Kaiping Faucet: electroplating quality and electroplating process of faucet

2022-02-14 98

  1. Selection of materials

The electroplating quality of faucet not only depends on the electroplating process, but also involves the faucet base material, casting process, electroplating pretreatment and other aspects. The faucet valve body is the primary component of the faucet. The material is cast brass. Zcu40znpb2 brand is common, and the average wall thickness of the casting is 3mm. The valve body, handle and valve cover of a good faucet are all refined with brass. After casting, processing, surface grinding and polishing, they are electroplated with nickel, decorated with 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 function of the product and improve the product level, multi-layer nickel plating process is also selected. However, in order to save production costs, some enterprises add a lot of waste copper into the cast brass, which makes the cast brass contain a lot of impurities. The appearance of the products made in this way is loose, contains more sand holes and is not corrosion-resistant. After the acid salt spray test, they show pitting and pitting corrosion. Some manufacturers even use the selected cast iron and zinc alloy as materials, because cast iron is easy to rust and zinc alloy is not corrosion-resistant. The faucet made of these materials is easy to show rust spots. After 2H acid salt spray test, the valve body shows a lot of rust spots, pits and other shortcomings. In other manufacturers, the faucet valve body is made of brass, while the handle and valve cover are made of cast iron, plastic and other low-quality materials. After the 24h acid salt spray test, the valve body often does not produce corrosion, while the handle and valve cover show serious corrosion, resulting in unqualified products and reducing the level of products.

  2. Casting process

Faucet valve body is the primary component of faucet, and its production method is generally sand casting and metal casting. Because the appearance quality of the faucet is very high, there shall be no visible pores, cracks, looseness and inclusions on the outer surface of the casting before electroplating; The faucet body of metal mold casting has fine arrangement, good appearance quality and high yield, and may also avoid the problem of environmental pollution caused by sand mold casting. Therefore, at present, most manufacturers use metal mold casting skills. However, the use of metal mold casting faucet valve, its outer 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 outer surface cooling rate is fast, and the casting arrangement is fine; The inner cavity is surrounded by sand core, and the cooling rate is slow, which is easy to produce shrinkage and porosity. Although some manufacturers choose cast brass with good material, after 24h acid salt spray test, the valve body still shows light loss and rust spots. The reason is that the casting process is not handled well when casting the faucet body. Therefore, only by strengthening the design of casting mold, melting and pouring of alloy, control of casting process and sorting of falling sand, can we cast qualified faucet body castings.

  3. Polishing and cleaning before plating qualified faucet 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 appearance of products, reduce the roughness of castings, and remove fine sand holes, burrs and other defects caused by casting. Because the appearance quality requirements of the faucet are relatively high, the coating on the external surface of the faucet shall be excellent, the arrangement shall be fine, smooth and uniform, the color and luster shall be uniform, the polished external surface shall be bright, and there shall be no appearance defects such as bubbles, scorching, separation and scratches. Polishing quality is the key factor to ensure electroplating quality, improve surface brightness and remove defects. Faucets are decorative products. It may be very sensitive to the appearance of the coating, such as scorching and pitting, even if it is very sensitive to the appearance of the coating, and even to the formation of fine blisters and burrs. For example, after passing the 24h acid salt spray test, there will be light loss and rust spots, even bubbling and overall corrosion. 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, and the polishing paste after polishing must be cleaned, so as to ensure the quality of electroplating. The existence of pollutants is the primary factor of burr and pitting in electroplating.

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  4. Control of electroplating process

The appearance of faucet is mainly nickel chromium plating. 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, as long as the process is strictly handled and the bath solution, rinsing water, equipment and production environment are kept clean, there are generally few electroplating quality problems. The non-corrosion phenomenon found in the test is mainly that some manufacturers reduce the electroplating time in order to reduce the cost. The coating is thin and can not fully make up for the pores of the coating. The corrosive solution corrodes to the matrix through the pores, showing a lot of rust spots.

  5. conclusion

1) cast brass or copper alloy with good quality shall be selected for the valve body, handle and bonnet of the faucet, and materials such as rust prone cast iron and non corrosion resistant zinc alloy shall be discarded;

2) select metal mold casting faucet valve body and pay attention to the casting process;

3) the grinding and polishing shall be complete, and the pre plating treatment shall be done well;

4) strictly implement the nickel chromium plating process standard, strengthen the process management and ensure the coating thickness.

Article source: Kaiping faucet www.belito. cn