The Basics of Bending Sheet Metal

An overview of minimum bend radii and bend orientation

By Scott Kaplan · September 13, 2016

Bending is a common sheet metal operation used to create flanges, curls, and seems. Additionally, sheets with bends are stiffer than their flat counterparts. For example, a flat sheet of aluminum is less stiff than that same sheet of aluminum bent into a V cross section. 

For all metals, however, there is a minimum bend radius at which the outer edge of the bend will crack. Minimum bend radii are typically specified in terms of sheet thickness (t) such as 1t, 2t, 3t, etc... We recommend a minimum bend radius of 1t for all sheet metal parts. Thus the smallest radius of any bend in a sheet should be at least equal to the thickness of the sheet. For example, if the thickness of the sheet is 1 mm, the minimum bend radius should be 1 mm. 

Below is Xometry's minimum bend radius reference table which is based on theoretical sheet metal gauge thicknesses:

Another important consideration when designing sheet metal parts is bend orientation. Bends originating from the same plane should be oriented in the same direction to avoid the need of reorienting the part. This will save both money and time. Keeping a consistent bend radius across all bends will also make designs more cost effective. Finally, it is important to note that bend accuracy increases as sheet metal thickness decreases. If bend precision is a critical requirement for your part, we recommend minimizing sheet thickness.

Let's take a look at some examples. There are two images below that show the correct bend radius for a 1 mm thick sheet (top) and the correct bend orientation for two bends in the same plane (bottom).

For more information on sheet metal fabrication, download our Sheet Metal Design Guide here.

Correct bend radius 
Correct bend radius
Correct bend orientation
Correct bend orientation

Posted in Machining

Tags

About Xometry

Xometry is your one-stop shop for manufacturing on demand. Xometry works with 32% of Fortune 100 companies, offering 24/7 access to instant pricing, expected lead times and manufacturability feedback. Xometry’s nationwide network of 4,000+ partner manufacturing facilities guarantees consistently fast lead times across a broad array of capabilities, including CNC Machining, 3D Printing, Sheet Metal, Metal Stamping, Die Casting, Extrusion, Urethane Casting, and Injection Molding.

Featured Content

How to Choose the Right CNC Material for Your Part

Regardless of your industry, choosing the right material is one of the most important components in determining the overall functionality and cost of your part. Here are some quick tips for choosing the right material.

Read on  

What is Plasma Cutting?

Plasma cutting is a manufacturing technology classified as a sheet metal cutting process since it is often used to cut metal sheet or tube stock quickly. Learn about the benefits of using plasma cutting over other types of subtractive manufacturing processes.

Read on  

What is Laser Cutting?

Laser cutting is a manufacturing technology classified as a sheet metal cutting process since it is often used to cut industrial sheet metals. Learn about the benefits of using laser cutting over other types of subtractive manufacturing processes.

Read on