Main Differences Between Deep Draw and Metal Stamping

With the development of metal processing, it is critical to choose the correct process to manufacture metal components. Deep drawing stamping and metal stamping are two different processes that can produce metal parts according to the needs of the product. Deep draw metal stamping is a sheet metal forming process that produces high dimensional accuracy and a smooth surface finish. Whereas metal stamping is made by striking a metal plate with a die to form the desired shape.

The following points illustrate the difference between deep draw stamping and metal stamping.

Accuracy

The accuracy of a deep drawn parts are measured by the thickness of the material and the radius of the interior corners. Deep draw stamping generally produces more precise parts than metal stamping. A high degree of dimensional accuracy can only be achieved with single-point deep drawing.

The surface finish of metal stamped parts is always rougher than that of drawn parts, and the dimensional accuracy is also lower.

Surface treatment

Deep draw sheet metal parts generally have a smoother surface finish than metal stamped parts because there is only one deformation process during position manufacturing.

Stamping requires two processes (forming and recessing) to produce the part, which is resulting in a more complex and rougher surface finish. An embossing process can be added to enhance the appearance of the formed sheet metal part. Despite this, it doesn’t improve its structural properties, as it only increases the material thickness without changing shape or size. The embossing process does not provide structural support for the part.

Bending

Deep drawn metal parts are often formed by using a two-piece bending system to create sharp bends. A single point extrusion die is the best type of deep drawing dies as it provides maximum dimensional accuracy and produces accurate bend angles.

Precision metal stamping cannot produce tight bends or angles suitable for many functional parts. However, some metal parts can be stamped into the desired shape and then transferred to another assembly fixture where they can be produced by bending, thus eliminating any additional operations while ensuring that quality remains high.

Production Cost

Deep drawing press is more expensive than stamping press because two presses are required to operate.  A main press is required for deep drawing and a second press is required for stamping. However, because deep drawn parts are more accurate than stamped parts, they require less post-processing work, resulting in lower costs due to reduced scrap and labor costs.

Material thickness

On average, deep drawn cases have thinner cross-sections than stamped cases due to metal flow during the forming of process. The material is redistributed throughout the process, eliminating material accumulation on the mold walls for even distribution. This redistribution also enhances the flow of metal particles throughout the part, thereby enhancing mechanical properties.

When designing consistent strength, deep draw stamping provides better results because of its ability to redistribute material. Although sheet metal stamping can also produce parts of uniform thickness, but the reliability is not high and it is difficult to achieve uniform thickness.

Design

When designing a part for deep drawing, designers must take into account the bending and stretching limitations of the sheet metal. These constraints need to be considered when determining wall thickness, corner radii, and other features to ensure the part can be successfully deep drawn. Complex parts with sharp bends are not suitable for deep drawing.

Metal stamping service does not have this limitation and can be used more freely regardless of the forming process.

Easy to manufacture

Deep drawn sheet metal components can be produced quickly and easily on high-volume production lines. The process is simple and does not require extensive tool changes. Production of sheet metal stamping parts is more challenging and often requires more setup time. This leads to longer lead times and higher production costs.

Mass production

Deep drawing applications is more suitable for high productivity. This is a fast and cost-effective way to produce large quantities in a short time. The embossing process also plays an important role in mass production as it provides better control over the surface finish of the molded parts.

Precision stampings is limited in mass production due to its low speeds, which makes them less efficient in mass production.

Strength

Deep drawn parts are stronger than stamped parts because the stretching of the metal during the deep-drawing process results in greater flexibility, which increases strength. The stamping process does not have the same ability to draw metal, which results in less flexibility. This lack of elasticity makes stamping components more prone to failure when subjected to high stresses. The increased strength of drawn stamped parts is a significant advantage compared to stamped steel parts. It is the first choice for applications requiring high reliability.

Appearance

One of the disadvantages of deep drawing metal stampings is that it can sometimes cause surface deformations such as wrinkles, stretching and tearing. While these distortions are not always visible, they can result in a less desirable appearance. Metal Stamping Process produces a smooth surface without deformation. From a purely aesthetic point of view, this makes stamping more desirable.

Formability

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

Application Notes

Parts with light weight and high strength-to-weight ratio are more suitable for deep drawing manufacturing. The deep drawing process results in a thinner cross-sections than stamped parts without sacrificing mechanical properties. Parts to resist corrosion should also be manufactured using deep drawing, as this process produces higher quality surface finish and dimensional accuracy. Stamping parts are not suitable for producing parts with a high strength-to-weight ratio and/or corrosion resistance.

Volume

Deep drawing stamps is more suitable for high volume production, while stamping is the preferred method when the number of parts is small. This is because metal stamping cost is lower than that of deep drawing, and it is more suitable for small batch production. Deep drawing requires a lot of setup cost, but can be produced in large quantities quickly, so it is best suited for mass production. Stamping uses lower cost equipment and requires very little labor to produce many stamped parts.

Material

Most deep drawn parts are made of steel, aluminum and copper alloys, while most stamped parts are made of mild steel or alloy steel. However, there is no hard and fast rule for this, and both processes can be used in a variety of materials to produce various components.

Form

The final shape of a part depends on the method of forming it – deep drawing or stamping. As mentioned above, drawn elements have thinner in cross-section than stamped parts, which means they can be formed into more complex shapes. Besides, Deep drawn parts also have tighter tolerances than stamped parts.

Manufacturing Process

The forming process of stamping parts is usually one step. In contrast, forming a deep drawn part can include many steps, including die design, material preparation, blanking, drawing, 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. Additionally, stamping requires less machine maintenance. Because it uses less force than deep drawing, thus reducing the operating costs of the process.

Post-processing

Once the stamping parts are produced, they can be used immediately as no additional processing is required. While deep drawn parts require several post-processing operations including deburring, surface treatment and painting.

Lubricant

When producing deep drawn parts, they may come into contact with lubricants and fluids. Therefore, we must to use materials that are resistant to these substances. This can be achieved by hardening or coating material or using less sensitive materials such as plastics and ceramics, as they do not react easily with water and other chemicals.

Summarize

• Deep drawing stamping is a metal forming process that uses punches and dies to draw 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 deep drawn parts, and it is limited in mass production.
• Deep drawn parts are stronger than stamped parts because the metal is stretched during deep drawing process.
• Stamped parts are not as strong as deep drawn parts because they do not stretch the metal.
• Design features that require high formability are best suited 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.

Do you want to know which one is the best methods for your new project? Please feel free to contact us today.