FANUC Series 16i/160i/160is-MB, Series 18i/180i/180is-MB5, Series 18i/180i/180is-MB. Operator's Manual

20. AXIS CONTROL FUNCTIONS

PROGRAMMING

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S In C-axis servo delay compensation (G83), compensation is not

applied to the integer part of the gear pitch. The compensation

direction is opposite to that of the C-axis rotation.

D C-axis synchronous

S C-axis handle interrupt

shift

During synchronization between the hob axis and C-axis, manual

handle interrupt can be performed for the C-axis. The C-axis is

shifted by the amount of the handle interrupt.

For details of handle interrupts, refer to the relevant manual supplied

by the machine tool builder.

S Synchronous shift by programming

During synchronization between the hob axis and C-axis, the C-axis

can be interrupted using G01. In this case, be careful not to exceed the

maximum cutting speed.

Example: Hob shifting during synchronization

G01 Y__ C__ F__ ;

D Manual setting of

When the rotation of the position coder is stopped, the position of the

one-rotation signal

one-rotation signal is shifted in the CNC as if the one-rotation signal had

been output with the position coder at the current position.

For details, refer to the relevant manual supplied by the machine tool

builder.

D Retract function

In both automatic and manual operation mode, retract movement can be

made over the distance specified by parameter No. 7741, along the axis

set by bit 0 (RTRx) of parameter No. 7730.

For details, refer to the relevant manual supplied by the machine tool

builder.

Limitations

D Setting a rotation axis

Set a rotation axis as the C-axis (workpiece axis).

(Bit 0 (RoTx) of

parameter No. 1006 = 1)

D Gear ratio of the spindle

Set parameter No.7700#5 to 0 and also set the gear ratio of the spindle

(bob axis) and Position

(bob axis) to the position coder in parameter No.7711.

coder

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20. AXIS CONTROL FUNCTIONS

20.8

In the same way as with the hobbing machine function, to machine

(grind/cut) a gear, the rotation of the workpiece axis connected to a servo

SIMPLE ELECTRIC

motor is synchronized with the rotation of the tool axis (grinding

GEAR BOX

wheel/hob) connected to the spindle motor. To synchronize the tool axis

(G80, G81)

with the workpiece axis, an electric gear box (EGB) function is used for

direct control using a digital servo system. With the EGB function, the

workpiece axis can trace tool axis speed variations without causing an

error, thus machining gears with great precision.

Some conditions must be satisfied for setting the workpiece axis and tool

axis. For details, refer to the relevant manual provided by the machine

tool builder.

20.8.1

Simple Electric Gear

Box (G80, G81)

Format

G81 T _ L _ Q _ P _ ; Starts synchronization.

S_ M03 (or M04) ;

Starts tool axis rotation.

M05 ;

Stops tool axis rotation.

G80 ;

Cancels synchronization.

T : Number of teeth (Specifiable range: 1 to 1000)

L : Number of hob threads

(Specifiable range: -21 to +21 with 0 excluded)

Q: Module or diametral pitch

Specify a module in the case of metric input.

(Unit:

0.00001 mm, Specifiable range: 0.01 to 25.0 mm)

Specify a diametral pitch in the case of inch input.

(Unit:

0.00001 inch^-1, Specifiable range: 0.01 to 25.0 inch^-1)

P : Gear helix angle

(Unit:

0.0001 deg, Specifiable range: -90.0 to 90.0 deg.)

* When specifying Q and P, the user can use a decimal point.

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Explanations

D Synchronization control

Start of synchronization

When synchronization mode is set with G81, the synchronization

switch of the EGB function is closed, and synchronization between the

tool axis and workpiece axis starts. At this time, synchronization

mode signal SYNMOD is turned on. During synchronization, the

rotation of the tool axis and workpiece axis is controlled so that the

relationship between T (number of teeth) and L (number of hob

threads) can be maintained. Moreover, the synchronous relationship

is maintained regardless of whether the operation is automatic or

manual during synchronization.

G81 cannot be specified again during synchronization. Moreover, the

specification of T, L, Q, and P cannot be modified during

synchronization.

Start of tool axis rotation

When the rotation of the tool axis starts, the rotation of the workpiece

starts so that the synchronous relationship specified in the G81 block

can be maintained.

The rotation direction of the workpiece axis depends on the rotation

direction of the tool axis. That is, when the rotation direction of the

tool axis is positive, the rotation direction of the workpiece axis is also

positive; when the rotation direction of the tool axis is negative, the

rotation direction of the workpiece axis is also negative. However, by

specifying a negative value for L, the rotation direction of the

workpiece axis can be made opposite to the rotation direction of the

tool axis.

During synchronization, the machine coordinates of the workpiece

axis and EGB axis are updated as synchronous motion proceeds. On

the other hand, a synchronous move command has no effect on the

absolute and relative coordinates.

Termination of tool axis rotation

In synchronism with gradual stop of the tool axis, the workpiece axis

is decelerated and stopped. By specifying the command below after

the spindle stops, synchronization is canceled, and the EGB

synchronization switch is opened. At this time, the synchronization

mode signal (SYNMOD) is turned off.

Cancellation of synchronization

The position of the workpiece axis after travel during synchronization

is reflected in the absolute coordinates when synchronization is

canceled; from this point, absolute command programming is enabled

for the workpiece axis. By setting bit 0 (HOBRST) of parameter No.

7700 to 0, synchronization can also be canceled upon reset.

* The synchronization mode is canceled by a servo alarm, PS000

alarm, or emergency stop.

