Metal Fabrication Resources by Blackstone Advanced Technologies

Blackstone Advanced Technologies Blog
Oct 11, 2018 11:52:27 AM

CHECKLIST: Sheet Metal Design Guidelines & Tolerances

sheet metal design guidelinesTo manufacture sheet metal efficiently, reduce errors, and cut costs, you have to apply the engineering principle of design for manufacturing (DFM). DFM simplifies manufacturing sheet metal by considering design guidelines and tolerances that will ensure your component can actually be produced correctly. Remember, just because something looks amazing on a computer screen doesn’t guarantee it’ll turn out that way in the real world.

But knowing what protocols you should follow requires having a plan. To help you get started, use this checklist of guidelines for sheet metal design and tolerances:

Sheet Metal Design Guidelines: Know Your Basics

Here are a few essential elements to consider as you develop your sheet metal design guidelines:

  • Bend relief. It's vital for designers to indent the sheet metal designs to simplify the bending process during manufacturing. This indentation is referred to as the bend relief, and it should have a width that is the same as or larger than the thickness of the sheet metal. The depth of the bend relief should be the same as or larger than the bend's internal radius.

  • Bending radius of the sheet metal. The more flexible your sheet metal is, the easier it is to get a small inner bend radius. The radius of your sheet metal should be at least the same as the sheet metal's thickness.

  • Minimum flange width. If you want your product to look its best, consider the minimum width of the flange. To avoid sheet metal marks, the flange should be more than 4x the thickness of your sheet metal.

  • Hole size. It's essential to define the exact hole size so you can reduce potential errors during the manufacturing process. Any hole size that is more than the thickness of the sheet metal should be specified.

  • Hole and bend distance. Without sufficient spacing between a bend and a hole, you risk deforming the sheet metal when your vendor bends it. A good rule of thumb is to establish a demarcation point between the hole's edge and the bend line that’s at least 2x the sheet metal's thickness.

Specify Sheet Metal Tolerance Values

When you accurately specify tolerances, you can ensure your parts:

  • Fit correctly
  • Can be made with minimal quality control
  • Can be made at a lower manufacturing cost

Really, all of these points help reduce overall manufacturing expenses. So, ensure you specify your tolerance values every time!

Avoid applying tolerances that are unnecessarily tight. Also, consider the fit. Determine the type of fit you need to achieve, such as a press fit or sliding fit.

Finally, consider the shape of the sheet metal. For instance, the tolerance on a diameter is 2x that of the radius' tolerance.

Final Thoughts

Manufacturing sheet metal requires considering the design of your sheet metal and the necessary tolerance values. By keeping these best practices in mind, you can improve the manufacturability of your sheet metal and produce a high-quality project.

sheet metal size charts