CNC Programming Skills: Live Tool Drilling Cycles on a Fanuc Lathe

This is the third e-book in the series, “CNC Programming Skills.” The first book, which was published in December 2014, dealt with the program entry and editing procedures on Fanuc machines. The second book, published in January 2015, explained the intricacies of the canned cycle G73 on a Fanuc lathe. The present book explains how to use the canned cycles for drilling/tapping/boring using live tools on a lathe with Fanuc 0i or a similar control.
A good number of jobs require machining by both lathe and milling machines. A flange with bolt holes is one example. While turning and facing are done on a lathe, the holes need to be drilled on a milling machine (or a drilling machine). Involvement of two different machines with independent setup requirement increases the cycle time as well as production cost, despite the fact that the operation on the milling machine is very simple.
To address this issue, these days higher-end lathes come equipped with live-tooling arrangement, allowing certain milling-like operations such as drilling, boring and tapping anywhere on the face of the workpiece, as well as in the radial direction at any angular position. The live tools can also be used for operations like polygon turning (e.g., to make hexagonal bolt head) and cylindrical interpolation (e.g., to make a cylindrical cam).
We will restrict our discussion to drilling/boring/tapping operations only which are very common. To facilitate these operations, a number of built-in canned cycles are available. We would be explaining these with suitable examples in quite detail so as to cover nearly everything a programmer needs to know about them.
With this book in your hand, you would not need to refer to any other book or manual for the purpose of efficiently using these canned cycles, nor would any guidance from any programming expert be needed. The following excerpts from the book would give some idea of the style of presentation in the book:
Front/Side Drilling Cycles (G83/G87):
On a milling machine, two separate G codes are available for full-retraction peck drilling (suitable for holes with large length to diameter ratio) and high-speed (partial retraction) peck drilling applications (G83 and G73, respectively). On a lathe, however, there is only one G code available for both types. The selection between the two types is done through a parameter. When parameter 5101#2 is set to 0, G83/G87 become high-speed peck drilling cycles. On the other hand, when this parameter is set to 1, these become full-retraction peck drilling cycles. These cycles are explained in Figs. 2 and 3, which correspond to 5101#2 set to 0 and 1, respectively. Selection of retraction-type through this parameter is valid when parameter 5161#0 is set to 0 (the default value). When set to 1, G83.5/G87.5, and G83.6/G87.6 are used for partial and full retractions, respectively. While the full-retraction cycle draws the chips out of the hole after each peck (which makes it suitable for very deep holes), the high-speed cycle clears the chips in its final retraction only, though it does break the chips and allows the coolant to flood and cool the cutting zone as well as the tool.
Syntax
G83 X(U)_ C(H)_ Z(W)_ R_ Q_ P_ F_ K_ M_ for front drilling
G87 Z(W)_ C(H)_ X(U)_ R_ Q_ P_ F_ K_ M_ for side drilling
where
X(U)_ C(H)_ or Z(W)_ C(H)_: Hole position data
Z(W)_ or X(U): Position of the bottom of the hole
R_: Position of R-point
Q_: Peck length in micron (one-tenth of thou in inch mode)
P_: Dwell in millisecond at the bottom of the hole
F_: Feedrate
K_: Repeat count (non-modal data), if needed
M_: M code for C-axis clamp, if needed
M51 (C-axis indexing mode ON)
G00 X50 C0 Z20 (Initial position of the tool)
M03 S1000 (Live spindle starts)
G83 X40 C0 Z-45 R-15 Q5000 P1000 F10 M31
(First hole drilled; C0 not needed)
(or G83 U-10 H0 W-50 R-15 …)
C90 M31 (Second hole drilled)
(or H90 M31)
C180 M31 (Third hole drilled)
(or H90 M31)
C270 M31 (Fourth hole dr