Vacuum aluminum brazing furnace operation process

Vacuum aluminum brazing furnace operation procedures
1.1 open up preparation
1.1.1 check whether the electrical connectors are fastened and whether the components are clean and normal.
1.1.2 turn on the main switch of the water cooling system and the sub switches to ensure the water pressure of 0.1 to 0.3MPa.
1.1.3 turn on the compressed air switch.
1.1.4 turn on the main switch of the inflatable system. (if the process is not necessary, it can not be opened).
1.1.5 power switch.
1.1.6 switches all the switches on the electrical control box.
1.1.7 adjust the control instrument to meet the requirements of vacuum brazing technology.
1.1.8 Oil Diffusion Pump Heating: When the diffusion pump is in a vacuum state, open the maintenance valve, start the maintenance pump, the diffusion pump vacuum delay, the oil diffusion pump heating in advance.
1.2 start up process
1.2.1 opens the furnace door, sends the workpiece into the furnace, and closes the lid.
1.2.2 open bypass valve, start the slide valve pump and vacuum the furnace.
1.2.3 when the vacuum degree of the furnace is less than 670 Pa, pay attention to observing the roots of the roots pump do not rotate and start the roots pump.
1.2.4 When the vacuum in the furnace reaches 10 Pa, and the diffusion pump is heated to the temperature (about 90-120 minutes), close the bypass valve, close the maintenance valve, stop the maintenance pump. Open the main valve and open the high vacuum valve on the diffusion pump. The diffusion pump is used for vacuuming the furnace body.
1.2.5 When the vacuum in the furnace reaches the specified value, it can be heated by electricity, and the furnace begins to heat up and keep warm (programmed according to the set process curve).
1.2.6 brazing heating process, the furnace is cut off and stopped heating.
1.2.7 turn off the high vacuum valve. Stop diffusion pump heating and strengthen the cooling of the pump body.
1.2.8 stop roots pump, open the maintenance valve, start the maintenance pump. Delay the main road valve and stop the slide valve pump.
1.2.9 strengthen furnace cooling (as required).
1.2.10 When the furnace temperature drops to the dischargable temperature (determined by brazing process), make furnace preparation (or according to process requirements to fill high purity nitrogen ahead of time, accelerate cooling).
1.2.11 opens the furnace body bleed valve, causes the pressure inside the furnace to restore to the atmospheric pressure, closes the stove body bleed valve.
1.2.12 open the furnace door and remove the workpiece.
1.3 stop furnace
1.3.1 turn off the main switch of the inflatable system.
1.3.2 when the oil temperature of the oil diffusion pump is below 50 C, maintain the valve and stop the pump. At this point should open the bypass valve, start the slide valve pump, so that the furnace to maintain a vacuum state of 1 *10-1 Pa (vacuum meter display value), then close the bypass valve, stop the valve pump.
1.3.3 turn off the compressed air switch.
1.3.4 turn off the main switch of the water cooling system.
1.3.5 disconnect the power master switch.

