Retrace
Bu içerik henüz dilinizde mevcut değil.
Something is wrong and the tool is still in the cut. You want to back out the way you came in, not lift and hope.
Retrace winds the program backwards along the path that was actually executed. It follows the same arcs, the same corners and the same feed direction, in reverse, rather than a straight line to somewhere safe.
Then you wind forward again along the same path and carry on.
Winding back
Section titled “Winding back”- Feed hold, so the machine is stopped on the path.
- Turn RETRACE on. The machine is now in retrace mode, and nothing moves yet.
- Hold
REVERSEto wind backwards. It moves while you hold the key and stops when you let go, like jogging. - Hold
FORWARDto wind forwards again. - Turn retrace off and resume.
Winding is under your thumb the whole time.
Cycle start is refused while retrace is on
Section titled “Cycle start is refused while retrace is on”Leave retrace mode first. A start that silently exited retrace would resume from whichever point you happened to have wound to, which is not necessarily where you meant to carry on from.
Where it will stop: barriers
Section titled “Where it will stop: barriers”Retrace winds back along the path, but there are points it cannot wind past, because what happened there cannot be undone by moving backwards. When it reaches one it stops and tells you.
| It will not wind back past | Because |
|---|---|
| a tool change | the tool in the spindle is not the one that cut the path behind it |
| a probing move | the measurement already landed in an offset |
| thread cutting | the thread was cut synchronised to the spindle; running the geometry backwards does not un-cut it |
| rigid tapping | the same, with the tap still in the thread |
| spindle synchronisation | the spindles were coupled; the coupling is not reversible by rewinding |
| a program stop, optional stop, or program end | the program deliberately ended there |
| a work offset change | coordinates before and after the change mean different things |
a G92 shift | the same |
| a change of kinematics | the path behind was solved against a different machine geometry |
Retrace takes you back through cutting, not through everything that ever happened.
The retained path has a length
Section titled “The retained path has a length”The control keeps the path it has executed in a buffer of a few hundred segments. Wind back far enough and you reach the end of what was retained, and retrace reports that it is exhausted.
So retrace is for backing out of the situation you are in: the last few moves, the current feature. It is not for rewinding a four-hour program to the start. That is what block search is for.
Retrace or block search?
Section titled “Retrace or block search?”| Retrace | Block search | |
|---|---|---|
| Moves along | the path that was actually cut | nothing, it jumps |
| Good for | backing out of a cut, inspecting a feature you just made | restarting a long program part way in |
| Reach | the last few hundred segments | any block in the program |
| Restores tool and M codes | no, it refuses to cross them | yes, it replays them |
They solve different halves of the same problem. Retrace gets you out of where you are. Block search gets you back to where you were.
What retrace does not do
Section titled “What retrace does not do”- It does not put material back. Winding backwards through a cut moves the tool along the path; it does not undo the cut.
- It does not reverse the spindle. The spindle keeps turning the way it was; only the path direction reverses.
- It does not survive a reset. A reset ends the program, and with it the retained path.
Where to go next
Section titled “Where to go next”- Block Search restarts from a chosen block.