The troubleshooting of vacuum hot pressing sintering furnace requires a systematic diagnosis based on its multi system collaborative characteristics, including temperature control, vacuum sealing, pressure regulation, and electrical safety. The following are common troubleshooting methods and preventive measures:

1、 Temperature control system malfunction

Abnormal temperature (too high/too low)

Cause analysis: Damaged heating element; Temperature sensor failure; Improper PID parameter settings.

Exclusion method: Use a multimeter to check the resistance of the heating element. If there is an open circuit or short circuit, replace the molybdenum/tungsten wire of the same specification; Disconnect the thermocouple from the thermostat, verify the accuracy with a standard instrument, and replace it if the error exceeds the limit; Optimize the proportional coefficient and integration time through experiments to restore temperature control accuracy.

Uneven heating

Cause analysis: Improper layout of heating elements leading to local overheating; Uneven distribution of heat field inside the furnace.

Exclusion method: Re wrap the heating element to ensure consistent density; Adopting a multi zone temperature control design, with a minimum of 3 zones, dynamically adjusting the power of each zone.

2、 Vacuum system malfunction

Vacuum degree decreases or cannot be evacuated

Cause analysis: aging and damage of the sealing ring; The performance of the vacuum pump decreases; Pipeline blockage or valve leakage.

Exclusion method: Replace the high-purity graphite sealing ring, reinstall the flange bolts, and tighten them to the recommended torque; Clean the pump chamber, replace contaminated vacuum pump oil, repair or replace worn molecular pump bearings; Use a helium mass spectrometer leak detector to locate the leak point, clean up impurities in the pipeline, and repair damaged bellows.

Abnormal noise and vibration of vacuum pump

Cause analysis: Foreign objects entering the pump chamber; Rotor wear; The coupling is loose.

Exclusion method: Stop the machine and disassemble the pump body, remove foreign objects such as metal shavings, polish and repair minor wear, and replace the rotor in severe cases; Re tighten the coupling bolts and replace the damaged rubber shock absorber pads.

3、 Pressure system malfunction

Insufficient pressure or large fluctuations

Cause analysis: Hydraulic pump/pneumatic pump malfunction; Pressure sensor drift; Pipeline leakage.

Exclusion method: Repair or replace the plunger and sealing ring; Calibrate the sensor with a standard pressure gauge and replace it when the error is greater than ± 1%; Check the high-pressure oil pipe joint and replace the oil resistant rubber gasket.

Mold cracking or size deviation

Reason analysis: Insufficient strength of mold materials; Pressure exceeding the limit; Release agent failure.

Exclusion method: Choose hard alloy or silicon carbide ceramic molds; Set the loading value based on the rated pressure of the mold; Evenly apply boron nitride suspension with a thickness of less than 0.1mm.

4、 Electrical and control system malfunction

Touch screen has no display or buttons malfunction

Cause analysis: PLC power module failure; Loose wiring; Software conflict.

Exclusion method: Restart the controller and unplug the cable again; Reinstall the system software, back up data, and restore factory settings.

Frequent false alarms (over temperature/over pressure)

Cause analysis: Poor sensor contact; Electromagnetic interference; The alarm threshold is set too low.

Exclusion method: Check the thermocouple wiring and stay away from interference sources such as frequency converters; Set the temperature alarm threshold to the set value+5 ℃ and the pressure alarm to 110% of the working pressure.

5、 Other common problems and maintenance suggestions

Cooling system malfunction: Regularly clean the water pump filter, acid wash and remove scale; Check the fins of the heat exchanger and blow the accumulated dust with compressed air.

Insufficient purity of protective atmosphere: Use argon gas with a purity of ≥ 99.999% and install molecular sieve adsorbers to purify the gas.

Daily maintenance plan: Check the oil level and sealing status of the vacuum pump daily; Clean the furnace every week and check the connection of heating elements; Calibrate pressure sensors monthly; Annual comprehensive maintenance of vacuum pumps and replacement of aging insulation materials.