Generally, electroplating can be divided into full plating and partial plating according to its plating area. Many parts that require partial electroplating need to be insulated and protected on their non-plated surface, which requires different partial insulation methods to meet the technical requirements of construction to ensure that the non-plated surface of the parts will not be plated, especially if there are special requirements Parts.
Based on daily work experience, several local electroplating process methods commonly used in electroplating are now introduced.
1. Bandaging
This method is to insulate and protect the non-plated surface with tape or plastic strips, tape and other materials. The method of wrapping depends on the shape of the part. The wrapping method is suitable for simple parts, especially round parts with regular shapes. Bandaging is the simplest method of insulation protection.
2. Special Fixture Method
The special fixture method is also called the profiling fixture method. In other words, for some parts with more complicated shapes, special insulating fixtures can be designed to imitate the shape of the parts, which can greatly improve production efficiency. For example, when the inner diameter or outer diameter of the bearing is partially chrome-plated, a special bearing chrome-plating fixture can be designed, and this fixture can be used repeatedly.
3. Wax Protection Law
The characteristics of using wax preparations for insulation are that it has good bonding performance with parts, a wide temperature range of use, and the end of the insulating layer will not warp. Therefore, it is suitable for parts that require high tolerances on the size of the insulation end and have more complex shapes. In addition, wax preparations can also be used repeatedly, with little loss, but its use method is more complicated and the cycle is longer. When applying wax preparations, the parts should be preheated to 50～70℃, and then coated with melted wax preparations. First apply a thin layer to cover the entire surface that needs to be insulated. At this time, the wax should not solidify in the middle, and then repeat the application. To the required thickness. After coating, in the warm state before cooling to room temperature, trim the insulation edge with a knife, and then wipe the surface to be plated repeatedly with a cotton ball dipped in gasoline. This operation must be very careful. After plating, the wax preparation can be melted and recovered in hot water or a special wax bucket, and then the parts can be cleaned with a solvent such as gasoline or a water-soluble cleaning agent.
4. Paint insulation method
Lacquer insulating coatings are often used for insulation protection during electroplating. This insulation protection method is easy to operate and can be applied to complex parts. Commonly used insulating coatings include perchlorovinyl anticorrosive varnish (such as G52-1.G52-2), polyvinyl chloride insulating coating, nitro glue, etc.