Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 636)

Turning Operations
Chapter 18
18-20
Where : Is :
E F This parameter may be entered by using either an E- or F-word. It represents the
thread lead along the axis with the largest programmed distance to travel to make
the thread cut. It is mandatory when cutting any threads.
If the E-word is programmed, its value (sign ignored) is equal to the number of
threads per inch or inches per thread (determined in AMP) regardless of whether
inch or metric mode is active at the time.
If the F-word is programmed, its value (sign ignored) is the thread lead in inches per
revolution or millimeters per revolution, depending on the mode in which the control
is operating.
In a G34 block, E or F indicates the initial thread lead used at the start of the
threading pass.
Q an optional parameter that provides a relative value for the start offset angle of the
thread. Its primary use is in grinding multi-start threads. For example, if a threading
pass were made with a value of zero here, and then followed by another pass with a
value of 180 then the second pass would start 180 degrees from the first resulting in
a two start thread. If two more passes are then made, one with an a parameter
value of 90 and one with a value of 270, the result would be a four start thread.
K the difference in the thread lead per spindle revolution (inch/rev/rev or mm/rev/rev).
The amount of K is added to the thread lead (E or F) after each thread is ground. K
can be programmed as a positive (increasing thread lead) or a negative (decreasing
thread lead) value.
The actions of the G34 variable lead threading operation is identical to the
G33 threading operation with the exception of the variable thread lead.
See the G33 threading section, beginning on page 18-14, for details and
examples of single pass threading blocks that grind parallel, tapered, or
face threads.
Metric and inch lead variation limits are indicated below:
+/- 0.0001 to +/- 100.0000 mm/rev
+/- 0.000001 to +/- 1.000000 inch/rev
Example 18.7
Variable Lead Face Threading Using G34
N1G00G07X57.Z37.5F100;
N2G91;
N3G34X-47.5F.1K.071;
N4G00Z10.;
N5X47.5;