Method for scraping off excessive portion of workpiece

A method for scraping off automatically an excessive portion projecting from a datum face of a workpiece by a cutting tool, comprising the steps of:

• selecting a datum face in a region of the workpiece where the excessive portion is absent,
• measuring in three dimensions a surface shape of the excessive portion of the workpiece projecting from the datum face,
• calculating areas of two-dimensional cross-sectional shapes of the excessive portion projecting from the datum face at intervals along each of a series of corresponding feed courses,
• after calculating the two-dimensional areas, scraping off the excessive portion along each feed course with the cutting tool by feeding the cutting tool along each of the moving feed courses while controlling a speed of the cutting tool in a moving direction, the speed of the cutting tool along each feed course being substantially inversely proportional to the corresponding calculated two-dimensional area.

A method for scraping off automatically an excessive portion of a workpiece by a cutting tool, the method comprising the steps of:

• measuring a surface shape of the excessive portion of the workpiece;
• from the measured surface shape, pre-calculating a cross-sectional area variation of the excessive portion substantially along a proposed feed course;
• setting a feed speed of the cutting tool in accordance with the pre-calculated cross-sectional area variation of the excessive portion along the feed course, such that the larger the pre-calculated cross-sectional area of the excessive portion is, the smaller the feed speed of the cutting tool along the feed course is, and the smaller the pre-calculated cross-sectional area of the excessive portion is, the larger the feed speed of the cutting tool along the feed course is;
• after pre-calculating the cross-sectional area variation, moving the cutting tool along the feed course with the set feed speed to scrape off the excessive portion along the feed course.