Operating Procedure for a High-Temperature Sintering Furnace

1. Loading

  1. Inspect all heating elements inside the furnace to confirm there are no abnormalities
    — such as breakage, excessive wear, deformation, or broken screws.
  2. After confirming everything is normal, load materials using the loading trolley.
  3. The materials must not exceed the designed size, and should maintain a 5–10 cm clearance from the heating elements.

2. Heating / Temperature Rise

  1. Close the furnace door. Confirm cooling water and compressed air are active.
    Then start the vacuum system to begin pumping down.
  2. When high vacuum is reached, close the vacuum ball valve to hold pressure.
    Confirm there is no leakage to prevent damage to equipment and products when heating.
  3. Enter the production temperature recipe according to the required process.
  4. Turn on the main circuit and voltage regulator (main heating switch).
  5. Change the control mode to Automatic Power Control.
    • Automatic: controlled by the temperature controller
    • Manual: current adjusted using three potentiometer groups
  6. Press RUN on the instrument (red indicator lights) to start temperature control.
  7. During heating, monitor current, voltage, and internal vacuum pressure at all times.
  8. If step-skipping (program jump) is needed during heating, each of the three heating zones must be controlled separately.
    The three zones should jump simultaneously. Observe water temperature to prevent overheating.
  9. Adjust PID settings properly according to temperature segments and heating rates.
  10. In case of an alarm, clear the alarm by pressing “Alarm Reset” on the left side of the screen.
  11. If power failure occurs during operation, switch to backup power as quickly as possible to maintain cooling.
    Check that the pneumatic vacuum valve is closed to prevent backflow into the furnace.

3. End of Heating

  1. Turn off the voltage regulator and main circuit.
  2. Below 300°C, shut down the vacuum system:
    • Close the vacuum valve
    • Then shut down Pump #2 Roots Pump → Pump #1 Roots Pump → Screw Pump (fore-pump)
  3. Below 200°C, the furnace door can be opened for unloading.
  4. Below 100°C, cooling water can be turned off.

4. Vacuum System Procedure

  1. Check that all manual ball valves on the furnace body and pump set are closed.
  2. Close the furnace door.
    If the air cylinder pressure is insufficient, the door may not seal—confirm pressure first.
  3. Confirm that the pump flushing valve and dewaxing tank are installed properly.
    Start the fore-pump. After the fore-pump reaches reduced pressure, open the pneumatic vacuum ball valve.
    (If furnace door is not sealed, vacuum will not drop.)
  4. When the resistance vacuum gauge shows below 3000 Pa, start Roots Pump #1.
  5. When vacuum reaches below 800 Pa, start Roots Pump #2.
    (If started too early, the main pump load will be too high and may cause overload trip.)
  6. When vacuum reaches below 20 Pa, close the pneumatic vacuum ball valve to hold pressure.
    Confirm whether the furnace has air leakage.

5. Pump Set Cleaning

  1. While the pump is running, open the manual cleaning valve to draw in alcohol.
    (Important: Make sure the drain valve is open during cleaning.)