What Is Stamping?- Types, Operation & Application

What Is Stamping?

Stamping or pressing is a method of manufacturing that converts flat sheets of metal into final shapes. In this process, a flat sheet of metal, in the form of a blank or coil, is placed in a stamping press, A tool and die surface forms the metal into a final shape.

Stamping includes a variety of manufacturing process for sheet-metal forming such as, punching in a machine press or stamping press, blanking, embossing, bending , flanging, and coining.

It could be a one-step process where the press stroke creates the desired shape on the sheet metal part, or it could happen in a sequence of steps. Typically, stamping is accomplished on sheet metal, but it can also be accomplished on other materials such as polystyrene.

Progressive dies are often fed from coil steel, coil reel for an uncoil to a straightener to untwist the coil and then to a feeder which advances the material into the press and dies a predetermined feed length. The number of stations in the die could be determined by the complexity of the part.

Stamping is typically performed on cold metal sheets (see Forging for hot metal forming operations).

A Brief History

It is thought that the first coins appeared around the 7th century BC. These coins appear to have been minted by the Lydians in present-day Turkey, Seed. Coin hammering was the primary technique used to produce coins until 1550. In Germany, Marx Schwab used a new stamping technology to use up to 12 men to power a large wheel to stamp the metal for coins. Punching processes evolved during the 1880s.

Stamped parts were used for mass-produced bicycles in the 1880s. Stamping provided an alternative to die forging and machining with reduced costs. These stamped parts were not as strong as die forged parts, but were of sufficient quality.

In 1890, the US received stamped bicycle parts from Germany. US bicycle manufacturers began to partner with US machine tool manufacturers to make stamping machines to their specification. Ongoing research and development, allowed Western Wheel to stamp most of the bicycle parts.

Several auto manufacturers have transitioned to stamping parts for their vehicles. Henry Ford disregarded the recommendations of the engineers that stamping parts were the technology of the future, and took until the company could no longer produce enough product to meet the demand produced from die forging, and he was forced into stamping parts.

In the development of metal stamping, and forging and deep drawing, presses of various kinds have been the foundation of metal manufacturing. With the improvements in processes, presses and its centralized automation are able to move more metal in one press stroke. Presses and connected automation devices are able to increase the production rates, reduce labour costs and provide more safety to the worker.

Within the state of the art of metal stamping today, controls, like I-PRESS with Connected Enterprise can provide history, reports and the I-PRESS & Automation can be monitored remotely or mobile device. Data collection is a new trend with the emphasis on production in the future looking at historical data.

Types of Metal Stamping

There are three major types of metal stamping techniques: progressive, four-slide, and deep draw.

1. Progressive Die Stamping

Progressive die stamping consists of multiple stations, which, in sequence, have different functions.

First, strip metal is fed through a progressive stamping press. The strip is unwound from a coil and fed into the die press at a constant speed while each station in the tool executes another cut, punch, or bend. The actions of each subsequent station build on the previous stations work, ultimately creating the part.

Sometimes a manufacturer might have to change the tool on a single press multiple times, or operate multiple presses, the first station would perform the first action, the second press would perform the next action, and so on until the part is complete, Often, with multiple presses even secondary machining services were required to actually create a complete part. In this way, progressive die stamping is the best choice to build metal parts with complex geometry:

• Faster turnaround
• Lower labor cost
• Shorter run length
• Higher repeatability

2. Fourslide Stamping

Fourslide, or multi-slide, is a type of horizontal alignment, meaning there are four different slides, in other words, four different tools operating at once on the workpiece. This process allows for complicated cuts and bends to develop some of the most complicated parts.

Four slide metal stamping can have a number of advantages compared with conventional press stamping that makes it more appropriate for certain applications. Here are some specific advantages:

• Versatility for more complicated parts
• More flexibility for design changes

As the name implies, a four-slide has four slides therefore up to four different tools (one for each slide) can be used to execute multiple bends at the same time. When the material is fed into a four-slide the bending occurs in quick succession by each separate shaft equipped with a tool.

3. Deep Draw Stamping

Deep drawing process consists of pulling a blank sheet of metal into the die via a punch. This forms the blank sheet of metal into a desired shape. When the part depth is greater than the diameter, this process is called “deep drawing”.

