Six Helpful Design Tips for Sheet Metal Fabrication

Jul 31, 2020

Six Helpful Design Tips for Sheet Metal Fabrication

Summary: Following these six design tips for sheet metal fabrication can lead to faster and cheaper rapid prototyping for metal parts.

Sheet metal fabrication—like CNC machining, injection molding and 3D printing—is most effective if a product design is optimized at the design stage. In other words, the design of a part can play a critical role in determining its successful manufacturing. At the same time, design features and strategies can actually lead to more efficient production, which in turn leads to faster manufacturing times and lower costs. There is no down side, really.

The following tips for sheet metal fabrication should be taken into account at the design stage to ensure that your parts or products can be produced efficiently. It is also important to note that based on the nature of sheet metal fabrication, in which a part is formed by bending, punching or cutting a thin metal sheet, wall thicknesses across a given component should be uniform.

Design Tips

Hole Size

When designing your sheet metal part, ensure that any holes in the structure have a diameter at least equal to that of the thickness of the sheet metal material. Adhering to this design tip reduces the chance of a tool breaking or becoming damaged, which can increase production times and costs. Similarly, using consistent hole size diameters across a given part can speed up production because fewer tool changes will be required. Finally, holes should be placed away from curls and not be placed closer than six times the material’s thickness from each other.

Bend Radius

When designing a sheet metal part, it is important to keep in mind that the smaller a bend radius, the more strain it creates for the workpiece. As a general rule, the inside radius of a bend should be equal to the sheet metal thickness. (This is especially true for ductile metals such as stainless steel. Other more brittle metals often benefit from an even larger bend radius.)

Bend orientation

Bending is a common forming technique used for sheet metal, in which brakes bend a part into a desired geometry. To facilitate the production process and reduce overall costs, it is a good idea to ensure that bends, as much as possible, have the same orientation. This eliminates the need to reorient the parts in the manufacturing process, which saves time and ultimately money.


In sheet metal fabrication, hems are used to create safe edges on products by folding the edge of the metal sheet onto itself. A key design tip to follow when integrating a hem into a part is to avoid flat hems. Instead, an open or tear-dropped hem is often preferable, because they have less risk of fracture. When designing open hems, it is advisable to maintain an inside diameter at least equal to the thickness of the sheet metal. The hem’s length (i.e. how much is folded in) should be at least four times the thickness measurement. Tear-dropped hems should follow the same ratios, but also take into account an opening measuring at least 1/4 of the sheet metal thickness.


When designing a part with tabs or notches, there are specific measurement ratios that result in an optimized design. For instance, tabs should not be longer than five times their width, and they should be at least as wide as twice the sheet metal’s thickness. Notches, for their part, should be at least as wide as the material is thick and are best situated at least 1/8 of an inch away from each other. If notches or tabs are placed near a bend, they should be at least three times the material thickness (plus the bend radius) away from the bend, otherwise they can become warped or deformed.

Tooling choice

This design tip applies not only to sheet metal fabrication but also CNC machining. By designing parts with bends, radii and holes that can be made with conventional tools, manufacturing services such as RapidDirect can save time across the production process. In other words, if you maintain standard measurements and sizes across your sheet metal part, it will be faster and cheaper to manufacture. In a similar vein, the more simple a part’s design is, the easier (and cheaper) it is to produce.

RapidDirect, your ideal partner for sheet metal fabrication

Overall, sheet metal fabrication is a versatile production process for metal parts and is used across many, many industries. No matter what the application, each of these design tips will help streamline the production of your part, resulting in an easier and cheaper job.

At RapidDirect, our team of experts is happy to work with you to ensure your design is optimized for our sheet metal fabrication processes, and to provide vital support throughout the design preparation phase. Any issues that arise at the design stage can therefore be evaluated and fixed before moving into production, saving everybody time and money. Get your sheet metal fabrication quote now.

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