Vacuum brazing furnace failure and troubleshooting methods

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The vacuum brazing furnace is the key to ensure the stable operation of the equipment and the quality of brazing. The following is classified according to common fault types, and provides cause analysis and solutions:

Vacuum system failure

The vacuum system is the core to ensure the normal operation of the brazing furnace. Any abnormal vacuum will affect the quality of vacuum brazing.

1.The vacuum degree of the vacuum brazing furnace cannot reach the set value. Reasons: vacuum pump failure (such as mechanical pump, diffusion pump, molecular pump damage or abnormal operation); furnace body leakage (seal ring aging or damage, connection parts not tightened); vacuum pipeline blockage or leakage; vacuum gauge failure, false vacuum value. Troubleshooting method: Check the operating status of the vacuum pump, clean the pump body or replace the pump oil; perform leakage detection on the furnace body (such as detection with helium mass spectrometer or soapy water method), replace the seal ring or repair the leakage point; clean or replace the blocked vacuum pipeline; calibrate or replace the vacuum gauge.

2.The vacuum system of the vacuum brazing furnace has a slow pumping speed. Reasons: The vacuum pump has not been maintained for a long time, the pump oil is emulsified or contaminated; the pipeline or filter device is blocked; there are volatiles (such as brazing material residues, pollutants) inside the studio. Troubleshooting method: Replace the vacuum pump oil and perform regular maintenance; Check and clean the pipeline and filter device; Clean the inner wall of the furnace chamber and the surface of the workpiece to ensure that the workpiece is free of grease or moisture.

3.The vacuum degree of the vacuum brazing furnace drops too fast (leakage) Reason: The vacuum brazing furnace door is poorly sealed; the seal is deformed or aged under high temperature; the flange connection is loose. Troubleshooting method: Check the vacuum brazing furnace door and seal, adjust the sealing pressure or replace the sealing ring; select high temperature resistant sealing materials under high temperature environment; check the flange connection and tighten it again.

Failure of the electrical system of the vacuum brazing furnace

1.Causes of damage to the heating element: The heating element is aged or broken after long-term use; the current is too large to cause overheating and burning; the product accidentally touches the heating element during operation. Troubleshooting method: Replace the heating element and check whether the element material matches the process temperature; calibrate the current control system to avoid current fluctuations; strengthen the operating specifications, fix it, and avoid misoperation.

2.Abnormal causes of the temperature control system of the vacuum brazing furnace: Failure of the temperature sensor (such as thermocouple); failure of the temperature control instrument; control program error or hardware problem. Troubleshooting: Check and replace thermocouples; calibrate or replace temperature control instruments; check control system programs and repair hardware faults.

3.Causes of power failure: unstable power supply voltage; aging or short circuit of lines; damaged control circuit boards. Troubleshooting: Install a voltage stabilizer to ensure stable power supply; check electrical circuits and repair aging or short circuit parts; replace damaged control circuit boards.

Failure of vacuum brazing furnace heating system

1.Causes of uneven heating: unreasonable layout of heating elements; failure of temperature control system, resulting in local overheating or overcooling; workpiece placement deviates from the center of the furnace cavity. Troubleshooting: Adjust the layout of heating elements to make them evenly distributed; calibrate the temperature control system; ensure that the workpiece is placed in the center of the furnace cavity to avoid heat flow obstruction.

2.Causes of slow heating: insufficient heating power; aging of the furnace cavity insulation layer, increased heat loss; poor circuit contact. Troubleshooting: Check whether the heating system power meets the requirements, repair or replace; replace the insulation layer material; check and repair the poor circuit contact part.

Problems related to vacuum brazing quality

1.Incomplete weld or poor wetting Causes: Insufficient vacuum, oxide film on the workpiece surface; Insufficient brazing temperature or holding time; The surface of the brazing material or parent material is not cleaned. Troubleshooting method: Increase the vacuum, clean the furnace cavity and the surface of the workpiece; Adjust the temperature and holding time; Ensure that there is no oil or oxide film on the surface of the workpiece and the brazing material.

2.Causes of pores in the weld: Insufficient vacuum exhaust, gas residue on the surface of the workpiece; Volatile impurities in the brazing material. Troubleshooting method: Improve the efficiency of the vacuum system, extend the exhaust time; Select a higher purity brazing material.

3.Causes of overheating or deformation of the parent material: Too long holding time or too high temperature; Uneven temperature field distribution. Troubleshooting method: Optimize the holding time and temperature curve; Adjust the layout of the heating elements to ensure a uniform temperature field.

Vacuum Brazing Furnace