HyperFinish

Derya Lenbet is the Director Global Sales at Thielenhaus Technologies.  

HyperFinish is a further development of the microfinishing or superfinishing process, whereby the increase in process speed, which is significantly higher than that of conventional finishing, is the main factor here. The oscillation frequency is considerably increased by using a direct drive compared to a conventional mechanical oscillation unit. Furthermore, it is possible to superimpose the sinusoidal oscillation movement of the tool with an additional high-frequency radial or linear oscillation, which can amount to over 3,600 double strokes per minute (60 Hz). The higher oscillation frequencies result in a much greater material removal per time unit, since the tool remains capable of cutting even at high peripheral workpiece speeds due to the increased frequency.

In tests to optimize productivity, our development engineers have found out that growth can only be achieved by extremely high oscillation frequencies. The method is based on a harmonic sinusoidal speed curve of the tool. This is coupled with the electronic adaptation of all parameters of the primary and secondary tool oscillation including oscillation angle and strokes via the NC control to the respective process.

Faster tool movement means shorter process times and higher productivity. In the case of roller bearings, for example, machining times can be reduced by an average of 30 percent, and in some cases by even up to 35 percent, while the removal rate can be increased by up to 60 percent. Since the tool ensures significantly more material is removed, in certain applications a 1-station machine can be used instead of a 2-station machine. This reduces investment costs by around 30 percent. A machine with only one station also reduces the overall setup times and thus the operating costs. These factors are particularly important in sectors such as the automotive and roller bearing industries, where there is high cost pressure.

HyperFinish does not only mean shorter process times with more material removal rate, but also an increase in workpiece quality. This enables the user of this technology to meet the constantly increasing quality requirements of his customers. Thanks to the special oscillation method, the dimensionally optimized tool can achieve better results with regard to roundness and fine waviness. In this way, work can be carried out faster and better with the conventional tool types.

Machining of ball bearing raceways with the microfinishing process optimized with HyperFinish technology

The results illustrated in the figures for machining of ball bearing raceways were achieved with a 1-step finishing process and a tool-to-workpiece contact time of only six seconds. The originally rough surface with an Ra greater than 0.6 µm was reduced to an extremely fine surface of 0.017 µm. The high precision of the machining is reflected in the profile shape of Pt = 1.1 µm. In order to manufacture such precision bearings, a 2-step process is absolutely necessary in conventional production.

Brush deburring is another application that has already been tried and tested. With brush kinematics optimized by HyperBrushing, the deburring of flat-finished sealing surfaces to the bore edges contained therein can be improved with a uniform edge rounding on high-precision automotive injection components. An additional processing stage such as high-pressure water jet deburring can thus be emitted on these edges.

"In the further developments of the process," explains Director Global Sales Derya Lenbet, "the focus is the goal of transferring the positive effects of HyperFinish - such as up to 35 percent shorter processing times, improved qualities and lower investment costs - to the machining of roller elements and shaft-shaped workpieces as well". He sees great potential for improvement, particularly in the stone or strip machining of functional surfaces on shafts.