Metal stamping is the process of shaping parts with the use of a tool set. This tool set punches or stamps holes and shapes into a metal sheet. This process can be a very fast, effecient and cost effective process to form many types of parts from a wide variety of metal sheets. Intricate part designs, dimensional stability and repeatabiltiy are common benefits of metal stamping.
Parts have been fabricated by the metal stamping process, since the beginning of the Industrial Revolution.. The invention of the metal stamping press led to the production of parts for the military and agriculture industries.
The metal stamping process produces parts for many different industries including, aerospace, automotive, defense, electrical, medical and consumer goods. Electrical circuits, fasteners, soda cans, kitchen appliances and automotive parts are just a few examples of the wide variety of parts that are manufactured using the metal stamping process.
Many alloys of metal are used in the metal stamping industry. Alloys such as aluminum, brass, bronze, copper, zinc, steel, stainless steel and even precious metals like gold and silver are supplied to the stamper in coils or sheets for processing. The thickness of the coil or sheet can vary from .010" to 1/2"
Metal stamping comes in many forms. Common stamping forms include conventional or single action, progressive dies, turret type, deep drawing, shearing, blanking, embossing and piercing. Many stamping methods are needed to efficiently produce various required parts.
The stamping operations are performed with the use of punches and dies made from heat treated tool steel or carbide. These tools are machined to the desired shape, heat treated and ground to the final dimensions. These tools can be very complex and be required to perform flawlessly under very high stresses and high speeds. Metal stamping tools require excellent edge retention, good toughness and wear resistance. These grades of tool steel are usually hardened to RC 58-62.
Conventional or single action dies generally perform just one operation such as piercing a hole into a steel blank. These dies are used for heavier guage parts and smaller quantities.This type of stamping requires high tonnage presses due to the amount of force needed to punch the heavy gauge metals. Common press sizes include 500 to 1500 tons. Automotive chassis components are commonly produced on these type of presses.
Progressive die designs are fast and cost effective. This method has from 2 to as many as 15 stations performing many different stamping operations in a metal sheet. Each station performs one operation, then the sheet or coil advances to the next station for another operation. Intricately shaped punches are fed through a die plate to punch the shape into the coil. All of these stations perform many operations on a single part. Progressive dies produce parts such as computer components, brackets and aircraft components.
Turret type presses produce parts in thin gauge sheets. These presses are capable of performing as many as 1000 operations per minute. These are low tonnage but very high speed presses. Electical circuits and components are common products produced on turret presses.
Deep drawing is a form of stamping where the coil or sheet is stretched through the use of a punch and die to form a part. A fair amount of stress is placed on the tooling to stretch the coil stock. Commonly produced parts include beverage cans, aerosol cans and stainless steel kitchen sinks.
Shearing and blanking are metal stamping methods that are used to cut a part from a coil or sheet. The embossing process stamps a design onto the face of a coil or sheet. Piercing is the process of pucnhing a hole into a part or sheet. Coining is a process where the part is blanked and embossed at the same time. Many of these processes are combined and performed in one machine at various stages.
Due to the high pressure and fast speeds of the stamping operations, die maintenance becomes very important. The cutting edge of the tool can dull or chip requiring replacement or resharpening. Proper maintenance will prevent press downtime. Proper tool steel selection will also help to prevent loss of edge retention. See our article on Tool Steel Selection to assist you. Then take a look at the Charts for comparison of many common tool steels.