Hole positioning is an essential aspect of custom sheet metal part design. Though engineers often rely on CAD or other design programs when placing holes in their designs, it's important to consider how the fabrication process will impact their performance. Placing a hole too close to a part's edge or bend radius can affect its durability, appearance and function.
When you send a part design to manufacture, you expect the final product to look and function how it does in your plans. As a result, you need to plan hole positioning correctly the first time. Understanding hole positioning in sheet metal fabrication can save you time and money and help your manufacturer deliver the results you're after.
What Happens When a Hole Is Positioned Improperly?
A hole placed too close to the edge of a sheet metal part has the potential to affect performance. Designed to attach the part to another component using a rivet or other fastener, the hole and surrounding metal may tear or crack, compromising the structural integrity of the product. This effect worsens as more force is applied. Depending on the application, this cracking can decrease the part's lifespan or even make it unusable.
When a hole is placed too close to a future bend in the metal, it can become warped during bending. This warping occurs when part of the hole is affected by the pull of the bending process. The bend drags the surrounding metal and changes its shape, resulting in a deformed hole that's difficult or impossible to accurately thread. The only ways to avoid warping are to drill the hole after bending, which can be expensive, or to move the hole position farther from the bend radius.
Calculating Minimum Edge Distance and Bend Distance
Selecting a hole position too close to a part's edge or bend radius can significantly impact the performance of the final product. Fortunately, calculating a better hole placement is usually simple.
For applications where hole placement must be near the edge, the hole distance from the edge should always be equal to or greater than material thickness. Keep in mind, however, that some applications require more distance. For example, you may want to increase the distance to 1.5 times the material thickness or more for complex designs in the material handling or construction industries.
To calculate how close a hole can be to a bend, you need to use a different formula. In most cases, minimum hole bend distance equals 1.5 times sheet thickness plus bend radius, though the multiplying factor may increase as hole size increases in diameter.
Though these calculations can help you approximate the minimum distance you'll need to place between a hole and the edge or bend in sheet metal, different situations call for different specifications. Other factors to consider include:
Contact the Fabrication Experts at APX York Sheet Metal
Proper hole positioning helps ensure a smooth fabrication process and a final product that performs as expected. At APX York Sheet Metal, we have 71 years of experience in custom metal fabrication. If you need a manufacturer capable of managing precise hole positions in sheet metal, we can help. Contact us for a free quote today to see how we can manufacture your design.