CNC thread cutting issue
CNC thread cutting issue
(OP)
When i cut the ACME thread on CNC Lathe,i face a problem:
the first tooth is a little wider than the others (about 7 teeth totally), as i know that when we use the CNC lathe to cut the thread, there will be a short incorrect threaded length at the beginning and the end,the lengh is depends on machine time constant T,but after i have set the constant to 0.033s, the error still exists,are there any tips for this issue?
Thanks
the first tooth is a little wider than the others (about 7 teeth totally), as i know that when we use the CNC lathe to cut the thread, there will be a short incorrect threaded length at the beginning and the end,the lengh is depends on machine time constant T,but after i have set the constant to 0.033s, the error still exists,are there any tips for this issue?
Thanks





RE: CNC thread cutting issue
RE: CNC thread cutting issue
Slow the spindle down if you cannot increase the air cutting.
Most cnc lathes have a constant they are constrained by in thread cutting i.e. the speed at which they 'sinc' on newer lathes it is 6000 i.e. at 2000 revs you can pitch 3mm max and at 4000 revs 1.5mm max pitch.
With acme style long pitches you will come across the problem of correspondingly low spindle speeds and therfore not much torque.
The min distance of air cutting can be as much as 2 x pitch.
RE: CNC thread cutting issue
RE: CNC thread cutting issue
RE: CNC thread cutting issue
You may have to center drill the part and use a live center, or chuck closer to the threading area to reduce part deflection.
RE: CNC thread cutting issue
RE: CNC thread cutting issue
The thread can be overlayed perfectly with the 50 times template under the optical comparator.
The system we are using is FANUC-0T series
G92 thread cutting cycle means the cutter infeed direction is perpendicular to the spindle axis--the cutter three edges machine the shaft at the same time.
G76 mutiple thread cutting cycle means the cutter infeed along one side of the tooth, then only two edges machine at the same time--maybe the machining force is less than G92.
The spindle speed is 200RPM now.
Thanks for all your help!