Machine and method of grinding molding die

A grinding apparatus for processing a first surface of a workpiece and a second surface of said workpiece, said second surface intersecting said fist surface, said apparatus comprising:

• a frame including a pair of supports standing in opposing relation to each other and a support frame which is stretched between and secured to the respective upper end portions of said supports;
• first moving means provided on said support frame in such a manner that said first moving means is reciprocatable in a first horizontal direction;
• second moving means provided on said first moving means in such a manner that said second moving means is reciprocatable in a second horizontal direction which intersects the first horizontal direction at right angles;
• third moving means provided on said second moving means in such a manner that said third moving means is reciprocatable in the vertical direction;
• a wheel head having a longitudinal axis, said wheel head being provided on said third moving means to be movable in the vertical direction;
• grinding means provided on said wheel head for performing a grinding operation on said first and second surfaces of said workpiece;
• first pressing means operatively connected between said third moving means and said wheel head to urge said wheel head in the direction of the longitudinal axis thereof toward said first surface of said workpiece so that said grinding means is pressed against said first surface of said workpiece while performing the grinding operation;
• and
• second pressing means operatively connected between said third moving means and said wheel head to urge said wheel head in a direction intersecting the direction of the longitudinal axis of said wheel head toward said second surface of said workpiece so that said grinding means is pressed against said second surface of said workpiece while performing the grinding operation;
• said apparatus further comprising control means operatively connected with and controlling said first and second pressing means so that, when two directions among three directions are selected as directions of movement of said grinding means, at least one of said first and second pressing means presses said grinding means against said surfaces of said workpiece in the remaining one of said three directions with a predetermined pressure.