Hitachi Seiki G841 Tapping cycle
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    May 2019
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    Default Hitachi Seiki G841 Tapping cycle

    Seicos Sigma 18M which is a Fanuc 18i with Hitachi's U/I but it should be the same for the 10 and 16 also

    Might be useful to someone as I couldn't find this on the internet and had to sacrifice 1 good OSG tap and one worn out tap to figure it out. Despite what the manual and controller say G84 is not for rigid tapping and does not synchronize the spindle and Z servo. It will kind of work at low RPMs like 300 with a 3/8" tap but the spindle reverses faster than the Z servo and you can see it on the spindle load. I found one thread on here where someone was having a similar issue but never seems to have found a solution.

    Well per the Hitachi Seiki manual G741 and G841 are direct tapping cycles for high speed high accuracy tapping. Also this cycle orients the spindle so you can peck tap or even go back and retap the same hole(s) after the tapping cycle has been cancelled.

    Also G251 P0 (on) P1 (off) is lookahead that appears to not have the bell shaped accel/deccel Like G08 P1 does. For fast roughing G251 seems to be faster as it doesn't seem to slow in the corners to stay on path.

    Playing with the new to me machine with a 30hp 12000 rpm spindle and 1600ipm feeds is entertaining to say the least.

    Hopefully this helps someone out there

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