Research On Key Technology Of Spiral Groove Processing On Combustor Nozzle

In the field of aerospace manufacturing, the processing of the spiral cooling channel, which is on the combustion chamber nozzle of liquid rocket engine, is a key technology. The scheme with double disc-milling cutters and four-axis linkage is adopted to process loxodrome groove of rocket nozzle currently. However, cutter interference of milling and low rigidity of milling head affect the process precision of loxodrome grooves directly. Therefore, researches on the interference during the processing are of great significance for the improvement of manufacturing precision.In this paper, the mathematical model of loxodrome curve is studied systematically, and the interference model between the disc-milling cutter and the spiral rib is described mathematically in details. The computing process of the combustion chamber profile data is analyzed so that improvements of the bottom curve calculation are made. The tool path is described and a general method of depicting tracks of disc-milling cutter is obtained.Factors which affect the interference between the disc-milling cutter and the spiral rib in the milling process are summarized and analyzed. It is discussed in details that how the model is applied to simulate and calculate the interference and the affect law of each factors is attained. The interference becomes much severer and the residual rib is thinner when the groove is deeper, disc-milling cutter’s radius is larger and the gasket is thinner. The impact of the gyration radius and the helix angle depend on different types of contours. The results are important and useful for choosing cutting parameters.The process scheme of double disc-milling cutter for loxodrome groove is researched and deformation of the milling head structure is simulated and analyzed. The law of deformation with different cutting parameters is concluded. The theoretical analysis is verified with experiments and a method of feeding is suggested for reducing its influence on machining accuracy. In order to improve the accuracy and performance of the machine, calibration and compensation for the machine tool equipment are made with the laser interferometer.The exploration in this article can be used as the basis for a quantitative description of the interference in the milling, and the results can also be used to guide the selection of cutting parameters in order to improve the precision and efficiency.