Evacuated oven

Responsible: Anders Liljeborg

An oven going up to 200 °C can also be evacuated using a membrane pump on the floor under the table. This oven is used for baking resists and drying washed vacuum parts.

Manual for diaphragm pump, pdf.

 


 


Temperature display and controls:
  • Heat Temperature setting button, press and hold down, then press up- or down-arrow to set the temperature. Maximum is 200 °C.
  • Time Time setting button, press and hold down, then press up- or down-arrow to set the time. This should normally be set to continuous operation, the display should show "--.--". This setting is arrived at by using down-arrow all the way to zero time. Time is displayed in hours and minutes, "HH.MM".
  • Ramp button, normally not be used. Sets the time to reach the set temperature. This should normally be set at "--.--", it means that the set temperature is reached in shortest possible time.
    NOTE! This setting can sometimes accidentally be at "00.00" which means infinite ramp time, the oven never reaches set temperature.
  • Unlabeled button, should not be used.
  • Power on/off button, should normally always be on. Continuous operation gives the most stable temperature.

 


Vacuum gauge for the evacuation of the oven. Must show 1000 mBar for door to open. Evacuating the oven makes drying of cleaned parts more efficient, and bakeing of resists is made in a clean environment.

 


Vacuum and venting controls. From left to right: Nitrogen venting inlet, vent valve, evacuating valve button.
Before evacuating the oven, check that the oven door is tightly closed and that the snap-lock has engaged.
  • Check that the vent valve is closed, turned fully clockwise.
  • Turn on the pump with the power switch on the pump, located on the floor, under the table.
  • Open evacuating valve to the pump with the green button.
  • If all is OK, the pressure should go down to 100 mBar within a minute, and continue down towards zero after several minutes.
Vent and open the oven after use:
  • Close the evacuating valve with the green button.
  • Stop the pump.
  • Slowly open the vent valve knob, look at the vacuum gauge at the same time. Let the pressure increase slowly up to 1000 mBars.
    Note! The venting is done by nitrogen at 4 bars. It is possible to over-pressurize the oven which is harmful!
  • When approaching 1000 mBar close the vent valve and try to open the oven door. If not possible to open, carefully open the vent valve again to increase the pressure a little. Close the vent valve!
  • Try to open oven door. If not possible, repeat the above step.
Never open the vent valve and leave the oven. This will lead to over pressure and might destroy the oven!

Problem with contaminations inside the oven.

Anders Liljeborg Nanostructure Physics, KTH.