HEIDENHAIN TNC 360 User Manual - Manual (Page 119)

5-35 TNC 360
5 Programming Tool Movements
5.5 Path Contours – Polar Coordinates
Example for exercise: Tapping
Given Data
Thread:
Right-hand internal thread M64 x 1.5
Pitch P: 1.5 mm
Start angle A
S
: 0°
End angle A
E
: 360° = 0° at Z
E
= 0
Thread revolutions n
T
: 8
Thread overrun
• at start of thread n
S
: 0.5
• at end of thread n
E
: 0.5
Number of cuts: 1
Calculating the input values
• Total height H: H = P . n
P = 1.5 mm
n = n
T
+ n
S
+ n
E
= 8 + 0.5 + 0.5 = 9
H = 1.5 mm . 9 = 13.5 mm
• Incremental polar coordinate angle IPA:
IPA = n . 360°
n = 9 (see total height H)
IPA = 360°
. 9 = 3240°
• Start angle A
S
with thread overrun n
S
n
S
= 0.5
n = 1 = 360°, n = 0.5 = 180° (half a revolution)
The starting angle of the helix is advanced by 180°. With positive
rotation this means that A
S
with n
S
= A
S
– 180° = –180°
• Starting coordinate: Z = P . (n
T
+ n
S
) = –1.5 . 8.5 mm = –12.75
Note:
• The thread is being cut in an upward direction towards Z
E
= 0; therefore
Z
S
is negative.
Part program
0 BEGIN PGM 360535 MM
1 BLK FORM 0.1 Z X+0 Y+0 Z–20
2 BLK FORM 0.2 X+100 Y+100 Z+0
3 TOOL DEF 1 L+0 R+5
4 TOOL CALL 1 Z S 1500
5 L Z+100 R0 FMAX M6
6 L X+50 Y+50 FMAX
7 CC
8 L Z–12.75 R0 FMAX M3
9 LP PR+32 PA-180 RL F100
10 CP IPA +3240 IZ+13.5 DR+ RL F200
11 L X+50 Y+50 R0
12 L Z+100 FMAX M2
13 END PGM 360535 MM
A =0
°
E
A =0
°
A
A = 0
°
DR+
A = –180
°