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FANUC Series 30i/300i/300is-MODEL A. Machining Center System. User's manual - page 293

D.RANGE OF COMMAND VALUE

APPENDIX

B-63944EN/03

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- Rotary axis

Increment system

IS-A IS-B IS-C IS-D IS-E

Least input increment (deg)

0.01

0.001

0.0001

0.00001

0.000001

Least command increment (deg) 0.01

0.001

0.0001

0.00001

0.000001

Max. programmable dimension
(deg)

999,999.99

999,999.999

99,999.9999

9,999.99999

999.999999

Max. rapid traverse (deg/min)

999,000 999,000 100,000 10,000 1,000

Feedrate range (deg/min)

0.01 to 999,000

0.001 to 999,000

0.0001 to 100,000 0.00001 to 10,000 0.000001 to 1,000

Incremental feed (deg/step)

0.01
0.1
1.0
10.0

0.001
0.01
0.1
1.0

0.0001
0.001
0.01
0.1

0.00001
0.0001
0.001
0.01

0.000001
0.00001
0.0001
0.001

Tool compensation amount
(deg)

0 to

9,999.99 0

9,999.999 0

9,999.9999 0

9,999.99999 0

999.999999

Backlash compensation amount
(pulses)

0 to

9,999 0

9,999

Dwell (sec)

0 to 999,999.99

0 to 999,999.999

0 to 99,999.9999

0 to 9,999.99999

0 to 999.999999

NOTE

*1 The feedrate range shown above are limitations

depending on CNC interpolation capacity. As a
whole system, limitations depending on servo
system must also be considered.

*2 If the mode of input is switched between inch input

and metric input, the maximum compensation value
that can be set at inch input time is (maximum
compensation value)

1/25.4. If a value

exceeding this value is specified at inch input time,
the compensation value is not converted to a metric
value correctly when the mode of input is switched
to metric input.

*3 The unit is the detection unit.
*4 Depends on the increment system of the axis at in

address X.

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APPENDIX

E.NOMOGRAPHS

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NOMOGRAPHS

Appendix E, "NOMOGRAPHS", consists of the following sections:

E.1 INCORRECT THREADED LENGTH...................................2302
E.2 SIMPLE CALCULATION OF INCORRECT THREAD

LENGTH.................................................................................2304

E.3 TOOL PATH AT CORNER ...................................................2306
E.4 RADIUS DIRECTION ERROR AT CIRCLE CUTTING .....2309

E.NOMOGRAPHS

APPENDIX

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E.1

INCORRECT THREADED LENGTH

The leads of a thread are generally incorrect in

and

, as shown in

Fig. E.1 (a), due to automatic acceleration and deceleration.
Thus distance allowances must be made to the extent of

and

the program.

Fig. E.1 (a) Incorrect thread position

Explanation
- How to determine

(mm ). . . . (1)

V =

60RL

: Time constant of servo system (sec)

V : Threading speed (mm/sec)
R : Spindle speed (min

-1

)

L : Thread feed (mm)
Time constant T

(sec) of the servo system: Usually 0.033 s.

- How to determine

= {t - T

+ T

exp( -

)} V

. . . . . (2)

a = exp( -

)

. . . . . (3)

: Time constant of servo system (sec)

V : Threading speed (mm/sec)
Time constant T

(sec) of the servo system: Usually 0.033 s.

The lead at the beginning of thread cutting is shorter than the specified
lead L, and the allowable lead error is

∆

L. Then as follows.

∆

When the value of “a” is determined, the time lapse until the thread
accuracy is attained. The time “t” is substituted in (2) to determine

Constants V and T

are determined in the same way as for

. Since

the calculation of

is rather complex, a nomography is provided on

the following pages.

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APPENDIX

E.NOMOGRAPHS

- 2303 -

- How to use nomograph

First specify the class and the lead of a thread. The thread accuracy, a,
will be obtained at (1), and depending on the time constant of cutting
feed acceleration/ deceleration, the

value when V = 10mm/s will be

obtained at (2). Then, depending on the speed of thread cutting,

for

speed other than 10mm/s can be obtained at (3).

(Note) See the graph in reference later in the manual for an actual example.