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20. AXIS CONTROL FUNCTIONS

D Helical gear

When a helical gear is to be produced, the compensation of workpiece axis

compensation

rotation is needed according to the travel distance on the Z-axis (axial

feed).

Helical gear compensation is performed by adding compensation pulses

calculated from the formula below to the workpiece axis:

Z sin (P)

Compensation angle =

360 (For metric input)

p T Q

Z Q sin (P)

Compensation angle =

360 (For inch input)

p T

where

Compensation angle: Signed absolute value (deg)

Z: Amount of travel on the Z-axis after the specification of G81

(mm or inch)

P : Signed gear helix angle (deg)

T: Number of teeth

Q: Module (mm) or diametral pitch (inch^-1)

The values of P, T, and Q are to be programmed.

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D Direction of helical gear

When bit 2 (HDR) of parameter No. 7700 = 1

compensation

(a)

(b)

(c)

(d)

– Z

- Z

C :

Z :

P :

Compensation

direction

(e)

(f)

(g)

(h)

-C

– Z

- Z

C :

Z :

P :

Compensation

direction

When bit 2 (HDR) of parameter No. 7700 = 0 (Items (a) to (d) are

the same as for 1.)

(e)

(f)

(g)

(h)

-C

– Z

- Z

C :

Z :

P :

Compensation

direction

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D Coordinates in helical

In helical compensation, the machine coordinates and absolute

compensation

coordinates of the workpiece axis (4th axis) are updated by the amount of

helical compensation.

D Retraction

By turning on the retract signal RTRCT (on a rising edge) in automatic

operation mode or manual operation mode, a retract movement can be

made over the distance specified in parameter No. 7741 on the axis set in

bit

0 (RTRx) of parameter No. 7730. Upon completion of retract

operation, the retract completion signal RTRCTF is output.

D Feedrate at retraction

For retract operation, the feedrate specified in parameter No. 7740 is used.

During retract operation, the feedrate override capability is disabled.

D Retraction during

When the retract signal is turned on in automatic operation, retract

automatic operation

operation is performed, and automatic operation is stopped at the same

time.

D Synchronization

A synchronization coefficient is internally represented using a fraction

coefficient

(K2/K1) to eliminate an error. The formula below is used for calculation.

(a, b : Number of detector pulses per rotation of the tool axis, and number

of detector pulses per rotation of the workpiece axis (parameter Nos. 7772

and 7773), respectively)

Synchronization coefficient =

In the formula above, K2/K1 is obtained by reducing the right side to

lowest terms, but K1 and K2 must satisfy the following restriction:

-2147483648

x K2

x -2147483647

x K1

x 65535

When this restriction is not satisfied, the PS181 alarm is issued when G81

is specified.

D Manual handle interrupt

During synchronization, a manual handle interrupt can be used for the

workpiece axis and other servo axes.

D Move command during

During synchronization, a move command can be programmed for the

synchronization

workpiece axis and other servo axes. Note, however, that incremental

command programming for cutting feed must be used to specify a

workpiece axis move command.

Limitations

D Feed hold during

For retract movement, the feed hold capability is disabled.

retraction

D Retraction when alarm is

This function does not include a retract function used when an alarm is

issued

issued.

D Rapid traverse during

In synchronization mode, a cutting feedrate can be specified for the

synchronization

workpiece axis (4th axis). Rapid traverse cannot be specified using G00.

D Maximum speed

The maximum speeds of the tool axis and workpiece axis depend on the

detectors used.

D G code command during

During synchronization, G00, G28, G27, G29, G30, G53, G20, and G21

synchronization

cannot be specified.

D Drilling canned cycle

When this function is used, the drilling canned cycle cannot be used.

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Examples

O1000 ;

N0010 M19 ;

Performs tool axis orientation.

N0020 G28 G91 C0 ;

Performs reference position return

operation of the workpiece axis.

N0030 G81 T20 L1 ;

Starts synchronization between the tool

axis and workpiece axis.

(The workpiece axis rotates 18° when

the tool axis makes one rotation.)

N0040 S300 M03 ;

Rotates the tool axis at 300 min^-1.

N0050 G01 X

; Makes a movement on the X-axis

(for cutting).

N0060 G01 Z

; Makes a movement on the Z-axis

(for machining).

- - - - - - - - - - - - - - - - ;

N0100 G01 X

; Makes a movement on the X-axis

(for retraction).

N0110 M05 ;

Stops the tool axis.

N0120 G80 ;

Cancels synchronization between the

tool axis and workpiece axis.

N0130 M30 ;

20.8.2

This function provides the capability that skip function or high speed skip

function can be commanded for work axis in the EGB(Electronic Gear

Skip Function for EGB

Box) synchronization mode.

Axis (G31.8)

The features are as follows.

- The program block to enable the function is not interrupted until the

total number of skip signal inputs reaches a value specified in the same

block.

- The synchronization by EGB is not stopped by any of skip signal

inputs.

- The machine coordinate position of the EGB axis (work axis) at each

time of the signal inputs is stored in one of consecutive custom macro

variables. The top number of the variables is specified in the block.

- The total number of the inputs is stored in another specified variable.

As for the EGB function, see the chapter “1.14 Simple Electric Gear Box”

of the Connection Manual (Functions) B-63523EN-1.

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20. AXIS CONTROL FUNCTIONS

Format

G81 T_ L_ ;

(EGB mode on)

G31.8 G91 a0 P_ Q_ R_ ;

(EGB skip command)

a : EGB axis (Work axis)

P : The top number of the consecutive custom macro variables in

which the machine coordinate positions of the EGB axis (work

axis) at the skip signal inputs are stored.

Q: The maximum allowable number of the skip signal inputs.

