Fixed cycle (Back boring)

Q: What does Mazak G-code G87 do?

G87 — Fixed cycle (Back boring) on the MAZATROL SmoothX control (INTEGREX e-670H). (Direction determined by bits 3 & 4 of I14) (b ) Value except 0 ····· M04 at R-point X, Y, P, Q, D, and/or J(B) can be omitted. Initial-point return is always used for G87 (even if the current modal is of G99). Whether argument J or B is to be used depends on the value that has been set in bit 1 of Parameter F84 bit 1 = 1: Argument J-command (argument J-command), setting a B-command will cause the table to rotate. Be care- ful in that case to ensure no interference between the workpiece and the tool. In G91 (incremental data input) mode, the direction of hole machining is automatically determined according to the sign of Z data (the sign of data at address R will be ignored). At the hole bottom, M05 and M00 are outputted.

Q: What is the programming format of G87?

G87 [Xx Yy] Rr Zz [Pt Qq ] Ff [Dd Jj (Bb )]

Machine-specific. This G-code reference is specific to the Mazak INTEGREX e-670H / e-670H-S with the MAZATROL SmoothX control (EIA/ISO programming manual H747PB0030E). G-code availability depends on fitted options, and groups and behaviour differ between Mazak models and control generations — verify against the manual for your own machine before programming with any code.

What it does

(Direction determined by bits 3 & 4 of I14) (b ) Value except 0 ····· M04 at R-point X, Y, P, Q, D, and/or J(B) can be omitted. Initial-point return is always used for G87 (even if the current modal is of G99). Whether argument J or B is to be used depends on the value that has been set in bit 1 of Parameter F84 bit 1 = 1: Argument J-command (argument J-command), setting a B-command will cause the table to rotate. Be care- ful in that case to ensure no interference between the workpiece and the tool. In G91 (incremental data input) mode, the direction of hole machining is automatically determined according to the sign of Z data (the sign of data at address R will be ignored). At the hole bottom, M05 and M00 are outputted.

G87 is modal (group 09) — it stays in effect until another code of the same group replaces it.

Programming format

G87 [Xx Yy] Rr Zz [Pt Qq ] Ff [Dd Jj (Bb )]

Address words

t c : Dwell (in time or No. of revolutions) d 0 : Distance from point Z
q 0 : Amount of relief on the XY-plane j 0 : 0 or omitted ········· M03 at R-point
f 0 : Feed rate
Note: For a horizontal machining center, if the value of bit 1 of parameter F84 is 1
t c : Dwell (in time or No. of revolutions)
t c : Dwell (in time or No. of revolutions)

Notes & precautions

For a horizontal machining center, if the value of bit 1 of parameter F84 is 1

Source

Mazak PROGRAMMING MANUAL for EIA/ISO PROGRAM, manual H747PB0030E, section 13-1-18 G87 [Back boring], p. 3-11, 13-19, 13-20. Reference and explanation only — not a reproduction of the manual.

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