The daily maintenance of a vertical vacuum furnace is a key link in ensuring its long-term stable operation, extending its service life, and ensuring production quality. Maintenance work should revolve around core components such as vacuum system, heating system, mechanical structure, cooling system, and furnace cleaning. The following are specific maintenance measures and precautions:
1. Vacuum system maintenance
Vacuum pump maintenance
Regular oil change: According to the frequency of use, replace the vacuum pump oil every 3-6 months (if mineral oil needs to be replaced more frequently) to avoid oil pollution affecting the pumping efficiency. Before changing the oil, it is necessary to drain the old oil and clean the inside of the pump body.
Oil level check: Check the oil level before starting up every day to ensure it is within the range of the oil gauge and avoid pump body wear caused by lack of oil.
Air inlet filtration: Regularly clean or replace the air inlet filter to prevent dust from entering the pump body. It is recommended to check it every 1-2 months.
Exception handling: If the vacuum pump produces increased noise, fuel injection, or oil leakage, it is necessary to immediately shut down and inspect the coupling, return valve, or seal, and replace the parts if necessary.
Vacuum pipeline inspection
Leak detection: Use a helium mass spectrometer leak detector or soapy water to detect pipeline connections every month, with a focus on inspecting flanges, valves, and welding points to promptly repair any leaks.
Pipeline cleaning: Clean the dust accumulation on the inner wall of the pipeline every six months to avoid blockage that affects the pumping speed.
2. Heating system maintenance
Heating element inspection
Appearance inspection: visually inspect the resistance wires (such as silicon carbon rods and silicon molybdenum rods) weekly for any breakage, deformation, or oxidation, and replace damaged components in a timely manner.
Resistance test: Use a multimeter to measure the resistance value of the heating element every quarter. If the deviation from the initial value exceeds 10%, it needs to be replaced.
Uniformity calibration: Every year, a professional organization is commissioned to test the temperature uniformity of the heating zone, ensuring that the temperature difference is ≤ ± 5 ℃ (adjusted according to process requirements).
Thermocouple maintenance
Position calibration: Check monthly whether the insertion depth of the thermocouple meets the requirements to avoid measurement errors caused by contact with the furnace wall or workpiece.
Insulation test: Use a megohmmeter every quarter to test the insulation resistance of thermocouples, ensuring it is ≥ 100M Ω to prevent signal interference.
Replacement cycle: The service life of thermocouples is generally 1-2 years, and mandatory replacement is required upon expiration.
3. Mechanical structure maintenance
Furnace door and sealing components
Sealing ring cleaning: Use a dust-free cloth to wipe the furnace door sealing ring daily to remove oil and impurities, and apply vacuum silicone grease monthly to maintain lubrication.
Sealing test: Conduct a pressure holding test every quarter. After closing the furnace door, evacuate to the maximum pressure and observe the pressure rise of ≤ 10Pa within 30 minutes to be qualified.
Lubrication of hinges: Add high-temperature resistant grease to the furnace door hinges every six months to ensure smooth opening and closing.
Maintenance of transmission components
Fan inspection: Check the bearings of the circulating fan for oil shortage every week, and supplement high-temperature lubricating grease (such as molybdenum disulfide) if necessary.
Motor fastening: Check the motor fixing bolts for looseness every month to avoid equipment displacement caused by vibration.
Chain tension: If the equipment is equipped with a chain drive, adjust the chain tension quarterly to prevent slipping or breakage.
4. Cooling system maintenance
Water cooling pipeline maintenance
Water quality management: Use deionized water or softened water as the cooling medium, and test the water conductivity of ≤ 10 μ S/cm every month to prevent scaling.
Flow monitoring: Check the cooling water flow rate daily to ensure it is normal and ≥ 5L/min (adjusted according to equipment requirements) to avoid local overheating.
Pipeline cleaning: Use citric acid solution to circulate and clean the water-cooled pipeline every six months to remove scale, and thoroughly rinse it after cleaning.
Pump maintenance
Operation status check: Listen to the sound of the water pump running every week to see if it is normal, and observe if there is any water leakage or abnormal vibration.
Bearing lubrication: Add lubricating oil to the water pump bearings every six months to extend their service life.
5. Cleaning and protection of furnace body
Furnace cleaning
Daily cleaning: After each batch of production is completed, use a vacuum cleaner or soft bristled brush to clean the residue in the furnace to avoid volatilization and contamination of the workpiece.
Deep cleaning: Use acetone or alcohol to wipe the inner wall of the furnace every quarter to remove oil stains and oxide layers. After cleaning, it needs to be dried.
Furnace body anti-corrosion
External surface protection: Check the furnace shell weekly for scratches or corrosion, and promptly repaint to prevent rusting.
Grounding inspection: Confirm monthly that the grounding resistance of the equipment is ≤ 4 Ω to ensure safe operation.
6. Electrical system inspection
Line safety
Insulation test: Use a megohmmeter every quarter to test the insulation resistance of power and control lines, ensuring it is ≥ 1M Ω.
Wiring Tightening: Check all electrical wiring terminals monthly for looseness to avoid poor contact and potential malfunctions.
Control system calibration
Parameter backup: Backup the parameters of PLC or temperature controller annually to prevent data loss caused by misoperation.
Software update: Upgrade the control system software in a timely manner according to the manufacturer’s recommendations to optimize device performance.
7. Maintenance records and plans
Establish archives: Establish a maintenance ledger for each device, recording maintenance time, content, replacement parts, and abnormal situations.
Develop a plan: Based on the frequency of equipment usage and manufacturer recommendations, develop an annual maintenance plan and strictly implement it.
Personnel training: Regularly provide maintenance knowledge training to operators to improve equipment maintenance capabilities.