We provide a large number of vacuum solutions for different coating processes. In addition to the independent vacuum pump, we also supply a complete set of vacuum system. The dry screw vacuum pump is especially suitable for the coating process – lamp coating. It has been proved that the screw vacuum pump combined with roots vacuum pump is the standard solution for medium vacuum coating application.
Vacuum plasma spraying (VPS) is a kind of plasma enhanced coating process in vacuum. This process gives the surface some properties, but the carrier material does not change. When the volume of the vacuum chamber is 19000l, this system is not only the largest vacuum plasma spraying system, but also the attempt of using the dry vacuum technology dry screw vacuum pump.
Practical application of screw vacuum pump in plasma spraying coating system
The coating technology of vacuum plasma spraying system requires a double wall water-cooled vacuum chamber. The parts to be coated are placed inside and the treatment chamber is then closed. The vacuum system will discharge the chamber at a pressure of 0.08 mbar. This ensures that the oxygen in the atmosphere and the water vapor attached to the components are completely evacuated and will not have a negative impact on the components. It also creates conditions for the production of extremely pure gas environment. Then, the pressure of the treatment room and argon will be refreshed to 100 mbar, and then further evacuated to 1 mbar.
The actual coating will only start when the process gas mixture enters and the plasma burner is turned on. This is customized for individual coatings and materials. The coating is mainly affected by energy input, gas and gas mixture used, temperature, coating time and pressure level of single process step.
In the case of high current, the plasma produces an arc, which transfers energy to the coating. The spray powder is mixed in the gas jet, and the liquid droplet is formed at the temperature range of 20000 degrees Celsius, and is accelerated, compressed and sprayed onto the surface of the workpiece. A processing robot in the vacuum chamber moves the plasma burner during this process and ensures that all components are evenly sprayed. The whole painting process takes about 30 minutes.
Screw vacuum pump is the backup pump of vacuum system. The vacuum system is divided into three stages. In each case, it consists of two vacuum boosters, which pre compress the evacuated air and flushing or process gas, and then transmit it to two additional vacuum boosters working in parallel. Therefore, before the gas mixture or gas is further compressed in the downstream screw vacuum pump, additional compression will be generated to achieve the final pressure of the system. The size of the propeller used is coordinated to achieve a pumping speed of 12000 cubic meters per hour. The vacuum system can quickly reach the pressure required for the initial evacuation of 0.08 mbar in the vacuum chamber, but can work in all pressure ranges up to 900 mbar, and accurately maintain the required set point for the process.
In addition to frequency control drive, dry screw vacuum pumps have other advantages, that is, they are water-cooled. This means that the operating temperature can be set or set to a temperature range to prevent the process gas from condensing in the vacuum pump. Both vacuum pumps are connected to the cooling water system of the vacuum plasma spraying coating system. This also provides ionized cooling water for the entire system. Due to the cooling of water, there is no heat release. The practical application of the dry screw vacuum pump in the plasma spraying coating system runs in a completely dry process. This means that they do not need to operate the fluid in the compression chamber and can be mixed with the process gas.
Vacuum coating machine is a special equipment specialized in evaporation aluminum plating on plastic surface. It has fast film forming speed, firm film, bright color, and is not easy to be polluted. The coating with good compactness, high purity and uniform film thickness can be obtained by the electroplating equipment, which does not produce waste liquid and waste water and can avoid environmental pollution. It is an ideal equipment for large-scale production. The equipment is widely used, mainly in automobile reflective net, handicraft, jewelry, shoes and hats, clocks and watches, lamps and lanterns, decoration and other industries. It is mainly composed of vacuum chamber, exhaust system, evaporation system and electrical equipment.