Analyzing micro-geometric deviations of a helical gear profile as a function of material and machining parameters in the hobbing, shaving and carbonitriding processes

Gear materials need a more in-depth analysis to verify the conditions of chemical elements and their structural formations. Among them, the focus is often related to the thermochemical treatment process, which should ensure low levels of distortion in micro-geometry due to its high level of mechanical accuracy. In gear manufacturing processes where profile and helix errors are defined in operations prior to thermochemical treatment, process designers are faced with challenges to ensure tooth quality levels. Processes such as hobbing and shaving are important in gear manufacturing. This study addressed the influence of some factors on the gear manufacturing finishing process, as well as the steel alloy microstructure, on the geometric distortion levels in the profile and helix. All stages of the experiments were followed in a controlled manufacturing process, observing the behavior of micro-geometric parameters in each manufacturing phase in the hobbing, shaving, and carbonitriding processes. This analysis was performed on DIN 19MnCr5 alloy steel batches whose microstructures are different, after analyzing them in a laboratory to characterize each one. These observations can lead to important decisions being taken in the manufacturing process to improve a product, regarding the profile and helix parameters. Decisions can also be made about optimizing manufacturing processes.