Method for incremental sheet forming using resilient tooling

Abstract

A dual sided incremental sheet forming method for incrementally forming sheet materials such as sheet metal that provides opposed primary and secondary forming tool assemblies. The primary forming tool assembly provides a rigid tool and the secondary forming tool assembly provides a compressible and resilient backing layer. The rigid tool applies force to one surface of the 2024/054570 sheet material while the resilient backing tool applies counter force to the opposite surface of the work piece as it supports the work piece along predetermined, successive paths of formation created as the primary forming tool assembly moves relative to the sheet material. The direction of travel of the primary forming tool relative to the sheet material is alternated either as to each successive path of formation, or as to predetermined groupings of paths of formation.

1 . A method for incrementally forming a work piece having at least one work area and having first and second opposed and substantially parallel surfaces positioned on an X-Y plane of an “X”, “Y”, “Z” three-dimensional orthogonal coordinate system, comprising:
 a. providing an apparatus having:
 i. a primary forming tool assembly positioned adjacent to and facing the first surface of the work piece; and 
 ii. a backing forming tool assembly having a compressible and resilient surface layer that is positioned adjacent to and facing the second surface of the work piece;
 wherein the primary forming tool assembly and the backing forming tool assembly are configured and arranged for independently moving in a predetermined sequence and pattern relative to each other, and 
 wherein the primary forming tool assembly further comprises a tool shaft having a tip that is arranged to face toward the first surface of the work piece and positioned opposite the backing forming tool assembly; 
 
 
 b. positioning the primary forming tool assembly relative to the work piece to move to a predetermined X, Y, Z coordinate so as to be adjacent to the first surface of the work piece within the work area; 
 c. positioning the backing forming tool assembly relative to the work piece to move simultaneously to a predetermined Z coordinate within the work area so as to be in contact with the second surface of the work piece and opposite the position of the primary forming tool assembly; 
 d. advancing the primary forming tool assembly toward the work piece along the Z-axis to another predetermined Z coordinate so as to cause the tip of the tool shaft to contact and exert a forming force on the first surface of the work piece at a localized area of contact within the work area, thereby:
 i. forming the work piece into a predetermined configuration; and 
 ii. compressing the resilient surface layer of the backing forming tool assembly to support the second surface of the work piece resulting in a localized force within the area of contact while the work piece is being formed; 
 
 e. moving the primary forming tool assembly relative to the work piece on an X-Y plane along a predetermined set of coordinates while the tip of the tool shaft remains in contacting relation with the first surface of the work piece at substantially the same Z coordinate for exerting the forming force so as to follow a predetermined path of formation substantially parallel to the X-Y plane as the work piece is consistently formed in the Z direction within the work area; 
 f. retracting the primary forming tool assembly away from the work piece; and 
 g. repeating steps “b” through “f” to form additional paths of formation by:
 i) sequentially utilizing incrementally progressing values for the predetermined Z coordinates, and 
 ii) alternating the direction of travel of the primary forming tool assembly, counterclockwise or clockwise, along successive paths of formation until the work piece is fully formed in the work area. 
 
 
     
     
         2 . The method of  claim 1 , wherein the direction of travel to form the additional paths is alternated for successive groupings of paths of formation. 
     
     
         3 . The method of  claim 1 , wherein the direction of travel to form the additional paths is alternated for each successive one of the additional paths. 
     
     
         4 . The method of  claim 1 , further comprising the steps of:
 h. providing a controller assembly being capable of simultaneously coordinating the respective positioning of the primary forming tool assembly and the backing forming tool assembly in relation to each other;   i. providing at least one sensor to measure the amount of formation of the work piece at specified positions along the path of formation of the work piece;   j. comparing the measurements from the sensor to a predetermined amount of formation at the same specified positions along the path of formation;   k. relaying the resulting compared measurements to the controller assembly; and   l. adjusting the position of at least one of the primary forming tool assembly and the backing forming tool assembly relative to preprogrammed amounts of formation along the paths of formation so as to form the work piece into the predetermined configuration.   
     
