METHOD OF MAKING CUTTING TOOL INSERTS WITH HIGH DEMANDS ON DIMENSIONAL ACCURACY

摘要

The present invention relates to a method of making cutting tool inserts with high demands on dimensional accuracy by - mixing by milling of powders forming hard constituents and binder phase, - forming the powder mixture to bodies of desired shape, - sintering the formed bodies, - grinding with high accuracy the sintered bodies to inserts with desired shape and dimension, - possibly edge rounding of cutting edges and - providing the ground inserts with a wear resistant non-diamond or non-diamond-like coating. According to the method the ground inserts are heat treated prior to the coating operation in an inert atmosphere or vacuum or other protective atmosphere below the solidus of the binder phase for such a time that the micro structure of the surface region is restructured without causing significant dimensional changes. In this way inserts with unexpected improvement of tool life and dimensional accuracy have been achieved.