In custom sheet metal fabrication, the structural integrity and forming accuracy of a manufactured part is essential to its utility. For a part to perform as expected, the sheet metal must be bent accurately without tearing or warping around the bend. Achieving the perfect bend can be challenging in certain formed features. To counter metal's natural tendency to deform around the bend, it's sometimes necessary to add a bend relief.
Thankfully for designers and fabricators, adding a bend relief to a part is fairly easy and can simplify the bending process significantly. Learn more about these important design elements below.
What Is Bend Relief?
In sheet metal, a bend relief is an incision cut along the sides of a planned bend. Though bend relief lengths and widths vary between projects, they all share a common goal: preventing tearing and part deformation during the bending process.
During the bending of sheet metal, material around the bend tends to stretch and deform. The metal between a bend and a flat surface, if there is any, tends to stretch and tear as the bend is created, which results in a deformed and structurally weak component. A bend relief creates space between the bent and unbent surfaces so that the edge of the sheet metal is perpendicular to the bend itself. The gap between the bend and surrounding material allows us to shape the sheet in the press brake cleanly, eliminating cracking and tearing.
Because a bend relief serves a simple purpose, you can choose its shape to meet the needs of your design. Common bend relief shapes include rectangular and obround. At minimum, the size of the bend relief should equal the material thickness plus the inside bend radius.
When Is a Bend Relief Required?
Not every bend requires a bend relief. For example, if you were bending a piece of sheet metal perfectly in half with no cutouts, you could create the bend accurately without including a bend relief. In general, you only need to include one when there's material on either side of a bend that you do not want bent or deformed.
What Are the Benefits of Bend Relief?
The main purpose of sheet metal bend relief is to prevent unwanted deformation during the bending process. However, parts that use bend relief when appropriate come with other benefits, including that they:
Are easier to manufacture: A wide bend relief makes it easier for the manufacturer to position the sheet over the end of the tooling. It also keeps the part from shifting in the press brake.
Contribute to a stronger product: Without bend relief, the metal around a bend may crack. If the finished part is exposed to enough vibration or flexure, these cracks can grow and compromise the part's structural integrity. By preventing cracks, a bend relief allows you to create a stronger product.
Look more professional: The bend relief creates a clean separation between bent and unbent material, making the finished part look more attractive.
Contact APX York Sheet Metal for Custom Metal Fabrication
Bend relief is just one of the factors that contributes to successful metal fabrication. At APX York Sheet Metal, we complete all parts of the metal fabrication process in-house and specialize in bending. We can take on projects of all sizes and deliver your product quickly. Call or contact us for a free quote today to learn more about our custom fabrication services.