Causes and solutions for zinc alloy plating foaming

Zinc alloy is easy to mold, has high plasticity, low cost and high processing efficiency. It is widely used in sanitary ware, bags, shoes and accessories. However, the igniting problem of zinc alloy ( electroplating ; spraying) has been annoying the hardware factory and electroplating factory. friend.

The experience of the electroplating factory needles of a number of hardware factories that have been serviced has been compiled on the experience of zinc alloy foaming, which has the following aspects:

1. At the beginning of the design of zinc alloy products, it is necessary to consider the feeding port and the slag discharge port and exhaust setting of the mold. Because the workpiece flow path of feeding and slagging is smooth and uncontained, no water stains are generated, no dark bubbles are formed, which directly affects whether the subsequent plating is blistering, and the qualified feeding and slag discharging die are die-casting the workpiece, and the surface is smooth and white, Waterless stains.

2. In the mold development, we must also consider the tonnage and pressure of the molding machine. We will personally experience a 20-30 incident of foaming after zinc alloy plating. A hardware factory friend picks up a few million big orders, and the mold opens 8 pieces. No matter how to solve the pre-plating treatment, there are always 20-30% foaming. Finally, the mold is blocked by 4 pieces and changed into 4 pieces. There is no bubble in the plating.

3. The front surface of the rolling liquid, polishing paste, oxide layer is not cleaned, there is a long rolling, the workpiece after rolling, the surface is bright, many employees of the electroplating process of the electroplating plant are pickled and led to the surface The attached pulverizer was not washed and foamed for a long time. The roller-rolling agent used in the other rolling mills also has a great relationship, and some surfactants in the pulverizing agent are extremely difficult to wash off.

4. The product is made into alkali copper (a lot of copper bottoms commonly known as hardware friends). Before the plating tank, there is still an oxide film (picked film) on the surface of the workpiece. The wax removal and degreasing film are not treated. Therefore, the release film is very important. In the early years, it is also possible to use anti-staining salt to remove it. It is environmentally friendly to prevent the discharge of wastewater containing anti-staining salt. It is recommended to use LJ-D009 release film, which is superior to anti-staining salt, and can remove nickel layer and COD emission. International standard

5. Alkali copper plating tank organic matter, many impurities, free cyanide is not in the range, test the alkali copper cylinder composition, see if the sodium cyanide is low or sodium hydroxide is high! If the brightener is added high, the alkali copper cylinder The cleaning is very important, it is recommended to treat the carbon once every 3-5 days.

6. The conductivity of the alkali copper cylinder is also very important. Whether the anode is dissolved normally or not, the anode copper plate is sufficient to cause foaming.

7. The zinc alloy product foams out after coming out of the oven; it may be caused by uneven temperature of the oven, that is, the temperature is too high. Because the die casting is not tight, the zinc alloy water stains are easy to enter the acid, and the acid and zinc even have a surface. In the case of plating, a chemical reaction still occurs, and a large amount of hydrogen gas is generated. When the pressure inside is higher than the atmospheric pressure, the high temperature generates bubbles.