Programming of left-hand trapezoidal thread

Machining left-hand thread , If the spindle rotates in the forward direction , When the lathe tool rest is in front , The tool should be X Forward feed （ From the spindle to the tool rest ）; When the lathe tool rest is placed behind , The tool should be X Negative feed （ From the tool rest to the spindle ）. use G32 The programming is as follows ,（ First, use the slotting cutter to process the rectangular thread , Reprocess the two waists of the trapezoid . According to the groove bottom width （3-1×tan15°×2=2.464） selection 2mm Grooving knife , because 2.464-2=0.464, therefore #3=#3+0.464. The selected values of cutting parameters are for reference only .）

Procedure reference ：

M03S400

G00X85Z12

#1=0

#2=1.75

N200#3=0

N100G00X[#1+80]

G32Z-45F6

G00X85

Z[#3+12]

#1=#1-0.1

IF[#1GE-3.5]GOTO200

#3=#3+0.464

IF[#3LE0.464]GOTO100

N300G00Z[12+#3+#2TAN[15]]

X[76.5+2*#2]

G32Z-45F6

G00X85

#2=#2-0.05

IF[#2GE0]GOTO400

N400G00Z[12-#2*TAN[15]

X[76.5+2*#2]

G32Z-45F6

G00 X85

#2=#2-0.05

IF[#2GE0]GOTO300

G00Z300

M30