Tubular Stamping vs. Other Tube Metal Forming Processes

If yoThere are lots of options out there for manufacturing tubular metal parts, including roll forming and tubular hydroforming. Now add to the mix tubular stamping.

A relatively new metal forming technology, tubular stamping — or “tube stamping” — has a lot of things going for it and opens up a whole host of possibilities for realizing innovative designs without compromise due to factors like cost, weight, or manufacturing limitations. It’s also incredibly fast, which makes it ideal for large-volume productions and demanding schedules (or both).

Like roll forming, tubular stamping makes tubular metal parts from flat stock. This keeps costs and weight down. And like tubular hydroforming, tube stamping can create complex, asymmetrical parts, which opens up a lot of design options.

You can learn more about the inherent characteristics of tubular stamping by downloading our white paper, “An Introduction to Tube Stamping.” Here, though, we’re going to take a quick look at what distinguishes tube stamping from roll forming and tubular hydroforming.

Roll Forming vs. Tubular Stamping

Roll forming is a widespread method of metal forming that manufactures tubular metal parts from flat sheets of metal. It does so by passing flat metal stock through a series of roller dies to give the stock a desired shape. This process continues incrementally until the desired shape has been accomplished.

If you need a simple tubular shape or even a tubular shape with an asymmetrical profile, roll forming may be the answer. However, roll forming cannot be used to produce asymmetrical parts. If a roll-formed metal tube is welded shut, though, it can be used as a work piece for tubular hydroforming, which can subsequently turn a simple roll-formed tube into a more complex shape.

Like roll forming, tubular stamping begins with flat stock. But rather than being rolled, this sheet is subjected to a series of stamping operations in order to bring its ends together in a tubular shape.

Moreover, a tubular stamping setup can also be arranged so that it stamps parts into asymmetrical shapes and incorporates supplemental operations such as coining. This eliminates the need for any additional metal forming techniques to finish a complex part, although tube stamping can also be used to create work pieces for other metal forming processes, such as tubular hydroforming, just like roll forming.

Tubular Hydroforming vs. Tube Stamping

Tubular hydroforming starts with a welded metal tube. It fills this tube with water and pressurizes the tube inside of a mold that outlines a finished shape. The pressurized liquid within the tube forces the metal work piece to conform to the shape of the cavity, resulting in a more complex tubular part.

While tubular hydroforming can be used to produce amazing shapes, it inherently depends on other metal forming processes to deliver tubular work pieces before it can begin. Tubular hydroforming also proceeds piece by piece. In other words, when the mold is occupied, you have to wait until the hydroforming process is complete before starting another production sequence. Either that or have several tubular hydroforming stations going at once.

Tubular stamping, on the other hand, doesn’t depend on other metal forming processes, such as roll forming, to get it started with work pieces. Instead, it produces its own tubular work pieces right from sheet. And when the stamping presses are running, a tubular stamping production line can work on multiple pieces at a time (as many as there are stamping stations). Both of these factors speed up production significantly.

The Benefits of Tubular Stamping

While roll forming and tubular hydroforming have their advantages and are suitable for a wide variety of applications, they also have their limitations. Roll forming can’t produce complex parts. Hydroforming depends on the availability of existing tubular work pieces and can take more time than you may have. Tubular stamping, on the other hand, overcomes the design limitations of roll forming while offering an “all in one” solution for creating complex tubular parts quickly.

That’s not to say, though, that there isn’t a place for roll forming or tubular hydroforming. Roll forming is still a fast and inexpensive way to produce simple tubular metal parts since the costs and time required for setup are minimal. Tubular hydroforming, on the other hand, still offers the best potential for manufacturing parts according to the most innovative design specifications. Somewhere in between is tubular stamping — a fast method for producing relatively complex tubular parts that are both lightweight and inexpensive.

The point is, each tubular metal manufacturing project will have its own requirements, whether they are design, cost, or schedule related. Selecting the right metal forming process will depend on evaluating the circumstances to determine which will work best. To find the right fit, it’s important to know about the available techniques and to work with a manufacturing partner that has the expertise to help you decide which one is right for your project.

If you’re interested in talking with a company with more than 70 years in the business, or just learning more about tubular stamping, please contact us at (423) 745-9090. Mills Products is one of the few manufacturers in the U.S. to offer this innovative “tube stamping” technology.