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5 Common Sheet Metal Design Mistakes to Avoid


When designing an enclosure, panel, or part, you have many design aspects that need to be taken into consideration, in addition to all of your requirements. It can be difficult to manage everything you need to keep track of, especially if you are new to the world of custom manufacturing. To ensure that you get the final part that suits your project requirements, you should avoid sheet metal design mistakes, which we have outlined in this blog.

1) Placing cutouts close to bend lines

Violating our minimum bend rules and placing cutouts too close to the bend is a common mistake. In this case, a cutout may stretch or flare out when the sides get bent by our press brakes or LVD machines. This can cause some issues particularly if you are fitting a component inside of a cutout.

A cutout close to a bend
Placing a cutout close to a bend can cause problems

Having said that, there are situations when you have to place a cutout closer to a bend to accomplish a design goal. This problem can easily be avoided by using notches to leave your cutout in perfect form.

Notching can be useful when you:

  • Need a flange smaller than the minimum bend
  • Do bend sectioning
  • Need to accommodate standoffs, connectors, and PCI cards

You can delve deeper into the concept of notching by reading this blog post.

2) Selecting the wrong finish for your end application

Generally, a finish for a part or enclosure serves two purposes – protection and aesthetics. At Protocase, a common finish is powdercoat as it serves both purposes. It can offer protection from minor scratches, while giving your final part or enclosure a very vibrant look.

There are instances where a bare metal finish is required. You also have the option of no finish, which is best for economics but not for aesthetics. There is grained finish and media blasting finish which is the most aesthetically pleasing of the bare metal finishes. An added bonus is that graphics applied by digital print or silkscreen still look great. Parts with a vibratory finish also look great – this is more recommended for CNC machined parts though.

Chemical conversion coating and passivation finishes are meant to protect your parts by altering the properties of the outermost layer. Having your parts dipped in our chem-film and passivation tanks is useful for giving your part improved electrical conductivity. These provide a really great primer layer for adding powdercoat on top of it. This process will also reduce corrosion of the parts over time.

3) Forgetting about powdercoat thickness

It’s important to keep in mind that once powdercoat is applied, you need to allot an additional 0.003”-0.005” per side on your cutout dimensions. If you ignore this when designing, your cutouts may not be big enough to fit the components you are assembling into your enclosure.

4) Keeping bend radius too tight

When a piece of sheet metal is getting bent, the resulting bend isn’t a perfect 90-degree angle. Instead, the bend will have a slight curve to it, or rather the corners will have a radius.

If the bend radius is made too tight, then it can become a major weak point in the sheet metal. This could cause your part to break easily or deform which will severely affect the components housed inside.

We have our bend radius charts on our website for you to check out and understand the bend ratios of each metal before you begin your design. The harder and thicker the metal, the greater the minimum bend radius. Again, the best advice is to consult our chart for your material and thickness of choice.

5) Not checking out Protocase resources

To ensure that you have the most flawless experience ordering custom sheet metal parts and enclosures with us, we produce a lot of useful resources. Our website is filled with design guides, bend radius charts, tolerances and frequently asked questions.

Screenshot of Protocase resources page
Our Resources section has a lot of useful information

On the other hand, our YouTube channel has a new Proto Tech Tip video released every week which focuses on aspects of sheet metal and CNC design. Going through these resources will go a long way in ensuring that you minimize sheet metal design mistakes.

Our priority is to ensure that your experience of ordering with us is as easy as humanly possible. If you require any help with sheet metal design, do not hesitate to contact us. We are here to help you revolutionize your workflow and source your parts way faster!

If you found the tips covered in this blog post helpful, but want to learn about many other topics in sheet-metal design, our guide is an awesome resource. Download it for free on our website. Happy designing!

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