part meets quality specifications. Locating parts involved in feeding and guiding include stock guides, guide plates, and side pressure plates. Those involved in feeding and pitch control include starting stops, fixed stops, pilot pins, and side cutters. Those used for positioning blanks or workpieces include locating pins and locating plates.
Blank-holding and Stripping/Ejection Parts
These parts serve to hold the blank in place and ensure the removal or ejection of scrap or stamped parts that may be lodged on the punch or within the die cavity, thereby allowing the stamping process to continue.
Blank holders prevent the blank from shifting or bouncing. Stripper plates facilitate part removal and scrap clearance. Generally, "stripping" refers to removing the part or scrap from the punch, while "pushing" and "ejecting" refer to removing them from the die cavity. Mechanisms installed in the upper die are typically called "pushers," while those in the lower die are called "ejectors."
Guiding Parts
Their primary function is to ensure the precise alignment of the punch and die and to maintain smooth movement of the die components; they consist of guide pillars, guide bushings, guide plates, and similar elements.
Supporting Parts
These parts connect and secure the aforementioned components in their respective positions or link the die to the press; they serve as the structural foundation of the die. Key examples include the upper die shoe, lower die shoe, retaining plates, backing plates, and die shanks.
These are primarily used to fasten and connect various stamping die components, such as bolts, screws, and cylindrical pins. The assembly of the aforementioned guiding and supporting components forms the die set. The die set serves as the framework for the entire die; all die components are mounted onto it, and it bears the full load during the stamping process. The upper die shoe connects to the press slide via a die shank, while the lower die shoe is secured to the press bolster using screws and clamping plates. The guiding mechanism of the die set maintains the precise alignment between the upper and lower dies, guiding the movement of the punch and ensuring a uniform clearance during stamping. Die sets and their constituent parts have been standardized, with specific technical specifications established for them.
Die sets are categorized into guide-post types and guide-plate types. The most widely used are those employing guide posts and guide bushings as the guiding mechanism. Depending on the feeding method, these standard die sets are available in configurations such as rear guide-post, center guide-post, diagonal guide-post, and four-post designs. When designing a die, the appropriate type is selected based on the specific requirements of the punch and die (matrix). The size specifications for the die set can be selected directly from standards based on the outer dimensions of the die matrix.