The machine cuts perfect straight lines but oval arcs. This is often a mismatch between 1860 and the acceleration for the orthogonal axes. Ensure that the 1860 values for X and Y (or X and Z) are identical for circular moves. Uneven acceleration distorts circles into ellipses.
In FANUC CNC systems, parameter 1860 is related to the "Long Piece" or "Long Part" function, which allows for machining of long workpieces that exceed the standard travel limits of the machine. fanuc parameter 1860 full
For finishing passes with very small feedrates (F 500–2000 mm/min) and fine stepovers, a is desirable to maintain sharp detail. However, you must ensure the servo gain (1825) is also high (100–200). This combination is called high-gain, fast-response tuning. The machine cuts perfect straight lines but oval arcs
1860 Parameter Name: Movement pulse (CMR) Data Type: Integer (Valid data range typically 1 to 32767) Uneven acceleration distorts circles into ellipses