Understanding Hydroforming and Metal Fabrication

Metal fabrication is the term used to refer to any process that shapes, cuts, or molds metals into finished products. Rather than creating a product from ready-made parts, fabrication creates it from raw or semi-finished materials. There are many metals fabrication processes, and which one is used on any product depends on the material being used and the final product required.

Most fabricated products are manufactured from a range of metals and their alloys. A few of the most used metals fabrication include brass, gold, silver, tin, copper, aluminum, titanium, nickel, iron, magnesium, and steel. Usually, fabricators start with stock metal parts like rods, bars, billets, and sheets when crafting new products. Visit to learn more about the properties of brass.

What’s the Difference Between Fabrication and Welding?

In the metalwork industry, these two terms are very popular. Even though they vary slightly from each other, they are often used interchangeably by people who aren’t quite knowledgeable about this field. So, what’s the difference? Fabrication encompasses all the processes involved in the manufacturing of metal, whereas welding is a part of the fabrication process.

You can say that fabrication may include welding, however, welding is always a part of the former. Metal parts can be fabricated without welding but if a material is being welded, it’s definitely undergoing a fabrication process.

Types of Fabrication

Before a fabrication method is chosen, several factors such as the purpose of the product, the material, and the part geometry should be taken into consideration. The following are the most common fabrication processes:

  • Casting
  • Forging
  • Welding
  • Machining
  • Stamping
  • Folding
  • Cutting
  • Punching
  • Drawing
  • Shearing
  • Extrusion

What is Hydroforming?

Hydroforming is a fabrication process that is employed in shaping malleable metals like aluminum into structurally strong pieces. In this process, some of the attributes of the material are retained. The procedure uses a high-pressure hydraulic fluid to force metals into a die. It is an important fabrication technique in the automobile industry as it is used in crafting the unibody construction present in many cars today.

How Does it Work?

Hydroforming machines make use of a negative mold in the desired shape or the shape of the end-product. A light metal sheet is then inserted into the mold and secured properly in place before hydraulic pistons inject a pressurized fluid into the mold. Once this is done, half the process is over and what’s left is for the pressure of the fluid to force the sheet against the mold. This shapes the metal sheet into the desired shape or design. After some time, the pressurized liquid is released and the newly shaped sheet is removed, having been turned into a positive copy of the negative mold.

Types of Hydroforming

There are several types of hydroforming that are used in fabrication. As expected, the selected method depends on the material and the product to be crafted. Each process has its limits and projects for which they are most suitable. Below are some of the most common types of hydroforming:

  • Panel: This process is carried out under extremely high pressure to achieve great material flow. It is widely used in the automobile and aerospace industry for crafting aerodynamic products.
  • Low-pressure: This process is mostly employed when there’s a need for slight alterations in the shape of a workpiece.
  • High-pressure: Manufacturers use this process when they need to reshape a panel or tube into a completely new shape.
  • Tube: Utilizes low pressure to enhance the structural integrity, strength, and overall performance of a material.
    Other types of hydroforming include:
  • Explosive: This is used as an alternative to conventional hydroforming and can be done with or without a hydraulic fluid. Rather than injecting a highly pressured fluid to force the material into the die, this process utilizes an explosive charge. This charge is placed on the side of the metal with the highest pressure and once it detonates, a tremendous amount of pressure is created which forces the metal into the die. One advantage of this method is that it can be used with explosive welding. Click here to learn more about explosive welding.
  • Hydrochemical Metal Forming: This method combines a mechanical punch and hydraulic pressure. It allows manufacturers to form metals with a degree of tightness and deformation that can be controlled to achieve desired results. Therefore, the procedure is primarily used in the production of flat panels.
  • The procedure is quite simple. By expanding the metal into the die using hydraulic pressure, the strain is spread evenly across the surface of the material. Once this is done, a punch is employed to re-deform the metal into a flat panel design.
  • Pillow: Pillow hydroforming is a method that is used in forming two steel sheets that have been previously welded around their perimeters. In this process, hydraulic fluid is infused into the welded part. This action forces the sheets in opposite directions against two negative molds. The procedure is commonly used to craft steel pillars with a wide base and narrow top sections.

Benefits of Hydroforming

The following are some of the benefits that a hydroforming company and manufacturer enjoys from this process:

  • Low work-hardening
  • Materials can be optimized for cost effectiveness
  • Cost of tools is relatively inexpensive and can be easily and quickly replaced
  • Minimizes material thin-out
  • The procedure is suitable for irregular contours and complex shapes and designs
  • One cycle in a hydroforming press can replace multiple traditional draw operations
  • Tearing, shock lines, wrinkling, and draw marks are eliminated.

Hydroforming in the Transportation Industry

Although hydroforming is also used in other industries, it is one of the most applied metal fabrication processes in the production of automobile parts. Since it was first used, its use and practice have expanded greatly. Today, many sports cars are built using hydroformed parts, thanks to the capabilities of unibody construction. Not surprisingly, manufacturers of motorcycles and bicycles also employ this process in the production of several parts.

Final Thoughts

While the range of applications of hydroforming has expanded since it was first used, many designers are yet to accept the process. However, manufacturers that have successfully incorporated the procedure into their operations enjoy the fact that products crafted using this method are strong and relatively lightweight.

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