Method of minimizing waviness on a workpiece by a grinding process, computer program and grinding machine for making the same

Abstract

The present invention relates to a method of minimizing waviness on a workpiece (100) by a centerless grinding process comprising the steps of providing a grinding machine (1) comprising a first grinding wheel and a second grinding wheel (2a, 2b) rotating about a first rotation axis and a second rotation axis (A-A, B-B) respectively, and a supporting blade (3) arranged between the grinding wheels (2a, 2b) and adapted to support the workpiece (100); performing, by said grinding machine (1), a first working step in which the workpiece completes a first number of revolutions (ν1), and in which the supporting blade (3) places the workpiece (100) at a first working height (hw1) from a plane containing the first rotation axis (A-A) and the midpoint of the second rotation axis (B-B); performing, by said grinding machine (1) a second working step, after first working step, in which the piece (100) completes a second number of revolutions (ν2), and in which the supporting blade (3) places the workpiece (100) at a second working height (hw2), other from the first working height (hw1). The method is characterized in that the first and second working heights (hw1, hw2) are determined before the first working step, by means of an algorithm which receives as inputs geometric parameters of the grinding machine (1), geometric parameters of the workpiece (100), the first and second number of revolutions (ν1, ν2), and an array of pairs of heights of the first and second working steps (hw1, hw2), the algorithm being configured to calculate for each pair of working heights (hw1, hw2) a first transformation matrix associated with the evolution of the geometry of the workpiece (100) during the first working step, and a second transformation matrix associated with the evolution of the geometry of the workpiece (100) during the second working step; calculate for each pair of working heights (hw1, hw2) the spectral radius (ρlmax) of the product of the first and the second transformation matrices in symbols - outputting the pair of working heights (hw1, hw2) corresponding to the smallest spectral radius (ρlmax).

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