(Range of command value: 1 - 200)

R : The number of the custom macro variable in which the total

number of the inputs is stored.

This data is usually the same as the value specified by Q.

Therefore this is not necessarily specified. Specify it when the

total number should be confirmed.

Explanations

G31.8 is a one-shot G code.

During the execution of the G31.8 block, the machine coordinate

positions of the EGB axis (work axis) at the skip signal inputs are stored

in the consecutive custom macro variables where the top number of the

variables is specified by P and the maximum allowable number of the skip

signal inputs is specified by Q.

The total number of the skip signal inputs (i.e. the same value specified

by Q) is stored in the variable specified by R.

Examples

G81 T200 L2 ;

(EGB mode on)

X_ ;

Z_ ;

G31.8 G91 C0 P500 Q200 R1 ; (EGB skip command)

After 200 times of skip signal inputs, 200 machine coordinate positions

of the C axis are stored respectively in the consecutive custom macro

variables #500 - #699.

The total number of skip signal inputs (i.e. 200) is stored in the custom

macro variable #1.

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NOTE

In the G31.8 block, only the EGB axis (work axis) should be

commanded. When another axis is commanded, the P/S

alarm (No.5068) will occur.

If P is not specified in the G31.8 block, the P/S alarm

(No.5068) will occur.

If R is not specified in the G31.8 block, the total number of

skip signal inputs is not stored in the custom macro variable.

The numbers of custom macro variables specified by P and

R must be the existing ones. If any nonexistent variable is

specified, the P/S alarm (No.115) will occur.

If all the variables ranged by P and Q are not among the

existing ones, the P/S alarm (No.115) will occur, too.

You can select the type of skip functions, normal skip

function or high speed skip function, by the parameter

HSS(No.6200#4).

When high speed skip is selected, you can select a valid

signal among high speed skip signals by setting parameter

9S1 to 9S8 (No.6208#0 to #7).

The parameters No.6201#0 and #1 are not effective for the

G31.8 function.

The machine coordinate positions stored in macro variables

do not include any compensation amount based on position

errors and servo time constant (loop gain).

Alarms

Num-

Message

Contents

ber

5068

G31.8 FORMAT ER-

When skip function for EGB axis (G31.8)

ROR

is specified, there are wrong command as

follows:

- Movement command is specified for

EGB axis (work axis).

- More than one axis has been specified

- P has not been specified in G31.8

block.

- Q has been specified out of range.

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20. AXIS CONTROL FUNCTIONS

20.8.3

Spindle Electronic

Gear Box

General

A gear can be shaped (grind/cut) by the synchronization of the workpiece

axis rotation to the tool axis (grinding axis /hob) rotation by using two

spindles as a tool axis and a workpiece axis. To synchronize these two

axes, the Electronic gear box (EGB) is used.

In the Spindle EGB, the synchronous pulse is produced from the feedback

pulse of the position detector attached to the tool axis (master axis) in the

motor control, and the workpiece axis (slave axis) rotates with the pulse.

Feedback pulse from Master side to Slave side is forwarded by the

communication between spindle amplifiers.

The specifications of the Spindle EGB control are as follows:

1) The Spindle EGB synchronization is started by specifying T

command (number of teeth) and L command (number of hob threads),

which determine the synchronous ratio, in G81 block. The Spindle

EGB synchronization is canceled by specifying G80.

2) The synchronous ratio is calculated from T and L command in G81

block and the number of position detector pulses per rotation about

the tool and the workpiece axis (parameter setting).

3) This function has the retract function like the hobbing function.

4) The cutting helical gear is performed by specifying Q command

(module or diametral pitch) and P command (gear helix angle) in G81

block.

5) The Spindle EGB synchronization is maintained regardless of

whether the operation is automatic or manual.

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CNC

2nd spindle (Slave)

Position feedback

Velocity feedback

ÔÔÔÔÔ

ÔÔÔÔÔÔÔÔÔÔ

Position

uilt-in

ork-

elocity

motor &

piece

ÔÔ

ÔÔÔcontrolÔÔ

control (PI)

ommand

osition gain

etector

ear)

ÔÔÔÔ

ÔK2/K1 : Synchronous ratioÔÔ

Ôα : Feedforward ratioÔÔÔÔ

ÔÔαsÔÔ

ÔÔÔÔÔÔÔÔÔ

ÔÔÔÔ

EGB mode

ÔÔÔ

ÔÔÔÔK1ÔÔK2

ÔÔÔ

Position feedback

Velocity feedback

–

ÔÔÔÔÔ

ÔÔPositionÔÔ

ÔÔÔÔ

Built-in

ÔÔÔÔÔÔ

Velocity

Tool

ÔÔ

command Ô

ÔÔÔÔcontrolÔÔ

control (PI)

Ômotor &Ô(Hob)

Position gain

Detector

ÔÔÔÔÔ

ÔÔÔÔÔÔÔÔÔÔ

1st spindle (Master)

* The master axis can use the rotation command with spindle mode.

Fig. 20.8.3 (a) Block diagram for Spindle EGB control

Explanations

Format

G81 T_ L_ Q_ P_ ;

Starts synchronization.

G80 ;

Cancels synchronization.

T : Number of teeth (Specifiable range : 1 to 1000)

L : Number of hob threads (Specifiable range : -200 to 200 with 0

excluded)

Q: Module or diametral pitch

Specify a module in the case of metric input.

(Unit : 0.00001mm, Specifiable range : 0.01 to 25.0mm)

Specify a diametral in the case of inch input.

