How To Design A Sheet Metal Enclosure

metal enclosure

What Is Sheet Metal Enclosure?

A sheet metal enclosure is a type of housing or box-like structure made from thin sheets of metal. It is typically used to protect electronic components or other objects from the environment and can also be used for a variety of other purposes, such as reducing noise or providing a decorative finish. Sheet metal enclosures are available in a variety of shapes, sizes, and materials, and can be customized to meet specific needs.

In order to ensure the long-term success of your end product, thoughtful design and testing are required to ensure the metal enclosure’s size and dimensions meet your product’s design-for-manufacturability needs, while combining functionality, cost-effectiveness, long life, and safety.

sheet metal parts for telecom

Sheet Metal Enclosure Design Software

There are several software packages available for sheet metal enclosure design, such as SolidWorks,Autodesk Inventor, Solid Edge, and Fusion 360. Each offers a range of features and capabilities that can be tailored to your specific needs.

SolidWorks is a popular 3D CAD software used for sheet metal enclosure design. It offers a suite of tools for creating and customizing sheet metal parts, such as 3D sketches, sheet metal operations, and automated flat patterning.

The technical engineers in mamful metal fabrication factory have years design by using solidworks and can quickly create new designs and make modifications to existing parts with precision, shortening the time to market and ensuring parts meet the highest quality standards.

Metal Enclosure Material Selection

The material selection for a sheet metal enclosure depends on the application and environment in which it will be used.

Some common materials used for sheet metal enclosures include aluminum, stainless steel, galvanized steel, and cold rolled steel.Each of these materials has its own unique properties which make it suitable for specific applications.

Aluminum is lightweight and corrosion-resistant, making it ideal for outdoor applications. Aluminum is lightweight and corrosion-resistant, making it ideal for applications where weight is an issue.

Stainless steel is strong and durable, making it perfect for high-traffic areas.Stainless steel is much more corrosion-resistant than cold rolled steel and is often used in outdoor or marine applications.

Galvanized steel is corrosion-resistant, making it suitable for corrosive environments.

Cold rolled steel is strong and has good electrical properties, making it suitable for electronics applications.Cold rolled steel is strong, affordable, and the most common material used for sheet metal enclosures.

sheet metal material

Mamful as sheet metal enclosure manufacturers could go with stocked materials decided by you, and have your enclosure, parts, or components built in 2-3 days. However, if your design requires a different type of metal, we can also order it for you but which need to take a few extra days on top of our usual 2-3 day turnaround.

What Must Be Included When Designing A Metal Enclosure

Sheet metal enclosure bendinng

1.Bending Height

The minimum bend height of sheet metal is twice the thickness of the sheet metal plus the bending radius, i.e. H ≥ 2t + R, as shown in the figure below. If the bend height of sheet metal is too low, the sheet metal will be easily deformed and distorted when bending, and it is not easy to get the desired part shape and size.

When the bending is a sloped edge, it is most likely to cause distortion due to the bending height being too small, as shown in the figure below. In the original design, due to the bending height being too small on the left side, distortion is likely to occur when bending, resulting in poor bending quality. In the improved design, the height of the left side bending can be increased or the minimum portion of the bending height can be removed, so that no distortion will occur when sheet metal bending, and the bending quality will be high.

bending sloped edge deformation
2.Bending radius

To ensure the bending strength, the bending radius of sheet metal should be greater than the minimum bending radius of the material, and the minimum bending radius of various commonly used sheet metal materials is shown in the following table.

No. MaterialMinimum bending radius
1 08、08F、10、10F、DX2、SPCC、E1-T52、0Cr18Ni9、1Cr18Ni9、1100- H24、T2 0.4t
2 15、20、Q235、Q235A、15F 0.5t
3 15、20、Q255 0.6t
4 1Cr13、H62(M、Y、Cold rolling) 0.8t
5 45、50 1.0t
6 55、60 1.5t
7 65Mn、60SiMn、1Cr17Ni7、1Cr17Ni7-Y、1Cr17Ni7-DY、SUS301、0Cr18Ni9、SUS302 2.0t
t: material thickness

Of course, the larger the bending radius of sheet metal, the greater the bending rebound, and the harder it is to control the bending angle and bending height, so the bending radius of sheet metal needs to be reasonably specified.

In addition, sheet metal manufacturers tend to use zero bending radius, which makes it easier to control the bending height and bending angle, but the zero bending radius is prone to external cracking or even fracture after bending of the sheet metal, and the bending strength is relatively low, especially for hard sheet metal materials, and after a period of production, the angle on the die will gradually become smooth, and the bending size will become difficult to control.

