Using tap to process threaded holes is a common processing method, which is mainly applicable to threaded holes with small diameter (d<30) and low requirements for hole position accuracy.
In the 1980s, flexible tapping method was adopted for threaded holes, that is, flexible tapping chuck was used to hold the tap, and the tapping chuck could be used for axial compensation to compensate the feed error caused by the asynchrony between the axial feed of the machine tool and the spindle speed, so as to ensure the correct pitch. The flexible tapping chuck has complex structure, high cost, easy damage and low processing efficiency. In recent years, the performance of CNC machining centers has gradually improved, and the rigid tapping function has become the basic configuration of CNC machining centers.
Therefore, rigid tapping has become the main method of thread processing.
That is, the screw tap is clamped with a rigid spring collet, and the feed of the spindle is consistent with the spindle speed controlled by the machine tool.
Compared with the flexible tapping collet, the spring collet has the advantages of simple structure, low price and wide application. In addition to holding the tap, it can also hold the end milling cutter, drill bit and other tools, which can reduce the tool cost. At the same time, rigid tapping can be used for high-speed cutting, improve the efficiency of the machining center and reduce the manufacturing cost.