(Unit : 0.00001inch^-1, Specifiable range : 0.01 to 25.0inch^-1)

P : Gear helix angle

(Unit : 0.0001deg, Specifiable range : -90.0 to 90.0deg)

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20. AXIS CONTROL FUNCTIONS

NOTE

Specify G81 and G80 code only in a block.

D Parameter setting

The following parameters should be set for the Spindle EGB control.

(1) Master axis number (Parameter No.7771) * Only Cs contour axis

(2) Slave axis number (Parameter No.7710)

(3) Number of position detector pulses per rotation about master axis

(Parameter No.7772)

(4) Number of position detector pulses per rotation about slave axis

(Parameter No.7773)

(5) Spindle EGB master axis enable (Parameter No.4352#7)

(6) Spindle EGB slave axis enable (Parameter No.4352#6)

(7) Number of sinusoidal waves from master spindle position

detector(Parameter No.4386)

NOTE

The master axis number should be set smaller than the

slave axis number.

D Starting/canceling of

When the rotation of the tool axis (master axis) starts after G81 is

synchronization

specified, the EGB synchronization starts with the synchronous

relationship specified in G81 block, and the rotation of the workpiece axis

(slave axis) starts. When the EGB synchronization starts, the

synchronization mode signal SYNMOD<F65#6> is turned to “1”.

When the rotation of the tool axis is stopped, the workpiece axis stopped

in synchronism. Then the EGB synchronization is canceled by specifying

G80. When the EGB synchronization is canceled, the synchronization

mode signal SYNMOD<F65#6> is turned to “0”.

G81 cannot be specified again during the EGB synchronization.

Moreover, the specification of T, L, Q, and P cannot be modified during

the synchronization. Specify the starting and canceling of

synchronization at the tool axis (master axis) stopping.

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Synchronization start

command (G81)

Synchronizationmode

Synchronization mode signal

SYNMOD<F65#6>

Tool axis rotation command

Tool axis stop command

Tool axis rotation speed

Work piece axis rotation

speed

Synchronization cancel

command (G80)

Fig. 20.8.3 (b) Example timing for starting/canceling synchronization

Program example

O1000 ;

N00010 G80 ;

N00020 G28 G91 B0 C0 ; Performs reference position return

operation of the tool and the workpiece

axis.

N00030 G81 T20 L1 ;

Starts synchronization.

N00040 Mxx ;

Rotates the tool axis by velocity

command of PMC axis control.

N00050 G04 X1000 ;

Waits until rotation of the tool axis is

constant.

N00060 G01 X_ F_ ;

Makes movement on the X-axis(for

cutting).

N00070 G01 Z_ F_ ;

Makes movement on the Z-axis(for

machining).

- - - - - - - - - - - - ;

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20. AXIS CONTROL FUNCTIONS

N00100 G01 X_ F_ ;

Makes movement on the X-axis(for

retraction).

N00110 Myy ;

Stops the tool axis.

N00120 G80 ;

Cancels synchronization.

N00130 M30 ;

Helical gear

When a helical gear is to be produced, the compensation of the workpiece

compensation

axis rotation is needed according to the travel distance on the Z-axis (axial

feed axis: parameter No. 7709 setting). Helical gear compensation is

performed by adding compensation pulses calculated from the formula

below to the workpiece axis.

sin(P)

Compensation angle

+ Z

360

(For metric input)

p T Q

Compensation angle +Z Q sin(P)

360 (For inch input)

p T

where

Compensation angle : Signed absolute value (deg)

Z: Amount of travel on the Z-axis after the specification of G81 (mm

or inch)

P : Signed gear helix angle (deg)

T: Number of teeth

Q: Module (mm) or diametral pitch (inch^-1)

The values of P, T, Q, are to be programmed.

In helical gear compensation, the machine coordinates and absolute

coordinates of the workpiece axis are updated by the amount of helical

gear compensation. When P command and Q command are not specified

in G81 block, helical gear compensation is not performed.

The direction of helical gear compensation is determined by bit 2 (HDR)

of parameter No.7700

(1 is usually specified). The compensation

direction is shown in figure 2.4.

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(1) When bit 2 (HDR) of parameter No.7700 is 1.

(a)

(b)

(c)

(d)

- Z

C :

Z :

P :

Cmp. direc. :

(e)

(f)

(g)

(h)

- C

- Z

C :

Z :

P :

Cmp. direc. :

(2) When bit 2 (HDR) of parameter No.7700 is 0. (Items (a) to (d) are the

same as for (1))

(e)

(f)

(g)

(h)

- C

- Z

C :

Z :

P :

Cmp. direc

Cmp. direc. :

Fig. 20.8.3 (c) Direction of helical gear compensation

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20. AXIS CONTROL FUNCTIONS

D Synchronous ratio

The synchronous ratio of the Spindle EGB control is internally

represented using a fraction. The fraction is calculated from T and L

command in G81 block and the number of position detector pulses per

rotation about the tool and the workpiece axis (parameter setting).

Synchronous ratio : ^K2

K1+T a

L: Hob threads

T: Number of teeth of the work

a: Number of position detector pulses per revolution about the tool

axis (Parameter No.7772)

b : Number of position detector pulses per revolution about the

workpiece axis (Parameter No.7773)

This synchronous ratio is reduced to the lowest term, and it has the

following limit.

-32767 < K2 < 32767

1 < K1 < 65535

When K2 or K1 is out of this range, P/S alarm (No.181) occurs.

The values of K2 and K1 are set to the parameter No.4387 and No.4388

automatically when G81 is specified. If T is not specified in G81 block,

P/S alarm (No.181) occurs. If L is not specified in G81 block, the

synchronous ratio is calculated as L = 1.

