Naberezhnye Chelny Institute (branch) of Kazan Federal University, Naberezhnye Chelny, Russia:
D. T. Safarov, Cand. Eng., Associate Prof., Dept. of Materials, Technologies and Quality, e-mail: Safarov-dt@mail.ru

A. G. Kondrashov, Cand. Eng., Associate Prof., Dept. of Design and Technological Support of Machine-Building Industries, e-mail: kondrashovag@mail.ru

KAMAZ PJSC, Naberezhnye Chelny, Russia.
A. V. Chekh, Director of the Forging Plant, e-mail: ChehAV@kamaz.ru

The article presents an analysis of the allowance parameters on the processed elements of the workpieces, which ensure the efficiency and accuracy of the machining of machine parts workpieces. The best is the minimum allowable uniformly distributed allowance. The content of the methods for ensuring the allowance in the processes of machining workpieces of machine parts is considered. Existing methods, determining the distribution of the allowance according to the data of coordinate measurements, individually change the position of the mechanical base for processing the part. For crankshaft forgings, such an approach to providing the allowance parameters is impossible, since they are machined from a constant axis in the form of center holes. The article considers a method for calculating the optimal adjustment displacements of die equipment to ensure a minimum uniform allowance for the main and connecting rod journals of crankshaft forgings and favorable conditions for balancing the machined crankshaft forging. The values of the closed height of the stamp have been optimized, since this parameter is the main one, compensating for the change and cooling of the stamps during the stamping process, as well as the magnitude of the improvements in the engravings of the correction operation stamps. The results of applying the method to improve the geometric accuracy of heavy vehicle crankshaft f o rgings, which improves the distribution of the allowance from 1.3 to 2.5 times, depending on the results of measuring the original forging, are considered.

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