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EspañolThe faucet, also known as the faucet, is one of the most widely used and widely used water utensils for toilet and scrubbing. With the improvement of people's living standards and the continuous improvement of housing conditions and living equipment, the demand for mid-range faucets is increasing, and the quality requirements for the surface coating of the faucets are also higher.
1. Selection of raw materials
The electroplating quality of the faucet depends not only on the electroplating process, but also in various aspects such as the faucet substrate material, casting process, and pre-plating treatment. The valve body of the faucet is the main part of the faucet. The material is cast brass, and the ZCu40ZnPb2 grade is the most common, and the average wall thickness of the casting is 3mm. The valve body, handle and valve cover of a good faucet are all made of brass. After casting, processing, surface grinding and polishing, they are electroplated with nickel, decorative chrome or chrome-nickel alloy. If such products are processed before casting, electroplating, electroplating If the process is well handled, it is generally more resistant to corrosion. In order to enhance the corrosion resistance of the product and improve the product level, a multi-layer nickel plating process is also used. However, in order to save production costs, some enterprises add a lot of waste copper to the cast brass, so that the cast brass contains a lot of impurities. After the acid salt spray test, there are pitting and pitting corrosion. Some manufacturers even use cast iron and zinc alloys that have been screened as raw materials, because cast iron is easy to rust, and zinc alloys are not corrosion-resistant, and the faucets made of these materials are easy to show rust spots. There are many defects such as rust spots and pitting. There are also manufacturers who use brass for the valve body, while the handle and valve cover are made of cast iron, plastic and other inferior materials. After 24 hours of acid salt spray test, the valve body is often not corroded, and the handle and the valve cover are not corroded. The valve cover showed serious corrosion, resulting in unqualified products and reducing the level of products.
2. Casting process
The valve body of the faucet is the main component of the faucet, and its production methods generally use sand casting and metal casting. Because the surface quality of the faucet is very high, the outer surface of the casting before electroplating cannot have any visible pores, cracks, looseness and impurities; the faucet body cast by metal mold is finely arranged, with good surface quality and high yield, and It can also prevent the environmental pollution caused by sand casting, so most manufacturers currently use metal casting technology. However, the metal mold casting nozzle valve is selected, the outer surface is formed by a metal mold, and the inner cavity is formed by a coated sand core. When the copper liquid is poured into the metal mold cavity, the surface cooling rate is faster, and the castings are arranged finely; The cavity is surrounded by the sand core, the cooling rate is slow, and shrinkage porosity is more likely to occur. Although some manufacturers choose cast brass with better material, after 24 hours of acid salt spray test, the valve body still shows loss of luster and rust spots. Therefore, only by strengthening the design of the casting mold, the melting and pouring of the alloy, the control of the casting process, and the cleaning of the falling sand, can the qualified faucet body castings be cast.
3. Pre-plating polishing and cleaning qualified faucet castings need to undergo machining, grinding and polishing processes before electroplating.
Machining and grinding are the shaping of the product. Grinding and polishing mainly flatten the surface of the product, reduce the roughness of the casting, and at the same time eliminate the fine sand holes, burrs and other defects caused by casting. Because the appearance quality of the faucet is relatively high, the coating on the outer surface of the faucet should be well combined, the arrangement should be fine, the lubrication should be uniform, the color and luster should be uniform, the polished outer surface should be bright, and there should be no appearance defects such as bubbles, burns, detachment, and scratches. . Polishing quality is a key factor to ensure the quality of electroplating, improve surface brightness and eliminate defects. Faucets are decorative products. It is very sensitive to doping and ballast, and even very fine impurities may cause defects such as burrs, pits or pinholes on the surface of the electroplating, and even charring, blistering and peeling of the coating. For example, after the 24h acid salt spray test, there will be loss of light and rust spots, and even bubbling and general corrosion, etc., the previous treatment is very important. After casting, the sand and carbonized resin in the inner cavity, the grease, copper chips and copper powder left after machining, and the polishing paste after polishing must be cleaned to ensure the quality of electroplating. The presence of contaminants is the primary cause of burrs and pitting in electroplating.
4. Control of electroplating process
The surface of the faucet is mainly electroplated with nickel-chromium. The nickel-chromium electroplating process has a history of many years, the electroplating process is very sophisticated, the purity of chemical materials and additives is high, and the impurities are low; and the electroplating equipment is advanced, only strict process management is required during the electroplating process, and the bath, rinsing water, equipment and The production environment is clean, and there are generally fewer problems with electroplating quality. The phenomenon of non-corrosion resistance found in the inspection is mainly because some manufacturers cut down the electroplating time in order to reduce the cost, the coating is thin, and the pores of the coating cannot be fully compensated.
5. Conclusion
1) The valve body, handle and valve cover of the faucet should be made of cast brass or copper alloy with good quality, and cast iron that is easy to rust and zinc alloy that is not corrosion-resistant should be discarded;
2) Select the metal mold to cast the faucet valve body, and pay attention to the casting process;
3) Grinding and polishing should be complete, and pre-plating treatment should be done well;
4) Strictly implement the nickel-chromium electroplating process standards, strengthen process management, and ensure the thickness of the coating.
