(1) High rolling speed
Generally, in the dry hobbing process, the line speed of the high-speed steel hob of the coating (TiAlN) is required to reach 180m/min
Even higher; the line speed of the hard alloy steel hob is required to reach 300
m/min. In order to realize this high-speed hobbing processing, the tool spindle can generally be realized by an electric spindle; for the worktable, a new-designed gear transmission system with automatic clearance elimination is used to replace the traditional worm and worm gear transmission system, LIEBHERR, GLEASON
The worktables of high-speed gear hobbing machines of other companies have adopted torque servo motor technology, and the worktable speed can reach more than 800 r/min.
(2)
Quick separation of chips
Due to the high temperature, if the chips cannot be quickly separated from the tool, workpiece and machine tool, it is easy to cause thermal deformation and affect the machining accuracy, so iron chips can be removed quickly and effectively. In dry hobbing, the high-speed hobbing of the hob is generally used to make the iron filings quickly leave the tool and the workpiece. Many companies have also put forward some machine tool structural improvements in response to the chip removal problem, such as using gravity to speed up the removal of iron filings, and avoiding the iron filings from directly falling on the workbench, and then assisting with high-pressure cold air to achieve rapid and effective chip removal. Have
Some companies also use stainless steel heat shields. On the one hand, the surface of stainless steel is smooth, which facilitates the removal of iron filings. On the other hand, the heat conductivity of stainless steel is small, which reduces the heat transfer of iron filings to the workbench and bed.
(3)
High speed hob
The hob material for dry hobbing was initially developed using cemented carbide steel, but due to the high cost of cemented carbide steel hobs, the powder metallurgy high speed steel hobs and TiAlN coated high speed steel hobs developed in recent years have replaced hard alloy steel hobs. The trend of high-quality alloy steel hobs for dry hobbing. In a research report, Liebherr Company has performed the processing of hard alloy hob (Carbide) dry hob, powder metallurgy high-speed steel hob (HSS-PM) and conventional high-speed rigid hob (Conv.HSS). The time and processing cost are compared. Comparative analysis results show that, compared with conventional machining, dry hobbing has shorter processing time and lower cost; the use of powder metallurgy high-speed steel hobs even has better dry hobbing results than the use of cemented carbide steel hobs .
Link to this article：The key technical points of MQL gear hobbing micro lubrication processing
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