A forming and fabrication technique ideal for various metals, including steel, copper, aluminum, brass, and stainless steel, hydroforming offers great versatility for a wide range of applications. Using fluid at a pressure of 20,000 psi or greater, this process allows for great cost-efficiency compared to traditional processes requiring multiple stamps and welding.
Facilitating the manufacture of lighter, stronger parts at a lower cost per unit, hydroforming can be done through two different methods: sheet hydroforming or tube hydroforming.
The Benefits of Tube Hydroforming
The most common type of hydroforming is tube hydroforming, in which metal tubes are expanded into a desired shape using two die halves.
If the shape has bends that deviate from a straight line, the tube hydroforming process begins with the loading of a raw tube into a bender to create the proper curvature and allow the tube to fit the dies. The tube is then put into a preform press for initial shaping, followed by insertion into a hydroforming press to create its final shape. Once pressurized water inside the tube produces the desired shape, the finished parts go through a wash. Any additional cuts, etches, or trims are made by lasers.
Frequently used for automotive exhaust components and sink faucets, tube hydroforming is both cost-effective and versatile in the number and variety of parts it can produce. The process allows for the creation of stronger structural components than can be achieved with other methods, with a high stiffness-to-weight ratio. Tube hydroforming also allows for thin wall tubing, as well as excellent bending strength and torsional stiffness. Offering weight- and part-reduction opportunities, tube hydroforming can be much more efficient than traditional stamping or welding processes.
Seamless parts can be made, and incredibly flexible design options are available, such as cross-sectional shape transitions from round to elliptical, large radius sweeps, and multi-sided cross sections. The elimination of the welding process reduces distortion and dimensional variation while increasing rigidity. In short, tube hydroforming produces stronger tubes that can support loads more efficiently than by the use of stamped sheet metal welded together into a tube shape.
The Benefits of Sheet Hydroforming
Sheet hydroforming typically wins out over other fabrication processes because it makes use of only one die and one sheet of metal, which is pushed into the die with high-pressure hydraulic fluid on one side to form the shape. Fluid cell sheet hydroforming can create shallow parts with open corners, and deep draw processes can make taller closed-corner parts. Workable metals include steel, stainless, aluminum, titanium, and copper.
Sheet hydroforming can be used in place of many other metal forming processes, and the machines used for this process consolidate all operations into a single step — often eliminating the need for secondary services such as annealing and welding. Because of this, more complex contours and shapes are possible, and parts can be made more efficiently regardless of their complexity.
The high-quality surfaces created are ideal for finishing purposes, and the process allows for a higher ratio of stiffness to weight. Since most sheet hydroformed parts are completed in one cycle, tooling costs can be reduced by up to 90%. Mated dies are eliminated, and sheet hydroforming tooling can be easily manufactured from standard materials.
Since it’s not necessary to use as thick a material to start with, significant material savings are possible, which also reduces the weight of the finished item. Also, because the applied shaping force is multidirectional, so there is less chance of thinning or stretching. And again, finishing is not necessary for many applications because parts form uniformly, smoothly, and scratch-free.
Deciding Whether Hydroforming is Right for You
Quite often, the choice comes down to metal stamping vs. hydroforming when selecting the best method for metal fabrication. Evaluate the needs of your specific application, and keep in mind the various benefits of hydroforming — from reduced labor and tooling costs to optimized efficiency and streamlined processes. Since hydroforming works well with different materials — including copper, aluminum, and steel — it’s well-suited to be a fabrication solution for many applications.
Whether you’re manufacturing medical instruments, sporting goods, handrails, sink faucets, or automotive components, hydroforming services provide the reliability and versatility needed to ensure optimal product performance while allowing for significant cost savings.