Die Basics 101: Introduction to Stamping

When I lead workshops, it’s common to encounter attendees who are new to the stamping die and pressworking industry. Some may be recent hires eager to grasp the nuances of stamping, while others might be individuals transferred from a different department, thrust into the complexities of the stamping sector.

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This article serves as the first installment in a series aimed at introducing novice toolmakers, die maintenance technicians, engineers, and press technicians to the world of stamping. Throughout this series, we will clarify what a die is, explain stamping operations, discuss the cutting and forming processes, and explore the various components and methods employed to stamp parts.

What Is a Stamping Die?

A stamping die is a unique, precision tool designed specifically to cut and shape sheet metal into predetermined profiles or shapes. Usually, the cutting and forming sections of a die are constructed from durable tool steel or sometimes carbide, which offers a wear-resistant solution.

Stamping is recognized as a cold-forming operation, meaning that no external heat is purposefully applied to the die or metal sheet. However, friction during cutting and forming will invariably generate some heat, causing stamped parts to exit the die at significantly elevated temperatures.

Dies come in many sizes, ranging from those utilized in producing microelectronics that fit in the palm of your hand to large industrial dies measuring 20 feet square and 10 feet thick for creating full automobile body sides.

The output of a stamping operation is known as a piece part (see Figure 1). Certain dies can produce multiple piece parts in a single cycle and can operate at speeds of up to 1,500 cycles (or strokes) per minute, using press force to facilitate performance.

Types of Stamping Dies

There exists a wide variety of stamping dies, each designed to perform two basic operations: cutting, forming, or a combination of both. Dies can be manually or robotically loaded, classified as line dies, while progressive and transfer dies are fully automated.

Understanding Cutting in Stamping

Cutting is one of the most prevalent operations employed within stamping dies. In this process, metal is severed by positioning it between two bypassing tool steel sections that possess a slight gap, referred to as cutting clearance. This cutting clearance varies depending on the metal properties, cutting operation, and desired edge condition, usually accounting for approximately 10 percent of the metal's thickness.

A significant force is necessary to cut through metal, often resulting in considerable shock to the die and press, momentarily stressing the metal to its failure point, leaving a cut edge featuring shiny sections known as "cut band" or "shear" alongside a "fracture zone" or "break line" (see Figure 2).

There are several distinct cutting operations within stamping. Common examples include:

• Trimming: Removing excess material to achieve the desired profile.
• Notching: A progressive process for shaping the edges of sheet metal.
• Blanking: Used to produce "blanks" or slugs for subsequent processing.
• Piercing: Creating round or special-shaped holes without retaining the slug.
• Lancing: Slitting the metal while keeping it attached.
• Shearing: Cutting the metal along a straight line).

Understanding the basic principles of stamping is critical for effective die maintenance and press operation. For valuable insights into stamping press cost management, consider diving deeper into the components discussed.

For comprehensive details regarding stamping press maintenance procedures, feel free to consult the resources available.