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Offset trajectory?

cncwhiz

New member
Anyone know why when you sketch a trajectory cut, I can't change the offset amount "sketch plane offset" without blowing the automatic cutaway and makning another one. This could be a real PIA if your sketch was very complex.
 
To do what you did, you must have selected a "MAKE DATUM" as your sketch plane. To change this, redefine the "AUTOMATIC CUT", "SKETCH", "SKETCH PLANE, then select "MAKE DATUM" again and enter the new amount that you want.


This used to work just fine, but when we went to Wildfire, this would leave the old datum on the screen and even though it had no "children", if you deleted it, you lost the whole NC sequence. I do not know if this has been fixed in Wildfire 2.0 or 3.0


What I have been doing since, is selecting a surface on the model, even a primary datum plane, and use the "AXIS SHIFT" parameter to offset the cut. The "AXIS_SHIFT" parameter only affects the "Z" axis so it works just fine. However, doing this can gouge the part if you shift it in the wrong direction, so be careful. Once you get used to using it, I think you will like it too.
 
Hi cncwhiz,


I agree that not having the make datum dimension accessible for modification makes things a bit more difficult, but you can do it without having to blow away the automatic cut.


First redefine the automatic cut (automatic cut > Redefine > Cut ). Then you have 2 options:


1- Redefine the sketch, then sketch plane > Alternate > Make Datum (make the new datum using a different offset). Then make sure to respond with "Same ref" for the orientation plane. If you select the same offset surface for the make datum, the sketch will work the same way just at differnt height.


OR


2- Height then Make datum. Height will overwrite the original sketch plane definiton (actually, it will project the cut motion onto the newly defined height).


Option 2 is preferred. Although both will work fine, it is much faster and does not touch at all your sketch, so there is no likelyhood of sketch failures.
 
The best practice is to sketch all of your trajectories on the retract plane. The plane should be created independent of the ref model (preferably offset from the default plane in the mfg assy). This will give you the most robust sketch. Then use the STARTHEIGHT and HEIGHT options to specify the starting and final depth of the cuts. You can do make datums at this point to control the offsets instead of using axes shifts.





Regards
 

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