How to distinguish the electroplating quality of faucet
Faucet, also known as faucet, is a widely used and widely used water appliance for washing and brushing. With the advancement of people's living standards and the continuous improvement of housing conditions and daily facilities, the demand for faucets is increasing, and the requirements for the surface coating quality of faucets are also high.
1. Selection of materials
The electroplating quality of water nozzle not only depends on the electroplating process, but also involves the base material of water nozzle, casting process, electroplating pretreatment and other aspects. The faucet valve body is the primary component of the faucet, and the material is cast brass. The valve body, handle and bonnet of a good faucet are all made of brass. After casting, processing, surface grinding and polishing, they are electroplated with nickel, decorative chromium or chromium nickel alloy. If such products are well treated in casting, electroplating pretreatment and electroplating process, they are generally corrosion-resistant. In order to enhance the corrosion resistance of products and advance the product level, multi-layer nickel plating process is also selected.
2. Casting process
The nozzle valve body is the primary component of the nozzle, and its production method is generally sand casting and metal casting. Due to the high surface quality requirements of the water nozzle, there shall be no visible pores, cracks, looseness and adulteration on the surface of the casting before electroplating; The nozzle body of metal mold casting has fine structure, good surface quality and high yield, and may also avoid the problem of environmental pollution caused by sand mold casting. Therefore, most manufacturers now choose metal mold casting technology. However, when the metal mold casting water nozzle valve is selected, its surface is formed by metal mold and its inner cavity is formed by coated sand core. When the liquid copper is poured into the metal mold cavity, the surface cooling rate is fast and the casting structure is fine; The inner cavity is surrounded by sand core, and the cooling rate is slow, which is easy to produce shrinkage and porosity defects. Although some manufacturers choose cast brass with good material, after 24h acid salt spray test, the valve body still has light loss and rust spots. The reason is that the effect of casting process is not handled well when casting the nozzle body. Therefore, only by strengthening the design of casting mould, melting and pouring of alloy, control of casting process and cleaning of falling sand, can we cast qualified nozzle body castings.
3. Polishing and cleaning before plating qualified nozzle castings need to go through machining, grinding and polishing processes before plating.
Machining and polishing are the shaping of products. Grinding and polishing mainly flatten the product surface, reduce the roughness of castings, and eliminate fine sand holes, burrs and other defects caused by casting. As the appearance quality requirements of the water nozzle are relatively high, the coating on the surface of the water nozzle shall be well combined, the organization shall be fine, smooth and uniform, and the color shall be uniform. The polished surface shall be bright without appearance defects such as bubbles, scorching, detachment and scratches. Polishing quality is the key factor to ensure electroplating quality, improve surface brightness and eliminate defects. Faucets are decorative products. It is very sensitive to adulteration and slag inclusion. Even subtle impurities may form defects such as burrs, pits or pinholes on the electroplated surface, and even scorch, blister and peeling of the coating. For example, after passing the 24h acid salt spray test, there will be light loss and rust spots, and even bubbling. The previous treatment is very important. The sand and carbonized resin in the inner cavity after casting, the grease, copper chips and copper powder left after machining, the polishing paste after polishing and other pollutants are cleaned, so as to ensure the quality of electroplating. The existence of pollutants is the primary factor of burr and pitting in electroplating.
4. Control of electroplating process
The surface of the water nozzle is mainly plated with nickel chromium. The nickel chromium electroplating process has a history of many years. The electroplating process is very sophisticated, with high purity of chemical materials and additives and less impurities; Moreover, the electroplating equipment is advanced. In the electroplating process, only strict process management is required, and the cleanliness of bath solution, rinsing water, equipment and production environment is adhered to. Generally, there are few electroplating quality problems. The non-corrosion phenomenon found in the test is mainly that some manufacturers reduce the electroplating time and the coating is thin in order to reduce the cost, which can not completely compensate the pores of the coating. The corrosive solution corrodes to the matrix through the pores, resulting in a lot of rust spots.
1) The valve body, handle and bonnet of the water nozzle shall be cast brass or copper alloy with good quality, and the materials such as easily rusty cast iron and non corrosion resistant zinc alloy shall be discarded;
2) Select metal mold casting nozzle valve body and pay attention to the casting process;
3) The grinding and polishing shall be thorough, and the pre plating treatment shall be done well;
4) Strictly implement the nickel chromium plating process specification, strengthen the process management, and ensure the coating thickness.
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