Hydroforming - Tubes MEE 3024

Hydroforming

Hydroforming Concept

Benefits  Increased strength to weight ratios  Multiple cross – section reshaping or section modules increase  Improved stiffness torsion and bending rigidly  Improvement in noise, harshness, vibration (NHV) Factor  Incorporation of hole punching, slot making, embosses during hydro forming process.  Reduction in number of manufacturing stages, hence reduced tooling costs  Reduction in welding, hence distortion and subsequent heat treatment  Greatly reduced springback due to stretching

Hole Piercing Accuracy

Springback Reduction No springback, only slight change in length Maximum springback due to tension and compression Minimal springback due to tension and no compression NP Take Moments Around NP

Hydroforming – Process Defects

Hydroforming System

Hydroforming Tooling Tube Bending Made Preform

Hydroforming Process – High Pressure Tube Perimeter and diameter < Die Perimeter and width Die Closes completely under no pressure Tube is pressurized to fill remaining open cavities in the die Friction from die/tube contact prevents sliding and leads to localized thinning in corners More complicated geometry possible

Hydroforming Process – Low Pressure Tube Perimeter and Dia. ~ Die Perimeter and Width Die Closes partially under no pressure Tube is pressurized to and die completes travel Pressure completes “fill” with no localized thinning in corners as perimeters approximately same Less complicated cross- sectional geometry can be formed