Patent ID: 7650201

Claim:
A method of determining a machined surface of a plate-like material capable of minimizing machining margin upon machining the plate-like material with two- or three-dimensional deformation to realize a uniform thickness, comprising the steps of: setting a surface plate surface of a measuring device as coordinates (X,Y), setting orthogonal coordinates (X,Y,Z) formed from a Z coordinate that is perpendicular to the coordinates (X,Y) on the surface plate, mounting the plate-like material as an object to be measured on the surface plate, and virtually configuring with a computer a plane ABCD that is parallel to the XY plane in which a distance from the surface plate is H, measuring a distance (height) Zm,n from coordinates (Xm, Yn) of the virtual plane ABCD to coordinates (Xm, Yn) of an upper surface of the plate-like material as an object to be measured m times in the X direction and n times in the Y direction while changing the coordinates (X, Y) for all areas of the plate-like material, and storing the measured data in a storage apparatus of the computer; searching for a maximum value and a minimum value of Zm,n regarding all coordinate points and calculating the difference thereof, and setting the value as H 0.0, 0.0 when no inclination operation is performed on the virtual plane ABCD; subsequently regarding a maximum fluctuation width and pitch predetermined in the Z axis direction, inclining the virtual plane ABCD against the surface plate by fixing end A of the virtual plane ABCD and respectively raising and lowering end C and end B at prescribed fluctuation widths B, C; calculating a distance (height) (Zm,n) B, C from all coordinate points (Xm,Yn) on the virtual plane ABCD to the corresponding coordinate point of the upper surface of the plate-like material each time the inclination is changed, and searching for the maximum value and the minimum value of (Zm,n) B, C and calculating the different H (B,C) thereof; and repeating the search for all combinations of B and C set in advance, and deciding the smallest value of H(B,C) calculated with all combinations of B and C as a parallel plane of a plane in which the virtual plane ABCD will be of a minimum machining margin.