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18 Important Differences Between Deep Drawing and Stamping

With the development of metal processing, the correct process for manufacturing parts is crucial. Deep drawing and stamping are two different processes that can produce parts according to the needs of the product.

Deep drawing is a sheet metal forming process that can produce high dimensional accuracy and smooth surface finish. Stamping is made by striking a metal plate with a mold to form the desired shape. Stamped parts are usually not as precise as deep drawn parts and have a rougher surface finish. The following information will help you determine whether deep drawing or stamping is more suitable for your needs.

The following points illustrate the difference between deep drawing and stamping.

Accuracy

The accuracy of deep drawn parts is measured by the thickness of the material and the radius of the inner corner. Deep drawing usually produces parts with higher precision than stamping. Only by using single point drawing can high dimensional accuracy be achieved. The surface finish of stamped parts is always rougher and has lower dimensional accuracy than that of drawn parts.

Surface

Deep drawn parts typically have a smoother surface finish than stamped parts, as there is only one deformation process during positional manufacturing. Stamping requires two processes (forming and indentation) to produce parts, resulting in a more complex and rougher surface finish. Embossing techniques can be added to enhance the appearance of formed metal panels. However, it has not improved its structural characteristics as it only increases material thickness without changing shape or size. The embossing process does not provide structural support for the parts.

Bending

Deep drawn parts are typically formed using a two-piece bending system to produce sharp angle bending. Single point extrusion molds are the best type of deep drawing because they provide maximum dimensional accuracy and produce accurate bending angles. Stamped parts cannot produce tight bends or angles suitable for many functional components. However, certain parts can be stamped into the desired shape and then transferred to another assembly fixture, where they can be produced by bending to eliminate any additional operations while ensuring a high level of quality.

Production cost

Due to the need for two presses for operation, the cost of deep drawing is higher than that of stamping equipment. Deep drawing requires a main press, while stamping requires a second press. However, due to the higher precision of deep drawn parts compared to stamped parts, they require less post-processing work, resulting in lower costs due to reduced waste and labor costs.

Material thickness

On average, due to the metal flow during the forming process, the cross-section of deep drawn parts is thinner than that of stamped parts. The material is redistributed throughout the entire process, eliminating material accumulation on the mold wall and achieving uniform distribution. This redistribution also enhances the flow of metal particles throughout the entire part, thereby enhancing mechanical performance. When designing consistent strength, deep drawing can provide better results as it can redistribute materials. Although stamping can also produce parts with uniform thickness, its reliability is not high and it is difficult to achieve uniform thickness.

Design

When designing parts for deep drawing, designers must take into account the bending and stretching limitations of the process by sheet metal. When determining wall thickness, corner radius, and other features, these limitations need to be considered to ensure that the part can be successfully drawn. Complex components with sharp bends are not suitable for deep drawing. Stamping does not have this limitation and can be used more freely without considering the forming process.

Easy to manufacture

It is possible to quickly and easily produce parts for deep drawing on a large-scale production line. The process is simple and does not require a lot of tool changes. The production of stamped parts is more challenging and usually requires more setup time. This leads to longer delivery times and higher production costs.

Mass production

Deep drawing is more suitable for high productivity. This is a fast and cost-effective way of mass production in a short period of time. Embossing technology also plays an important role in mass production, as it can better control the surface smoothness of formed parts. Stamping is limited in mass production due to its low speed, which results in lower efficiency in mass production.

Strength

Deep drawn parts are stronger than stamped parts because the stretching of the metal during the deep stamping process leads to greater flexibility, thereby increasing strength. The stamping process does not have the same ability to stretch metal, which leads to reduced flexibility. This lack of elasticity makes stamped parts more prone to failure when subjected to high stress. Compared to stamped parts, the increase in strength of deep drawn parts is a significant advantage. It is the preferred choice for applications that require high reliability.

Appearance deformation

One of the drawbacks of deep drawing is that it can sometimes cause surface deformation, such as wrinkles, stretching, and tearing. Although these deformations are not always visible, they may lead to less satisfactory appearances. Stamping can produce a smooth surface without deformation. From a purely aesthetic perspective, this makes stamped parts more popular.

Formability

Deep drawing is considered a formable process because it can easily deform metal sheets into complex shapes. Stamped parts are not as formable as deep drawn parts because the metal is not stretched, which limits its ability to deform into complex shapes. Parts that require deep drawing have higher formability than stamped parts.

Application precautions

Parts that are lightweight and have a high strength to weight ratio are more suitable for deep drawing. The deep drawing process results in a thinner cross-section of the part compared to the stamped part, without sacrificing mechanical performance. Parts that require corrosion resistance should also be produced using deep drawing, as this process produces higher quality surface finish and dimensional accuracy. Stamped parts are not suitable for producing parts with high strength to weight ratio and/or corrosion resistance.

Volume

Deep drawing is more suitable for mass production, and stamping is the preferred method when the number of parts is small. This is because the stamping cost is lower than that of deep drawing, making it more suitable for small batch production. Deep drawing requires a significant amount of setup costs, but it can be quickly produced in large quantities, making it the most suitable for mass production. Stamping uses low-cost equipment and requires minimal labor to produce many parts.

Material

Most deep drawn parts are made of steel, aluminum, and copper alloys, while most stamped parts are made of low-carbon steel or alloy steel. However, there are no mandatory regulations for this, and both processes can be used for various materials to produce various components.

Shape

The final shape of a part depends on the method of forming it - deep drawing or stamping. As mentioned above, the cross-section of deep drawn components is thinner than that of stamped parts, which means they can form more complex shapes. The tolerance of deep drawn parts is also stricter than that of stamped parts.

Manufacturing process

The forming process of stamped parts is usually one step. In contrast, the forming of deep drawn parts can involve many steps, including mold design, material preparation, cutting, stretching, trimming, and inspection. This means that the processing time of stamped parts is shorter than that of deep drawn parts, which can significantly reduce costs. In addition, stamping requires less machine maintenance as it uses less force than deep drawing, thereby reducing the operating costs of the process.

Post processing

Once stamped parts are produced, they can be used immediately because no additional processing is required, unlike deep drawn parts that require several post-processing operations, including deburring, surface treatment, and painting.

Lubricant

When drawing parts, they may come into contact with lubricants and fluids. Therefore, materials that are resistant to these substances must be used. This can be achieved by hardening or coating materials or using less sensitive materials such as plastics and ceramics, as they are less likely to react with water and other chemicals.

Summary

Deep drawing is a metal forming process that uses punches and molds to stretch metal into the desired shape. The stamping process uses points and anvils to deform the metal. The formability of stamped parts is not as good as that of deep drawn parts, and it is limited in mass production. Deep drawn components are stronger than stamped parts because the metal is stretched during the deep drawing process. Stamped parts are not as sturdy as deep drawn parts because they do not stretch metal. Design features that require high formability are most suitable for deep drawing. The cost of deep drawn parts is usually higher than that of stamped parts, but this cost is offset by their higher strength to weight ratio and corrosion resistance.