Maintenance and repair of vacuum coating equipment

Maintenance of vacuum coating equipment
1.1 maintenance of mechanical vacuum pump:
(1) The pump and its surrounding environment should always be kept clean.
(2) During the operation of the pump, the oil volume in the oil tank shall not be lower than the center of the oil pointer.
(3) vacuum pump oils of different types and brands cannot be mixed.
(4) The temperature rise of the pump in use shall not exceed 70 C.
(5) The oil of the new pump should be changed for 1 ~ 2 times after it is used for about 100 hours. After the replaced oil is no longer found to contain ferrous metal powder, it can be replaced
Extend the oil change period. The oil change period shall be determined according to the provisions of the instructions and the actual situation of use.
(6) The new pump and the repaired pump should be tested for 4 ~ 6h to check whether the pump meets the use requirements.
(7) After the pump is used for a long time (ranging from 2 to 3 years), the limit vacuum degree decreases, and it should be overhauled once. It should also
Clean and repair the system, pipeline, valve and motor.
(8) When the pump is in use, due to special accidents such as system damage, or when the air inlet is suddenly exposed to the atmosphere, the pump should be stopped as soon as possible and switched off
Disconnect the vacuum pipe connected with the system (close the low vacuum valve or clamp the vacuum clamp) to prevent oil injection and pollution of the workplace.
(9) Do not disassemble all parts of the pump without permission. (10) when the pump is not in use, use a rubber plug (CAP)
Plug the air inlet to prevent dirt and hard objects from falling into the pump. (11) Always pay attention to the development trend of vacuum technology, and try to introduce new technologies and materials (such as new pump oil) as soon as possible to improve the performance of the original system. For the above points, the corresponding operating procedures can be formulated and strictly implemented according to the specific situation.
1.2 daily maintenance of the whole set of equipment:
(1) Operators should be familiar with various instruments, pumps and various parts of equipment. Read and understand various instructions.
(2) The water pressure of cooling water should be kept between 0.1 ~ 0.2 MPa, and the outlet water temperature w 45C.
(3) The compressed air pressure is between 0.4 ~ 0.5 MPa.
(4) Before starting each boiler, check the cylinder capacity of protective gas to avoid insufficient gas filling, and replace the cylinder.
(5) If there is any abnormal condition after startup, it should be eliminated immediately or shut down to find the cause.

(6) Check the return water volume of each part frequently, and ensure that there is sufficient cooling water for each part during operation.
(7) (7) when the equipment is out of use, the gas in the furnace should be evacuated. If it is not used for a long time, it should be filled with protective gas, and the circulating water in the water-cooling jacket of the equipment should be discharged.
(8) The mechanical pump and roots pump should be changed and refueled regularly, and the oil cup of roots pump should always be filled with oil. When changing oil, be sure to
Drain the waste oil.
(9) When changing the oil of the diffusion pump, if there is oxidation inside, clean the oxidation layer inside the diffusion pump, and then replace it with new oil.
(10) The purity of the charged protective gas should not be less than 99.99%.
(11) Flammable, explosive and corrosive gases are not allowed to be used as protective atmosphere for this equipment.
(12) The equipment surface and instrument surface should be kept clean. It is not allowed to wipe the inner wall of the furnace with water or non vacuum
Wipe with an oily rag.
(13) the oil-water separator on the pneumatic triplex of the pneumatic system should often drain water, and the vacuum diffusion pump oil should be injected into the oil mist.
(14) The voltage of the whole equipment shall be within the range of 350 ~ 420 v. The three phases should be balanced.
(15) The regulation, electric contact pressure gauge, thermocouple, etc. should be often coated with diffusion pump oil to form an oil film between it and the seat,
Prevent air leakage. The above parts and flange connections are not allowed to be sealed with vacuum sealing mud for a long time.
(16) the bolts of each part shall be checked regularly. If they are found to be loose, they shall be tightened in time.
(17) When the equipment is working, pay attention to the display of each instrument and the sound of each pump, so as to find out the abnormalities in time and find out
(18) The operating environment of the equipment is at a relative humidity of 85% a and a temperature of 10 ~ 40 C. When disassembling and repairing the equipment, all parts are not
It is allowed to knock with a heavy hammer, and the sealing surface and sealing groove shall not be scratched.
(19) When the equipment is working, the operator shall not leave the post for a long time.
Maintenance of vacuum coating equipment
2.1 key points of maintenance of vacuum coating equipment:
The key point of maintaining vacuum equipment is to judge the fault. It is often that the vacuum cannot be pumped up. There may be several reasons. We must find out the reasons. Maybe the vacuum unit has insufficient pumping capacity, or the leakage rate is high, or both. At this time, you should observe and record patiently to find out the fault. For example, if the evacuation time is the same and the vacuum degree is low, close the main valve at this time. If the pointer of the vacuum gauge drops quickly, in most cases, the vacuum chamber leaks. At this time, the leakage point should be found out first. Such as vacuum
The pointer of the meter drops very slowly. In most cases, the pumping capacity of the vacuum unit is insufficient. At this time, we can focus on finding the vacuum pump and valve
To see where there is leakage, or the diffusion pump oil is polluted and oxidized; Or the front stage pipeline is not well sealed,
Insufficient pump oil; Or pump oil emulsification, shaft seal oil leakage and other faults.
1、 Detection leakage rate:
The most troublesome problem for users is the detection leakage rate. Leakage is divided into internal leakage and external leakage. External leakage is easier to detect, while internal leakage is difficult
Do some. For larger leakage points, the flame method can be used. Using the principle that air flow can make the flame deviate, vacuum first, such as using candles
Or the lighter is gradually searched near the suspicious point, and the flame will be found to shift to the leakage point, then the leakage point can be found.
(1) Find leaks and micro leaks:
Small leaks and micro leaks are more difficult to check. The commonly used method is to use the ionization tube to detect leaks by being sensitive to certain gases in a high vacuum state, such as acetone or ethanol. Use a medical syringe to spray acetone or ethanol into suspicious places. When it reaches the leak point, the pointer of the ionization meter will swing obviously. We must be patient to use this method to detect leakage. We must wait until the indication of the ionization meter is stable - that is, the pumping capacity and leakage rate of the vacuum unit are balanced, and then spray. Repeat several times to confirm the leakage point. (2) Search for leakage and external leakage: the internal leakage mostly occurs on the equipment with water-cooled jacket. No doubt is found in the external leakage inspection, but the following phenomena exist: the pumping speed of the mechanical pump is obviously low, the indication value of the vacuum gauge is low, the mechanical pump oil is quickly emulsified, and the iron-based parts in the vacuum chamber are obviously rusted. With the above conditions, internal leakage can be basically determined. For example, there is a 25 kg medium frequency furnace equipped with 2x-70 rotary vane pump and two zj-150 Roots pumps. When they are pumped together, they can only pump 10 Pa. The function of the zj-150 pump cannot be seen, and no external leakage is found, but there are conditions for the mechanical pump oil to emulsify quickly, and the iron base parts in the vacuum chamber are obviously rusted. After the disassembly equipment is cleaned, the furnace cover leakage is found by passing cooling water, and the rest is to find out the leakage point. Clean the inner wall first, and then connect the cooling water to see if there is any wet point. The wet point is the leakage point.
2、 Troubleshooting:
Find out the fault point and deal with it according to local conditions. The simple way is to replace parts, as small as rubber rings and bolts; As big as valves and vacuum pumps, you can change them as long as you have them on hand. The parts to be welded shall be carried out according to the requirements, and it is also necessary to confirm whether the requirements are met after welding.