Typical Example Analysis of Programs in CNC Lathe Parts Processing

CNC lathes mainly process rotary parts. Typical machining surfaces are nothing more than outer cylinders, outer cones, threads, circular surfaces, and slots. For example, to machine a part with the shape shown, it is appropriate to use a manual programming method. Since different CNC systems have different programming instruction codes, they should be programmed according to the device type. Taking the Siemens 802S CNC system as an example, the following operations should be performed.

(1) Determine the processing route

According to the principle of the first and second, the machining route is determined by the principle of fine grinding and coarsening. The outer contour is rough-processed by the fixed cycle command, and then the finishing is performed. Then the car is retracted and the thread is finally processed.

(2) Fixing method and selection of the tool point

The self-centering clamping of the three-jaw self-centering chuck is adopted, and the tool point is selected at the intersection of the right end surface of the workpiece and the rotation axis.

(3) Select tool

According to the processing requirements, four knives are selected, No. 1 is a rough-working external turning tool, No. 2 is a finishing outer turning tool, No. 3 is a grooving knife, and No. 4 is a thread-cutting knife. The cutter is used to test the knife, and the end face is machined at the same time.

(4) Determine the amount of cutting

The outer circle of the car, the spindle speed of the rough car is 500r/min, the feed speed is 0.3mm/r, the spindle speed of the finished car is 800r/min, the feed speed is 0.08mm/r, and the spindle speed is grooving and threading. 300r/min, feed rate is 0.1mm/r.

(5) Programming

Determine the intersection of the axis line and the center of the ball head as the programming origin. The machining procedure of the part is as follows:

Main program

JXCP1.MPF

N05 G90 G95 G00 X80 Z100 (tool change point)

N10 T1D1 M03 S500 M08 (outer round rough turning tool)

-CNAME=“L01”

R105=1 R106=0.25 R108=1.5 (Set blank cutting cycle parameters)

R109=7 R110=2 R111=0.3 R112=0.08

N15 LCYC95 (call roughing of the blank cutting cycle)

N20 G00 X80 Z100 M05 M09

N25 M00

N30 T2D1 M03 S800 M08 (outer round precision turning tool)

N35 R105=5 (Set blank cutting cycle parameters)

N40 LCYC95 (calling blank cutting cycle finishing)

N45 G00 X80 Z100 M05 M09

N50 M00

N55 T3D1 M03 S300 M08 (cutting cutter, knife width 4mm)

N60 G00 X37 Z-23

N65 G01 X26 F0.1

N70 G01 X37

N75 G01 Z-22

N80 G01 X25.8

N85 G01 Z-23

N90 G01 X37

N95 G00 X80 Z100 M05 M09

N100 M00

N105 T4D1 M03 S300 M08 (triangular thread turning tool)

R100=29.8 R101=-3 R102=29.8 (Set thread cutting cycle parameters)

R103=-18 R104=2 R105=1 R106=0.1

R109=4 R110=2 R111=1.24 R112=0

R113=5 R114=1

N110 LCYC97 (call thread cutting cycle)

N115 G00X80 Z100 M05 M09

N120 M00

N125 T3D1 M03 S300 M08 (cutting the turning tool, the knife width is 4mm)

N130 G00 X45 Z-60

N135 G01 X0 F0.1

N140 G00 X80 Z100 M05 M09

N145 M02

Subroutine

L01.SPF

N05 G01X0 Z12

N10 G03 X24 Z0 CR=12

N15 G01 Z-3

N20 G01 X25.8

N25 G01 X29.8 Z-5

N30 G01 Z-23

N35 G01 X33

N40 G01 X35 Z-24

N45 G01 Z-33

N50 G02 X36.725 Z-37.838 CR=14

N55 G01 X42 Z-45

N60 G01 Z-60

N65 G01 X45

N70 M17