This forming process is especially useful for parts that require a number of series of diameters and is an inexpensive alternative to turning operations that typically waste significant amounts of raw materials. Common applications and products used with deep drawing are:

• Automotive components
• Aircraft parts
• Electronic relays
• Utensils and cookware

Short Run Stamping

Short-run metal stamping has negligible tooling costs, which makes it particularly useful for prototypes or small projects. Manufacturers will use a blank, and a combination of custom tooling components and die inserts to create the part through bending, punching or drilling.

In comparison to traditional metal stamping processes, the custom forming operations and smaller run size will typically incur a higher per piece cost.

However, without the tooling costs for a larger run of parts, short run stamping is much more economical for various projects; especially projects needing excess speed.

Stamping Operation

Stamping is also known as pressing and is a process that involves placing flat sheet metal, in coil or blank (flat) form, into a stamping press. Inside the press, a tool and die surface forms the metal into a desired shape. Punching, blanking, bending, coining, embossing, and flanging are all stamping processes that form the metal.

• Bending: the material is deformed, bent along a straight line of action.
• Flanging: the material is bent along a curved line of action.
• Embossing: the material is stretched into a shallow pocket. Embossing is primarily used for decorative patterning and is mentioned here to distinguish it from repoussé and chasing.
• Blanking: cutting out a piece of material from sheet stock, to produce a blank for some subsequent operation.
• Coining: compressing or squeezing a pattern into the material. Coining has a historical basis and longevity in making coins.
• Drawing: the surface area on the blank is stretched into an alternate shape through controlled material flow. See also deep drawing.
• Stretching: increasing the surface area of a blank through tension, with no inward movement of the blank’s edge. Stretching is a common method in creating contoured sections of smooth car body parts.
• Ironing: squeezing the material and reducing the thickness along a vertical tooling wall. Ironing is utilized for beverage/pop cans and ammunition cartridge cases.
• Reducing/Necking: the method uses a gradual process to reduce the diameter along the open end of a vessel/tube.
• Curling: deforming material into a tubular profile. A common example would be door hinges.
• Hemming: folding forehead over its edge to add thickness. An example would be the edges of automobile doors.

Cutting and piercing can also be accomplished in stamping presses. Progressive stamping uses a combination of the above processes together with a number of dies lined up with the material strip taking one sequential step through the dies.

Benefits of Metal Stamping

If you need a metal part, component or product created, there are many advantages of partnering with a company that offers the services of metal stamping machines.

1. Precision

If your product needs to be cut with precision, a stamping company will have the appropriate equipment and processes. Cutting a shape with such precision can be expensive and one could be tempted to cut costs by being deficient in these processes.

A stamping company allows you the opportunity to provide a better quality product at a less expensive cost.

2. Consistency

Certain organizations or businesses may tell you that reliable consistency can only be achieved by cutting pieces on a one-by-one basis, but most of the top metal companies would disagree.

Consistency in mass production can be established by strategically controlling the total process that begins with consistent, computer-aided design (CAD), proper tooling, professional operators running metal stamping machines, also quality control which inspects each piece or part and ensures uniformity in products.

3. Mass production

This one speaks for itself. Do you require a lot of quality items? Hire a company that has the equipment and facilities to work on your project quickly and efficiently.

4. Workspace

If you outsource your stamping to a company outside your own, there is no longer a need for you to utilize your own time and place of business to produce those products.

You can focus on other areas of your business without having to worry about the details of production.

Application of Metal Stamping

Metal stamping can utilize a variety of materials based on the specific advantages of their unique metalworking characteristics for various applications across a range of industries.

Metal stamping can involve the forming and processing of base common metals to rare alloys to achieve applications based on the metallurgical characteristics of a specific type of metal or alloy or the ability to process materials various metals and alloys to achieve specific designs.

Certain industries use the electrical or thermal conductivity of beryllium copper to manufacture parts for applications in aerospace, electrical or the defense industry or the high strength of steel and its alloys for applications in automotive industries.

Some of the industries that utilize metal stamping companies include (but are not limited to):

• Automotive
• Industrial Machinery
• Consumer Electronics
• Aerospace
• Electrical
• Telecommunication

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