Study on the Improvement of Cutting Accuracy of NC Hobbing Machines : Improvement of Tooth Lead Error

In this paper, with the purpose of achieving high precision machining by means of NC hobbing machines, the problem points of the NC indexing system software, the angle detection accuracy of the hob and table axes, and the achievement of high precision of synchronism of the two axes is investigated. With regard to the indexing system software, numerical simulation of the tooth lead error was carried out, and it was clearly shown that the size of the unit used in carrying out the calculation had a strong influence on the machining precision. In addition, it was recognized that the quantization of the hob spindle encoder and the table spindle angle detection device exerted a great influence on the machining precision. Together with these results, gear cutting machining was carried out by means of the actual machine, making it possible to achieve an improvement in the tooth lead error.