please, a few questions about threading
Reply with Quotehello past self of myselfas rpm changes, the linear axis needs to catch up, and it requires a safe-travel, during which to sync with the rpm
during this travel, syncronicity is created, thus there is less sync at travel start, and sync is guaranteed at travel end; so, knowing this, is best to have syncronicity achieved before the tool starts to cut, thus clearance has to be long enough to allow syncronicity to occur
as long as syncronicity is achieved before cutting, the thread will look just fine, and also is possible to cut a thread at different rpms, as long as clearance is long enough, and phase shifts are taken into account, but is not recomanded to change the rpm while in-cut, because the linear axis will try to catch up ( to match the new rpm ), and will mess the existing thread
manuals provide the minimal travel, as a function of a machine specific constant and linear axis speed; for example, for s1234o/min and f1.5mm/o, the minimum delta is k*1234*1.5, where k is machine depentant, and there is a table that shows such values for some okuma machines
but spindle acceleration times are not linear, and differs with gear, and so, also the k value presented in the manuals, is just an average; please check attached image, that plots k value as a function of linear axis speed
once you have control over syncronocity, safe overides can be achieved, allowing to :
... thread at different rpms ( = okuma's variable spindle speed threading spec )
... chase treads, like roughing a thread somewhere else, then clamping it in the chuck, and finish ( = okuma's thread phase matching spec )
in other words, there are alternatives to some special functions / kindly
