Please note while programming – HEIDENHAIN TNC 620 (340 56x-02) Cycle programming User Manual
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HEIDENHAIN TNC 620
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5.3 CIR
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Please note while programming:
With an inactive tool table you must always plunge 
vertically (Q366=0) because you cannot define a plunging 
angle.
Pre-position the tool in the machining plane to the starting 
position (circle center) with radius compensation R0.
The TNC automatically pre-positions the tool in the tool 
axis. Note Parameter Q204 (2nd setup clearance).
The algebraic sign for the cycle parameter DEPTH 
determines the working direction. If you program 
DEPTH = 0, the cycle will not be executed.
At the end of the cycle, the TNC returns the tool to the 
starting position.
At the end of a roughing operation, the TNC positions the 
tool back to the pocket center at rapid traverse. The tool is 
above the current pecking depth by the setup clearance. 
Enter the setup clearance so that the tool cannot jam 
because of chips.
Danger of collision!
Use the machine parameter displayDepthErr to define 
whether, if a positive depth is entered, the TNC should 
output an error message (on) or not (off).
Keep in mind that the TNC reverses the calculation for pre-
positioning when a positive depth is entered. This 
means that the tool moves at rapid traverse in the tool axis 
to setup clearance below the workpiece surface!
If you call the cycle with machining operation 2 (only 
finishing), then the TNC positions the tool in the center of 
the pocket at rapid traverse to the first plunging depth.
