A Beginner’s Guide to Bladder and Tubular Hydroforming

Bladder and Tubular Hydroforming

Metals are everywhere around us. We see them in our cars, helicopters, building materials, home appliances, including kitchen utensils. But have you ever wondered how they are manufactured into different shapes? Well, technology is helping to make our world more beautiful. Let’s see a beginner’s guide to the bladder and tubular hydroforming.

Metal fabrication is done in various ways and hydroforming is one of them. This may sound like an ambiguous term, but we will explain it in detail. We will also discuss the types of hydroforming. This will help you to decide which one is suitable for your project.

What is Hydroforming?

This is a method of shaping components using force from liquids like hydraulic fluid, oil, or water. It is a cheap way to transform ductile metals such as stainless steel, aluminum, alloy steel, or brass, into various shapes and forms. Metals that can cold-form are mostly suitable for hydroforming. It makes them structurally stiff and strong. You can visit https://www.forging.org/forging/design/524-cold-forging-process.html to read more about cold forming.

Hydroforming further serves as a special type of die forming as it utilizes hydraulic fluids under high pressure to press room temperature working materials into dies. As a result, complex shapes that may be impossible to achieve ordinarily will be formed without welding any component. 

Industries that use this technique, particularly the aerospace and automobile industries, use it to manufacture rigid, stronger, and lighter single-piece structures. The structures are further utilized in manufacturing parts for airplanes and cars.

Types of Hydroforming

The two major types are tubular and bladder.


It uses metal tubes as the base of the created part, and it is particularly useful in the production of automobiles. In this method, high-pressure fluid is placed inside a tube, and then the metal sheets are pushed into a mold surrounding the tube. The mold shapes the metal sheets into different tubing and pipes of different weights, lengths, and shapes.

With this process, strength, stiffness, and dimensional accuracy are easily achieved. Also, automobile parts can be safely created and made to be lightweight. You can either use high pressure or low-pressure process in tubular hydroforming. 

To use a high-pressure process, ensure the die envelopes the tube totally before applying pressure. To use a low-pressure process, close the die, then apply moderate pressure to the tube. Whichever process you choose to use, you must first come up with a design of the part you want to create. Usually, designers and engineers research and draw a plan that is used to produce the prototype of what you want to produce.

Manufacturing metal parts with this method are quite labor-intensive. But it results in durable, light, and high-quality components. It is also popular because you can produce quality components at reduced costs. Automotive parts like bicycle parts are now lighter, agile, and studier than before because of tubular hydroforming.

In summary, the benefits of tubular hydroforming are:

  1. Increased overall quality
  2. High-level precision in production
  3. Greater stiffness and bending strength
  4. Utilization of fewer materials to produce lightweight parts
  5. More flexibility in the design and strength of products.


This type is known as deep draw or sheet hydroforming. The process involves placing a blank metal sheet in a press and applying pressure to it until it goes into a die. The technique is useful in manufacturing different parts. 

The industries that benefit from bladder hydroforming include commercial lighting, energy generation, aerospace, defense, and healthcare. Each of these fields requires specialized and complex parts and shapes that the manufacturers must adhere to. Therefore, the deep draw technique helps manufacturers to produce the exact shapes and surfaces required.

The method involves a bladder containing fluid such that the fluid and the metal sheets do not have any direct contact with each other. It is somewhat like stamping but employs the aid of rubber diaphragms. The diaphragms get support from an oil pressure of about 18000 psi. When there is an increase in the pressure, the metal is forced to go down into the die and take its shape.

This will bend or stretch the metal sheets into the desired shape without altering their strength. The outcome may either have several cross-sections and curved walls or be straight. However, the commonest shapes are cylinders and rectangles. Examples of parts created with bladder hydroforming are car frames, fuel tanks, cups, and cans.

The cost of production is reduced by half if you use this method because it only requires half of the die to work. The process begins with a punch, the die, a blank metal sheet, and a holder for the blank sheet. The holder is placed on the die while the blank sheet goes into it. The cavity of the die takes the resemblance of the desired shape. 

Tubular vs Bladder: Which is Better?

Tubular vs Bladder: Which is Better?

While both methods are important, a Bladder and Tubular Hydroforming Company cannot use them to obtain the same result. Bladder is used to transform flat and large components into specific shapes. Examples are lighting fixtures, antennas, and car doors. 

On the other hand, tubular hydroforming is utilized when you want to work on complex parts that involve curves. Examples are saxophone brass tubes, bicycle frames, car parts, and vehicle door handle. You can see that both methods are unique, and none is better than the other. The ideal method depends on the component you intend to create.

Hydroforming vs Metal Stamping

Hydroforming and metal stamping are both cold forming techniques. They are also better and becoming more popular than other metal forging processes as they offer a quick turnaround time and produce quality prototypes. However, hydroforming offers a more standardized method for producing components in terms of cost, efficiency, and quality.

The major advantages of hydroforming are:

  1. It does not require many tools to press and form the metal.
  2. You can easily mount the tools with no need for complicated manual adjustments.
  3. It can form unique curves and uncommon non-symmetrical shapes.
  4. It uses lesser materials and generates fewer wastes.
  5. It accepts a variety of materials.

Final Thoughts

Initially, hydroforming was used to make plumbing fixtures and kitchen spouts. However, it has developed beyond those areas as it is now popular in different manufacturing industries. This versatility makes the technique useful in manufacturing several unique parts. 

In addition, it offers a lot of benefits such as cost-effectiveness and the production of durable parts. The parts are also sturdy and structurally stiff, and you can choose between tubular and bladder processes depending on the kind of project you are undertaking.



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