EA C412FMS

Topics to be covered today:• Turning Part Programming• Example

G-Codes

• Majority of the earlier codes still valid

• G40- TNR compensation cancel

• G41- TNR left compensation

• G42- TNR right compensation

• G70- Finish cutting CC

• G71- Rough cutting CC

• G76- Thread cutting canned cycle

Function Fanuc

Spindle speed mode

G96 –constant surface speed

G97-constant RPM

Feed rate mode G94 – IPM or mm/min

G95 –IPR or mm/rev

Inch/Metric dimension

G20 – all dimensions in inch

G21- all dimensions in mm

Return to HP G28

INTRODUCTION

Z-axis

X-axisTool

X-axis travel

Tool

Z-axis travel

Z-axis is the axis of the spindle and X-axis is the direction of traverse motion of the tool post

STEPS FOLLOWED(TURNING OPERATION)

• Move the cutting tool to a point near the job in the rapid mode

• Set linear interpolation (G01) and move in X-direction to give the required depth of cut

• Move along Z-axis to the required length of the job

• Set rapid mode (G00) and retract the tool along X-axis

• Move to the start point using G00 mode

EXAMPLE-1Taper turning

15 5 15

35

Dia 15Dia 20

Given: The raw material available is 20 mm dia bar of length 35mm.

The operations involved are:

• Facing

• Turn to 15 mm diameter over 15 mm length

• Taper turning

15 5 15

35

Dia 15Dia 20

N005 G50 S1100

N010 G21 G90 G94 EOB

N015 M03 S1000

N020 T0101 EOB

N025 G00 X22 Z0.5 EOB

N030 G01 X0 F200 EOB

N035 Z0 EOB

N040 X20 (FACING)

N045 X15 EOB

N050 Z-15 EOB

N055 X20 Z-20 EOB

N060 Z-35 EOB

N065 G00 X25 Z20

N070 M30 EOB

Here, M06 need not be used because the tool and the spindle are independent. So there is no reason to stop the spindle for tool change.

G50 code followed by S1100 sets the maximum RPM of the spindle. This is the rated speed of the machine.

T0101 : - The tool offsets (length compensation)

EXAMPLE-2

20 5 10

R5

R520

N00 G90 G21 G94 EOB

N01 G28 U0 W0N02 T0404N03 M03 S1200

N04 G00 X0 Z1 EOB

N05 G01 Z0 F100 EOB

N06 G02 X10 Z-5 I0 K-5 F150 EOB

N07 G01 Z-15 EOB

N08 G03 X20 Z-20 I5 K0 EOB

N09 M30 EOB

Note that I have not used nose radius compensation. It has to be used here.

Tool Nose Radius Compensation

• The cutter compensation helps in making minor adjustments to the tool tip position in order to accurately produce machine features.

• Cutter compensation behaves differently based on whether tool tip programming or tool center programming is being used.

Tool center programming

G42

G41

With tool center programming, the tool will be automatically offset by the radius value that has been entered into the offset registry.

All surfaces will be affected with this mode

Tool tip programming

• With tool tip programming, only tapers and radii will be affected.

• Straight diameters and perpendicular faces will remain unchanged.

Error in profile

G71Multiple Turning CC

• A G71 causes the profile to be roughed out by turning.

• You need two blocks to specify all the values.• Example G71 U2.0 R1.5• G71 P10 Q20 U0.1 W0.1 F45

(i) U0.5 R1

U- Depth of cut in each pass along X-axis in mm

R- Retraction or retardation amount in mm

(i) G71 P_ Q_ U_ W_ F_

• Example G71 U2.0 R1.5• G71 P10 Q20 U0.1 W0.1 F45

(i) U0.5 R1 U- Depth of cut in mm R- Retraction or retardation amount in mm

(ii) G71 P_ Q_ U_ W_ F_

P- Starting block number

Q- End block number

U- Finishing allowance along X-axis in mm

W- Finishing allowance along Z-axis in mm

F- Feed rate

G70Finish Turning CC

• A G70 causes a range of blocks to be executed.

• This is used after compilation of G71.

• It has only one block.

• G70 P10 Q20

P- First block of cycle

Q- Last block of cycle

G72Multiple Facing CC

• A G72 causes the profile to be roughed out by facing.

• You need two blocks to specify all the values.• Example G72 W2.0 R1.5• G72 P10 Q20 U1.0 W1.0 F45(i) W2.0 R1.5

W- Depth of cut in each pass along Z-axis in mm R- Retraction or retardation amount in mm

(i) G72 P_ Q_ U_ W_ F_

• Example G72 W2.0 R1.5• G72 P10 Q20 U1.0 W1.0 F45(i) W2.0 R1.5 W- Depth of

cut in each pass along Z-axis in mm R- Retraction or retardation amount in mm

(ii) G72 P_ Q_ U_ W_ F_P- Starting block numberQ- End block numberU- Finishing allowance along X-axis in mmW- Finishing allowance along Z-axis in mmF- Feed rate

G76Threading Cycle

• G76 is a multi-pass threading cycle.

• Here also two blocks are required.

• G76 P031560 Q150 R0.5• G76 X17.96 Z-50 P1020 Q250 F1.5

• G76 P031560 Q150 R0.5• G76 X17.96 Z-50 P1020 Q250 F1.5

Code Meaning

P03 No of finishing passes

15 Pull out angle

60 Angle of thread

Q150 1000XMin depth of cut in mm (Here 0.150)

R0.5 Finishing allowance in mm

X17.96 Core diameter of thread

Z-50 Length of thread

P1020 1000XHeight of thread in mm (Here it is 1.020)

Q250 1000XDepth of first cut in mm (Here it is 0.25)

F1.5 Pitch or Lead of thread

Data table

O/DIA CORE PITCH DEPTH

1.6 1.1706 0.35 0.2147

For a metric thread

H=0.866Xp

EXAMPLE-1

20

10 5 10 10 10 5

102030

[BILLET X30 Z50]

N010 G21 G40 G98

N020 G28 U0 W0

N030 T0404

N040 M03 S1200

N050 G00 X30 Z5

N060 G00 Z1

N070 G71 U0.5 R1

N080 G71 P90 Q150 U0.1 W0.1

Note that I have not used nose radius compensation. It has to be used here.

EXAMPLE-1

20

10 5 10 10 10 5

102030

N090 G01 X0

N100 Z0

N110 G03 X10 Z-5 R5

N120 G01 Z-15

N130 X20 Z-25

N140 G01 Z-35

N150 G02 X30 Z-40 R5

(# Finishing Cycle)

N160 G70 P90 Q150

N170 G28 U0 W0

N180 M05

N190 M30