Gearing Manufacturing involves a series of process, among which cutter is one of the most essential tools. It is very important to select a reasonable cutter to machine a right gear wheel. As to the task of machining a helical gear wheel with 8 cutters and shank diameter cutters, a tooth number table is required.
Tooth number tables serve as a very handy reference when machining helical gears. It shows the machining details of the gear wheel and provide a guide for the selection of cutter sizes for the targeted number of teeth. The tooth number table for the machining of the helical gear wheel in the task includes the following information, including the cutterused(number of teeth), rake angle, pressure angle, clearance, and module ratio.
The first task is to decide the number of teeth of the helical gear. This varies depending on the purpose of the gear. Generally, a range of 20-50 teeth is recommended, however this will depend on the application. For instance, a greater number of teeth may be required for heavy-duty applications while a lower number may be suitable for lighter-duty applications. Once the number of teeth is determined, the other pertinent machine settings can then be determined.
The second step is to determine the rake angle and the pressure angle for the gear. These are important parameters for achieving the desired mechanical properties of the gear and should be set according to the required application. The rake angle is the angle between the cutting and return line on the tooth face and should be between 10 and 75 degrees. The pressure angle is the angle between the tooth face and the pitch line, and should be between 14 and 30 degrees for single-start helical gears.
The third step is to set the clearance and the module ratio for the gear. The clearance is the distance from the flank of the tooth to the root of the helical gear. Most common settings are 0.15 to 0.35 mm. The module is the ratio between the reference diameter of the gear and the number of teeth. A common module is a range of between 0.5 and 5.
Finally, the cutter used and shank diameter must be determined. Considering the fact that an 8 cutter and shank diameter is used in the task, it is essential to choose the cutters appropriately. The cutter used should have at least twice as many teeth as the helical gear, to provide an adequate level of machining. Generally, a shank diameter of between 3 and 12 mm is recommended.
By following the above steps and using the tooth number table, the optimal settings can easily be determined for any given set of cutting and shank diameter cutters. This eliminates the need for manual adjustment and saves on time and resources. With appropriate settings, a helical gear wheel can be machined successfully with good surface finish and precision.
