LH Rigid Tapping on Mitsubishi Meldas 500 Puma Lathe

runninwideopen said:

Hi all,

I've gone from scratching my head to pulling my hair out. I can't figure out how to get LH rigid tapping to work on this machine. I've tried the following things I've found on other threads.

M4 spindle rotation before my G84 - Starts off correct, spindle does not reverse at the bottom of the hole.
G74 - Program stops. No error. Nothing happens.
G84.1 - Bad G Code
G184 - Bad G Code
G88 - rapids in, then rapids to next position without threading out of the hole.

The book doesn't seem to mention reverse or LH tapping at all. If anyone has any other suggestions or another helpful thread that I haven't found yet, I'd appreciate it.

Click to expand...

DouglasJRizzo said:

M176 is motor polarity reverse. M177 is Motor polarity forward. On 2011 and newer Doosan's you would put the M176 on a line by itself BEFORE the M29, then, AFTER you cancel with a G80, you have an M177 on a line by itself.

On the Mits it "might" be different, check your M code list for "Motor Polarity."

Click to expand...

Vancbiker said:

Did you include D-1 in your code? Here is a clip from a Meldas lathe programming manual.....

Whether to carry out forward tapping or reverse tapping when executing the synchronous
tap cycle is determined by the sign for address D. (Positive: forward tapping, negative:
reverse tapping) If there is no address D command, forward tapping will take place with
the 1st spindle. If the 1st spindle is not serially connected, a program error (P182) will
occur.

Click to expand...