1. Visual Inspection: Observe the surface from multiple angles under bright light to confirm the absence of scratches, rust, pits, and other defects.
Compare with a standard template (such as an unpolished surface or an industry standard template) to assess minor imperfections.
2. Tactile Inspection:
Gently run your fingers along the surface to check for burrs, pinholes, and other unevenness, but be aware of subjective biases.
3. Tool Measurement:
Surface Roughness Tester: Quantifies roughness values; lower values indicate smoother surfaces.
Gloss Meter: Measures the intensity of reflected light; high gloss usually corresponds to high surface finish.
4. Professional Testing: Use a microscope to observe the microstructure to confirm the absence of cracks, pores, and other defects.
Refer to standards such as GB/T6175-2016 to ensure the surface finish meets the required grade (e.g., Class A nuts require higher precision).
Precautions: The surface of the nut must be cleaned before testing to avoid oil contamination interfering with the results; the tool must be calibrated for precision measurements.
