National Technical University of Ukraine «Kyiv Polytechnic Institute», Kyiv, Ukraine
MANUFACTURING OF INTERNAL THREADS BY SQUEEZING TAPS
The article deals with processing of internal threads with a large step and diameter up to 30 mm. The comparative characteristics of cutting internal threads and squeezing by taps as well as their advantages and disadvantages are shown. The recommendations on designing inlet cone of squeezing taps. New equations for determination of diameter of a hole for squeezing a tap are obtained. The process of the gradual developing the depression of a thread is considered and an uneven load on each tooth of intaking cone of the tap is shown. The dependences for determination of the thickness of the extruded metal layer from the thread pitch are obtained. Influence of different factors on the length of the lines of the contact areas of cross-sections and volumes of extruded material, from which the load on the teeth of the tap, its stability and the quality of the threads depend essentially. A formula for determining the accuracy of holes under the extrusion threads is obtained and the relevant recommendations are developed. Tab.1. Fig.8. Lit.6.
Keywords: internal thread, squeezing tap, inlet cone, diameter, step, long, square, volume