1. First, determine what level of precision you need. Different workpieces have completely different requirements for machine tools.

For common shaft and disc parts: positioning accuracy, repeatability, and spindle rigidity.

Precision molds: thermal stability, surface quality, five-axis linkage, spindle speed

Aerospace structural components: five-axis linkage, dynamic accuracy, volumetric accuracy

Impeller/Blades: 5-axis RTCP, oscillating head/turntable accuracy, dynamic tracking

Precision optical/medical components: spindle runout, thermal drift, micron-level positioning and environmental control

Large precision parts: machine tool rigidity, temperature compensation, and long-term accuracy retention

It is especially important to note that high positioning accuracy does not necessarily mean that the machined workpiece will be of high precision.

The actual machining accuracy of a machine tool is also affected by factors such as the lead screw, guide rail, spindle, thermal deformation, servo response, structural rigidity, cutting tools, and cutting parameters. High-speed, high-precision machine tools are actually a comprehensive matching problem involving multiple subsystems, including mechanical structure, drive motor, and control system.

2. Don't just look at the "positioning accuracy ±0.001 mm", this is the most common pitfall when purchasing high-precision machine tools.

At a minimum, the manufacturer should provide: positioning accuracy, repeatability, backlash/positioning error of each axis, straightness, perpendicularity, parallelism, spindle radial/axial runout, spindle thermal expansion, roundness/circular trajectory error, RTCP/rotary axis accuracy of the five-axis machine tool, and laser interferometer test report, etc.

3. Inspection items for machined parts : dimensional accuracy; geometric tolerances; flatness; roundness; coaxiality; surface roughness; consistency across multiple locations; and accuracy changes after several hours of continuous machining.

This is the only way to truly assess the quality of machine tools.

Especially for five-axis CNC machine tools, it is not enough to look at the positioning accuracy of a single axis. The final error of five-axis machining is also affected by geometric errors, servo errors, and dynamic errors.

5. High-precision machine tools, pay special attention to these hardware components.

Spindle: Maximum spindle speed; Spindle power; Spindle torque; Spindle bearings; Radial/axial runout; Thermal stability; Dynamic balance; Spindle cooling method.

Feeding system: Screw specifications; screw pretension; guide rail type; linear motor or ball screw; grating ruler; encoder resolution; axial acceleration; rapid traverse speed.