ADVANCES IN SHEET METAL HYDROFORMING TECHNOLOGY

Abstract

Hydroforming is technology which is based on influence of fluid under high pressure to the inner or outer
side of work piece wall. Implementation success of hydro forming process depends of a correct election of: die, material,
fluid pressure and other process parameters. Hydroformig process should be implemented by using optimal parameters
of the forming process that would allow stable and successful hydroforming process. Sheet metal forming by fluid under
pressure is applied in deep drawing, stretching of sheet, hydroforming of welded sheets, hydroformig with metal heating
etc.The basic tendencies of development of sheet metal forming process by fluid under pressure are to be improvement of
sheet deformability, improvement of tribological forming conditions, optimization of forming process, development of
new forming processes and new materials, automation of forming process, application of flexible tools, and
implementation of flexible and intelligent systems. Hydroforming is a cost effective method of shaping metals into
lightweight, structurally stiff and strong components. The automotive industry is one of the largest applicators of
hydroforming, which makes use of the complex shapes possible by hydro forming to produce stronger, lighter, and more
rigid unibody structures for vehicles. The hydro forming manufacturing technique is frequently employed in the shaping
of aluminium tubes for bicycle frames and sheet metal panels. Hydro forming uses a specialized type of die combined
with high pressure hydraulic fluid to deform the metal at room temperature into a shape forming die. Hydroforming
allows complex shapes with concavities to be formed, which would be difficult or impossible with standard solid die
stamping. Hydroformed parts can often be made with a higher stiffness to weight. Virtually all metals capable of cold
forming can be hydroformed, including aluminium, brass, carbon and stainless steel, copper and high strength alloys.In
hydroforming sheet there is bladder forming (where there is a bladder that contains the liquid, no liquid contacts the
sheet) and hydroforming where the fluid contacts the sheet (no bladder). A work piece is placed on a draw ring (blank
holder) over a male punch then a hydraulic chamber surrounds the work piece and a elatively low initial pressure seats
the work piece against the punch. The punch then is raised into the hydraulic chamber and pressure is increased to until
the pressure forms the part around the punch. Then the pressure is released and punch retracted and hydraulic chamber
lifted and the process is complete. This paper represents advances in sheet metal hydroforming technology