Abstract: The level of end-toothed disc accuracy has a direct effect on the indexing accuracy of the turret. The indexing error model of turret is proposed based on the analysis of end-toothed disc machining error and then the reliability index and reliability of end-toothed disc are obtained by using the second-order moment method and perturbation method. Using the indexing error model of end-toothed disc， and combing the reliability design theory with sensitivity analysis method， an analytical method for reliability and sensitivity design about end-toothed disc of power servo turret is proposed. The change rule of reliability and sensitivity about the random variable of end-toothed disc is given according to the example， and the effect on the indexing accuracy reliability of end-toothed disc is analyzed when the random variable of end-toothed disc changed. The study shows that， due to the different sensitive degree of design parameters to the indexing accuracy reliability， the sensitive parameters should be optimized so as to improve reliability of the end-toothed disc. Meanwhile， the as-proposed method may provide a theoretical basis for enhancing the reliability of the turret.

Key words: indexing end-toothed disc, machining error, indexing accuracy, reliability, sensitivity