The perfect appearance of the part illustrates Xavier's mastery of metal finishing.
Electro-galvanized surface treatment for CNC machined parts
Zinc electroplating, also known as cold galvanizing in the industry, is the process of using electrolysis to form a uniform, dense, well-bonded, anodic metal or alloy deposit on the surface of a manufactured part. Compared to other metals, zinc is a relatively inexpensive and easy to coat metal, is a low-value corrosion-resistant plating layer, is widely used to protect steel parts, especially against atmospheric corrosion, and is used for decorative purposes.
Types of zinc plating for CNC machined parts
Type | descriptive | Minimum salt spray time (H) | |
I | Plating only, no post-treatment | - | √ |
II | Colored Chromate Passivation | 96 | √ |
III | Colorless chromate passivation | 12 | |
IV | phosphoric acid conversion film | - | |
V | Colorless passivation without hexavalent chromium | 72 | √ |
VI | Colored passivation without hexavalent chromium | 120 | √ |
Environment for each film thickness
Classification number and conversion coating suffix | Minimum thickness of plating (um) | condition of service |
Fe/Zn 25 | 25 | SC4 - Very Harsh: Exposed to harsh conditions or frequent exposure to moisture, detergents, and salt water soluble waves, plus the possibility of damage from dents, scratches, or abrasion. |
Fe/Zn 12 | 12 | SC3-HARSH: Exposed to condensation, perspiration, rain and detergents. |
Fe/Zn 8 | 8 | SC2-Medium:Exposed to dry indoor environments, but occasional condensation, wear and tear. |
Fe/Zn 5 | 5 | SC1-Mild:Exposed to indoor atmospheres with rare condensation and minimal wear. |
Xavier Electro-galvanizing Capabilities
Base material: steel, copper alloy, zinc alloy, stainless steel, aluminum alloy
Reference standard: ASTM B633
Film thickness grade: 5μm, 8μm, 12μm, 25μm
Passivation method: environmentally friendly: blue white zinc, colored zinc, yellow zinc, black zinc
Non-environmentally friendly: military green zinc, white zinc, black zinc
Test methods: X-ray spectrometry film thickness test, zinc layer adhesion test, salt spray test, hydrogen embrittlement test;
substrates | Steel, copper alloy, zinc alloy, stainless steel | aluminum alloy |
Maximum processing size(cm) | 230*50*100 | 50*45*80 |
Maximum weight per unit (kg) | 100 | 40 |
CNC machined parts plating requirements
Plating Functionality
Electroplated zinc coatings should fulfill their functional requirements, including no hydrogen embrittlement, adhesion requirements and corrosion resistance requirements.
Thickness uniformity
High and low potentials exist in zinc electroplating, and the film will be thicker at high potential locations and thinner at low potential locations, affecting the uniformity of the coating thickness. Therefore, deposit surfaces that cannot be readily controlled to a specified thickness, such as threads, holes, deep recesses, angled bases and similar areas, are not normally subject to minimum thickness requirements.
Plating Appearance
The appearance of the plating shall be smooth and free from burns, blisters, pits, non-smoothness, knots, cracks, or localized absence of plating, as well as other defects that may affect use.
CNC machined parts zinc plating Case
Mixed Colors
blue zinc
zinc white
black zinc
Galvanized Case 5
army green zinc
Special Requirements for Electro-galvanizing - Sandblasting
Xavier has mature sandblasting and anti-sandblasting processes and technical capabilities to implement whole or partial sandblasting plating on the same product with steel parts, stainless steel, aluminum alloys, copper alloys, zinc alloys, etc. as the base material.
Sandblasting process is to use compressed air as a driving force, in order to form a high-speed jet beam will be sand abrasive high-speed jet to the surface of the workpiece that needs to be treated, so that the surface of the workpiece changes. Due to the impact and cutting effect of the abrasive on the surface of the workpiece, the surface of the workpiece obtains a certain degree of cleanliness and different roughness, so that the mechanical properties of the surface of the workpiece can be improved, so as to improve the fatigue resistance of the workpiece, increase the adhesion between it and the coating, and prolong the durability of the coating, as well as facilitating the leveling of the coatings and the decoration.
Local anti-sandblasting refers to the same product for the precise size of the parts or need to local special decorative parts do not need sandblasting, and take the method of shielding so that it is not sandblasted process, to provide solutions for the local anti-sandblast protection.