Questions You Should Know about steel sheet manufacturing

Avoid These 8 Common Errors in Sheet Metal Fabrication

1. Lack of Clarity in Prints: One of the foundational steps in sheet metal fabrication is having clear and detailed prints. It’s essential to ensure that all necessary details and critical dimensions are called out in the prints to transmit that information to people on the floor and the engineers who are programming the parts. A lack of clarity can lead to misinterpretations and mistakes down the line, potentially delaying your project timeline. 
2. Using Solid Models: While SolidWorks and AutoCAD are invaluable tools, it’s crucial to ensure that models are drawn as sheet metal, not solids. Incorrectly drawn models can lead to fabrication challenges, especially when working with corners.
3. Overcomplicating With Too Many Parts and Assemblies: Simplicity is often the key to efficiency. Overcomplicating designs with unnecessary parts and subassemblies can increase production time and costs. Engineers should evaluate the design to see if the number of parts can be reduced without compromising the product’s integrity. 
4. Overdesign: Using sheet metal that’s too heavy for the job can be overkill. Not only does it increase the weight, but it can also drive up costs. An option may be to switch to a lighter gauge sheet metal that takes the weight out of the product but still allows it to have the structure and rigidity of a thicker material. When it comes to choosing the right material for your project, trust the experts. Partner with a quality sheet metal fabricator early and get a second opinion.  
5. Forming Radius Too Tight: A tight forming radius can lead to cracking or other issues during the bending process. It’s essential to ensure that the radius is appropriate for the material and thickness being used.
6. Hole Locations and Fasteners Too Close: Hole and fastener locations too close to the bend radius make it difficult to put the fastener in and can stretch the hole. Always ensure there’s adequate spacing to maintain the integrity of the part.
7. Overcomplicated Hardware and Fastener Selection: While it might be tempting to stick to a specific type of hardware, like a weld nut or riv nut, sometimes more efficient or cost-effective options are available. Don’t get too fancy with hardware installation; sometimes, simplicity is best. 
8. Unrealistic Part/Component Tolerances: It’s essential to understand that different materials and fabrication types require different tolerances. Consider how the metal will behave and try to anticipate what various grades will do when bent, punched, stamped, cut, or welded. Designers should understand the fabrication process well to set appropriate tolerances.

1. Using Completed 3D Models of a Part with no Bends

This is probably the most basic issue we see. Sheet metal is flat and must be bent, formed, cut, lased, and sometimes cajoled into its final shape. It’s a very hands-on process. If you design your sheet metal part as a solid object, it’s important that you send us a CAD file that appears folded, but shows where bends should go. Related to this, because the raw materials are single sheets of metal, the entire part must have the same material thickness throughout. For example, if you create a part that uses 0.125 in. (3.175mm) thick aluminum, your entire part will need to be that same thickness.

2. Placing Features too Close to Bend Lines

A quick way to create difficulties during manufacturing is to place holes, tabs, or other features too close to a bend. So, how close can you get? Just follow the 4T rule. Keep all features at least 4x material thickness away from bend lines. So, if your design tells us to use 0.050 in. (1.27mm) copper, give your feature at least 0.200 in. (5.08mm) of clearance. If you don’t, the part will deform awkwardly in the press brake, and no one wants that.

3. Designing Perfectly Perpendicular Sheet Metal Corners

When you bend sheet metal in a press brake, the resulting bend doesn’t form a perfect 90-degree angle. Instead, the tool has a rounded tip that adds a radius to the bend. If you measure the length of that bent area and divide it by two, you’ll get the bend radius, a figure that is defined by the tool that made it. If the size of that curve is important to you, make sure you specify it in your model.

The most common internal bend radius (and our default) is 0.030 in. (0.762mm). An important consideration to remember is that the external bend radius—the one formed on the die side of the press brake toolset—is equal to the material thickness plus the internal bend radius.

Some designers like to get fancy and create different radii for each bend in a part. Want to save some money? Use the same radius for all of the bends. When your manufacturer doesn’t have to change tooling that saves you on labor costs.