Example) When the pulses for one rotation (360000) are specified to the

tool axis (master axis) on the following conditions, the pulses for position

control are distributed as Fig.20.8.3(d).

Hob threads L : 10

Number of teeth of the work T : 100

Number of pulse per one revolution of position detector on the tool

axis a : 360000

Number of pulse per one revolution of position detector on the work

axis b : 360000

360000

Synchronous ratio : ^K2

K1+T a

100

360000

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Position feedback

36000

Slave axis

*CMR

Cs command

Motor

Workpiece

Detector

(*1)

K2/K1 : Synchronous ratio

EGB

*K2/K1

(*1/10)

36000

360000

Master axis

*CMR

Tool axis

Detector

(*1)

Motor

Cs command

360000

Fig. 20.8.3 (d) Pulse distribution

As Fig. 20.8.3 (d), when 360000 pulses (Number of pulse for one rotation

of the master axis) are specified, the pulses for slave axis by EGB are equal

to the value which is multiplied to the number of pulse for one rotation

of the slave axis by the ratio of Hob thread and number of teeth (rotation

ratio between master axis and slave axis).

360000

1/10 = 36000

D Retract function

When the retract signal RTRCT<G66#4> is turned to “1” in auto mode

(MEM, MDI, etc.) or manual mode (HNDL, JOG etc.), the axis set in bit

0 (RTR) of the parameter No.7730 moves (retracts) by the amount set in

the parameter No.7741.

NOTE

Feedrate in retract is set to the parameter No.7740. Then

the feedrate override is not effective.

During the movement in retract, feed hold is not effective.

In case that retract signal is turned to “1” in auto mode, the

movement of the auto mode is hold and the retract

movement is done.

Limitations

1) The EGB synchronization is not canceled by RESET when bit 0

(HBR) of parameter No.7700 is set to 1. Set 1 to this parameter

usually.

2) The EGB synchronization performed even under the following

operation of the slave axis.

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20. AXIS CONTROL FUNCTIONS

– Interlock

- Feed hold

- Machine lock

The EGB synchronization should be started and canceled at the stop

of the master and the slave axis. It means that the tool axis (master

axis) rotation should be started while the synchronization mode

signal SYNMOD<F065#6> is “1” (Refer to Fig.2.3 Example timing

for starting/canceling synchronization). If the tool axis (master axis)

starts to rotate before the synchronization mode signal

SYNMOD<F065#6> is “1”, the synchronization does not perform

correctly.

Reference position return of Cs contouring control axis for master and

slave axis should be performed before G81 is specified. In the

synchronization mode, reference position return cannot be

performed. Do not change to reference position return mode in the

synchronization mode.

In case that the parameters for axis setting (No.7710,7771,4352) are

not set correctly, P/S alarm (No.010) occurs when G81 specified.

When G28/G27/G29G30/G30.1/G53 is specified in the synchronization

mode, P/S alarm (No.184) occurs. G28/G27/G29/G30/G30.1/G53

should not be specified in the synchronization mode.

During HPCC mode with RISC, the high-speed cycle cutting, the

high-speed liner interpolation, the high-speed remote buffer A, the

high-speed remote buffer B of DNC operation, and AI contour

control, this function is not available.

The slave axis position display is updated by synchronous pulse as

follows :

- Machine position display is updated.

- Absolute position display and relative position display are not

updated. When the synchronization is canceled, the pulses of the

synchronization are added to the absolute position display of the

slave axis.

The rotation direction of the workpiece axis depends on the rotation

direction of the tool axis. That is, when the rotation direction of the

tool axis is positive, the rotation direction of the workpiece axis is also

positive; when the rotation direction of the tool axis is negative, the

rotation direction of the workpiece axis is also negative. However, by

specifying a negative value for L, the rotation direction of the

workpiece axis can be made opposite to the rotation direction of the

tool axis.

10)During synchronization, a move command can be programmed for

the workpiece axis. Note, however, that incremental command

programming for cutting feed must be used to specify the workpiece

axis move command.

11)The synchronization mode is canceled by servo alarm, spindle alarm,

P/S alarm (No.000), or emergency stop.

12)The synchronization is not maintained in servo off status of the slave

axis.

13)When the EGB control is used, the drilling canned cycle cannot be

used.

14)The actual feedrate is displayed without the flexible synchronous

pulse.

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20. AXIS CONTROL FUNCTIONS

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Alarms

Num-

Message

Contents

ber

010

IMPROPER G-CODE

Parameters for axis setting are not set cor-

rectly regarding G81. (No.7710,7771,4352,

or Cs axis setting).

Confirm the parameter setting.

181

FORMAT ERROR IN

G81 block format error

G81 BLOCK

1)T(number of teeth) has not been

instructed.

2)Data outside the command range was

instructed by either T, L, Q, or P.

3)Calculation of the synchronous ratio has

overflowed.

Modify the program.

184

ILLEGAL COMMAND

A command not to be instructed during

IN G81

synchronization was instructed.

1)The slave axis is specified by G00, G28,

G27, G29, G30.

2)Inch/metric conversion by G20, G21

was instructed.

3)Cs contour control mode is not selected.

186

PARAMETER SETTING

Parameter error regarding G81

ERROR

1)The slave axis has not been set to be a

rotate axis.

20.8.4

In the electronic gear box

(EGB), when synchronization start or

cancellation is specified, synchronization is not started or canceled

Electronic Gear Box

immediately.

Automatic Phase

Instead, acceleration/deceleration is executed first.

Therefore,

Synchronization

synchronization can be started or canceled while the spindle is rotating.

