Patent AU-2020201952-A1 (AU)
Title: Computer implemented method and system for generating slope synchronized tool paths for incremental sheet forming
Inventor: ELFORD MICHAEL C
IPC: B21D31/00
Filed: 2020-03-18
Abstract: COMPUTERIMPLEMENTED METHODANDSYSTEMFOR 
GENERATING SLOPE SYNCHRONIZED TOOL PATHS FOR 
INCREMENTAL SHEET FORMING 
ABSTRACT 
There is provided a computer implemented method for generating slope synchronized tool paths 
(32) for incremental sheet forming (ISF) of a contoured part (36). The method includes 
performing a slope synchronized tool path application execution with a computer (64) and a 
slope synchronized tool path application (110). The slope synchronized tool path application 
execution includes defining equally spaced apart Z values (114a), along a Z-axis (116), that 
intersect a surface (80) of the contoured part (36); determining, for the Z values, a slope factor 
(122), to define an array (130) of Z values (114) and corresponding slope factor values (124); 
and setting a current Z coordinate (136b), and iteratively, calculating a stepdown (140); 
decrementing a current Z coordinate (136b) by the calculated stepdown (146); and determining 
an intersection (150) of the surface (80) with a horizontal plane (118a) at the current Z 
coordinate (136b), to produce a contour tool path loop (160). The method includes sending an 
output file (168) to a numerically controlled ISF machine (94), to incrementally form the 
contoured part (36).
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PROVIDING A COMPUTER SYSTEM COMPRISING A COMPUTER HAVING A PROCESSOR 12 DEVICE, AND COMPRISING A MODELING APPLICATION AND A SLOPE SYNCHRONIZED 
TOOL PATH APPLICATION, EACH IMPLEMENTED BY A COMPUTER READABLE 
SOFTWARE PROGRAM AND EACH EXECUTED BY THE COMPUTER 
DA 14 
PERFORMING, WITH THE COMPUTER AND THE SLOPE SYNCHRONIZED TOOL PATH 
APPLICATION, A SLOPE SYNCHRONIZED TOOL PATH APPLICATION EXECUTION 
DEFINING A PLURALITY OF EQUALLY SPACED APART Z VALUES ALONG A Z-AXIS, -16 
WHERE EACH Z VALUE INTERSECTS A SURFACE THAT APPROXIMATES A 
THREE-DIMENSIONAL GEOMETRY OF A CONTOURED PART 
DETERMINING, FOR EACH Z VALUE, A SLOPE FACTOR BASED ON A MAXIMAL Z-AXIS 
COMPONENT OF A NORMAL VECTOR, FOR THE SURFACE INTERSECTING EACH Z -18 
VALUE, TO DEFINE AN ARRAY OF Z VALUES AND SLOPE FACTOR VALUES THAT 
CORRESPOND TO THE Z VALUES 
SETTING AN INITIAL Z COORDINATE CORRESPONDING TO A STARTING PORTION -20 
OF THE SURFACE, AS A CURRENT Z COORDINATE 
THE SLOPE SYNCHRONIZED TOOL PATH APPLICATION EXECUTION THEN 
ITERATIVELY: 
CALCULATING A STEPDOWN AS A SUM OF A MINIMUM STEPDOWN AND A 
PERCENTAGE OF A MAXIMUM STEPDOWN LESS THE MINIMUM STEPDOWN, THE 22 
PERCENTAGE BASED ON A CURRENT SLOPE FACTOR FOR THE CURRENT Z 
COORDINATE, THAT IS CALCULATED BASED ON THE ARRAY OF Z VALUES AND THE 
SLOPE FACTOR VALUES THAT CORRESPOND TO THE Z VALUES 
DECREMENTING THE CURRENT Z COORDINATE BY THE CALCULATED STEPDOWN -24 
DETERMINING AN INTERSECTION OF THE SURFACE WITH A HORIZONTAL PLANE AT 
THE CURRENT Z COORDINATE, TO PRODUCE A CONTOUR TOOL PATH LOOP FOR 26 
THE CURRENT Z COORDINATE, WHEREIN THE SLOPE SYNCHRONIZED TOOL PATH 
APPLICATION CREATES A PLURALITY OF CONTOUR TOOL PATH LOOPS THAT ARE 
EACH RESPECTIVELY SPACED APART BY SLOPE SYNCHRONIZED STEPDOWNS, TO 
OBTAIN A SERIES OF SLOPE SYNCHRONIZED TOOL PATHS 
SENDING AN OUTPUT FILE, USING THE COMPUTER, TOA NUMERICALLY CONTROLLED 
ISF MACHINE, TO DIRECT AN ISF TOOL ALONG THE SERIES OF SLOPE SYNCHRONIZED 
TOOL PATHS, TO INCREMENTALLY FORM THE CONTOURED PART 
OPTIONALLY, PRIOR TO PERFORMING THE SLOPE SYNCHRONIZED TOOL PATH 
APPLICATION EXECUTION, PERFORMING, WITH THE COMPUTER AND THE MODELING 
APPLICATION, A SURFACE DISCRETIZATION OF THE 3D GEOMETRY OF THE 
CONTOURED PART, TO PRODUCE THE SURFACE COMPRISING A SURFACE MESH OF 
POLYGONS THAT APPROXIMATE THE 3D GEOMETRY OF THE CONTOURED PART 
FIG. 1A