Sandvik Coromant Threading - Manual (Page 92)

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5. Technical reference
Programming
Modern machine tools use computer numerical control (CNC) meth-
ods to produce complex parts in a consistent and automated man-
ner. This capability is especially important when producing threads.
CNC machines can process 2-dimensional and 3-dimensional
shapes using their coordinate axes, with each machine typically
having 3-axis (X, Y, Z) - though machines with up to 12-axes do ex-
ist. For threading, the methods of CNC programming differ in lathes
and machining centres and dedicated CNC programs exist for
threading and turning.
Programming – lathe
When thread turning, it is important to use the correct CNC code
to ensure good tool life, chip control, surface and tolerance. Fixed
cycles, or the dialog system are common ways to program a lathe
for threading. However, line programming (long-hand code) is the
optimum method and can be used with all CNC systems.
Obtaining the correct infeed (thread turning)
Modifi ed-fl ank infeed and radial infeed are the preferred methods of
achieving good threading results. Line programming is recommend-
ed to accurately control the infeed angle and number of passes.
Recommendations (thread turning)
• Correct thread programming is important - especially for large
threads and pitches.
• Use the recommended infeed depth in CoroGuide to ensure the
correct number of passes.
• With fl ank infeed, the angular displacement must also be calcu-
lated.