[BLAMOUR]

Is anyone out there clipping the back of a thread into a relief groove? I've been doing this with a G76 generated by Mastercam. The code looks like this for an external thread :

N6(CLIP BACK)
G54
G00 T0303
G97 S300 M03
G00 X3.16 Z-1.48 M08
G76 P010100 Q0050 R.005
G76 X2.51 Z-1.775 P1250 Q0400 R.1703 F.1667
M09
G00 X8.0 Z7.0
M05
M01

Basically, I'm using a grooving insert programmed on a -30 degree taper into the relief groove. This works really well after the front thread clip is proven, I can calculate the start point for the back clip. However, the tool is retracting out of the cut too quickly and it leaves a small burr at the end of the thread.

Is it possible to use a G32 and program the clipping tool to enter the relief at -30 degrees and then continue to the end of the relief at 0 degrees?

[fordav11]

G76 P010100 Q0050 R.005
G76 X2.51 Z-1.775 P1250 Q0400 R.1703 F.1667

The early retraction you are seeing is a chamfer at the end of the thread.
On the first line of the G76 the second 2 numbers of the P sets the chamfer amount which can be 0.0 to 9.9 and is expressed in 0.1 LEAD increments (2–digit number from 00 to 99).

Change your first G76 line to G76 P010000 Q0050 R.005 for no thread chamfer.

[BLAMOUR]

I added that .1 chamfer to keep the tool in the cut longer. It seemed to work best. I tried .2 and it was too much.
I can achieve this 'profile threading' on our Mazak as Mazatrol allows you to change 'X' and 'Z' values within the thread.
I'm just not sure if this is the equivalent to a G32.

The code might look like this:

T0700
G97 S300 M3
G0 X2.95 Z-1.63 M8
X2.8
G32 X2.51 Z-1.96 E.1667 (TAPER INTO THREAD)
Z-2.04 (STRAIGHT TO END OF RELIEF)
G0 X2.95

[fordav11]

it can be done if you get the Continuous Thread Cutting Option.
It's a very very uncommon option so unlikely you will have it.
see attached page from manual....

[BLAMOUR]

Thanks for your help. I'll check our machines for that option.

[sinha_nsit]

0-deg pull-out would interfare with the last thread, unless the tool has reached a groove.