POWER SKIVING HIGH QUALITY, PRODUCTIVITY AND COST EFFICIENCY IN GEAR CUTTING
In addition to traditional gear machining processes such as hobbing, gear shaping and broaching, skiving is a continuous machining process for soft and hard machining of internal and external gears [2]. The skiving process is characterized by the tool and workpiece axes arranged in a certain relationship to each other - the axis cross angle (Fig. 1). With the coupled rotation of workpiece and tool, a relative movement of the cutting edge in the tooth space is thus created. By superimposing a feed motion, both add to the movements to the feed speed and guide the cutting edge along the workpiece axis. In this way the tooth space is "peeled out" of the workpiece in several cuts (Fig. 2). The cutting speed results from the rotational speeds of tool and workpiece in relation to the axis cross angle. Significant for the skiving process is the short machining time (approx. 30 to 50 %) in comparison to the likewise flexible gear shaping and the ability to apply the gearing close to an interfering contour (workpiece shoulder). The smaller the axis cross angle, the closer towards the interference contour can be machined.
While the traditional alternative processes for gear machining such as broaching, gear shaping and gear hobbing are mainly used in technology-specific special machines, gear skiving can be applied on special machines and on modern 5-axis machining centers. In recent years, skiving has made a quantum leap in industrial manufacturing with the availability of modern control technology for spindle synchronization, tool technology for high-performance cutting and a machine structure that meets the high demands for rigidity and dynamics.
The main advantage of the above-mentioned process integration is that the components can be finished without or at least with fewer downstream machines. This eliminates a large part of the loading and unloading of the components, the intermediate transportation and the quality losses due to clamping faults in the subsequent machining processes.
