8 Critical DFM Rules for Sheet Metal Fabrication

When you are bringing a new product to market, speed and cost are everything. In the world of manufacturing, there is a concept called DFM (Design for Manufacturability). Put simply, it means designing your parts in a way that makes them easy - and therefore cheap - to build.

If a design is too complex or ignores the physical limits of metal, it leads to "manufacturing friction": higher prices, longer wait times, and a higher risk of errors. At Norck, we want to help you avoid those pitfalls.>

Whether you are an experienced engineer or a business owner developing a prototype, following these eight simple rules will ensure your sheet metal parts are high-quality and cost-effective.

1. Don’t Bend Too Tight (The Bend Radius)

Think of a piece of metal like a piece of cardboard. If you try to fold it too sharply, the outer edge will crack or "crazing" will occur.

• The Simple Rule: The inside "curve" of your bend should at least match the thickness of the metal.

• Business Impact: If you design all your bends to be the same size, we can use one single tool to make every fold. This saves us time on setup and saves you money on labor.

2. Give Your Holes Some Breathing Room

If you put the hole too close to the point where the metal is being bent, the hole will stretch and end up looking like an oval. This means that it becomes impossible to pass screws or pins through.

• The Simple Rule: Keep holes a minimum of two times the material thickness from any bend location.

• Business Impact: This ensures your component fits together flawlessly the very first time, eliminating costly errors known as "reworks" or discarded component parts.

3. Use "Bend Relief" to Prevent Tearing

When you bend metal alongside a flat edge, the metal tries to separate at the corner. To prevent this, we cut a very small notch, called a Bend Relief, at the corner.

• The Simple Rule: Add a small rectangular or circular cut-out at the end of your bend lines.

• Business Impact: It guarantees a clean and professional finish that will not make the part break due to pressure, which means your product is more resilient for your customer.

4. Make Your Flanges Long Enough

A "flange" is the part of the metal that is being bent up. Our machines need enough surface area to actually grab the metal to fold it. If the flange is too short, it’s like trying to fold a tiny sliver of paper with giant fingers.

• The Simple Rule: Make sure your flange is at least 4 times as long as the metal is thick.

• Business Impact: Longer flanges allow us to use standard tools. Short, "illegal" flanges require custom, expensive molds that can double your production costs.

5. Respect the "Grain" of the Metal

Metal sheets are made by being rolled out at a mill, which gives them a "grain," just like wood. Metal is much more likely to snap if you try to bend it in the same direction as the grain.

• The Simple Rule: Design your part so the folds happen across the grain, not with it.

• Business Impact: This is a "hidden" rule that prevents your parts from failing or cracking months after they’ve been delivered to your customers.

6. Avoid Long, Skinny Cutouts

Laser cutters use intense heat. If your design has very long, thin "fingers" or narrow slots, the heat can cause the metal to warp or twist like a Pringle chip.

• The Simple Rule: Keep any narrow cutouts at least 1.5 times wider than the thickness of the metal.

• Business Impact: This keeps your parts flat and accurate, ensuring they look high-end and fit into your final assembly without forcing them.

7. Plan for "Springback"

Metal is slightly elastic. When we bend it to 90 degrees and release the machine, it naturally wants to "spring back" a little bit (maybe to 88 or 89 degrees).

• The Simple Rule: Be flexible with your tolerances. If a part doesn't need to be perfectly 90.00 degrees to work, allow for a tiny bit of wiggle room in your specs.

• Business Impact: Being too strict on tolerances where it isn't necessary increases inspection time and cost. Standard sheet metal tolerances keep your project on budget.

8. Use Standard Hole Sizes

If you create a hole with dimensions exactly 5.123mm, we may have to procure a customized drill bit just for our needs.

• The Simple Rule: Use "off-the-shelf" hole sizes (like 5mm, 6mm, or 1/4 inch).

• Business Impact: What this means is that since we are using standard sizes, we can easily punch your order with our existing punching tools, which results in an almost instant turnaround for your order through our high-speed punching machines.

Conclusion: Why Partner with Norck?

At Norck, we believe that manufacturing should be transparent, accessible, and high-quality. You don't need to be a metallurgy expert to get professional results—you just need the right partner. Our platform uses advanced AI to check your designs against these rules the moment you upload them, providing you with instant feedback that helps you succeed.

By following this sheet metal design guide, you aren't just making the fabrication process smoother; you are making your business more profitable by reducing waste and speeding up your time-to-market. Whether you are producing a single prototype or a massive production run, our goal is to deliver perfection every time.

Ready to start your next project? Get an instant quote. If you have questions about specific materials or complex geometries, contact us today.