FANUC Series 30i/300i/300is-MODEL A. Machining Center System. User's manual - page 97

21.AXIS CONTROL FUNCTIONS

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21.6

TOOL RETRACT AND RECOVER

Overview

To replace the tool damaged during machining or to check the status
of machining, the tool can be withdrawn from a workpiece. The tool
can then be advanced again to restart machining efficiently.
The tool retract and recover operation consists of the following four
steps:

•

Retract

The tool is retracted to a predefined position using the TOOL
WITHDRAW switch.

•

Withdrawal

The tool is moved to the tool-change position manually.

•

Return

The tool returns to the retract position.

•

Repositioning

The tool returns to the interrupted position.

For the tool retract and recover operations, see “Tool retract and
recover ” in the Part III.

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:  Position at which tool retract switch is turned on
: Programmed position
:  Position at which tool is retracted by manual operation
: Retract path
:  Manual operation (retract path)
: Return path
: Re-positioning

Format

Specify a retraction axis and distance in the following format:

Specify the amount of retraction, using G10.6.

G10.6

_ ;

: In incremental mode, retraction distance from the

position where the retract signal is turned on

In the absolute mode, retraction distance to an absolute

position

The specified amount of retraction is effective until G10.6

is next executed. To cancel the retraction, specify the
following:

G10.6 ; (as a single block containing no other commands)

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Explanation
- Retraction

When the TOOL WITHDRAW switch on the machine operator's
panel is turned on during automatic operation or in the automatic
operation stop or hold state, the tool is retracted the length of the
programmed retraction distance.    This operation is called retraction.
The position at which retraction is completed is called the retraction
position.  The tool is retracted to the retraction position in linear
interpolation at the dry run feedrate. When retraction is completed,
the RETRACTIONS POSITION LED on the machine operator’s
panel goes on.
When the TOOL WITHDRAW switch is turned on during execution
of a block in automatic operation, execution of the block is interrupted
immediately and the tool is retracted.    After retraction is completed,
the system enters the automatic operation hold state.
If the retraction distance and direction are not programmed, retraction
is not performed. In this state, the tool can be withdrawn and
returned.
When the TOOL WITHDRAW switch is turned on in the automatic
operation stop or hold state, the tool is retracted, then the automatic
operation stop or hold state is entered again.
When the TOOL WITHDRAW switch is turned on, the tool withdraw
mode is set.    When the tool withdraw mode is set, the TOOL BEING
WITHDRAWN LED on the machine operator's panel goes on.

- Withdrawal

When the manual mode is set, the tool can be moved manually (jog
feed, incremental feed, handle feed, or manual numeral command) to
replace the tool or measure a machined workpiece. This operation is
called a withdrawal. The tool withdrawal path is automatically
memorized by the CNC.

- Return

When the mode is returned to automatic operation mode and the
TOOL RETURN switch on the machine operator's panel is turned off,
the CNC automatically moves the tool to the retraction position by
tracing the manually-moved tool path backwards. This operation is
called a return. Upon completion of a return to the retraction
position, the RETRACTIONS POSITION LED comes on.

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- Repositioning

When the cycle start button is pressed while the tool is in the
retraction position, the tool moves to the position where the TOOL
WITHDRAW switch was turned on. This operation is called
repositioning.    Upon completion of repositioning, the TOOL BEING
WITHDRAWN LED is turned off, indicating that the tool withdrawal
mode has terminated.  Operation after completion of repositioning
depends on the automatic operation state when the tool withdrawal
mode is set.
(1)  When the tool withdrawal mode is set during automatic operation,

operation is resumed after completion of repositioning.

(2) When the tool withdrawal mode is set when automatic operation

is held or stopped, the original automatic operation hold or stop
state is set after completion of repositioning. When the cycle
start button is pressed again, automatic operation is resumed.

Limitation
- Offset

If the origin, presetting, or workpiece origin offset value (or External
workpiece origin offset value) is changed after retraction is specified
with G10.6 in absolute mode, the change is not reflected in the
retraction position.  After such changes are made, the retraction
position must be respecified with G10.6.
When the tool is damaged, automatic operation can be interrupted
with a tool withdrawal and return operation in order to replace the tool.
Note that if the tool offset value is changed after tool replacement, the
change is ignored when automatic operation is resumed from the start
point or other point in the interrupted block.

- Machine lock, mirror image, and scaling

When withdrawing the tool manually in the tool withdrawal mode,
never use the machine lock, mirror-image, or scaling function.

- Reset

Upon reset, the retraction data specified in G10.6 is cleared.
Retraction data needs to be specified again.

- Retraction command

The tool withdrawal and return function is enabled even when the
retraction command is not specified. In this case, retraction and
repositioning are not performed.

WARNING

The retraction axis and retraction distance
specified in G10.6 need to be changed in an
appropriate block according to the figure being
machined. Be very careful when specifying the
retraction distance; an incorrect retraction distance
may damage the workpiece, machine, or tool.

