Need Help!- Storing an axis position

[sidswiss]

I'm trying to write a "chip drop" sub program for our lathes. How do I get the controller to remember it's last Z position? Citizen 32J machine. Mitsubishi control.
example;

...,
T1500
G50X6.3
G97S1=3500M96
G99G0X0.475Z8.2854T15
X0.3918F0.002
G1X0.3647Z8.299F0.0005
*****
Z9.185(HOW DO I STORE THIS Z?)
X0.473
G97G0X6.3T0

M98P500


(CHIP DROP SUB PROGRAM)
O500;
G98 G1 Z-0.1 F50.0;
G4 U0.5;
G1 Z(PREVIOUS Z(IE;Z8.299))F75.0;
M99


I WANT TO USE THIS SUB PROGRAM ON ALL DIFFERENT LENGTH PARTS. HOW DO I GET IT TO REMEMBER THE LAST Z POSITION?

[Al_The_Man]

You did not say what control you have?
For a while, Mitsubishi controllers have used storage variables 5001 to 5103 for machine coordinates, work coordinates, skip coordinates and Servo deviation.
Al.

[sidswiss]

Mitsubishi E32-4. I'm also doing this with our Star Lathes SV12, SV32, SV32-J with Fanuc 18i-TA.

[ChattaMan]

On our Fanuc mills we use #5003

e.g.
blah blah
Z9.185(HOW DO I STORE THIS Z?)
#500=#5003(PRESENT Z POS.)
X0.473
G97G0X6.3T0
blah-de-blah

9.185 will be stored in #500

[sidswiss]

Chataman,
You say "#500=#5003(PRESENT Z POS.)". Will I have to input that Z position on the variable page or will it store it automatically? My sub program should look like this.?.

e.g.
T1500
blah blah
Z9.185(STORE THIS Z?)
#500=#5003(PRESENT Z POS.)
X0.473
G97G0X6.3T0

M98 P500

(CHIP DROP SUB PROGRAM)
O500;
G98 G1 Z-0.1 F50.0;
G4 U0.5;
G1 Z#500 F75.0;
M99

I want to be able to throw the M98 P500 any where in any program at whatever Z length the chips ball up, maybe with an \ block skip at every tool change. Do I have to input the Z position in variable #5003?

[stevo1]

Yes the #500 will be set to 9.185 when it reads the #500=#5003. Now when you call your 500 sub program and write G1Z#500F75. it will go to Z9.185.

Originally Posted by sidswiss I want to be able to throw the M98 P500 any where in any program at whatever Z length the chips ball up, maybe with an block skip at every tool change. Do I have to input the Z position in variable #5003?

I would be careful of just "throwing a M98P500" in the program were ever you want and using a lot of block skips. If you are going to use the M98 a lot you must always know what #500 is set to and did you pick it up at the proper Z position. #500-#999 variables never clear even when you power down. They only change when either the program changes them or you do via MDI method.

So for example if you pick up a Z from another place and set the #500 to 2.6”. Now you slap a M98P500 in a program and forgot to pick up a Z for what you are doing and it is suppose to be Z9.185 you are going to have problems.

I would set the current position in your 500 program that way all you have to do is put the M98P500 in the program were you want and not have to worry about if you remembered to set the #500 variable.

e.g.
T1500
blah blah
Z9.185(STORE THIS Z?)
X0.473
G97G0X6.3T0

M98 P500

(CHIP DROP SUB PROGRAM)
O500;
#500=#5003----as long as you did not move your Z before the M98 call. Or put the M98 right after the Z.
G98 G1 Z-0.1 F50.0;
G4 U0.5;
G1 Z#500 F75.0;
M99

I would probably use one of your common variables #100-#199 these variables clear at power down. Less chance for error. If you wanted to be really safe you could use your local variables #1-#33. These clear at reset and program end. You could then put a statement in the program to alarm out if the Z position was never established.
Ex.
Blah blah
Z9.185
#1=#5003
..
..
M98P500
…
O500
IF[#1EQ#0]TH#3000=1(NO Z VALUE)—program will alarm out here if you forgot the #1=#5003 in your main program.
G1Z#1F75.
M99

Stevo

[sidswiss]

Thanks Stevo,
That makes total sense. Variable #1-#33 is the way to go. #500 is just for this example.

[sidswiss]

Hey Citezen E32/E25 guys,
If #5003 = Z1, what variable would Z2 & Z3 be? I want to put a statement in this sub-program that if #500* (Z3) <>, is anything other than zero, than skip sub-program. I wouldn't want to put the sub-spindle thru the guide bushing...again.

[stevo1]

Originally Posted by sidswiss Hey Citezen E32/E25 guys, If #5003 = Z1, what variable would Z2 & Z3 be? I want to put a statement in this sub-program that if #500* (Z3) <>, is anything other than zero, than skip sub-program. I wouldn't want to put the sub-spindle thru the guide bushing...again.

What do you mean by Z1, Z2, Z3? When we were talking about capturing the current Z in the program we referred to #5003. These are system variables of the machines current state.

This is not for all machines but for this situation:
#5001=current absolute “X” position
#5002=current absolute “Y” position
#5003=current absolute “Z” position

There can be only 1 current absolute Z position. So what positions are you looking for when you say Z2 and Z3?

Stevo

[psychomill]

Uh.... I think he's trying to capture current position Z at any given point in the cut? If so... you can't.... at least not to keep it programmable.

Why not just put in 'chip drop' subs at predetermined points along Z and just hard code it in?

[Superman]

Sorry guys , I don't work Mitsubishi ( so forgive my syntax, but you may understand )
but can I suggest another improvement
-- use incremental --
-- have an internal variant --
-- feed off @ 45 degree, rapid out , dwell, rapid in, feed in @ 45 to last cutting point --

None of these subs will not work if reverse tapers or inward steps exist by the way.


O500 (CHIP DROP SUB PROGRAM-**OD**);
#1=#5001 #3=#5003;
IF[#1 EQ #0] TH#3000=1 (NO X VALUE);
IF[#3 EQ #0] TH#3000=1 (NO Z VALUE);
IF[#3 GT #0] TH#3000=1 (+IVE Z VALUE); in case the origin is @ LH end
G98 G1 U0.2 W0.1 F50.0;
G0 W-[#3+0.1]; -ive times -ive = +ive (ie #3=-9.185 then W- x (-9.185+ 0.1) = W9.285 = Z0.1
G4 U0.5;
G0 Z[#1+0.1]
G1 X#1 Z#3 F50.0;
M99
(_);
O501 (CHIP DROP SUB PROGRAM-**ID**);
#1=#5001 #3=#5003;
IF[#1 EQ #0] TH#3000=1 (NO X VALUE);
IF[#3 EQ #0] TH#3000=1 (NO Z VALUE);
IF[#3 GT #0] TH#3000=1 (+IVE Z VALUE); in case the origin is @ LH end
G98 G1 U-0.2 W0.1 F50.0;
G0 W-[#3+0.1]
G4 U0.5;
G0 Z[#3+0.1]
G1 X#1 Z#3 F50.0;
M99

[ProProcess]

Originally Posted by sidswiss Hey Citezen E32/E25 guys, If #5003 = Z1, what variable would Z2 & Z3 be?

It would still be #5003.
These variables are per system just as 1-32 and 100-149 are.
So...
#100=#5003 in $1 would be Z1 position
#100=#5003 in $2 would be Z2 position
all of which you could and SHOULD test in MDI

Good Luck!

Originally Posted by sidswiss I wouldn't want to put the sub-spindle thru the guide bushing...again.

... this does not sound like much fun!