V=40mm/sec

V=20mm/sec

(3)

(1)

(2)

(V=10mm/sec)

Time constant of servo system

Fig. E.1 (b) Nomograph

NOTE

The equations for

, and

are for when the

acceleration/ deceleration time constant for cutting
feed is 0.

E.NOMOGRAPHS

APPENDIX

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E.2

SIMPLE CALCULATION OF INCORRECT THREAD
LENGTH

Fig. E.2 (a) Incorrect threaded portion

Explanation
- How to determine

∆

(mm)

R : Spindle speed (min

-1

)

L : Thread lead (mm)
* When time constant T

of the servo system is 0.033 s.

- How to determine

1800*( - 1 - lna)

(mm)

( - 1 - lna)

(mm)

R : Spindle speed (min

-1

)

L : Thread lead (mm)
* When time constant T

of the servo system is 0.033 s.

Following a is a permited value of thread.

-1-lna

0.005

4.298

0.01

0.015

0.02

3.605

3.200

2.912

Example

R=350rpm
L=1mm
a=0.01
then

350

1800 = 0.194

(mm)

3.605 = 0.701

(mm)

B-63944EN/03

APPENDIX

E.NOMOGRAPHS

- 2305 -

Reference

V : Speed in threading

Servo time constant

50msec

V=10mm/sec
( 0.39in/sec)

V=20mm/sec
( 0.79in/sec)

V=30mm/sec
( 1.18in/sec)

V=40mm/sec
( 1.57in/sec)

V=2in/sec

V=1in/sec

(V=10mm/sec)

33msec

8 (mm)

0.3 (in)

0.2

0.1

0.007

0.010

0.015

0.020

0.025

Metric thread

JIS class 1
JIS class 2

Unified thread

3.3 3.0 2.5 2.0 1.5

1.2

1.0 0.9

0.7

0.4

0.3 (mm) P Lead

P Lead

a= (

∆

5.0 4.0 3.5 3.0

2.5 2.0 1.75 1.5

1.25

1.0

0.9 0.8

0.75 (mm)

4 5

6 7 8 910 121314 161820

あ

7 8 9 1012 14161820

Ridge/inch

)

JIS 2A
JIS 3A

(Theoretical accuracy)

Fig. E.2 (b) Nomograph for obtaining approach distance

E.NOMOGRAPHS

APPENDIX

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E.3

TOOL PATH AT CORNER

When servo system delay (by exponential acceleration/deceleration at
cutting or caused by the positioning system when a servo motor is
used) is accompanied by cornering, a slight deviation is produced
between the tool path (tool center path) and the programmed path as
shown in Fig. E.3 (a).
Time constant T

of the exponential acceleration/deceleration is fixed

to 0.

Tool path

Programmed path

Fig. E.3 (a) Slight deviation between the tool path and the programmed

path

This tool path is determined by the following parameters:

•

Feedrate

, V

)

•

Corner angle (

)

•

Exponential acceleration / deceleration time constant (T

) at

cutting (T

= 0)

•

Presence or absence of buffer register.

The above parameters are used to theoretically analyze the tool path
and above tool path is drawn with the parameter which is set as an
example.
When actually programming, the above items must be considered and
programming must be performed carefully so that the shape of the
workpiece is within the desired precision.
In other words, when the shape of the workpiece is not within the
theoretical precision, the commands of the next block must not be read
until the specified feedrate becomes zero. The dwell function is then
used to stop the machine for the appropriate period.

B-63944EN/03

APPENDIX

E.NOMOGRAPHS

- 2307 -

Explanation
- Analysis

The tool path shown in Fig. E.3 (b) is analyzed based on the following
conditions:

•

Feedrate is constant at both blocks before and after cornering.

•

The controller has a buffer register. (The error differs with the
reading speed of the tape reader, number of characters of the next
block, etc.)

Fig. E.3 (b) Example of tool path

- Description of conditions and symbols

= Vcos

= Vsin

= Vcos

= Vsin

V : Feedrate at both blocks before and after cornering
V

: X-axis component of feedrate of preceding block

: Y-axis component of feedrate of preceding block

: X-axis component of feedrate of following block

: Y-axis component of feedrate of following block

Corner

angle

: Angle formed by specified path direction of preceding block and

X-axis

: Angle formed by specified path direction of following block and X-axis

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