HEIDENHAIN TNC 620 User Manual page 42

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Cycle fundamentals / Overviews
1.1 Introduction
1.1 Introduction
Frequently recurring machining cycles that comprise several
working steps are stored in the TNC memory as standard cycles.
Coordinate transformations and several special functions are also
available as cycles.
Most cycles use Q parameters as transfer parameters. Parameters
with specific functions that are required in several cycles always
have the same number: For example, Q200 is always assigned the
set-up clearance, Q202 the plunging depth, etc.
Danger of collision!
Cycles sometimes execute extensive operations. For
safety reasons, you should run a graphical program
test before machining.
If you use indirect parameter assignments in cycles
with numbers greater than 200 (e.g. Q210 = Q1), any
change in the assigned parameter (e.g. Q1) will have
no effect after the cycle definition. Define the cycle
parameter (e.g. Q210) directly in such cases.
If you define a feed-rate parameter for fixed cycles
greater than 200, then instead of entering a
numerical value you can use soft keys to assign the
feed rate defined in the TOOL CALL block (FAUTO
soft key). You can also use the feed-rate alternatives
FMAX (rapid traverse), FZ (feed per tooth) and FU
(feed per rev), depending on the respective cycle and
the function of the feed-rate parameter.
Note that, after a cycle definition, a change of the
FAUTO feed rate has no effect, because internally the
TNC assigns the feed rate from the TOOL CALL block
when processing the cycle definition.
If you want to delete a block that is part of a cycle,
the TNC asks you whether you want to delete the
whole cycle.
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TNC 620 | User's Manual Cycle Programming | 3/2014