Also, synchronization ratio can be changed while the spindle is rotating.

At synchronization start, automatic phase synchronization is performed

such that the workpiece axis position matches the position corresponding

to the spindle one-rotation signal. With this synchronization, the same

operation is performed as synchronization start caused by a one-rotation

signal in hobbing synchronization when using the functions of a hobbing

machine.

The spindle corresponds to the EGB master axis and the workpiece axis

corresponds to an EGB slave axis (Servo axis or Cs contouring axis).

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20. AXIS CONTROL FUNCTIONS

D Acceleration/deceleration

type

Spindle

speed

Synchronization

Synchronization start command

cancellation command

Workpiece-

axis speed

Synchronization

Acceleration

state

Deceleration

D Acceleration/deceleration

plus automatic phase

synchronization type

Spindle

speed

Synchronization

Synchronization start command

cancellationcommand

Workpiece-

axis speed

Automatic

Synchro-

Acceleration

phase

nization

Deceleration

synchronization

state

Format

D Acceleration/deceleration

type

G81 T_ L_ R1;

Synchronization start

G80 R1;

Synchronization end

T : Number of teeth (range of valid settings: 1-1000)

L : Number of hob threads (range of valid settings: -21 to +21,

excluding 0)

When L is positive, the direction of rotation about the workpiece

axis is positive (+ direction).

When L is negative, the direction of rotation about the workpiece

axis is negative (- direction).

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D Acceleration/deceleration

plus automatic phase

synchronization type

G81 T_ L_ R2;

Synchronization start

G80 R2;

Synchronization end

T : Number of teeth (range of valid settings: 1-1000)

L : Number of hob threads (range of valid settings: -21 to +21,

excluding 0)

When L is positive, the direction of rotation about the workpiece

axis is positive (+ direction).

When L is negative, the direction of rotation about the workpiece

axis is negative (- direction).

Explanations

D Acceleration/deceleration

type

Spindle

speed

Synchronization

Synchronization start command

cancellation command

Workpiece-

axis speed

Synchronization

Acceleration

state

Deceleration

G81R1 command

execution

Acceleration

Synchronizationmode

SYNMOD

G80R1 command execution

Deceleration

1. Specify G81R1 to start synchronization.

When G81R1 is specified, acceleration according to the acceleration

rate set in the parameter (No.2135,2136 or No.4384,4385) is performed

on the workpiece axis (slave axis). Once the synchronization feedrate is

reached, synchronization mode signal SYNMOD <F065#6> is set to 1,

and the G81R1 block is terminated.

2. For cancellation, specify G80R1 while the tool is moved away from

the workpiece.

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20. AXIS CONTROL FUNCTIONS

3. When G80R1 is specified, the EGB mode check signal is set to 0, and

deceleration according to the acceleration rate set in the parameter

(No. 2135,2136 or No.4384,4385) is started immediately. When the

speed is reduced to 0, the G80R1 block is terminated.

CAUTION

Linear acceleration/deceleration applies to synchronization

start/cancellation.

In automatic synchronization cancellation due to Reset or

P/S alarm

(No.000), deceleration is executed and

synchronization is canceled.

D Acceleration/deceleration

plus automatic phase

synchronization type

Spindle

speed

Synchronization

Synchronization start command

cancellationcommand

Workpiece-

axis speed

Automatic

Synchro-

Acceleration

phase

nization

Deceleration

synchronization

state

G81R2 command

execution

Acceleration

Automatic phase synchronization

Synchronization mode signal

SYNMOD

G80R2 command execution

Deceleration

1. Move the workpiece axis to the position that corresponds to that of the

one-rotation signal of the spindle.

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2. Specify G81R2 to start synchronization.

When G81R2 is specified, the workpiece axis is accelerated with the

acceleration according to the acceleration rate set in the parameter

(No.2135,2136 or No.4384,4385). When the synchronization speed is

reached, phase synchronization is performed automatically. Upon the

completion of phase synchronization, synchronization mode signal

SYNMOD <F065#6> is set to 1, and the G81R2 block is terminated.

3. For cancellation, specify G80R2 while the tool is moved away from

the workpiece.

4. When G80R2 is specified, the synchronization mode signal is set to

0, and deceleration according to the acceleration rate set in the

parameter (No.2135,2136 or No.4384,4385) is started immediately.

When the speed is reduced to 0, the G80R2 block is terminated.

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20. AXIS CONTROL FUNCTIONS

CAUTION

In automatic phase synchronization, specify the speed in parameter No.7776 and the

movement direction in parameter PHD, bit 7 of No. 7702.

In phase synchronization, rapid-traverse linear acceleration/deceleration

(with the time

constant specified in parameter No. 1620) is performed.

The workpiece-axis speed is obtained by superposing the speed in automatic phase

synchronization onto the speed corresponding to spindle rotation.

In consideration of this superposition, specify a position deviation limit in parameter No. 1828.

The one-rotation signal used for automatic phase synchronization is issued not by the spindle

position coder but by the separate pulse coder attached to the spindle and used to collect EGB

feedback information. This means that the orientation position based on the one-rotation

signal issued by the spindle position coder does not match the position used as the reference

for the workpiece axis when establishing phase synchronization for automatic phase

synchronization based on G81R2.

Moreover, the one-rotation signal of the separate pulse coder must be turned on for each

rotation of the spindle.

With the use of parameter No.7777, the position at which the phase of the workpiece axis is

matched can be shifted from the position corresponding to the one-rotation signal in automatic

phase matching.