Vacuum aluminum brazing furnace maintenance and repair
2.1 The outside surface of furnace and control cabinet should be wiped regularly to keep clean and clean, and the power supply and compressed air should be cut off when cleaning equipment.
2.2 When the furnace is dirty or dusty, wipe it clean and dry with silk cloth soaked with acetone or anhydrous alcohol.
2.3 regularly clean up the magnesium blocks on the inner wall of the furnace door once a month.
2.4 Do not use the oven for a long time, and then re-start the oven should be baked, the temperature reached 620 degrees Celsius, vacuum degree less than 10-3Pa insulation for an hour.
2.5 check whether the circulating pool is adequate before each shift, otherwise, add cooling water. The cooling water pressure should be greater than 0.1MPa, otherwise the waterway screen should be checked.
2.6 Before each shift check compressed air pressure should be greater than 0.5 MPa, otherwise check whether the pipeline leak, pressure reached the required value before allowing the start of the furnace.
2.7 During the welding process, the external temperature of furnace body, diffusion pump, cold trap, magnesium remover and other vacuum pumps should be checked regularly. When the temperature is too high, the cooling water pipeline should be checked and cleaned up in time.
2.8 When disassembling and assembling the parts of the sealing part, wash them with acetone or anhydrous alcohol, and then apply vacuum grease after drying.
2.9 the electrical connector of the electrical control system should be kept clean and fastened. Check each fastening electrical connector before tightening.
2.10 Insulation resistance of furnace should be checked regularly, and its value should not be less than 100_. When it is less than 100_, the resistance of electric heating elements, insulators, electrodes and heat shield should be carefully checked, and the furnace can be started after troubleshooting in time.
2.11 mechanical transmission parts should be lubricated regularly or lubricated according to general equipment lubrication requirements.
2.12 Vacuum units, valves, SCR regulators, instrumentation and other accessories are repaired and maintained according to the manufacturer’s instructions.
2.13 the workpiece and fixture should be clean and dry to prevent moisture and dirt from entering the furnace.
2.14, power failure should be maintained. It is necessary to ensure the absolute safety of operators, maintenance personnel and equipment when it is necessary to maintain under electrified condition.
2.15 Strictly follow the operating procedures, do not press the button at will, dial the switch, informal training personnel strictly prohibited operation.
2.16 The cooling water of vacuum furnace is very important, so it is not allowed to interrupt the cooling water during the whole working period. When the pump is damaged and can not supply water normally, the emergency tap water switch should be opened to keep the cooling water uninterrupted.
2.17 maintain pump maintenance and maintenance.
2.17.1 always pays attention to the oil level, and the oil level is the standard of the oil standard center when the pump runs normally. When the oil level is lower than the oil standard center, you should refuel.
2.17.2 The oil change period is decided by the user according to the use conditions and whether the performance requirements can be met. The general new pump is recommended to change oil once in 100 hours or so. The oil change period can be extended after the black metal powder can not be seen in the oil.
2.17.3 pump oil should be generally SY1634-701 vacuum pump oil, and can not be mixed with kerosene and gasoline.
2.18 maintenance and maintenance of slide valve pump
2.18.1 Should always pay attention to the oil level and oil cleaning, the new pump 150 hours after the oil change once, every 2-3 months after the oil change, if the use of poor conditions, vacuum drop, can shorten the oil change time.
2.18.2 In the cold zone, the water in the cooling water jacket must be completely drained after parking, otherwise the water in the water jacket will freeze and damage the pump shell.
2.18.3 If more time is not used, the pump will be opened every 7-10 days, about an hour to open the pump time, in order to avoid embroidery in the pump.
2.19 roots pump maintenance and maintenance
2.19.1 should always keep the pump room clean and dry.
2.19.2 Always pay attention to the lubrication of each part, if found to be insufficient lubricant should be timely supplement, if found to be unclean lubricant timely replacement, new pump use 30-50 hours should change oil, later can be determined according to the use of oil cycle.
2.20 maintenance and maintenance of diffusion pumps
2.20.1 The cooling water must be guaranteed to be unobstructed during the operation of the diffusion pump, and the cooling water can be closed after the pump working fluid has been completely cooled after stopping heating.
2.20.2 When the diffusion pump stops working, the vacuum should be maintained in the pump to avoid the deterioration of the pump oil. The exhausted gas should be dry, non-corrosive and dust-free.
2.20.3 If the diffusion pump is not used temporarily, it should be kept in a vacuum state during storage to avoid oil pollution and corrosion of various parts. And clean the remaining water in the cooling jacket.
2.20.4 Diffusion pump performance will gradually deteriorate after long-term work, should be regularly overhauled, whether the pump oil is reduced or oxidized, according to the corresponding requirements of refueling or replacement treatment. The parts and pump chamber are washed with aviation gasoline, then cleaned with silk dipped in ether or acetone, and dried at 80 ~100 ~C or dried with a hair dryer. After treatment, the assembly is carried out in sequence, keeping the pump core and pump bottom perpendicular to the pump cavity concentric, all levels of nozzle clearance should be adjusted according to the original requirements.

Vacuum aluminum brazing furnace matters needing attention
In order to ensure permanent safety after installation, the owner (operator) must fulfill the following requirements:
3.1 all local application safety regulations and accident prevention rules must be complied with.
3.2 equipment and any adjacent operating area must be accessible only to authorized trained personnel.
3.3 in case of possible danger, the equipment must be turned off immediately. Especially the switch of inflatable cylinders.
3.4 the equipment safety provisions provided must be effectively implemented and their effectiveness must be regularly tested.
3.5 the owner must instruct his employees (operators and other personnel) to take necessary protective equipment.
3.6 Employees who operate the equipment must be properly trained and aware of the inherent dangers involved in the operation of the equipment and how to protect them. Any possible problems or damage must be reported to the relevant managers.
3.7 Employees must always have proper physical and mental health in order to accomplish their tasks and avoid possible dangers.
3.8 the equipment is used in normal surroundings. It can not operate in dangerous area. It is strictly prohibited to store and use inflammable materials near the equipment, and to pile up any sundries within four meters of the equipment control cabinet, furnace door and other equipment.
3.9 the equipment must be operated in accordance with the prescribed usage and procedures.
3.10 Before any disposal of electrical equipment, the equipment or whole set of equipment to be disposed of must be disconnected from the power supply in accordance with the electrical operation regulations and local safety and accident prevention measures. Live maintenance is strictly prohibited.
3.11 the equipment must be operated under conditions of safety and no technical errors. Do not exceed the maximum operating temperature. Only the gas (nitrogen) stipulated in the contract can be introduced into the furnace.
3.12 nitrogen can cause suffocation. So the nitrogen must be discharged directly from the furnace into the external atmosphere, not directly into the closed workshop.
3.13 Before installing, opening, operating and maintaining the equipment, the personnel concerned must know and understand the full contents of the instructions for use and safety.
3.14 during the filling process, the front of the furnace body and the furnace cover must not be standing.