FANUC Series 30i/300i/300is-MODEL A. Machining Center System. User's manual - page 122

22.5-AXIS MACHINING FUNCTION

 PROGRAMMING 

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Format 
  - Startup (start of cutter compensation) (type 1) 

When bit 1 (SPG) of parameter No. 19607 is 0 

G41.2 (or G42.2) 

IP

_ D_ ;   

G41.2: Cutter compensation left (group 07) 
G42.2: Cutter compensation right (group 07) 

IP

_: 

Value specified for axis moving as viewed from the 
programming coordinate system (including rotary 
axis) 

D_: 

Code specifying the cutter compensation amount (1 
to 3 digits) 

 
When bit 1 (SPG) of parameter No. 19607 is 1 

G41.4 (or G42.4) 

IP

_ D_ ;   

G41.4: Cutter compensation left (group 07) 
G42.4: Cutter compensation right (group 07) 

IP

_: 

Value specified for axis moving as viewed from the 
programming coordinate system (including rotary 
axis) 

D_: 

Code specifying the cutter compensation amount (1 
to 3 digits) 

 

NOTE 

1  In a table rotation type machine (parameter No. 

19680 = 12), if an attempt is made to issue G41.4 
or G42.4 with bit 1 (SPG) of parameter No. 19607 
equal to 0, alarm PS0010 is generated. 

2  In a table rotation type machine, if an attempt is 

made to issue G41.2 or G42.2 with bit 1 (SPG) of 
parameter No. 19607 equal to 1, alarm PS5460 is 
generated. 

3  In machine not of the table rotation type machine, if 

an attempt is made to issue G41.4 or G42.4 with bit 
1 (SPG) of parameter No. 19607 equal to 1, alarm 
PS5460 is generated. 

 

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  - Startup (start of cutter compensation) (type 2) 

G41.6(or G42.6) 

IP

_ D_ Q_ ; 

IP

_ I_ J_ K_ ;   

      : 

G41.6: Cutter compensation left (group 07) 
G42.6: Cutter compensation right (group 07) 

IP

_: 

Value specified for axis moving as viewed from the 
programming coordinate system (including rotary 
axis) 

D_: 

Code specifying the cutter compensation amount (1 
to 3 digits) 

Q_: 

Tool’s angle of gradient (in degrees) 

I_ J_ K_:  Tool axis direction at the block end point as 

viewed from the programming coordinate system 

For type 2, do not specify a rotation axis but specify the direction at 
the tool end point as viewed from the programming coordinate system 
(table coordinate system), with I, J, and K.    Specifying a rotation axis 
causes alarm PS5460 to be generated. 
 
In a tool rotation type machine, I, J, and K can be specified in a 
G41.6/G42.6 command block; in a table rotation type machine, 
however, they cannot.    If an attempt is made to specify them, alarm 
PS5460 is generated. 
The following are the notes on type 2. 

NOTE 

1  If one or two of I, J, and K are omitted, the omitted 

ones of I, J, and K are assumed to be 0. 

2  In a block in which all of I, J, and K are omitted, 

the values of I, J, and K in the previous block are 
used. 

3  If there is only one rotation axis (a hypothetical 

axis is used), type 2 cannot be used.    In this 
case, if an attempt is made to issue G41.6/G42.6, 
alarm PS5460 is generated. 

4  If using the rotation axis rollover function or rotary 

axis control function, specify 360 degrees in 
parameter No. 1260 (mount of travel per rotation 
about the rotation axis). 

5  They can be used only with the settings that 

select the table coordinate system as a 
programming coordinate system (bit 5 (WKP) of 
parameter No.19696 = 0 and bit 4 (TBP) of 
parameter No.19746 = 1).    If an attempt is made 
to issue G41.6/G42.6 with the settings that select 
the workpiece coordinate system as a 
programming coordinate system, alarm PS5460 is 
generated. 

 

22.5-AXIS MACHINING FUNCTION

 PROGRAMMING 

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  - Canceling the cutter compensation 

G40 

IP

_ ;   

G40:  Cutter compensation cancellation (group 07) 

IP

_: 

Value specified for axis movement 

 

  - Selecting an offset plane 

When bit 1 (PTD) of parameter No. 19746 is 1, compensation is 
performed on the selected plane, on the assumption that the tool is 
pointing to the direction perpendicular to that plane. 