In order to reduce the bending force and ensure the bending size, sheet metal manufacturers use another method which is to pre-add a flanging process before the bending process, as shown in the following figure. This design also causes relatively low bending strength and easy fracture of sheet metal. Flanging is an extrusion process that forces local material to extrude a groove

3.Bending direction

When sheet metal bending, the direction should be as perpendicular as possible to the metal material’s fiber direction. When sheet metal bending is parallel to the metal material’s fiber direction, it is easy to produce cracks at the sheet metal bending place, the bending strength is lower, and it is easy to break.

4.Avoid bending failure due to the inability to press the material at the bending root

When sheet metal bending, it is often impossible to press the material and bend it or cause severe deformation due to other features too close to the root of the sheet metal bending.
Generally, at least 2 times the thickness of the sheet metal plus the distance of the bending radius should be ensured above the root of the sheet metal bending without other features blocking the press of the sheet metal bending, as shown in the figure below.

In the original design, the reverse press position is too close to the root of the sheet metal bending, resulting in sheet metal bending unable to press material and bending failure. For example, if the sheet metal draw bead is too close to the root of the bending, bending cannot be performed. At this time, the draw bead can be moved to the position of the original sheet metal root, as in the first design of the improved design.
If due to design requirements, both the draw bead and the bending position cannot be moved, then a process cut can be added to the corresponding root of the bending to ensure that the bending can be carried out smoothly, as in the second design of the improved design.

press material when bending
5.Ensure the bending gap to avoid bending interference.

Due to the existence of sheet metal bending tolerance, a certain bending gap needs to be ensured in the direction of sheet metal bending movement to avoid interference when bending and resulting in bending failure, as shown in the following figure is a simplified figure of a complex sheet metal bending part, the bending sequence is to bend the upper side first and then the right side.

bending interference

In the original design, there was no gap between the two bending sides. When the upper side was bent, when the right side was bent, due to the existence of sheet metal bending tolerance, it is likely that the right side will interfere with the upper side during the bending process. In the improved design, the right side and the upper side should at least keep a 0.2mm gap, which can effectively avoid bending interference.

6.Guaranteed bending strength

When sheet metal bending, it is necessary to ensure the bending strength. Bending strength is low on long and narrow parts and high on short and wide parts. Therefore, sheet metal bending should be attached to the longer side as much as possible, as shown in the figure.

For the same function, the original design had low bending strength because the bending was attached to the shorter side, while the improved design had high bending strength because the bending was attached to the longer side.

7.Reduce the bending process

The more sheet metal bending processes, the higher the mold cost and the lower the bending accuracy. Therefore, sheet metal design should try to reduce the number of bending processes, as shown in the following figure.

In the original design, sheet metal enclosure requires two bending processes, while in the improved design, sheet metal only needs one bending process to complete the bending of both sides at the same time.

Reduce the bending process
8.Avoid complex bends

The more complex the sheet metal bending process, the more material waste of the parts may be caused. Therefore, when the sheet metal enclosure has a complex bending, it can be considered to split the complex bending into two parts, although this goes against the principle of reducing the number of components, but it is more likely to bring about a reduction in product cost and an improvement in product quality. Of course, such design needs to be verified by strict calculation to avoid unnecessary losses.

9.align the holes on multiple bends

The tolerance of sheet metal bending is comparatively large, especially when multiple bends occur, the accumulation of tolerance makes it difficult to align the holes.


The more times the sheet metal is bent, the greater the bending tolerance will be. It is difficult to guarantee the accuracy of size for multiple bends of sheet metal, which is why it is difficult to align screw holes, rivet holes and self-clinching holes in sheet metal bending.


  • Designing a hole on the bend as a large hole or long round hole to allow for greater tolerance on the bend.
  • Adding two internal locating holes, increasing the internal positioning of the die to reduce the tolerance of sheet metal bending and ensure the alignment of the two holes on the bend.
  • Punching after bending, the size accuracy of the two holes can be guaranteed, but this will increase the complexity of the stamping die and the cost of the die. Generally not recommended.

The metal enclosure is used to store, protect and secure.They are designed to prevent unauthorized access to the contents, as well as to protect against damage from dust, shocks and water.Under this function, welding enclosure and surface treatment are key important steps. We would discuss these two points in our other aritcle.

Mamful sheet metal enclosure fabrication has years experiences on metal enclosure, You could visit here to see what kind of enclosure we have done before. Do not hesitate to contact us now for your metal enclosure design and manufacturing,we would be with you all time!

Emily Lee

Emily Lee

Hi there, I’m Emily, the sales manager of mamful metal fabrication in China that makes custom sheet metal parts more than 10years. And the purpose of this article is to share with you the knowledge related to metal parts factory from a Chinese supplier’s perspective.

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