Patent ID: 6418795
Filing Date: 2002-07-16
Classification: G01N

Abstract:
A method of measuring shear friction factor between a workpiece material and a forming tool through a backward extrusion process, comprising the steps of:positioning said workpiece material at a groove previously manufactured on the forming die by turning; pressurizing the workpiece material to form an extruded product by pressure of a downwardly moving punch; forming an annular tip on the extruded end of said extruded product; measuring an external diameter of said extruded product and a diameter of the annular tip, and obtaining a perpendicular distance between the annular tip and the external diameter of said extruded product by subtracting the diameter of the annular tip from the external diameter and dividing the subtraction result by two; and acquiring shear friction factor by calculating predetermined coefficients and a normalized perpendicular distance non-dimensionalized by thickness value of the extruded product, the thickness being defined as an interval between the external diameter of said extruded product and an external diameter of the punch.