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Development of a competitive manufacturing chain for high performance gears (DECOMAG)


The analogy process for gear shaving can be used to perform technological studies in the gear shaving process. Since the gear shaving process is a very complex process causing a large number of loads on the tool, it is very difficult to study certain effects and influences on the shaving result independently. That was done with the analogy process.
The technological studies on gear shaving will be used mainly to gain better understanding of certain loads on a shaving cutter. So far, it is not known what causes wear on shaving cutters and what effects this has on the quality of the shaved gear. With the results from the technological investigations on gear shaving, the effects on the tool life of different parameters like cutting speed, feed rate, chip thickness, tool material, work piece material and others will be known. It will also be possible to optimise gear-shaving processes in terms of tool life and to know the quality of the gear.
Investigations on a new shaving mode were carried out successfully. It was demonstrated that it is possible to increase the flexibility of flank modifications on the work-piece. It also seems possible to achieve better gear geometry through this shaving mode. This opens the way for new machine concepts and kinematics.
Pre-trials on rings show the potential of the dynamic quenching and indicate possible approaches for quenching on real gears. Application of injection-systems for diesel engines and gear-shafts could be possible in heat treatment as well. The team did also geometrical measurements and metallurgical analysis comparison between different treatment parameters (helium, nitrogen and air quenching) and currently hardened gears.
Basic material data giving a better precision of the heat-treatment simulation with new material. Flow stress and phase transformation data were measured for base material after carburising.
Result is simulation software for the shaving process. The software enables the analysis of the topology of the work piece gear flanks. It supports the development of an advanced shaving operation and makes investigation and understanding of process mechanism easier.
A new quenching sensor (QC3=Quench Control in Cold Chambers) was developed. This device makes quality-monitoring of the quenching possible for the automotive manufacturers.
Update and verification of heat treatment simulation software designed to be used to predict results of advanced case hardening. The system uses a general commercial FEM package ABAQUS and the developed subroutines. The verification was done by comparing the predicted and experimental case hardening response with different geometry of work-pieces. Main result is the gear distortion obtained with different distributions of heat transfer coefficients.
A deep analysis of the processes of each end-user has provided essential information about gear manufacturing. The result is a list, which defines the assessment criteria, development aims and results of evaluation of each end-user in the current manufacturing process chain. The list provides a definition of the gear quality parameters and tolerances with their related costs for each main manufacturing operation. The list will serve as basis for further investigations and for evaluation of a new process chain by other partners.
Power-shaving trials produced parts to evaluate the tool life time and geometrical accuracy. The parts can be compared to current shaving process. In addition, laboratory tests on gearboxes test bench were performed to validate the running behaviour of parts produced by power-shaving. It was demonstrated that power-shaving allows to reduce the machining time by increasing cutting parameters with similar tool life time as in current production and with acceptable pitting life time.
??Optimised fixtures provide more homogenous cooling conditions in the quenching chamber.
Visualisation of heat transfer coefficients in the hardening batch resulted in distribution of heat-transfer coefficients within the different teeth of the same gear, or different gears within a batch for the different end-users applications. Better understanding of the process mechanisms shows possible inhomogeneties in quenching and generates input data for the hardening simulation.
The simulation software for shaving tool grinding will be used mainly to support the production of shaving tools in terms of testing the machine settings to achieve the desired flank topology. It is also possible to test the handling of the topological shaving tool grinding process before any real process. Less errors will save time, money and resources during the production of shaving tools. The handling of the grinding machines becomes more transparent which may simplify the handling and learning process for employees and trainees. In addition, it will be possible to optimise gear shaving processes in terms of gear quality.