Some Basic Facts about Bladder and Tubular Hydroforming

Bladder and Tubular Hydroforming

Hydroforming is not a new process in the metal-making business. It is a strategic procedure that has been with us for over 70 years. This is considering the journey so far since the idea was patented by John Fox and Fred Leuthesser. This process has seen a lot of modifications and changes at large. This is why there are various ways it can be carried out. You should also know some of the various kinds of hydroforming techniques are better suited for certain metal-making projects. To know more about its history, you can visit: The reason is that the focus here is not its history but two of its forms. Here, we will shed some light on tubular and bladder hydroforming techniques.

Everyone that works or benefits from the metal-making industry is advised to keep reading. This is because of how relevant or (at least) informative this article will be for them.

About Hydroforming

About Hydroforming

Regardless of the form it takes, there is always an underlying principle that determines how hydroforming works. So, you need to understand what this is even if you are dealing with a specific form.

As a procedure for die forming which is instrumental in creating metals into various shapes, it relies on the use of hydraulic fluid. But this is not all there is to the process.

The hydraulic fluid in question is subjected to high-pressure application. The way this happens is where there are differences. This is where you need to understand the peculiarities of each and identify which is best for your project.

There are so many ways this process benefits those in the business of making metal products. However, you should know people who need to create strong things from ductile metals stand a lot to gain using hydroforming procedures.

Here is something to take note of before we delve into the tubular and bladder hydroforming discussion. One of the key differences between these beneficial metal-making processes is the items to be made eventually.

As the name suggests, tubular hydroforming is very beneficial for making metallic objects that have a tube-like structure. On the other hand, the bladder procedure is beneficial for making metallic objects that are sheet-like. Now that you have gotten this, let us discuss some more about both hydroforming procedures.

Bladder Hydroforming

This is instrumental in making metallic objects that are sheet-like as explained above. The name bladder is used because of how something known as a bladder holds up liquid that helps the entire procedure.

This liquid/fluid operates at room temperature before the high-pressure release to alter the sheet’s shape to conform to the intended design.

You should also know that this procedure is called flex-forming. So, you should not get confused if you hear it referred to in this manner.

Regardless of the procedural differences between this form of hydroforming and the one discussed below (tubular), there are shared similarities. The factors to be considered before engaging in either metal-making processes are one such. This has to do with metal or alloy properties (including material restrictions), and cost.

Tubular Hydroforming

Three basic things are involved before this procedure happens – Regulated pressure, tube, and dies. “Die” is pluralized (dies) because there are two ends of this part involved and very important in the entire metal-making process.

Speaking of dies, the fate of the procedure rests heavily on it. This is why care must be taken to make sure it is in the right proportion, size, and shape.

For the tube, this has to be well secured. This is why axial punches are used for sealing. This is important because of the critical role the tubes play in regulated pressure release.

This is because, after the closure of the dies, the hydraulic fluid operating at room temperature is let into these tubes. It is regulated pressure from the tube and shape of the dies that determine the eventual shape the metal alloy worked upon will take.

Factors to be Considered before Conducting Bladder and Tubular Hydroforming

The two discussed above are one of the best metal-making procedures under various circumstances. Here are some things you should take into consideration to make sure using either of them is the right thing:

Elongation Degree

The metal’s ability to withstand elongation is something that must be well thought about before using either of these procedures. This is why knowledge of the physical and even chemical characteristics of metals is needed.

These basics need to be well understood so that you do not use the wrong procedure. For instance, several steel alloys stand a better chance than aluminum for this procedure.

The reason is because of the physical and chemical properties. Just so you know, aluminum is less resilient when compared to steel. So, using steel is better even though aluminum is a lot more malleable.

Appropriate Alloy

Whether it is aluminum or steel you are using, it is not just enough to pick any alloy. This is because some alloys can handle the hydraulic fluid pressure better than others. Some will also not do a good job.

So, make sure you are using the right alloy regardless of the metal engaged. Let us use aluminum as an example. Grade W and T come highly recommended.

But even at that, Grade T is a lot better when dealing with structural tubes. Grade W on the other hand is better when dealing with decorative options.

Corner Restrictions

You have to understand the eventual metallic objects you are trying to make. The sort of bends and corners that is needed will determine if either hydroforming option will be used. And just as a reminder, the kind of object to be made determines the hydroforming option you would go for.

Operational and/or Purchase Cost

There is so much talk about the cost-effectiveness of both metal-making procedures. Well, this is just in a sense. The reason is that the machines that carry out these operations cost a lot.

Furthermore, the specialized manpower required to use these machines and monitor the entire process costs something as well. These and a few other reasons are why some industries that need Bladder and Tubular Hydroforming services work with some service providers.

This is instead of buying these machines and hiring hands to operate them. So, you need to consider the cost and decide how to go about things if you must use these procedures.


There are several forms of hydroforming procedures that have been developed. Tubular and bladder hydroforming are one such.

We have discussed some basic facts about them and hope that you understand them better. This is important in deciding if/when these procedures will be used.


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