Keyway slotting

[ETA]

Hi everyone,

What is the best way to program for keyway slotting with a single point cutter.

My first attempt is a 8mm keyway cut into a 25mm bore.

Doosan 220LM / Fanuc 0i-TC.

Have figured out the cutting stroke / speeds. How do you program the retraction & repeatition of the cuts with a sub.

Thanks
Fast learner

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[christinandavid]

Move to start position in main program.

Call sub program with an G65 P(sub pgm no) L(number of repeats)

Use incremental moves in sub program (G91) to perform one pass/retract/increment across.

If you want to start getting clever you could add another couple of arguments to the G65 line to specify a. Total Depth and b. Depth of Cut. You would then remove the L and use logic (macro B) in the sub program to work out required no of repeats.

DP

[ETA]

Thanks for the response.

You lost me after "move to......." I'll have to get my book out.........
Got most of it.

[dcoupar]

Your lathe doesn't use G91 for incremental. X and Z are absolute commands, U and W are incremental. Also, you can use M98 to call a sub G65 is usually used for Macro Calls. Lets say you want to make 20 passes:

X24.5 Z2.0 M19 (POSITION TO START POINT, ORIENT SPINDLE)
M98 P0201001 (CALL SUB O1001 20 TIMES)
G30 U0 W0 (RETRACT FOR INDEX)
M30

O1001(SUB)
G00 G98 U0.25 (RAPID UP 0.25MM IN X)
G01 Z-25. F200. (FEED TO DEPTH IN Z)
G00 U-0.20 (RAPID DOWN 0.2MM IN X)
Z2.0 (RAPID TO START IN Z)
M99

Program O1000 will be called 20 times, each pass 0.05 higher than the last:
X24.75
X24.8
X24.85
X24.9
X24.95
...
...


Also, as christinandavid suggests, you could write a macro that does this a little more elegantly with variables, etc.

[ETA]

DP,
Can you give me an example to work on.

Thanks
Roger

[ETA]

Spot on. Just what I was looking for.

Roger

[cush09]

Hi i was reading your post and I'm trying to do something similar on sc200 naukamura. Can i use a g74 canned cycle.

[cush09]

Doing a 4mm wide keyway in a 13.992 bore depth of keyway is .075.
thanks woody

[cush09]

working on sc200 naukamura

[cush09]

i figured out what i was doing.
thank you

[ollari]

Old thread but helpful, Thanks. Got my first slotting working with this, but I have a question. If i am making blind keyway without the relief, is there any options to retract the Z-axis with each pass? Lets say 0.05mm with each stroke. Just to slowly escape the chip build up. Machining plastics mostly.
Using this piece of code
X24.5 Z2.0 M19 (POSITION TO START POINT, ORIENT SPINDLE)
M98 P0201001 (CALL SUB O1001 20 TIMES)
G30 U0 W0 (RETRACT FOR INDEX)
M30

O1001(SUB)
G00 G98 U0.25 (RAPID UP 0.25MM IN X)
G01 Z-25. F200. (FEED TO DEPTH IN Z)
G00 U-0.20 (RAPID DOWN 0.2MM IN X)
Z2.0 (RAPID TO START IN Z)
M99

Thanks in advance

[z369]

Not entirely understanding your question. If you want to back off the bottom in Z just command it to do so in the sub program?

I.E.-

O1001(SUB)
G00 G98 U0.25 (RAPID UP 0.25MM IN X)
G01 Z-25. F200. (FEED TO DEPTH IN Z)

Z-24.95 (<~~~INSERT YOUR BACK OFF MOVE COMMAND HERE)

G00 U-0.20 (RAPID DOWN 0.2MM IN X)
Z2.0 (RAPID TO START IN Z)
M99

Could also do it in incremental too (W.05)

Personally, I would've used Macro to program something like this with a plane rotation command and WHILE/DO/END loop, but that's just me.