The precision of tooth form machining directly depends on the accuracy of the gear machining positioning datum.
Often utilized for tooth profile machining of disc sleeve gears are two positioning datums.
While some big module shaft gears pick the gear journal and one end face placement, the tooth shape processing of shaft gears usually chooses the center hole placing.
1. Face positioning-circle and end
Usually used for the manufacturing and processing of single-piece and small-batch gears, it has poor alignment efficiency.
The inner hole of the tooth blank is placed on the general mandrel; the center position of the hole is found by aligning the outer circle, so the radial runout of the outer circle of the tooth blank must be modest.
2. Positioning of inner holes and end faces
Its great output makes it quite popular in mass production gear manufacturing.
Long as the accuracy of the inner hole is strictly controlled, there is no need to align when positioning on the special mandrel; hence, the choice of the design benchmark and the measurement and assembly benchmark of the inner hole not only in line with the principle of "benchmark coincidence but also helps to make the tooth shape processing and other process benchmarks unified."