In automatic phase synchronization, when a synchronization command is issued again in a

synchronization state, movement about the workpiece axis is performed such that the position

corresponding to the one-rotation signal of the spindle matches the position about the

workpiece axis specified in the G81R2 synchronization start command executed first.

In automatic phase synchronization, movement is performed about the workpiece axis from the

current position to the nearest phase position in the phase synchronization movement direction

specified by the parameter.

Linear acceleration/deceleration applies to synchronization start/cancellation.

The acceleration/deceleration plus automatic phase synchronization type can be executed by

the PHS parameter, bit 6 of No.7702, without specifying an R2 command in a G81 or G80 block.

In automatic synchronization cancellation due to Reset or P/S alarm (No.000), deceleration is

executed and synchronization is canceled.

This item is for spindle EGB.

If the control mode of the master axis is the speed control, it is necessary to execute the position

coder orientation before that the automatic phase synchronization is started. In this case,

RFCHK3 (PRM4016#7) of the master axis must be set “0” to keep memorizing the one-rotation

signal position of the spindle in the speed control mode.

This item is for spindle EGB.

If the control mode of the master axis is Cs contouring, it is necessary to execute the reference

point return before that the automatic phase synchronization is started.

The acceleration rate parameter(No.2135,2136 or No.4384,4385) must not be changed in the

synchronization mode.

Do not cancel the synchronous mode by the reset when this function is used. (Set “1” in

patameter No.7700#0 HBR.)

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Examples

D Acceleration/deceleration

type

M03 ;

Clockwise spindle rotation command

G81 T_ L_ R1 ;

Synchronization start command

G00 X_ ;

Positions the workpiece at the machining position.

Machining in the synchronous state

G00 X_ ;

Retract the workpiece from the tool.

G81 T_ L_ R1 ;

Synchronization ratio change.

G00 X_ ;

Positions the workpiece at the machining position.

Machining in the synchronous state

G00 X_ ;

Retract the workpiece from the tool.

G80 R1 ;

Synchronization cancel command

D Acceleration/deceleration

plus automatic phase

M03 ;

Clockwise spindle rotation command

synchronization type

G00 G90 C_ ;

C-axis positioning

G81 T_ L_ R2 ;

Synchronization start command

G00 X_ ;

Positions the workpiece at the machining position.

Machining in the synchronous state

G00 X_ ;

Retract the workpiece from the tool.

G81 T_ L_ R2 ;

Synchronization ratio change.

G00 X_ ;

Positions the workpiece at the machining position.

Machining in the synchronous state

G00 X_ ;

Retract the workpiece from the tool.

G80 R2 ;

Synchronization cancel command

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20. AXIS CONTROL FUNCTIONS

D About the direction of

The EGB automatic phase synchronization is made on the premise that

the rotation (This item is

the rotation of the slave axis is the same direction as the master axis. Refer

for spindle EGB.)

to the following chart.

+ Command

+ Direction

Kp/S

Sensor

Motor

Spindle

[Master axis]

+ Feedback

[Slave axis]

a/A

+ EGB command

Kp/S

Sensor

Motor

Spindle

+ Direction

–

+ Feedback

When this function is used, the SFR/SRV function in Cs contouring mode

(*) can not use. If you want to change the rotary direction of the master

axis, you should change the sign of the master axis command.

(*) The SFR/SRV function in Cs contouring mode

The SFR/SRV signal is a serial spindle control signal that determines

the direction of rotation of the spindle in Cs contouring mode.

Alarms

Num-

Message

Contents

ber

181

EGB AUTO PHASE

Format error in block in which G80 or G81

FORMAT ERROR

was specified by EGB automatic phase

synchronization

(1) R is data outside of the instruction

range.

(2) Before the G81R2 command, the

master spindle isn’t returned to in the

reference point. (In case of Spindle

EGB)

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20.8.5

Electronic Gear Box 2

Pair

General

The Electronic Gear Box is a function for rotating a workpiece in sync with

a rotating tool, or to move a tool in sync with a rotating workpiece. With this

function, the high-precision machining of gears, threads, and the like can be

implemented. A desired synchronization ratio can be programmed.

Up to two sets of axes can be synchronized. A gear grinding machine can

be controlled, for instance, by using one axis for rotating the workpiece in

sync with the tool and another axis for performing dressing in sync with the

tool.

The electronic gear box is hereinafter called an EGB function.

D Configuration examples

Spindle

: EGB master axis serving as a tool axis

of controlled axes

First axis

: X

Second axis

: Y

Third axis

: C axis (EGB slave axis serving as a workpiece axis)

Fourth axis

: C axis (EGB dummy axis, which cannot be used as a usual

controlled axis)

Fifth axis

: V axis (EGB slave axis serving as a dressing axis)

Sixth axis

: V axis (EGB dummy axis, which cannot be used as a usual

controlled axis)

CNC

Spindle (master axis)

Spindle

Motor

Spindle

Detector

amplifier

First axis X (omitted)

Tool axis

Second axis Y (omitted)

Third axis

Detector

Slave axis

Position

Speed/current

Servo

Motor

C-axis

control

amplifier

EGB

Workpiece axis

K₁

Fourth axis

Synchronization

switch

Dummy axis

K1 : Synchronization factor

Follow-up

Error counter

Fifth axis

Detector

Slave axis

Position

Speed/current

Servo

Motor

V-axis

control

amplifier

EGB

Dressing axis

K₂

Sixth axis

Synchronization

Dummy axis

switch

K2 : Synchronization factor

Follow-up

Error counter

Fig.20.8.5

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NOTE

A sampling period of 1 ms is applied when feedback pulses

are read from the master axis; the synchronization pulses

for a slave axis are calculated according to synchronization

coefficient K; and the pulses are specified for position

control of the slave axis.

