Common surface treatment technology of PVD coating equipment

PVD coating is a coating prepared by physical vapor deposition (PVD technology). At first, it was mainly used for tool coating of high-speed steel, and then it was widely used. Its application scope is no longer limited to the cutting tool field, but gradually applied to aerospace, medical devices, electronic communications, automotive parts and other fields. In the preparation process of pvd coating equipment, there may be some surface defects. surface treatment technology should be used to improve its performance and use quality. Now let's share some common surface treatment technologies of pvd coating in pvd coating equipment.

1、 Ultrasonic cleaning

Ultrasonic cleaning can remove oil dirt, dust and oxidized impurities on the surface of pvd coated products, ensure the surface of products to be plated is clean, and improve the adhesion between film and substrate. In industrial production, for products to be plated with different surface conditions, ultrasonic cleaning generally includes rough cleaning and fine cleaning. Rough cleaning takes a short time. It is just a simple ultrasonic cleaning for degreasing and rust removal of the products to be plated, mainly for some products that have been coated on the surface or need to be passivated; Fine cleaning takes a long time, so it is necessary to use various functional tanks of the cleaning line to clean the products to be plated. After cleaning, the products can be directly loaded into the furnace for coating preparation.

2、 Deburring

The deburring methods generally include manual cleaning, semi-automatic wheel brush cleaning and glass bead sand blasting. Manual cleaning is very suitable for the treatment of carbide tool burrs. This is due to the small amount of burrs at the cutting edge, which is hard even if there is one, and the brittleness is large. It is easy to damage the cutting edge when using semi-automatic wheel brush cleaning and glass bead sand blasting. Semi automatic wheel brush cleaning is generally used for the burr treatment of gear hobbing cutter. It is to fix the cutter on the low-speed rotary table and use a stainless steel brush to press it on the cutter teeth for cleaning, but this method is inefficient. Glass bead sandblasting and deburring is a widely used pretreatment method in the coating industry at present. The equipment used is generally a dry sandblasting machine. The sand is glass bead. After deburring, the burrs on the edge disappear and the teeth are clean, which is conducive to the deposition of coating material particles.

3、 Sandblasting

Sand blasting is driven by compressed air to form a high-speed jet beam and spray it onto the surface of the workpiece to be treated to remove impurities, noises and oxide layers on the surface. At the same time, the product surface can reach a certain degree of finish, eliminate residual stress of the workpiece and improve the surface hardness of the substrate.

4、 Passivation

Passivation treatment is an important treatment process of chemical cleaning, which can prevent the corrosion of substrate. In addition, the passivation treatment can remove the burrs on the edge of precision and high-precision tools, clean the large particles on the coated surface and polish the surface coating. The sand materials used mainly include coarse sand and fine sand.

5、 Polishing

Polishing refers to the processing method of reducing the surface roughness of pvd coated products by using mechanical, chemical or electrochemical effects to obtain bright and flat surfaces. It refers to the surface modification of pvd coated products by using polishing tools, abrasive particles or other polishing media. The purpose of polishing treatment is to obtain smooth surface or mirror luster, and sometimes it is also used to eliminate luster. The polishing wheel is usually used as the polishing tool.

6、 Degassing

Degassing refers to the process of heating, insulating and cooling the ultrasonic cleaned products to be plated under vacuum environment to make sure that the blind holes, gaps, welding positions, as well as product surfaces and other parts of the products to be plated are free of impurities, oil stains and volatile materials that have been cleaned by ultrasonic cleaning, so as to ensure that the products will not be oxidized by impurities during coating It is a deep level cleaning method that may lead to coating off the membrane or even polluting the furnace cavity.

7、 Recoat

Generally, there are two methods of recoating: chemical recoating and electrolytic recoating, both of which are used to clean the old coating by chemical solution reacting with the coating surface. The chemical stripping solution is convenient and the equipment is simple, but the stripping speed is slow. Different kinds of coatings need specific chemical solutions to have effect. Electrolytic recoating can remove almost all coatings, and the recoating speed is fast, but the equipment cost is high, and the economic and practical performance is not as good as chemical recoating.

The common surface treatment technologies of pvd coating are mainly the above seven technologies. Different surface treatment technologies have different functions, but the quality of pvd coating has been improved, which can enhance the surface quality of the coating and improve the use effect.