Hydro Forming


Sheet metal hydro forming has been around since the mid 1950's. It is a method of forming a sheet metal blank onto a mold; by pressing the material into a rubber bladder that forms the cavity section of the shape. The flexible rubber Diaphragm allows for round, square and irregular shapes, as well as minimizes and sometimes eliminates draw marks normally created by traditional die forming.

Geometries / Shapes

Hydro Forming can produce many shapes, however it is ideally suited for complex or irregular geometries, typically with flowing radiuses and unique surface contours. 


Most metals may be hydro formed, however KIHM Specializes in super alloy or exotic metal forming. Materials such as Inconel™, Haynes™, Waspaloy™, and Rene™ alloys are typically where KIHM finds the most savings for their customers.  As hydro forming allows for complex and irregular shapes which typically may otherwise require significant machining / subtractive methods to achieve. By hydro forming these expensive hard metal alloys KIHM can provide significant savings to their customers, with an additional benefit of improved mechanical properties as compared to a machined component.

Aerospace-Specific Examples

Ducts, small shrouds, small heat shields, manifolds, and irregular housings.


Finishing. The flexible rubber diaphragm allows for round, square and irregular shapes, as well as minimizes and sometimes eliminates draw marks, wrinkling and shearing as compared to a traditional die forming. KIHM can also provide Laser Trimming capabilities to complete the component, post forming. Please see our laser overview for additional information.

Tooling. Hydro forming lends itself both to prototype and production quantities. Lead times are cut dramatically as hydro forming requires simple tooling as compared to other methods of manufacture. Additionally, the rubber diaphragm allows for complex shaping which may otherwise require multiple forming operations. Thus, hydro forming may allow for reduced tools and therefore reduced tooling costs.

Prototyping. Because tooling is minimized hydro forming can be a good fit for prototyping of complex components. As the design concept evolves tooling may be adjusted to match the part and quickly produce more prototypes.

Minimized Heat Treat. As more of the forming process can be accomplished in one processing step opposed to multiple traditional die forming steps, the need for successive heat treating operations is minimized.

Cost. As noted above the overarching benefit of hydro forming is the ability to achieve a complex or irregular shape with minimal processing steps, which ultimately results in a lower landed cost to our customers.  Whether it’s reduced tooling, less polishing or finishing or eliminating the need for additional heat treatment, given a complimentary geometry KIHM’s hydro forming process can deliver a best value component.