Have you CAM programmers seen the new Cut Plane transfer type in planar operations such as Floor & Wall and Cavity Mill yet? This transfer motion, new in NX12, keeps your machine Z axis at a constant plane when transfering from one cut motion to another. In other words, the Z value never changes while the cutter path is cutting each region as long as the path can reach a safe area to transfer around. For planar surfaces that require a high level of precision, this is ideal because the programmer need not worry about repeatability of the machine after a rapid and engage motion from one end to another. Granted, this would usually only concern machinists that require matched stepovers at the micron level, but there is an unexpected benefit for others as well; time savings.
Yesterday I did some test cuts with this on mirrored pocket features by roughing them out using Cavity Mill and finishing just the floors with Floor & Wall. In both cases I used the Cut Plane transfer on one pocket and the Previous Plane transfer on the other with Safe Clearance Distance set to 1mm. Because the Cut Plane transfer motion is output as a stepover, I can change its feedrate in the Speeds and Feeds dialog, which I did by cranking it up to 10,000mmpm. Since the Cut Plane transfer type takes the long way around instead of up and over, the total length of the path in the Cavity Mill operation with this transfer type is longer than the other. (10410.2mm vs. 8838.2mm) You would think then that this tool path would take longer, but the opposite turned out to be true. According to the machine clock, the Cavity Mill path with Cut Plane transfers took 22:17 and the Cavity Mill path with the Previous Plane transfers took 22:59. This results in a savings of 42 seconds in the Cut Plane transfer path. For mold and die shops this is not much, but in a production machine shop this is a long time.
The Floor & Wall operations showed similar results. Only the floor was being cut this time in one single Z level path. Using Cut Plane transfers took 2:43 and Previous Plane transfers took 3:19. Another big savings for one tool path.
See the Floor & Wall path with the Cut Plane transfer type in this video. Let us know what you think.
Yes, this new Cut Plane transfer type is available in NX12 and can be found in the Non Cutting Moves dialog. Users will find it as a new option in the Transfer Type drop down list of the Within Regions group under the Transfer/Rapid tab.
Floor & Wall, NX7.5 - NX11:
(clear. geom. bounding box, shortest distance,engage height 0)
Yes, as Juraj points out this can be done in a similar capacity using Bounding Box as the clearance option. However, in many cases going all the way to the bounding box is not practical. You may want to stay closer to a cut region which lies inward of the entire part. Cut Plane transfers also are smart enough to avoid geometry in the way of their path and still stay on the current plane.
these moves are generated as a stepover.
In default stepover feed is equal to cut feed.
If I want to increase the stepover feedrate I can do it. For example: F(stepover)=15000
But notice that stepover also do the cutting in some cut patterns. = collision
So I think there should be an option or rule to generate this moves as a rapid move.
We debated about this for some time when the project was being made. There was a concern about outputting this as a typical transfer motion because of machines that "dog leg" the rapid motions. The feedback from the customers driving this project as well as others working on it was that it would be safer to output this as a stepover instead to avoid crashing into the workpiece while traversing so closely to it. The stepovers can have a different programmed feedrate from the Feeds & Speeds dialog, as you say, so the total run time can still be quick. We just reduced the risk of machine collisions that wouldn't be found outside of true machine simulations. Also, while many machines don't rapid in the dog leg fashion, many others do have a hard time with rapid motions as arcs. Notice that the Cut Plane transfer motions arc around the cut regions instead of making hard turns. Many machine tools would create short, choppy moves and slow down while trying to move around the arc at G00. The operator would then have to output all rapids as G01 then to compensate, which adds to usability problems with extra steps to memorize.
The typical use case for Cut Plane transfers is facing off regions that have critical tolerances (think mating surfaces). A programmer would likely use the Zig or Follow Part patterns for consistent stepovers that are off the part for perfect and beautiful surface finishes.