Offset plane 

Plane selection command 

IP

_ 

XpYp G17 

; Xp_Yp_ 

ZpXp G18 

; Xp_Zp_ 

YpZp G19 

; Yp_Zp_ 

(Example:    In the case of Fig. 22.5.2 (a), the XpYp plane is selected.) 
The two axes of a selected plane must be included in the three basic 
axes (the axes for which parameter No. 1022 is set to 1 to 3). 
 
When bit 1 (PTD) of parameter No. 19746 is 0, compensation is 
performed on the plane perpendicular to the tool direction specified 
with parameters Nos. 19697, 19698, and 19699, regardless of which 
plane is selected. 
 

NOTE  

 

This function is enabled for tool side offset only.    If 
leading edge offset is specified, alarm PS5460 is 
generated. 

 
 

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Explanation 
  - Tool's angle of gradient in type 2 

For type 2 of 3-dimensional cutter compensation, the tool's angle of 
gradient can be specified with address Q in a G41.6/G42.6 command 
block.    The tool's angle of gradient refers to the angle by which the 
tool direction to be assumed when machining is actually performed is 
inclined from the direction specified with (I, J, K) toward the traveling 
direction on the plane formed by the tool direction specified with (I, J, 
K) and the traveling direction in the programming coordinate system.   
(See Fig. 22.5.2 (b).) 
Because in general, the normal direction of the machining surface is 
specified with (I, J, K), if it is desired to incline the tool direction to be 
assumed when machining is actually performed from the normal 
direction toward the traveling direction, correction may be performed 
with a Q command. 
If the direction specified with (I, J, K) matches the tool direction to be 
assumed when machining is actually performed, no Q command is 
necessary. 
 

 

Tool direction to be assumed when 
machining is actually performed 

(Plane perpendicular to the "tool direction to be 
assumed when machining is actually performed") 

Tool direction 
specified with (I, J, K)

Traveling 
direction of 
machining

Tool's angle of gradient (Q) 

Compensation plane 

Tool center path 
(path after compensation)

Programmed path 
(path before compensation)

Cutter 
compensation 
vector 

 

Fig. 22.5.2 (b)    Tool's angle of gradient in type 2 

 

 - Cutter compensation 

The function for 3-dimensional cutter compensation in a table rotation 
type machine basically performs operations in conformance with 
3-dimensional cutter compensation in a tool rotation type machine.  
The operations different from those of 3-dimensional cutter 
compensation in a tool rotation type machine are mainly described 
below.   
For the specifications and cautions not mentioned here, see the 
description of 3-dimensional cutter compensation in a tool rotation 
type machine. 

22.5-AXIS MACHINING FUNCTION

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 - Startup 

When cutter compensation for the rotary table is specified (G41.2 or 
G42.2, G41.4 or G42.4, a dimension word other than 0 in the offset 
plane, or a D code other than D0) in the offset cancel mode, the CNC 
enters the offset mode. 
Startup is specified with positioning (G00) or linear interpolation 
(G01). 
 

NOTE  

 

If a command such as circular interpolation (G02 or 
G03) and involute interpolation (G02.2 or G03.2) is 
specified at startup, alarm PS0034 is issued. 

 

  - Commands in the offset mode 

In the offset mode, compensation is performed for positioning (G00) 
and linear interpolation (G01). 
 

NOTE  

 

If a command such as circular interpolation (G02 or 
G03) and involute interpolation (G02.2 or G03.2) is 
specified in the mode for 3-dimensional cutter 
compensation in a table rotation type machine, 
alarm PS5460 is issued. 

 

  - Offset mode cancellation 

If a block satisfying either of the following conditions is executed in 
the offset mode, the CNC enters the offset cancel mode: 
1 

G40 is specified. 

2  0 is specified as a code specifying the cutter compensation 

amount (D code). 

When offset cancellation is to be performed, neither circular (G02 or 
G03) nor involute (G02.2 or G03.2) command can be specified.    If 
offset cancellation is specified in such a mode, alarm PS0034 is 
issued. 
 

