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It is really difficult to explain G76 cycle. My suggestion is to refer to FANUC Manual. But I see a hitch here ! at the feed of 203 mm / rev, your tool will travel at 20 M/ min for carrying out threading ! (Assuming 100 rpm). This is next to impossible to achieve for an average CNC Lathe ! The machine will trigger alarm and stop !

I have another Idea; Use internal threading tool on a turn-mill centre and carry out threading while interpolating "C" axis with "Z" axis. This would generate kind of broaching action but, if you use very fine depth of cut then such broaching is practically possible.

After studying the communication I am sorry to comment that you are just a beginner ! You tend to ask explanation for each and every code ! How would you be possibly able to carry out C-Z interpolation ??!! It is really difficult to show you each and every thing to carry out the operation on this kind of written conversational platform ??!! All what I can do is to give tips only.

I originally asked if anyone here had a tutorial for how to use c-axis interpolation or C Z axis interpolation. If any has a tutorial or information on how to use the C Z axis together i would be very grateful.

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O1111(INTERPOLATING C WITH Z)
G40
G28U0 (ZERO RETURN IN X)
G28W0 (ZERO RETURN IN Z)
G28H0 (ZERO RETURN IN C AXIS)
T0101 (TOOL CHANGE TO TOOL NO 1 AND OFFSET NO 1)
G90 (ABSOLUTE PROGRAMMING)
G0Z20.0M08 (RAPID POSITIONING TO Z20.0 AND COOLENT ON)
X13.208Z2.0 (RAPID POSITIONING TO FINAL GROOVE DEPTH IN X AND Z2.0)
G1Z0.0F0.5 (FEED POSITIONING TO THE FACE OF THE WORK PIECE)
(USE CORRESPONDING M CODE AND CHANGE FEED TO MM / MIN)
G01C360Z-203.2F30 (C-Z INTERPOLATION AT 30 MM/MIN)
G0X12.0M09 (RAPID RETRACTION IN X TO AIR GAP INSIDE THE BORE AT THE END)
Z2.0 (RETRACTING BACK TO Z2 MM)
(SWITCH BACK TO FEED IN MM / REVOLUTION)
G28U0
G28W0
G28H0
M30
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HERE IT IS IMPORTANT TO 1) SELECT METRIC PROGRAMMING, 2) SELECT FEED IN MM/MIN
NOW I SUGGEST YOU NOT TO BLINDLY FOLLOW THE CODES, REFER TO THE PROGRAMMING MANUAL AND CHECK THE MEANING OF THE CODES, IT IS LIKELY THAT "C" AXIS NEED TO BE SELECTED AND IT IS TO BE LOCKED / UNLOCKED AT DIFFERENT PLACES IN THE PROGRAM. I CAN NOT DICTATE THE CODES WHICH MAY BE CONTROLLER SPECIFIC.

REGARDS,

JASMIN SHAH

thank you for your help. Just one last thing: suppose the helix is 1 full revolution in 16" would that be possible and how would that change the code and parameters of the program

Dear Friend,

In case if you have to turn one full rotation for 16 inches : You first plot a graph where "X" axis is the distance and "Y" axis being the angle of rotation in degrees. The extreme point on "X" axis is 16 inches and the corresponding extreme point on "Y" axis of the graph is 360 degrees. Join the straight line between (0,0) and (16,360).

Now you find where you will have to stop machining on "X" axis of your graph. Mind well Here "X" axis of the graph is actually the traverse of the tool in your machine "Z" Axis. So, for example you choose to stop at 6 inches then draw a vertical line starting from 6 inches on your "X" axis of the graph; let it cut the plotted curve(in this case it is a straight line), find the corresponding co-ordinate on "Y" axis. This reading of "Y" axis on the graph is actually the angle of rotation at which you have to stop.

In other words, you can find any C-Z interpolation value that you want from this graph. Once you understand this straight line relationship, then you can change your C-Z values as you want.

Only thing you have to make clear in your mind is : The graph is true for the given pitch (i.e. distance in one revolution). As you can understand that in case if the component length is much less that the pitch then you can plot this graph and decide as to where to stop i.e. limiting C-Z values.

Best of luck,

Jasmin Shah