Main cause
1) Incorrect adjustment of split exchange gear
2) Wrong selection of hob
3) Incorrect workpiece blank size
4) When hobbing helical gear, the additional movement direction is not correct
Resolvent
1) Readjust the split exchange gear and check whether the middle wheel is correctly added
2) Reasonable selection of hob
3) Replace workpiece blank
4) Increase or decrease intermediate wheel in differential exchange gear