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Alternating flank infeed with G92 threading

Ukraine Train

Cast Iron
Joined
Feb 10, 2014
Location
Ohio
Fusion 360 has an alternating flank infeed option and I have it posting thread cutting with G92. Does G92 support variable Z position starts? I want to try this but I'm using customer supplied castings and don't want to risk scrapping any.

This is the code I get. It's a 3.125"-8 internal thread.
N19 G0 X2.903 Z0.1151
N20 G18
N21 G92 X3.0405 Z-1.4466 F0.125
N23 X3.0561 Z-1.4511
N25 X3.068 Z-1.4477
N27 X3.0781 Z-1.4506
N29 X3.0869 Z-1.448
N31 X3.0949 Z-1.4503
N33 X3.1023 Z-1.4482
N35 X3.1091 Z-1.4502
N37 X3.1156 Z-1.4483
N39 X3.1217 Z-1.4501
N41 X3.1275 Z-1.4484
N43 X3.133 Z-1.45
N46 G0 X2.903 Z0.1969
 
Fusion 360 has an alternating flank infeed option and I have it posting thread cutting with G92. Does G92 support variable Z position starts? I want to try this but I'm using customer supplied castings and don't want to risk scrapping any.

This is the code I get. It's a 3.125"-8 internal thread.
N19 G0 X2.903 Z0.1151
N20 G18
N21 G92 X3.0405 Z-1.4466 F0.125
N23 X3.0561 Z-1.4511
N25 X3.068 Z-1.4477
N27 X3.0781 Z-1.4506
N29 X3.0869 Z-1.448
N31 X3.0949 Z-1.4503
N33 X3.1023 Z-1.4482
N35 X3.1091 Z-1.4502
N37 X3.1156 Z-1.4483
N39 X3.1217 Z-1.4501
N41 X3.1275 Z-1.4484
N43 X3.133 Z-1.45
N46 G0 X2.903 Z0.1969

Hello Ukraine Train,
Yes it does, as do all Thread Cutting functions. However, your example code is not going to achieve alternating flank in-feed, only a varying Z End point for the Thread. All successive DOCs for the Threading Cycle will be applied at Z0.1151 for the Blocks N21 through N43.

Regards,

Bill
 
Hmm... I see what you mean. How would I format it to actually get alternate flanking? Z start point between each X DOC?
 
Hmm... I see what you mean. How would I format it to actually get alternate flanking? Z start point between each X DOC?

Hello Ukraine Train,
Yes, you would have to put a rapid move to a New Z Start Coordinate before each X DOC and include G92 and Z in each case, it becomes a new G92 cycle for each Thread pass.

What control and model are you using? If Fanuc, using a Two Block G76 Format (FS16 Standard Format), you can set the control via parameter to use FS15 Format (One Block G76 Format). Using the FS15 Format, you can specify alternate Flank Cutting via a P address in the G76 Block.

Alternatively, you could write a fairly simple User Macro program to achieve what you want with the G92 cycle.

Regards,

Bill
 








 
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