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21.7

ELECTRONIC GEAR BOX

21.7.1

Electronic Gear Box

Overview

This function enables fabrication of high-precision gears, screws, and
other components by rotating the workpiece in synchronization with a
rotating tool or by moving the tool in synchronization with a rotating
workpiece. The rate of synchronization can be specified with a
program. The synchronization of tool and workpiece axes with this
function adopts a system in which the synchronization is directly
controlled by digital servo, so that the workpiece axis can follow up
the speed fluctuations on the tool axis with no error, thereby allowing
fabrication of high-precision cogwheels. In the subsequent
explanation, the Electronic Gear Box is called the EGB.
There are several conditions in the setting and so on of the workpiece
axis and the tool axis, and refer to the appropriate manual provided by
the machine tool builder.

- Example of controlled axis configuration

Spindle  :  EGB master axis : Tool axis
1st axis  :  X axis
2nd axis  :  Y axis
3rd axis  :  C axis (EGB slave axis : Workpiece axis)
4th axis  : C axis (EGB dummy axis : Cannot be used as a normal

controlled axis.)

Spindle amp.

Motor

Spindle (master axis)

1st axis X (omitted)
2nd axis Y (omitted)

Tool axis

3rd axis C
slave axis

4th axis
dummy axis

EGB

: Sync coefficient

Error counter

Sync switch

Motor

Detector

Velocity/current control

Servo amp.

Position control

Workpiece axis

C axis

Separate detector

FFG

Follow-up

Spindle Detector

CNC

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Format

Parameter EFX(No.7731#0)=1

Parameter EFX

(No.7731#0)=0

Parameter HBR

(No.7731#5)=1

Parameter HBR

(No.7731#5)=0

Start of synchronization

G81 T

＿

( L

＿

)

( Q

＿

) ;

G81.4 R

＿

( L

＿

)

( Q

＿

) ;

G81.4 T

＿

( L

＿

)

( Q

＿

) ;

Cancellation of synchronization

G80 ;

G80.4 ;

(*1)

(*2)

(*3)

T(or R) : Number of teeth (Specifiable range: 1 to 1000)
L : Number of hob threads (Specifiable range: -200 to +200)

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 0, it follows the setting of bit 3 (LZR) of parameter No.7701.
If L is not specified, the number of hob threads is assumed 1.

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 pitch in the case of inch input.

(Unit:

0.00001inch

-1

, Specifiable range: 0.01 to 254.0 inch

-1

)

P : Gear helix angle

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

*1  Use it for machining centers.
*2  Use it for lathes.
*3  Use it for machining centers.

This format enables specification of the same G codes as those for lathes.

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

NOTE

Specify G81, G80, G81.4, and G80.4 in a single
block.

Explanation
- Master axis, slave axis, and dummy axis

The synchronization reference axis is called the master axis, while the
axis along which movement is performed in synchronization with the
master axis is called the slave axis.  For example, if the workpiece
moves in synchronization with the rotating tool as in a hobbing
machine, the tool axis is the master axis and the workpiece axis is the
slave axis.
Which axes to become the master and slave axes depends on the
configuration of the machine.    For details, refer to the manual issued
by the machine tool builder.
A single servo axis is used exclusively so that digital servo can
directly read the rotation position of the master axis.  (This axis is
called the EGB dummy axis.)

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- Synchronization control

(1) Start of synchronization

If G81 is issued so that the machine enters synchronization mode,
the synch switch of the EGB function is closed, and the
synchronization of the tool and workpiece axes is started.
During synchronization, the rotation about the tool and
workpiece axes is controlled so that the relationship between T
(number of teeth) and L (number of hob threads) is maintained.
During synchronization, the synchronization relationship is
maintained regardless of whether the operation is automatic or
manual.
Specify P and Q to use helical gear compensation.
If only either P or Q is issued, alarm PS1594 is generated.
If, during synchronization, G81 is issued again without
synchronization cancelation, alarm PS1595 is generated if ECN,
bit 3 of parameter No. 7731, is 0.    If ECN, bit 3 of parameter No.
7731, is 1, helical gear compensation is conducted with the
synchronization coefficient being changed to the one newly
specified with T and L commands if T and L commands are
issued, and if T and L commands are not issued and only P and Q
commands are issued, helical gear compensation is conducted
with the synchronization coefficient kept intact.  This allows
consecutive fabrication of helical gears and super gears.

(2) Start of tool axis rotation

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

(3) 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.

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(4) Cancellation of synchronization

When cancellation of synchronization is issued, the absolute
coordinate on the workpiece axis is updated in accordance with
the amount of travel during synchronization. Subsequently,
absolute commands for the workpiece axis will be enabled.
For a rotation axis, the amount of travel during synchronization,
as rounded to 360-degree units is added to the absolute
coordinate.
In the G80 block, only O and N addresses can be specified.
By setting HBR, bit 0 of parameter No. 7700, to 0, it is possible
to cancel synchronization with a reset. If the manual absolute
signal is ON, the absolute coordinate is updated.

Synchronization is automatically canceled under the following
conditions:
<1>  An emergency stop is applied.
<2>  A servo alarm is generated.
<3>  Alarm PW0000 (POWER MUST BE OFF) is generated.
<4>  An IO alarm is generated.

CAUTION

1 Feed hold, interlock, and machine lock are invalid

to a slave axis in EGB synchronization.

2 Even if an OT alarm is issued for a slave axis in

EGB synchronization, synchronization will not be
canceled.

3 During synchronization, it is possible to execute a

move command for a slave axis and other axes,
using a program. The move command for a slave
command must be an incremental one.

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