Explanations

D Synchronization start

When the ratio of the master-axis travel to the slave-axis travel is

specified, synchronization starts.

Format

T _t

G81.5

;

P p

b 0 L l

Master-axis travel Slave-axis travel

Specify the master-axis travel in either of the following ways.

1. Master-axis speed

T t

: Master-axis speed (1 v t v 1000)

2. Master-axis pulse count

P p : Master-axis pulse count (1 v p v 999999999)

Specify a pulse count on the condition that four pulses

correspond to one period in the A and B phases.

Specify the slave-axis travel in either of the following ways.

1. Slave-axis travel

bj b : Slave-axis address

: Slave-axis travel indicated in units of the minimum

travel increments

(the range of valid settings for usual axis movement

applies)

When j = 0, the specified command is regarded as

being a command for the slave-axis speed,

described below. In this case, if L is not specified, an

alarm is output.

2. Slave-axis speed

b 0 L"l b : Slave-axis address

: Slave axis speed (1 v l v 21)

CAUTION

A move command can be issued by a program to the slave

axis or other axes during synchronization. In this case, the

command shall be an incremental command.

A G00, G27, G28, G29, G30, G30.1,G33 or G53 command

cannot be issued to the slave axis in synchronization mode.

Controlled-axis detach cannot be used for the master axis

or the slave axis.

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20. AXIS CONTROL FUNCTIONS

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NOTE

A manual handle interruption can be issued to the slave axis

or other axes during synchronization.

The maximum feedrates for the master axis and the slave

axis are limited according to the position detectors used.

An inch/metric conversion command (G20 or G21) cannot

be specified in synchronization mode.

The machine coordinates for the slave/dummy axis are

updated in synchronization mode.

D Synchronization end

Format

With a G80.5 b 0 command, synchronization is canceled.

b is the address of the slave axis.

Canceling synchronization for each axis by issuing a command

Synchronization of the slave axis specified by ? is canceled.

A cancellation command can be issued only for one axis in one block.

When b 0 is not specified, the synchronization of all currently

synchronized axes is canceled.

When a synchronization cancellation command is issued, the absolute

coordinates for the slave axis are updated according to the amount of

travel during synchronization. For a rotation axis, the value obtained

by rounding off the amount of travel during synchronization to the

nearest 360 degrees is added to the absolute coordinates.

Canceling synchronization by a reset

For an axis for which a parameter is set to allow synchronization to be

canceled by a reset, HBR, bit 0 of No. 7700, is set to 0, allowing

synchronization to be canceled by a reset. When a manual absolute

signal is on, the absolute coordinates are updated.

Others

Synchronization is automatically canceled under the following

conditions.

(1) Emergency stop

(2) Servo alarm

(3) P/S alarm No.000 (indicating that the power should be

turned off)

D Description of

A command compatible with that for a hobbing machine can be used as

commands compatible

a synchronization command.

with those for a hobbing

Such a command cannot be used when a canned-cycle option is provided.

machine

Specify which axes starts synchronization with such a command by using

parameter No. 7710.

(1) Synchronization start

When the following command is specified, synchronization of spindle

axis and C axis starts

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20. AXIS CONTROL FUNCTIONS

G81 T_(L_)(Q_P_);

T : Number of teeth (range of valid settings: 1 to 1000)

L : Number of hob threads (range of valid settings: -21 to +21,

excluding 0)

The sign of L determines the direction of rotation

for the workpiece axis.

When L is positive, the direction of rotation for the workpiece

axis is positive (+ direction).

When L is negative, the direction of rotation for the workpiece

axis is negative (- direction).

When L is not specified, the number of hob threads is regarded

as being 1.

Q: Module or diametral pitch

In metric input, specify a module

(unit : 0.00001 mm, range of valid settings : 0.1 to 25.0 mm).

In inch input, specify a diametral pitch

(unit : 0.00001 [1/inch], range of valid settings: 0.1 to 254.0 [1/inch])

P : Twisted angle of a gear

(unit : 0.00001 degrees, range of valid settings : -90.0 to 90.0

degrees)

Specify P and Q to use helical gear compensation. In this case, if only one

of P and Q is specified, an alarm (P/S 181) is generated.

The decimal point can be specified in Q and P.

When a G81 command is issued to change to synchronization mode, the

EGB mode confirmation signal for the workpiece axis becomes “1” and

synchronization starts between the spindle and the workpiece axis.

During synchronization, control is performed such that the ratio of the

spindle speed to the workpiece-axis speed is the same as that of T

(number of teeth) to L (number of hob threads).

When a G81 command is again specified during synchronization without

canceling synchronization, an alarm (P/S 181) is generated.

(2) Synchronization end

When the following command is specified, sysnchronization is

cancelled.

G80;

Synchronization of all synchronized axes is canceled.

When a synchronization cancellation command is issued, the absolute

coordinates for the slave axis are updated according to the amount of

travel during synchronization.

For a rotation axis, the value obtained by rounding off the amount of

travel during synchronization to the nearest 360 degrees is added to the

absolute coordinates.

In a G80 block, do not specify addresses other than O or N.

(3) Helical gear compensation

For a helical gear, the workpiece axis is subjected to compensation for

movement along the Z axis (axial feed axis) according to the twisted

angle of the gear.

Helical gear compensation is performed with the following data.

Z sin(P)

Compensation angle +

360 (In metric input)

p T Q

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FANUC Series 16i/160i/160is-MB, Series 18i/180i/180is-MB5, Series 18i/180i/180is-MB. Operator's Manual - page 20