FOCUS ON HYDROFORMING
HIGH-PRESSURE FORMING
We outline the utility of various hydroforming processes for manufacturing complex and close-tolerance parts .
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“ Parts that normally require multiple steps or expensive progressive dies can often be formed in a single cycle with sheet hydroforming .”
Internal high-pressure forming ( hydroforming ) is a methodology for the manufacture of hollow metal components , a process that has grown enormously since the mid- 1990s . There are numerous applications for customers in various sectors . The hydroforming process is very suitable for developing complex , irregularly shaped parts or products . The final shape can be achieved in fewer steps and with less manual correction . Heavy-gauge and ‘ difficult ’ materials can be formed into complex shapes with close tolerances .
In hydroforming , tube and pre-forms are expanded from the inside out by a liquid working medium in a closed die . This method makes it possible to manufacture hollow components with a complex external shape and especially favourable strength properties . It is used in a variety of industries , especially in the automotive and aerospace industries to manufacture lighter , stronger as well as rigid one-piece structures . It is ideal for applications that require the creation of asymmetrical , complex or long and shallow components .
In sheet hydroforming , a metal sheet is placed over a die before highly pressurised water forces it down and makes it conform to the shape of the mould . In tube hydroforming , a pre-existing tube is set between two dies , and water pushes the interior of the tube to expand and conform to the new shape . Both processes allow for the seamless forming of new shapes and parts in common metal alloys without welds .
Sheet hydroforming
Sheet hydroforming is a metalforming process that uses pressurised hydraulic fluid in a flexible diaphragm to shape sheet metal against a single , un-mated tool . The process can create a wide range of complex geometric shapes from a variety of materials including aluminium ; steel ; stainless steel ; titanium ; niobium ; Inconel ; copper and more . It is used when large and flat components are required in a particular shape .
“ Sheet hydroforming presses can combine or even replace different metalforming processes including spinning ; press-brake forming ; traditional draw forming ; rubber pad forming ; progressive die forming and more . These machines can also consolidate multiple steps into a single cycle , virtually eliminating secondary finishing processes such as polishing , annealing or welding ,” said Beckwood Corporation . The two primary types of sheet
Flexform TM , also called fluid cell forming , sheet-metal forming ( Quintus Technologies ). hydroforming presses are fluid cell and deep draw . Fluid cell presses create shallow parts with open corners while deep draw presses are used for taller parts with closed corners . Deep draw hydroforming machines use pressurised hydraulic fluid ( either water or oil ) to force sheet metal into or around a single solid mould . The hydraulic chamber is sealed by a flexible rubber diagram , which acts as the female portion of the tooling and can be paired with any mould .
Rubber pad forming is a deep drawing technique that is suitable for the production of small and medium-sized batches .
The uniform pressure exerted by the diaphragm in sheet hydroforming is suitable for creating complex geometric shapes which are difficult using traditional forming methods . Parts that normally require multiple steps or expensive progressive dies can often be formed in a single cycle through sheet hydroforming . Cans , boxes or parts with curved flanges , which have a tendency to wrinkle , also benefit greatly from the controlled flow of material .
Tube hydroforming
“ Tube hydroforming is extremely advantageous , because it allows manufacturers to create precise replications of the same part without needing to weld or join the two halves of the tube . Hydroforming also leaves the part with a highquality finish that reduces the need for most