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Common Tube Bending Mistakes (and Why They Happen)


Bending a metal tube requires a powerful machine. But used incorrectly, things can go wrong quickly. An improperly bent tube underperforms and wears out quickly. 

Not to mention they generally look bad. 

To make the best bends that meet your needs and your budget, you need a balance of power, precision, speed, safety, and cost effectiveness. Otherwise, one of the following can happen. 

Misplaced Pressure 

Excessive pressure doesn’t compensate for using the wrong tools or poorly placed die. In fact, too much pressure can break your tools or cause a bad bend. 

If too much pressure is placed on the point of the bend, it can flatten or break. If pressure is placed too far away, buckling can happen (more on that in a second).  

The pressure needs to be applied in the right place to the right extent. Precision is key. 

Using the Wrong Machine for the Job 

CNC (computer numerically controlled) benders are powerful, versatile machines that offer great accuracy. They work great for complex shapes and advanced bends, but they’re not always needed for simple bends. By using a manually controlled machine, you can increase speed and save money. 

Similarly, some bends have a mandrel inserted in the tube to maintain shape and integrity. Other times, empty bending is a better solution, allowing for up to 15% flattening. This is a perfect economical approach that’s great for a number of applications. 

On the other hand, utilizing manual bending machines and/or empty bending for high-accuracy projects can result in an inadequate product. 

Too Much Flattening 

While some flattening is okay on certain jobs, too much flattening is a serious problem when it comes to tube bending. If too much stress is placed on the outside radius during the bending process, the tube can’t maintain its shape, causing the outside to bend in, flattening the tube. 

This is fixed by reducing stress and utilizing a larger bend centerline radius. Additionally, you can increase the wall thickness of the tube itself beforehand. 

Utilizing a mandrel also protects against flattening. 

Buckling and Wrinkling 

A proper bend should be as smooth as the tubing leading up to it. If you’re seeing wrinkles or buckling, you’ve got a bad bend. This happens when the cross section of the bend fails to support the pressure of the bending. 

As mentioned earlier, this generally stems from applying pressure too far away from the die or not using a mandrel when you should. 

The Best Bends at an Affordable Price 

When it comes to an accurate, economical tube bending production, Ever-Roll has you covered. Whether you need high-accuracy mandrel bending, or affordable mass-production bending where a degree of flattening is okay, we offer great service at an affordable price. 

Contact us today! 

bent on perfection.

bent on perfection.

3988 Lawrenceville Dr.

Springfield, OH 45504

Phone: (937) 964-1302 (Office)

Email: sales@ever-roll.com