Calculation of the geometric parameters of a cutting taps with opposite-sheared screw chip grooves

With the spread of products made of fiber-reinforced composites (FRC) in various industries, the issue of their efficient assembly is becoming increasingly important. The most common methods of joining parts from FRC, which include bonding, riveting and the use of various inserts, have a number of significant disadvantages, which necessitate the search for new, more effective solutions. One of the most promising methods for assembling parts from FRC is the use of threaded connections, which are widely used in the form of metal and polymer inserts. However, a number of technological restrictions imposed on the process of installing these inserts force us to turn to the threads obtained in the composites themselves. In this case, the production of threads is possible both at the stage of forming uncured products, which imposes restrictions on their shape and size, and by methods of blade processing, which are currently little studied. The process of mechanical processing of workpieces from FRC is significantly different from the processing of homogeneous materials, which does not allow directly using the existing recommendations for metal processing. Specific defects of treated surfaces, which are inherent only to FRC, necessitate the development of special tools that take into account the peculiarities of various types of composites. The analysis of the results of preliminary experimental studies on threading with traditional taps showed that the cutting angles on the auxiliary cutting edges formed by the lateral sides of the thread profile have the greatest influence on the quality of the threads being cut in FRC workpieces. To ensure favorable cutting conditions in these areas, the design of a special tap with opposite-sheared screw chip grooves has been developed. For this design, a method has been prepared for calculating the cutting angles on auxiliary cutting edges, which makes it possible to prepare the design of this tap for processing a specific type of FRC by ensuring the optimal cutting angles taken from literature sources or obtained from experiments.