Single-stage Dies (Engineering Dies)
A single-stage die is a tool designed to perform only one specific operation in the stamping process-or a portion of a complex operation-resulting in lower production efficiency compared to progressive dies. However, they can be used in a setup that mimics progressive production by sequencing operations according to the product's forming process. Types include punching, bending, flattening (for products requiring high flatness), shearing, and deep-drawing dies. The product is formed sequentially across multiple machines and dies; intermediate steps such as welding, tapping, or component insertion can also be integrated into the process.
Progressive Dies
In this process, stamping operations are performed continuously; the input is sheet metal, and the outputs are scrap and the finished stamped product. The defining characteristic is the continuous nature of the operation, which allows for high levels of automation and efficiency. Progressive dies are typically used for products with simpler forming requirements-often those that can be formed in a single pass and are needed in large volumes, such as iron housings for fan rotors. After the stamping stages are complete, additional processes like spot welding, riveting, tapping, and surface treatment can be performed to finalize the part.
Upper and Lower Dies
Stamping dies are divided into the punch (upper die) and the die (lower die). Factors such as the clearance between the upper and lower dies and the sharpness of the cutting edges directly affect the quality of the sheared edge.
Most traditional techniques are applicable to stainless steel stamping; however, it is important to note that stamping stainless steel requires 60% more force than stamping low-carbon steel. Consequently, the press frame must be capable of withstanding these higher forces.