A One-Minute Overview of the Key Features of CNC Punching Dies

Numerically controlled punching dies are specialized process equipment used in cold stamping to form materials—whether metallic or nonmetallic—into finished parts or semi-finished blanks; such dies are commonly referred to as cold-stamping dies. Stamping is a room-temperature forming process in which a die mounted on a press applies pressure to the material, causing it to either separate or undergo plastic deformation and thereby producing the desired part.

CNC punching dies are indispensable process equipment in stamping production and are highly technology-intensive products. The quality, production efficiency, and manufacturing cost of stamped parts are directly linked to the design and fabrication of the dies. The level of die design and manufacturing technology is a key indicator of a country’s overall product-manufacturing capability, significantly influencing product quality, production efficiency, and the ability to develop new products.

Numerically controlled punching dies come in various forms and are generally classified according to the following primary characteristics:

1. Classified according to the nature of the forming process, blanking dies are used to separate material along a closed or open contour, such as blanking dies, punching dies, cutting-off dies, trimming dies, and edge-cutting dies. Bending dies are used to bend a workpiece or other blank along a straight line (or a curved line), thereby producing a workpiece with a specified angle and shape. Drawing dies are used to form a blank into an open hollow part, or to further modify the shape and dimensions of an existing hollow part. Forming dies directly reproduce the shape of the punch and die to produce a blank or semi-finished workpiece, with only localized plastic deformation occurring in the material itself. Examples include bulging dies, necking dies, flanging dies, corrugating dies, hemming dies, and finishing dies.

2. CNC punching dies are classified according to the degree of process integration: single-operation dies complete only one stamping operation per stroke of the press; compound dies have a single station where two or more stamping operations can be performed simultaneously within a single press stroke; progressive dies (also known as continuous dies) have two or more stations along the material feed direction, enabling two or more stamping operations to be carried out sequentially at different stations during a single press stroke.

Typically, CNC punching dies consist of two types of components.

First are the process components, which directly participate in completing the machining operation and are in direct contact with the blank; these include working parts, locating parts, and stripper/pressing parts. The second category comprises structural components, which do not directly participate in the finishing process nor come into direct contact with the blank. Their function is to ensure the proper execution of the mold’s finishing operations or to enhance the mold’s performance; examples include guide components, fasteners, and standard parts. It should be noted that not all molds are required to include all six types of components—particularly single-station dies—but working parts and essential fixing parts are indispensable.