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 PROGRAMMING 

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  - If selecting the table coordinate system as a programming coordinate system 

If bit 4 (TBP) of parameter No. 19746 is 1 and bit 5 (WKP) of 
parameter No. 19696 is 0, specifying 3-dimensional cutter 
compensation causes the table coordinate system to be selected as a 
programming coordinate system.    The table coordinate system refers 
to the workpiece coordinate system fixed to the table when 
3-dimensional cutter compensation. 
In the blocks subsequent to the one in which 3-dimensional cutter 
compensation is specified, the table coordinate system rotates with the 
rotation of the table. 
A linear axis (X, Y, Z) command is assumed to be issued on the table 
coordinate system. 
Specifying linear interpolation causes cutter compensation to be 
performed on the linear interpolation command on the table coordinate 
system. 
The table coordinate system does not rotate with the rotation of the 
tool head. 
 
The cancel (G40) block becomes a block that suppresses buffering. 
 
It is possible to switch between absolute and relative coordinate 
displays, using bit 2 (DET) of parameter No. 19608 as follows: 

•

 

When DET is 0, the position in the table coordinate system is 
displayed. 

•

 

When DET is 1, the position in the workpiece coordinate system 
is displayed. 

Note, however, the distance to go is always that in the programming 
coordinate system. 

NOTE 

1  If the 3-dimensional cutter compensation mode is entered 

when the table coordinate system is used as the 
programming coordinate system, look-ahead 
acceleration/deceleration before interpolation is 
automatically enabled.    Be sure to specify the following 
parameters: 

(1)  Bit 1 (LRP) of parameter No.1401 = 1:     
 

Linear rapid traverse 

(2)  Bit 5 (FRP) of parameter No.19501 = 1:     
 Acceleration/deceleration 

before interpolation is used 

for rapid traverse. 

(3)  Parameter No. 1671:     
 

Acceleration of acceleration/deceleration before 
interpolation for rapid traverse 

(4)  Parameter No. 1672:     
 

Change time for bell-shaped acceleration/deceleration 
before interpolation for rapid traverse 

(5)  Parameter No. 1660:     
 

Maximum permissible acceleration for 
acceleration/deceleration before interpolation 

If they are not specified, alarm PS5463 is generated. 

22.5-AXIS MACHINING FUNCTION

 PROGRAMMING 

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NOTE 

2  When table rotation axis movement is specified in the start 

block of 3-dimensional cutter compensation, after the 
movement is completed, the workpiece coordinate system 
is fixed to the table and assumed to be a table coordinate 
system. 

3  In the mode of 3-dimensional cutter compensation, do not 

change the workpiece coordinate system or change the 
workpiece offset value.    If an attempt is made to specify 
workpiece coordinate system selection (G54 to G59), alarm 
PS5460 is generated. 

 

  - If selecting the workpiece coordinate system as a programming coordinate 

system 

If bit 4 (TBP) of parameter No. 19746 is 0 or if bit 4 (TBP) of 
parameter No. 19746 is 1 and bit 5 (WKP) of parameter No. 19696 is 
1, the programming coordinate system does not rotate with the 
rotation of the table, being fixed to the workpiece coordinate system. 

 

  - Angle of the rotation axis in type 2 

For an explanation of how the rotation axis end point is determined 
when the tool direction is specified with an IJKQ command in type 2, 
see the explanations of cutter compensation in a tool rotation type 
machine, "Angle of the rotation axis in type 2 (if the operating range 
is not specified)" and "Angle of the rotation axis in type 2 (if the 
operating range is specified)". 
 
 

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 PROGRAMMING 

22.5-AXIS MACHINING FUNCTION

 

 

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22.5.3 

Cutter Compensation in Composite Type Machine 

 

Overview 

This function can perform 3-dimensional cutter compensation in a 
5-axis machine having a rotary table and a tool axis as shown in Fig. 
22.5.3 (a). 
Shown below is a 5-axis machine that has tool axis A on the X-axis 
(the tool axis direction is along the Z-axis) and table rotation axis B on 
the Y-axis. 
This machine configuration is used as a sample configuration in the 
following explanation unless otherwise noted: 

 

X 

Y 

Z

Machine 

coordinate 

system 

C 

Z 

+

- 

X 

+

- 

Y

+ 

- 

A 

Workpiece 
coordinate 

system 

Table 

coordinate 

system

The table coordinate system is rotated according to the
table rotation.    It is possible to specify whether to create
a part program in the workpiece coordinate system or in
the table coordinate system, using an appropriate
parameter. 

 

Fig. 22.5.3 (a)    Machine having a tool rotation axis and table rotation 

axis