AGMA 15FTM12 PDF

Due to increasing tolerance requirements for gearboxes and gears, it has become more and more important to establish quality circles in production. A quick detection and correction of the causes of tolerance violation is essential for high quality. This paper shows the possibilities and procedures of searching for the root cause in general, especially with problems in hobbing and generation grinding using multi-start tools.

A new simulation tool has been developed, which allows for the simulation of typical faults that occur during hobbing and generation grinding. The calculated contour on the workpiece is treated as a measured curve, making it easy to compare workpiece measurements and simulations. In this way, possible error causes can be simulated and compared with the real gear surface.

This paper uses practical examples to demonstrate the following applications for simulation. The influence of the tool parameter’s "number of starts" and "number of flutes" on the cutting result is shown in connection with the axial feed parameter. Protuberance and tooth tip rounding on the tool influence the profile form generated on the workpiece. Wobble and eccentric in the tool clamping creates an s-shaped pattern on the profile, based on the number of starts on the tool. The form of the pattern changes with different parameters.

In high-speed gearboxes, ripples on the gear surfaces are frequently the cause of noise problems. Simulation of a tool error and a subsequent evaluation of the ripples enable conclusions to be drawn about the excitations caused by the tool error during the cutting process. A practical comparison between the ripple measurement of a hobbed and subsequently honed gear and the simulation shows that the noise-related ripples on the finished part arises already in the pre-machining stage.

The applications presented in this paper show that the results of the simulation are a very good match with practical tests. Thus, the simulation software is a highly precise tool for determining and eliminating the causes of deviations in production. At the same time, design engineers and planners can quickly and easily develop new process and tool designs, thereby significantly reducing the costs involved in testing.