     
         5 . The method of  claim 4 , further comprising the step of selecting the sensor so as to be of a contact type such that the sensor measures the amount of formation of the work piece by physically contacting the work piece. 
     
     
         6 . The method of  claim 4 , further comprising the step of selecting the sensor so as to be of a non-contact type such that the sensor measures the amount of formation of the work piece without physically contacting the work piece. 
     
     
         7 . A method for incrementally forming at least two work areas of a work piece initially having a generally flat configuration and first and second opposed surfaces, positioned on an X-Y plane of an “X”, “Y”, “Z” three-dimensional orthogonal coordinate system, comprising:
 a. positioning a primary forming tool assembly adjacent to the first surface of the work piece in a first one of the at least two work areas, said primary forming tool assembly having a tool shaft comprising a tip capable of forming the work piece when forcibly engaged therewith, the tip having a hardness value that is greater than that of the work piece; 
 b. positioning a backing forming tool assembly adjacent to the second surface of the work piece, said backing forming tool assembly capable of being moved in the Z direction, said backing forming tool assembly further having a compressible and resilient outer surface layer; 
 c. advancing said backing forming tool assembly toward the work piece along the Z-axis to contact and support the second surface of the work piece opposite the position of the primary forming tool assembly; 
 d. advancing said primary forming tool assembly along the Z-axis relative to the work piece to a predetermined Z coordinate so as to cause said tip of the tool shaft to engage the first surface of the work piece along a predetermined path of formation in a given direction and provide a predetermined amount of forming force thereon to form the work piece; 
 e. maintaining the position of the backing forming tool assembly to provide a reactive force on the second surface of the work piece to the forming force; 
 f. moving said primary forming tool assembly relative to the work piece on the X-Y plane along a predetermined set of X-Y coordinates while the tip of the tool shaft remains in contacting relation with the first surface of the work piece at substantially the same Z coordinate for exerting the forming force, thereby to follow the predetermined path of formation substantially parallel to the X-Y plane as the work piece is consistently formed in the Z direction; 
 g. positioning said backing forming tool assembly along a predetermined path of formation opposite to the above given direction in tandem with the movement of said primary forming tool assembly to remain substantially opposite said tip of the primary forming tool assembly with the work piece therebetween, thereby maintaining localized force on the work piece; 
 h. retracting said primary forming tool assembly and said backing forming tool assembly from the work piece; 
 i. re-positioning the primary forming tool assembly adjacent to the first surface of the work piece in another one of the at least two work areas; 
 j. repeating steps “b” through “h” successively within the other work area of the work piece; 
 k. re-positioning the primary forming tool assembly adjacent to the first surface of the work piece in the first one of the at least two work areas; 
 l. repeating steps “b” through “k” to form additional paths of formation in the at least two work areas by:
 i) utilizing an incrementally progressing value for the forming Z coordinate, and 
 ii) alternating the direction of travel, counterclockwise or clockwise, along a path of formation at the incrementally-progressed forming Z coordinate. 
 
 
     
     
         8 . The method of  claim 6 , wherein the direction of travel to form the additional paths is alternated for successive groupings of paths of formation. 
     
     
         9 . The method of  claim 6 , wherein the direction of travel to form the additional paths is alternated for each successive one of the additional paths 
     
     
         10 . The method of  claim 6 , comprising:
 m. re-positioning the primary forming tool assembly adjacent to the first surface of the work piece in the first one of the at least two work areas;   n. repeating steps “b” through “k” to form additional paths of formation in each of the at least two work areas by:
 i) utilizing additional incrementally progressing values for the Z coordinates, and 
 ii) alternating the direction of travel, counterclockwise or clockwise, along the additional paths of formation at the incrementally-progressed forming Z coordinates. 
   
     
     
         11 . The method of  claim 8 , comprising:
 o. successively repeating steps m. and n. until the work piece is fully formed in the at least two work areas.