Cosmetic standards
Published on Saturday, 05. February 2005
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Content Guide：In CNC machining, surface treatment standards are established to ensure that parts meet specific functional, aesthetic, or durability requirements. Below are some common surface treatment standards and their applications
In CNC machining, Surface Treatment standards are established to ensure that parts meet specific functional, aesthetic, or durability requirements. Below are some common surface treatment standards and their applications:
Surface roughness is a critical measure of the smoothness of a part's surface, commonly represented by Ra (arithmetic mean roughness) or Rz (maximum height roughness).
Roughness Grade | Ra (μm) | Rz (μm) | Application Scenarios |
|---|---|---|---|
N12 (Rough Machining) | 25–50 | 100–200 | Non-contact surfaces, raw material surfaces |
N11 | 12.5–25 | 50–100 | General non-mating surfaces |
N10 | 6.3–12.5 | 25–50 | General mating surfaces |
N9 | 3.2–6.3 | 12.5–25 | Precision mating surfaces |
N8 | 1.6–3.2 | 6.3–12.5 | High-precision mating surfaces |
N7 | 0.8–1.6 | 3.2–6.3 | High-precision bearing surfaces |
N6 | 0.4–0.8 | 1.6–3.2 | Optical components, precision instruments |
N5 | 0.2–0.4 | 0.8–1.6 | Ultra-high-precision surfaces |
Based on the material, functional requirements, and operating environment of the part, appropriate surface treatment methods are selected.
Surface Treatment Method | Standard | Application Scenarios | Remarks |
|---|---|---|---|
Anodizing | ISO 7599, MIL-A-8625 | aluminum alloy parts, improves corrosion and wear resistance | Can be colored |
Electroplating | ISO 2081, ASTM B633 | Steel, copper, and other metals, improves corrosion resistance and conductivity | E.g., zinc plating, nickel plating |
Electroless Nickel Plating | ISO 4527, ASTM B733 | Increases hardness, wear resistance, and corrosion resistance | Suitable for complex-shaped parts |
Spray Coating | ISO 12944, ASTM D638 | Improves corrosion resistance and appearance | E.g., powder coating, paint spraying |
Passivation | ASTM A967, QQ-P-35 | Stainless steel parts, improves corrosion resistance | Removes surface free iron |
Polishing | ISO 1302, ASTM B46.1 | Improves surface finish and aesthetics | Suitable for appearance parts |
Sandblasting | ISO 8501, SAE J444 | Cleans surfaces, increases adhesion | Suitable for pre-treatment before coating |
Surface hardening treatments are commonly used to improve wear resistance and service life.
Hardening Method | Standard | Hardness Range | Application Scenarios |
|---|---|---|---|
Carburizing and Quenching | ISO 2639, ASTM E18 | 55–65 HRC | High-wear parts |
Nitriding | ISO 9001, ASTM E18 | 60–70 HRC | High-precision, high-wear parts |
Surface Hardening | ISO 3754, ASTM E18 | 50–60 HRC | Localized wear-resistant treatment |
Coating treatments are used to improve corrosion resistance, wear resistance, or special functionalities.
Coating Type | Standard | Thickness Range | Application Scenarios |
|---|---|---|---|
DLC Coating | ISO 20523, VDI 3198 | 1–5 μm | High-wear, low-friction parts |
TiN Coating | ISO 23223, VDI 3198 | 2–5 μm | Tool and mold surfaces |
CrN Coating | ISO 23223, VDI 3198 | 2–5 μm | High-corrosion-resistant parts |
After surface treatment, inspections are conducted according to relevant standards.
Inspection Item | Standard | Inspection Method |
|---|---|---|
Roughness Inspection | ISO 4287, ASME B46.1 | Roughness tester |
Coating Thickness Inspection | ISO 2178, ASTM B499 | Magnetic thickness gauge |
Hardness Inspection | ISO 6507, ASTM E18 | Hardness tester |
Corrosion Resistance Inspection | ISO 9227, ASTM B117 | Salt spray test |
Surface treatment standards should be selected based on the part's material, function, and operating environment.
Different industries (e.g., aerospace, automotive, medical) may have specific surface treatment requirements.
Ensure the part's surface is clean and free of oil, oxidation layers, etc., before surface treatment.
If more detailed surface treatment standards or industry-specific requirements are needed, please provide additional information!
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