Annotation of precision of planar drilling machine for gantry mobile CNC

Annotation of precision of planar drilling machine for gantry mobile CNC

The precision of nc machine tool includes geometric accuracy, transmission accuracy, positioning accuracy, stressing positioning accuracy and working accuracy.

Machining accuracy is an important index to measure the performance of machine tools. There are many factors affecting machining accuracy, such as machine tool or workpiece deformation, tool wear and cooling, and workpiece vibration. The accuracy of the machine itself is an important factor, such as the parallelism of the tool's central axis and the tool's feed path during drilling.

1. geometric accuracy

The geometrical precision of machine tool refers to the geometric precision of the working surface of the basic part of machine tool. The shape of the workpiece processed by the machine tool is determined by the relative motion of the tool and the workpiece, while the tool and the workpiece are determined by the trajectory of each axis of the machine tool, so the geometric accuracy is the most basic condition of machining accuracy.

For example; The perpendicularity of the X-axis motion track of the machine tool relative to the Y-axis motion track, the perpendicularity of the X-axis relative to the z-axis and the verticality of the Y-axis relative to the z-axis, the planeness of the workbench face relative to the parallelism of the X-axis relative to the XY plane, and the parallelism of the spindle axis relative to the z-axis trajectory.

2. Transmission accuracy

Transmission accuracy refers to the relative motion precision of the end and end of the transmission mechanism in the machine tool.

For example; The servo motor drives the pulley, and the pulley drives the pulley at the end of the wire rod through the belt, so as to realize the linear motion of the driving wire through the wire rod rotation. The error between the distance that the servo motor moves through the intermediate mechanism and the theoretical distance is the transmission accuracy

3. Positioning accuracy

Positioning accuracy: the accuracy of the actual position achieved by the main components of the machine at the end point of the movement, the error between the actual position and the theoretical position, and the guarantee of positioning accuracy include not only the driving basis but also the axial channeling of the screw, electrical accuracy, screw precision, etc.

4. relocation accuracy

Relocation accuracy: the maximum error between the actual position of a machine part that has reached the same position several times

The geometrical accuracy, transmission accuracy, positioning accuracy and relocation accuracy of the machine tool are all tested without load of the machine tool, also known as the static accuracy of the machine tool. The static accuracy is mainly determined by the precision of the machine tool's mother machine, main parts, screw rod, bearing, spindle and assembly precision

5. Working accuracy

The static accuracy reflects the precision of the machine tool itself, and also reflects the actual machining accuracy of the machine tool. In the actual machining process, there are many factors that affect the machining accuracy of the machine tool, such as the rigidity of the machine tool itself, the power of the spindle, the torque of the positioning shaft, the rigidity of the cutter, the deformation and cooling of the workpiece, and so on.

Common name notes:

Verticality: the vertical error of the machine shaft relative to other machine shaft;

Positioning accuracy: the difference between actual walking distance and theoretical walking distance;

The precision of the circle test of the principal axis includes: the parallelism of the Central Line and the trajectory of the Z axis of the principal axis, the perpendicularity of XZ and YZ, and the parallelism of the trajectory of the Z axis of the principal axis is measured by clamping the bar onto the principal axis. The direction of the z-axis moves up and down.

Spindle runout: the bar assembly is clamped on the power head, and the spindle is used to measure the error value of the bar rotation in a percentile.