Multiaxis Kinematic Error Compensation Mapping Protocols after Transit
Post-transit multi-axis kinematic re-mapping corrects structural settling and shock displacement to restore five-axis spatial accuracy to sub-ten-micron limits.
NAS 979 Cutting Test
Meaning
Machining evaluation standards developed by the Aerospace Industries Association determine the dynamic contouring accuracy of multi-axis machine tools through standardized cutting operations. Aerospace manufacturers require the nas 979 cutting test to verify the dynamic performance of a machine before using it to produce flight-critical components. This machining standard ensures that mechanical play, servo lag and contouring errors are evaluated under real material-removal forces.
Specimen Geometry
Precision test pieces must feature specific geometric shapes that challenge the coordination of multiple linear and rotational axes. The standard nas 979 cutting test employs a circle and a diamond shape machined on a single metal block. These complex shapes force the machine controller to continuously interpolate between different axes, making any lag or misalignment highly visible on the surface finish of the finished block.
Test Procedure
Preparation for the test requires mounting a block of aluminum or steel on the machine table and running a specific toolpath program at set feed rates. While executing the nas 979 cutting test, the operator ensures that the cutting tool and workpiece setup are perfectly rigid to eliminate tool deflection as a source of error. The cut must be performed in a single continuous pass to evaluate the machine’s ability to maintain constant feed rates during directional transitions.
Evaluation Criterion
Inspection of the completed specimen involves measuring dimensional deviations and surface roughness with a coordinate measuring machine. By utilizing the nas 979 cutting test, quality assurance teams can calculate the deviation of the machined profile from the nominal CAD file. Discrepancies in the roundness of the circle or the taper of the cone reveal specific faults like axis backlash, stick-slip or gain mismatches in the servo drives.
These findings provide a direct assessment of whether the machine is capable of holding the tight tolerances needed for aerospace bulkheads and rib structures. Machine tool rebuilders rely on these measurements to tune the velocity loop parameters and adjust the physical gibs of the machine axes to restore original factory performance.