Part cleaning & general finishing
Published on Friday, 11. February 2005
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Content Guide：In CNC machining, part cleaning and finishing are critical steps to ensure part quality and performance. Below are the standards and guidelines for part cleaning and general finishing
In CNC machining, part cleaning and finishing are critical steps to ensure part quality and performance. Below are the standards and guidelines for part cleaning and general finishing:
The purpose of part cleaning is to remove oil, cutting fluid, metal chips, and other contaminants generated during machining to ensure smooth subsequent processes (such as Surface Treatment or assembly).
Cleaning Method | Application Scenarios | Cleaning Medium | Precautions |
|---|---|---|---|
Ultrasonic Cleaning | Small precision parts, removal of tiny particles and oil | Water-based cleaners, solvents | Avoid damage to fragile parts |
Spray Cleaning | Medium-sized parts, removal of surface oil and debris | Water-based cleaners, alkaline cleaners | Ensure compatibility of cleaning agents with materials |
Vapor Degreasing | High-precision parts, removal of stubborn oil and grease | Solvents (e.g., trichloroethylene) | Operate in a well-ventilated environment |
Manual Wiping | Large parts or localized cleaning | Non-woven cloth, alcohol, acetone | Avoid using cloths that leave fiber residues |
High-Pressure Air Blowing | Removal of loose debris and dust | Compressed air | Ensure appropriate air pressure to avoid damaging parts |
Cleanliness Requirements: Determine cleanliness levels based on part usage (e.g., ISO 16232 or VDA 19 standards).
Residue Inspection: Use white cloth wiping or microscopic inspection to ensure no visible oil, particles, or residues.
Drying Requirements: Ensure thorough drying after cleaning to avoid moisture-induced corrosion.
Finishing is performed to improve dimensional accuracy, surface finish, and functionality of parts.
Finishing Method | Application Scenarios | Machining Accuracy | Surface Roughness (Ra) |
|---|---|---|---|
Precision Turning | Cylindrical or rotary parts | IT6–IT7 | 0.8–3.2 μm |
Precision Milling | Flat surfaces, curved surfaces, or complex geometries | IT7–IT8 | 0.8–6.3 μm |
Grinding | High-hardness materials or high-precision parts | IT5–IT6 | 0.1–0.8 μm |
Polishing | Appearance parts or parts requiring high surface finish | - | 0.025–0.4 μm |
Lapping | Ultra-high-precision parts, such as optical components or precision molds | IT4–IT5 | 0.012–0.1 μm |
Dimensional Tolerances: Based on drawing requirements, typically referencing ISO 2768 or ASME Y14.5 standards.
Surface Roughness: Select appropriate roughness levels (e.g., Ra values) based on part functionality.
Geometric Tolerances: Includes flatness, roundness, cylindricity, etc., complying with ISO 1101 or ASME Y14.5 standards.
After cleaning and finishing, strict quality inspections are required.
Inspection Item | Inspection Method | Standard |
|---|---|---|
Cleanliness Inspection | White cloth wiping, particle counting, microscopic inspection | ISO 16232, VDA 19 |
Dimensional Inspection | Use calipers, micrometers, coordinate measuring machines (CMM) | ISO 2768, ASME Y14.5 |
Surface Roughness Inspection | Roughness tester | ISO 4287, ASME B46.1 |
Geometric Tolerance Inspection | Coordinate measuring machines (CMM), projectors | ISO 1101, ASME Y14.5 |
Material Compatibility: Cleaning agents and machining fluids must be compatible with part materials to avoid corrosion or chemical reactions.
Environmental Control: Maintain a clean environment for cleaning and finishing to avoid dust and contamination.
Process Sequence: Cleaning is typically performed after finishing, but intermediate cleaning may be required in some cases (e.g., before polishing).
Tool Selection: Choose appropriate tools and parameters during finishing to ensure surface quality and accuracy.
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