Six Key Points of Daily Maintenance and 20 Fault Handling Methods for Vacuum Furnaces

Daily Maintenance For vacuum pumps with a gas ballast function, inspect them before starting the furnace every day and run the gas ballast for 30 minutes as needed to remove moisture from the pump oil. Regularly check the pressure of cooling water, compressed air and hydraulic systems, as well as the flow of cooling water. Inspect the rubber seals and flange surfaces of the furnace door before closing the furnace. Ensure no sand or debris is present; wipe the rubber seals and flange surfaces with a clean lint-free cloth, apply vacuum grease evenly, then close the furnace door. Workpieces must be cleaned before being placed into the furnace for processing. After oil quenching, thoroughly clean all oil from the oil-immersed material frames and conveying components. Air-cooled motors are typically in continuous use and cannot be started under vacuum—they must only be started after inflation, with an electrical interlock protection device installed for safety. Roots pumps can only be started when the vacuum degree reaches 133Pa or higher, and must also be equipped with an electrical interlock protection device. Additional Maintenance: Open the drain valve of compressed air pipelines daily to discharge accumulated water. Regularly check if the inlet and outlet temperature indicators of cooling water are normal; touch and inspect electrode connectors, furnace doors, transformer cooling water pipes and other parts for abnormal local overheating. Fault Phenomena, Causes and Handling Methods Low vacuum degree: Contaminated, insufficient or diluted pump oil → Clean the vacuum pump and replace with new pump oil. Too short pumping time → Extend the pumping time. Clogged suction filter → Clean or replace the exhaust filter. Air leakage: Turn off the power after pumping down → Inspect solenoid valves, pipe joints, vacuum pump suction valves and gaskets around the working chamber for air leakage. Loud noise: Worn or cracked vacuum pump coupling → Replace the coupling. Clogged or misaligned exhaust filter → Clean/replace the exhaust filter and reinstall it correctly. Oil spraying from vacuum pump: Dislodged O-ring of the suction valve → Unplug the vacuum pipe from the pump nozzle, remove the suction nozzle, take out the pressure spring and suction valve, gently stretch the O-ring several times, reinsert it into the groove, then reassemble. Worn vane → Replace the vane. Oil leakage from vacuum pump: Clogged oil return valve → Remove the oil return valve and clean it (see manual for details). Loose oil sight glass: Drain the oil first → Remove the oil sight glass and wrap PTFE tape or a thin plastic film around the thread. Excessive oil fume from vacuum pump: Clogged or contaminated suction filter → Clean or replace the exhaust filter. Contaminated pump oil → Replace with new pump oil. Clogged oil return valve → Clean the oil return valve (see manual for details). No heating: Burnt heating strip → Replace the heating strip. Burnt heating time relay (two lights on at startup, OMRON light is yellow) → Replace the time relay. Burnt heating wire: Replace the heating wire and fasten it securely; Poor contact of heating temperature band switch → Repair or replace the switch; Failure of heating AC contactor to reset → Repair (blow away foreign matter with air) or replace the contactor. Continuous heating: Poor contact or burnt heating time relay → Adjust the contact between the time relay and socket, or replace the relay. Uneven, loose or non-sealing closure: Deformed steel box → Adjust the steel box; Improper heating time/temperature setting → Reset to the appropriate parameters. Excessively long motor reverse rotation → Swap the wiring of any two phase power lines (excluding the ground wire). Poor air flow in pressurized air circuit → Straighten and unclog the pressurized air circuit. Core Industry Terms Translation (Vacuum Furnace/SMT Universal Version)