Prognosis of the local tool wear in gear finish hobbing

Abstract

Gear finish hobbing is a method for soft finishing of external cylindrical power transmission gears. The application of this process is required when the process chain of gear production is to be set up completely free of coolant. Since this finishing technology is relatively new, there is some practical experience, but no fundamental knowledge regarding economical process design. One challenge in process design is that unbalanced tool wear typically leads to geometrical deviations of the machined gear profile. The aim of the investigations described in this paper is to develop a wear model which is capable to predict the local tool wear of gear finish hobbing tools. This model is based on analogy cutting trials and geometrical analyses of the chip geometries in gear finish hobbing. The results of the model are validated by flycutting trials with different local loads on the tool. The validation shows that an optimization of the local tool wear development can be achieved by means of the prediction model. Therefore, an optimization of the technological process parameters can be carried out based on this model to reach an efficient process design.

Gear finish hobbing: potentials of several cutting materials

“…Theses points were investigated in several research projects at WZL. In the project ''Potenziale des Wälzfräsens im Schlichtschnitt bei extrem hohen Schnittgeschwindigkeiten'' the influence of several cutting materials on the tool life was investigated in an analogy trial [1,2]. Based on these investigations the AiF research project ''Potenziale des Fertigwälzfräsens von Verzahnungen'' was developed.…”

“…The most common soft finishing processes are gear shaving and gear finish hobbing. Compared to hard finishing processes and the gear shaving process, gear finish hobbing offers high potentials to realize an economical and ecological finishing process of gears [1,2]. The economical advantages are the possibility to use only one machine tool and one clamping system for the hole machining operation.…”

“…The process of gear finish hobbing is most commonly divided in a roughing and a finishing process [1,2]. In the roughing process the highest amount of material is machined.…”

Characterization of the Cutting Forces Generated During the Gear Hobbing Process: Spur Gear

“…Numerical models have been developed using Computer-Aided Design (CAD) [1,2,9], Finite Element Analysis (FEA) [3,10] or analytical based approaches, [11,12]. Using these models, the prediction of the machining parameters such as chip geometry, chip flow, tool wear, cutting forces, etc… become possible considering the real workpiece, tool and production data, [1,5,6,[13][14][15].…”