Computer-Controlled Multiaxial Forging

Abstract

A computer-based apparatus for performing a multiaxial forging method is disclosed. The apparatus comprises a process control computer and a pair of forging dies connected thereto, wherein each of the dies comprises a piston ( 1, 2 ), said pistons being moveable along a common axis (z), and wherein a shaping anvil ( 3 ) is mounted on each of the pistons ( 1, 2 ), and the pistons ( 1, 2 ) are equipped with position measuring sensors. The apparatus further comprises a measuring instrument ( 20 ) attached to the pistons ( 1, 2 ) of the dies for directly measuring the distance between the two pistons ( 1, 2 ) at a location adjacent to the workpiece.

1 . A method of computer-controlled multiaxial forging of a workpiece, wherein a workpiece having a z-directional initial width, h0, is subject to multiple-step forging by means of a pair of forging dies moving along a first axis, z, and wherein after each forging step, the opposite dies are moved away from the workpiece and the workpiece is rotated around a second axis y, characterized by that before starting each forging step:
 finding the surfaces of the workpiece to be shaped by moving the dies by predetermined intervals, f, to the opposite surfaces of the workpiece to be shaped until a predetermined contact force, F R , F L , thereof is achieved,   upon reaching the contact forces, storing an actual starting position, P R (i), P L (i), for each of the working surfaces of the forging dies,   based on said actual starting positions, P R (i), P L (i), and the initial z-directional width, h0, of the workpiece, calculating and storing the z-directional width w(i) of the workpiece along the first axis z is before the actual shaping step,   calculating a z-directional cyclical advancement dz(k) of the dies belonging to the actual forging step according to the equation:
     dz ( k )=0.5* δt *{dot over (φ)}( i )* w ( i )* e   −{dot over (φ)}(i)*(δt*k)  
 
   
       where δt is the duration of one advancement cycle [s], {dot over (φ)}(i) is the deformation rate [1/s] specified for the i-th forging step, w(i) is the z-directional width [mm] of the workpiece before carrying out the shaping operation in the i-th step, i is the number of the forging step, and k is the cycle number of advancement which is incremented after each cycle, and
 moving both dies from their actual initial positions, P R (i), P L (i), by cyclical advancements dz(k) until the deformation specified for the actual i-th forging step is achieved. 
 
     
     
         2 . The method of  claim 1 , wherein the forging steps are repeated until a predetermined z-directional deformation of the workpiece is achieved. 
     
     
         3 . The method of  claim 1 , wherein in each shaping step, the current z-directional width of the workpiece is determined by directly measuring the distance between the two pistons at a location adjacent to the workpiece. 
     
     
         4 . A computer-based apparatus for performing a multiaxial forging method according to  claim 1 , wherein the apparatus comprises a process control computer and a pair of forging dies connected thereto, wherein each of the dies comprises a piston ( 1 ,  2 ), said pistons being moveable along a common axis (z), and wherein a shaping anvil ( 3 ) is mounted on each of the pistons ( 1 ,  2 ), and the pistons ( 1 ,  2 ) are equipped with position measuring sensors, and wherein the apparatus further comprises a measuring instrument ( 20 ) attached to the pistons ( 1 ,  2 ) of the dies for directly measuring the distance between the two pistons ( 1 ,  2 ) at a location adjacent to the workpiece. 
     
     
         5 . The apparatus according to  claim 4 , wherein the apparatus further comprises a camera connected to the process control computer for taking photos of the workpiece in predetermined states thereof. 
     
     
         6 . Non-transitory computer program product for computer-controlled multiaxial forging, the computer program product comprising a computer-readable medium having a plurality of computer program instructions stored therein, which are operable to cause a computer to perform the steps of the method  claim 1 .