Comparison of 5-axis and 3-axis finish machining of hydroforming die inserts

The recent growth in hydroforming technology has sparked interest in altern ative methods to the current conventional die manufacturing techniques. Hyd roforming dies typically have shallow forming channels and open, low curvat ure surfaces, making them ideally suited fbr 5-axis machining. To fully app reciate the benefits and to proper-ly demonstrate the capabilities of 5-axi s machining for hydroforming dies, a comparison of 5-axis and 3-axis finish machining was done. Two hydroforming die insert sets were machined on a 5- axis machine with a tilt/rotary table. The tool paths for 5-axis machining were generated using custom software based on a modified form of a tool pos itioning strategy called the principal axis method. The quality of generate d 3-axis toolpaths was verified against the machining times of a third set of die inserts, similar to those machined in 5-axis, by an independent indu strial mould and die manufacturer using a 3-axis highspeed machine. A compa rison of the generated 3-axis paths versus the 5-axis paths for one of the die inserts was made using total finish machining tool path lengths to elim inate differences in machines. The results show that the generated 3-axis r oot paths are longer than the 5-axis paths by at least 247%. The paper disc usses the different tool-path generation methods along with the geometry of cusp formation and the effect of tool selection. Methods to improve the 3- axis results are also presented