Method for machining slide core hole and measurement/correction system for use in machining of slide core hole

A measurement/correction system for use in machining of an inclined slide core hole, comprised of a core pocket and a rod hole, in a mold as a workpiece by means of a five-axis machine tool having, in addition to X-axis, Y-axis and Z-axis, an A-axis for pivoting of a spindle head and a C-axis for rotation of a table, said system comprising:

• a probe mounted to the front end of the spindle of the spindle head and having a terminal for contact with a machined surface of the mold;
• means for reading and executing an uncorrected machining program prepared to execute a series of process steps for machining the slide core hole in the mold with the five-axis machine tool;
• means for executing a measurement program which, after machining of an intermediate pocket hole in the mold surface where a spot-faced hole is formed, the machining being pre-machining before machining of the core pocket, is to measure with the probe the position of the center of the rod hole in a seating surface of the intermediate pocket and the position of the seating surface of the intermediate pocket;
• arithmetic means for calculating the coordinates of the actual reference point of the rod hole for use as a reference in machining of the rod hole, based on data on the measurement with the probe carried out by execution of the measurement program;
• correction means for comparing the measured position of the reference point of the rod hole with the coordinates of a reference point of the rod hole, previously set in the machining program, and, if there is an error, rewriting the coordinates of the reference point on the program to the measured coordinates of the reference point;
• and
• means for executing a corrected machining program with the rewritten reference point in order to carry out precision shaping machining of the core pocket while expanding the intermediate pocket.