Using Z in drill cycles (ver14.7)

[HuFlungDung]

Well, after gently crashing my machine, I beat and beat on this problem and finally figured out what was going on

Here is the scenario: I have a lathe peck drill cycle set up in Camsoft to do a typical G83 peck drilling sequence. This is something that I thought I had proven out and had working flawlessly.

Here was a typical program sequence that was enough to give me some grief:

G92 Z1.
S500 M3
G00 X0 Z.15
M8
G83 Z-.72 R.1 K.1 F1.5
G80
T0
G30

I happened to call for INCCODE within my G83 logic, as I prefer this method for general application of drilling.

Now, if I execute each line in single step mode it works fine.
If I execute the program in Continuous mode, it works fine.

So what is left, you ask? : run in Single step down to the M8 and then switch to Continuous mode just before the G83 command is read. For whatever reason, doing this causes the machine to seek a new rapid plane some 1.058" in Z-, from whence it drills incrementally by additional Z-.72 depth and comes to rest at Z-.908, which should have been Z.15, the clearance plane.

I could find no reason for the distance that it chose to move and I searched hard for it!

However, if I wrote
G00 X0 Z.15
M8
G01 X0 Z.15 <----inserted this line
G83 Z-.72 R.1 K.1 F1.5

Then the machine would not make the uncalled for movement.

So I sought a workaround so that I would not have to remember to put a dummy G01 in front of the canned cycle. What it seems to be is that the Z value used with the G83 must have caused some kind of confusion with the distance to go in Rapid, as I simply removed the 'Z' and substituted a 'W' for the G83 drill depth and the problem went away.

Now I do not have to fear twisting my toolpost off line again, for that reason, anyways.

This problem may have been fixed in later versions of Camsoft, but it may be a rare enough case that no one has stumbled upon it. Perhaps it may give someone a clue where to look one day for the inexplicable events that arise from PC based cncs

[Karl_T]

Interesting...

I checked and none of the default lathe .cbk I have include a G83. I'm guessing you clipped it out of a mill default .cbk. I've seen two versions of the drill cycle G codes in default mill .cbk files. The newer ones go like this:

IF\775=0THEN\776=z:[G83]:\775=83:EXIT
IF\775=81THEN[G81]
IF\775=82THEN[G82]
IF\775=83THEN[G83]
IF\775=84THEN[G84]
IF\775=85THEN[G85]
IF\775=86THEN[G86]
IF\775=87THEN[G88]
IF\775=88THEN[G89]
-----G83

All the actual moves are done in the correct macro. Is this what you're using?

Karl

[HuFlungDung]

No, I wrote my own macro, you can do that, you know

It is a strange quirk alright, but because of the method that exposed the problem, I don't think it is anything about how the logic in the macro runs, rather there is some miniscule difference between a command to Singlestep versus Cyclestart. Obviously they are different, of course, but not just in the way one would expect.

The other factor could also be using a Z command for drill depth in a G8x cycle could cause confusion as Camsoft reckons Z to = z which is the current movement command, and in the case of a canned cycle, of course one does not intend to use Z as a simple motion or positioning command. That is why I think switching the parameter name to W (or any non active axis name) cures the problem.

[Citron]

hi guys

I will post a complete set of canned cycles my client made for his Fagor and another set from a Fanuc control he imulated using CNC Professional using v15. I know they have 16 now. I will get that next time. With v15 I found this to be a great asset. I personally didn't know the system had this much power. I wrote because I am interested to see what others have. I really see so much that can be done beyond canned cycles for making g&m codes to imulate any machine brand. I haven't been involved in doing any retros lately but the CNC Professional is my hands down choice from now on for every thing I do.

johnny

[Karl_T]

Originally Posted by HuFlungDung No, I wrote my own macro, you can do that, you know

I'm nearly complete with my Hardinge lathe upgrade, haven't installed the canned drill cycles yet. When I get home next month, I'll be sure and do this first with copies of macros from the latest Camsoft .cbk (I was an engineer, why design when you can shamelessly plagiarize?) I let you know if I can duplicate this "program feature" on my control.

Karl