Forging for gear machining
Usually, the bevel gears of larger specifications are formed on special large-tonnage hydraulic block presses, while the bevel gears of smaller sizes are usually formed on ordinary cold forging presses with special block dies.
Usually, the bevel gears of larger specifications are formed on special large-tonnage hydraulic block presses, while the bevel gears of smaller sizes are usually formed on ordinary cold forging presses with special block dies. The latter method has the characteristics of high production efficiency and low cost. Only the size of the forging is limited by the occlusion pressure of the mold base, and the forming of large-sized bevel gears cannot be completed.
Considering the economy of gear mold manufacturing, especially for cemented carbide gear molds, electrical discharge machining is still the main mold-making process in the precision forging industry of gears, but the generative machining of tooth-shaped electrodes has been completely replaced by high-speed milling and CNC machining the trend of. For warm forging and hot forging forming dies with a quenching hardness of about 50 degrees Rockwell, high-speed milling has far surpassed electric discharge machining in terms of processing speed and accuracy, and has obvious advantages in terms of die life. As long as the cost of cutting tools is solved, high-speed milling can completely replace electric discharge machining in terms of warm forging and hot forging gear dies.
Another outstanding advantage of the positive extrusion forming process is that the mold tooth shape is obtained by CNC wire cutting, and the ideal tooth shape can be obtained through programming when machining gears with a small number of teeth without worrying about undercutting. In the case of processing special tooth shape or modifying tooth shape, it is more convenient, faster and more accurate to use CNC wire cutting to process tooth shape than gear generation processing or profiling processing.
Spline cold forging is a special case of gear positive extrusion. The forming of an involute spline is equivalent to extruding a longer spur gear, and the extrusion of a rectangular spline is similar to that of an involute spline. On the other hand, small modulus spur gears can be obtained by dividing the involute spline shaft.