Before plating, the surface of the substrate should be thoroughly removed from grease, oxides and other impurities to ensure the bonding strength of the plating layer and avoid peeling or blistering.
Author: Anna
I. Pre-treatment and process control
1. Substrate cleaning and activation
Before plating, the surface of the substrate should be thoroughly removed from grease, oxides and other impurities to ensure the bonding strength of the plating layer and avoid peeling or blistering.
Complex shaped parts need to be charged into the tank, if necessary, using step feeding (inrush current of 50%-100% of the normal current) to enhance the bonding strength.
2. Precise control of process parameters
Strictly regulate the temperature of the plating solution, current density and pole pitch: uneven temperature will easily lead to excessive internal stress of the plated layer, and too high current density may cause brittleness of the plated layer.
Regular maintenance of the plating solution is required to check the trivalent chromium content and solution concentration to avoid impurity contamination affecting the quality of the plated layer.
3. Plating thickness management
The thickness of hard chromium plating is generally controlled above 20μm, but too thick (such as more than the process standard) will reduce the bonding force and toughness, and need to be adjusted in stages by step feeding.
II. Daily use and maintenance
1. Surface protection
Avoid hard objects scraping or bumping the chrome-plated surface to prevent breakage of the plating layer leading to oxidation or corrosion of the underlying metal.
Use soft cloth or sponge for cleaning, disable steel wire ball, acidic/alkaline cleaner, recommend neutral cleaner or special chrome plating maintenance agent.
2. Environmental adaptation
Chrome plated parts need to be kept dry and avoid prolonged immersion or exposure to humidity to minimize the risk of oxidation.
Avoid direct sunlight or high temperature environment (e.g. long term exposure of automotive chrome strips) to prevent discoloration or deterioration of the plating.
3. Repair of breakage
Slight scratches can be handled by polishing paste, serious rust spots need to be repaired by grinding and then re-plating; complex parts are recommended to use brush plating or chemical plating for local repair.
III. Special scene notes
1. Plastic chrome plating
Give priority to ABS and other easy-to-plate materials, control the surface roughness (should not be too light or too rough), to ensure the adhesion of the plating layer.
Plastic chrome plating needs to strictly regulate the current density and solution concentration to prevent the plating solution from penetrating and causing deformation of the substrate.
2. Environmental protection and safety
The production link needs to deal with chromium-containing wastewater and waste gas, prohibit hexavalent chromium process (such as the use of trivalent chromium instead), the operator needs to wear protective equipment.
IV. Common Problems
Loss of plating layer: mostly due to incomplete pretreatment or contamination of plating solution, it is necessary to strengthen the degreasing process and filter the plating solution regularly.
Tumor/burr: Take out the workpiece and polish it regularly, and continue to use step feeding when re-entering the tank.
Chrome plating operation should focus on pre-treatment, process parameter control and daily maintenance, and adjust the strategy for different substrates (metal/plastic) and environments (industrial/civilian) in order to balance functionality, aesthetics and safety.