There are a number of ways of thinking about this but I prefer to think of it this way; Clearance height is the height at which the tool will move between operations. Safe height is the height at which it will move between areas in the same operation.freman wrote: ↑Thu Nov 05, 2020 8:06 pm
I always find the safe height / clearance height terminology rather confusing but what it means also seems confused.
In the attached FCStd I have a series of drill holes. The approach to the first one is done at clearance height but in between all others it skims along at safe height.
The above link shows the space between safe and clearance as "space for clamping".
If I had clamped in that zone I would not have any clamps left !
Am I misusing this or is it as confused at it appears to be?
Thanks for the reply.You should never position the clamps inside the working envelope of an operation but if you have to, you can always manually set the safe height high enough to clear.
If you need to put clamps in an area that Path would otherwise expect to be clear, what else would you suggest? How is Path expected to know that you have a clamp in the working envelope?If I need to set safe height equal to clearance height to clear clamps, then the distinction becomes null.
I'll need to study your file closer,including your post processor. Are you sure this is a Path G1 move to start-depth rather than the beginning of a canned cycle?Another problem exposed by this example file is that the drilling operation is descending from clearance to safe at drilling speed , not rapid. Since this is supposed to "safe" space , outside of the stock, what is the point in G1-ing this movement. It should G0 down to safe height then G1 from there. Was this done to avoid a specific geometric problem?
This too gets into the nuance of canned cycles.If the "safe space" was traversed as a rapid the case, the objection of not moving to clearance between each hole disappears. A rapid up and rapid down would not be a problem.
Again,I'm not sure what you expect us to do. There are real-world situations where intermediate clamps are needed but you haven't told me how we should know about them.I don't know of hand whether this notion of moving between different areas within the same operation makes sense on the other 2.5D tools but I can't see it as meaningful here.
The "you should never" argument does not appropriate. This bar is 800mm long. I require intermediate clamping. I have already had to machine the other pockets with safe=clearance, which is indeed a lot slower than it should be.
Good question. Maybe someone with experience in other cam software can weigh in. Maybe we need to create another kind of object or dressup to indicate a no-go or clamping area but implementing it is going to be a nightmare.What is the reference for how this is done and what these terms mean? Is there a standard method, or was this just the way it was chosen to be done when Path WB was written?
No, looking at the unexpanded Gcode before the post processor ( inspect g-code ) the canned cycle starts from clearance on the first hole, there is no move down to safe ht, first. So this is not related to any of the post proc code.I'll need to study your file closer,including your post processor. Are you sure this is a Path G1 move to start-depth rather than the beginning of a canned cycle?
Code: Select all
(bar-fix-Drilling) (Begin Drilling) G0 F50.000000 Z21.000000 G90 G99 G83 F1.000000 Q3.000000 R-0.500000 X170.000000 Y-15.000000 Z-20.000000 G80 G0 Z3.000000 G83 F1.000000 Q3.000000 R-0.500000 X320.000000 Y-15.000000 Z-20.000000
There may be a case for this ( though I remain to be convinced ) but my point here was that the doc is incorrect. If this is the thinking behind it, the concept of the "envelope" should be a caveat to the current statement this space is "safe".If you need to put clamps in an area that Path would otherwise expect to be clear, what else would you suggest? How is Path expected to know that you have a clamp in the working envelope?
Assuming that the user can tell what route FC will take and anticipate the envelope is not guaranteed, it not always that obvious. I already have a few lumps missing from my clamps where I got caught out by this unsafe "safe space". One thing I did intend to raise at some point is ordering of "base geometry" being taken into account.Good question. Maybe someone with experience in other cam software can weigh in. Maybe we need to create another kind of object or dressup to indicate a no-go or clamping area but implementing it is going to be a nightmare.
I think too, that the documentation is wrong. If course can clamps be in the way on vertical moves, because they are misaligned, but as we currently don't make any proposals where to place clamps, this can be neglected. Indicating clamps in an image can thus affect only horizontal moves. And I would expect "Space for clamping" to be indeed "Safe space for clamping", i.e. it is safe to make horizontal moves above that height. For anything else it is safe to move above stock.
herbk wrote: pinged by pinger macro
yes, - for both.
I think "Space for clamping" still implies it is protected space and that this is what the difference between these two confusing terms is about.Indicating clamps in an image can thus affect only horizontal moves. And I would expect "Space for clamping" to be indeed "Safe space for clamping"