CNC lathe
Cutting variable lead threads on a CNC lathe is an important aspect of its characteristics. The variable lead thread has two types of groove width and tooth width. The groove variable width lead thread is easy to process and will not be described. Here we talk about the processing method of tooth variable width lead thread. The workpiece is shown in Fig. 1. The outer diameter of the machined workpiece is 40mm, the bottom diameter is 30mm, the first lead is 10mm, and the lead of the back is 12mm, 14mm, 16mm...the rectangular single thread right-hand thread with the width of 5mm.
The equipment used is the Omori R2J50L system. The variable lead thread cutting command is G34 X(U)__Z(W) __F__K__, where X and Z are the coordinates of the end point of the turning, and U and W are the incremental coordinates of the relative starting point of the cutting end point. , F refers to the thread lead, these have the same meaning as the thread cutting command G32, K refers to the increase (decrease) amount of each lead of the thread.
CNC lathe
Through analysis, we know that the processing of a tooth with a variable width lead thread can only be achieved by changing the lead F and the corresponding starting point.
The knife width used is 3mm.
The procedure is as follows:
00001
G50 X100 Z50.
M03 S80
T0100 G99
G00 X60. Z8.
M98 P0002L25
G00 X60. Z7. 3
M98 P0003L25
G00 X60. Z6. 6
M98 P0004L25
G00 X60. Z6.
M98 P0005L25
G00 X1000.
Z50.
M30
0002
G00 U-20.
G34 Z-52. F6. K2.
G00 U19.6
G00 Z8.
M99
0003
G00 U-20.
G34 Z-52. F5.3 K2.
G00 U19.6
G00 Z7.3
M99
0004
G00 U-20.
G34 Z-52. F4.6 K2.
G00 U19.6
G00 Z6.6
M99
0005
G00 U-20.
G34 Z-52. F4. K2.
G00 U19.6
G00 Z6.
M99
The above program is the workpiece's first lead for processing 10mm, as shown in Figure 2, gradually go to the positive direction, that is, the right side of the groove knife, until the first lead is 8mm, processed into Figure 1 The shown tooth is a variable width lead thread.
CNC lathe
There is another way is the first lead for the 8mm processing, as shown in Figure 3, gradually go to the negative direction, that is, the left side of the slot knife, until a lead of 10mm, processed into Figure 1 The shown tooth is a variable width lead thread.
The G34 instruction follows the same rules as the thread cutting G32 instruction, but the following points must also be taken into account during application:
(1) Select the tool width according to different requirements.
(2) Reasonably set the F value and the distance from the starting point according to different situations. Correctly select the amount of knife to be used. The amount of the tool to be shot is superimposed. For example, the first tooth catches the knife 0.1mm and the tenth tooth catches up. It is 1mm, so it is necessary to consider that the tool strength and the cutting amount exceed the knife width.
(3) As the leading angle of the thread of the variable lead thread increases with the increase of the pitch, the sharp angle of the sharpening on the left side of the knife amount is equal to the rear corner of work plus the maximum lead angle of the thread.
(4) The first pitch from turning starting point is F+K.