Siemens SINUMERIK 840D, Operating Manual, Page: 373 / 610

Programming technological functions (cycles)
8.4 Turning - only for G code programs
Milling
Operating Manual, 03/2010, 6FC5398-7CP20-1BA0
373
Parameters Description Unit
DA Thread changeover depth (inc)
First machine all thread turns sequentially to thread changeover
depth DA, then machine all thread turns sequentially to depth 2 ·
DA, etc. until the final depth is reached.
DA = 0: Thread changeover depth is not taken into account, i.e.
finish machining each thread before starting the next thread.
Machining:
 Complete, or
 from turn N1
N1 (1...4) start thread N1 = 1...N or
 only thread NX
NX (1...4) 1 from N threads
8.4.7 Thread chain (CYCLE98)
Function
With this cycle, you can produce several concatenated cylindrical or tapered threads with a
constant pitch in longitudinal and face machining, all of which can have different thread
pitches.
There may be single or multiple threads. With multiple threads, the individual thread turns
are machined one after the other.
You define a right or left-hand thread by the direction of spindle rotation and the feed
direction.
The infeed is performed automatically with a constant infeed depth or constant cutting cross-
section.
●
With a constant infeed depth, the cutting cross-section increases from cut to cut. The
finishing allowance is machined in one cut after roughing.
A constant infeed depth can produce better cutting conditions at small thread depths.
● With a constant cutting cross-section, the cutting pressure remains constant over all
roughing cuts and the infeed depth is reduced.
The feedrate override has no effect during traversing blocks with thread. The spindle
override must not be changed during the thread machining.