CNC Knowledge: An article to help you master 7 gear processing methods!

1

Gear cutting

The workpiece is fixed on the vertical spindle, and the hob is fixed on the horizontal axis of rotation. The rotational speeds of these axes are synchronized so that the feed rate on the outer circumference of the part is the same as the helical movement speed of the hob. The part is usually rotated several times to form complete teeth. The angle between these axes is adjusted according to the desired gear ratio angle.

2

Skiving process

A cutting tool with an inclined insert rotates around an axis oriented toward the axis of rotation of the workpiece. The peripheral speed of the tool is equal to the speed of the inner surface of the workpiece. The tilt allows the tool to cut with an axial peeling motion across the inside diameter of the workpiece as they rotate together. The tool continues to rotate, moving radially and axially until the teeth are complete.

3

Gear shaping processing

This method is largely similar to gear milling, but the biggest difference is that this method can also be used to make internal gears. The machined tool is shaped like a gear or a single tooth cutting tip moves axially to cut the inside diameter of the workpiece.

The tool movement is repeated until the desired tooth depth is reached. This unique cutting process is repeated for each tooth. While the tool continues to vibrate axially, slowly rotate the tool and workpiece to continue the process of cutting the gear shape.

4

Worm grinding wheel, gear grinding

Worm wheel grinding is also a generation grinding method. The working principle of worm grinding wheel is to grind involute cylindrical gears with a worm-shaped grinding wheel. The basic principle is similar to that of gear hobbing (as shown in the figure below). The grinding wheel engages and rotates with the workpiece, the workpiece is continuously indexed and developed into an involute tooth shape, and the width of the tooth is machined by axially feeding the workpiece.

When grinding helical gears, the workpiece is given additional movement by the differential device to machine the gears with corresponding helix angles. Before grinding, most of the material on the gear tooth surface should be removed by the gear forming method, because this method only grinds the tooth surface. The workpiece is fixed on a vertical axis of rotation and the grinding tool is on a horizontal spindle.

The rotation of these two axes is coordinated so that the advance of the part edge is consistent with the helical pattern of the tool. It usually takes several rotations of the workpiece to grind the entire tooth surface. The angle between the shafts is adjusted according to the desired gear angle.

5

Gear shape grinding

The grinding accuracy of the formed grinding wheel without generating movement mainly depends on the dressing accuracy of the grinding wheel and the positioning accuracy of the grinding wheel. When grinding spur gears, the shape of the axial cross-section of the grinding wheel is the tooth shape of the end face of the workpiece; When grinding helical gears, the shape of the axial cross-section of the grinding wheel is the spatial contact line between the grinding wheel and the theoretical tooth surface of the workpiece in the axial plane of the grinding wheel projection.

The gear grinding of the shape grinding wheel adopts single tooth indexing, and the workpiece is fed axially to achieve full tooth width grinding. When grinding helical gears, as the workpiece is advanced axially, additional rotational movement must be made to achieve the corresponding helix angle.

6

Gear Planing

Gear planing can generally process the tooth surfaces of spur gears or racks. The rack cutting tool moves back and forth along the gear axis toward the periphery, and at the same time, the tool slowly moves toward the center until it reaches the gear. shape of teeth. The tool remains at the same distance from the axis and continues to move tangentially to the workpiece while the workpiece slowly rotates.

7

Gear milling

The workpiece is mounted axially, perpendicular to the axis of the gear cutter. The gear bur moves along the workpiece axis and mills the tooth space. The workpiece is then rotated a tooth-to-tooth distance and the milling process is repeated. The part is machined gradually until the tooth grooves are milled around the entire part. To obtain helical gears, the cutter is tilted during cutting and the workpiece rotates slowly as the cutter moves along the axis of the workpiece.