Vacuum (reduced pressure) drying is a process of heating substances in a vacuum state and evaporating moisture and volatile components. In a reduced pressure state, the boiling point of liquids decreases, allowing drying to be performed at low temperatures. This is a drying method that can efficiently remove liquids while preventing denaturation of heat-sensitive substances and components. Here, we will explain what vacuum drying is and how it works.
2. What is Vacuum Drying (Reduced Pressure Drying)
3. Advantages of Vacuum Drying (Reduced Pressure Drying) | Fast Drying
4. Disadvantages and Precautions of Vacuum Drying
5. Types of Other Drying Methods
- Blow Drying
- Hot Air Drying
- Suction Drying
- Spin Drying
- Vapor Drying
6. For Cleaning Challenges, Contact JFE Electronics
1. "Drying" is Important in the Cleaning Process
The cleaning process can be broadly classified into three stages:
- (1) Cleaning
- (2) Rinsing
- (3) Drying
The (3) drying mentioned here refers to the operation of removing liquids that are adhering to or contained in the cleaning object.
In (1) Cleaning, which is the main stage of the cleaning process, it will be treated as a defective product if rinsing liquid remains adhering to the cleaning object however perfect the result of cleaning is.
This is because if liquid remains on the surface of the cleaning object, it will cause oxidation and stains, forming water marks. Therefore, like cleaning, the drying process plays an extremely important role.
2. What is Vacuum Drying (Reduced Pressure Drying)
Vacuum drying (reduced pressure drying) is a drying method that promotes the evaporation of moisture by utilizing the correlation between atmospheric pressure and boiling point. The temperature at which a liquid boils and vaporizes is called the boiling point. When atmospheric pressure decreases, the boiling point also decreases, making vaporization easier. By applying this physical phenomenon and using a pump to reduce the atmospheric pressure inside the dryer containing the cleaned items, it becomes possible to dry efficiently even at low temperatures.
3. Advantages of Vacuum Drying (Reduced Pressure Drying) | Fast Drying
Vacuum drying is a drying method that utilizes the relationship between atmospheric pressure and boiling point. By reducing the atmospheric pressure inside the drying equipment using a vacuum pump, the boiling point of the liquid decreases and boiling occurs, improving the drying speed.
Furthermore, because the cleaning liquid vaporized by reduced pressure is sucked by the vacuum pump, the gas inside the drying equipment does not become saturated and drying continues persistently.
Additionally, vacuum drying can vaporize and remove liquid remaining between parts.
4. Disadvantages and Precautions of Vacuum Drying
Vacuum drying can vaporize and remove liquid remaining between parts, but during this vaporization process, there is a possibility that the liquid will freeze. This is because cooling occurs due to the absorption of heat accompanying vaporization, ultimately causing freezing.
For this reason, when performing reduced pressure drying, it is necessary to take measures to deal with the cooling effect accompanying vaporization, such as heating the cleaned items or drying equipment, or alternately repeating reduced pressure and opening to atmosphere.
5. Types of Other Drying Methods
Industrial cleaning drying methods include blow drying, hot air drying, suction drying, spin drying, vapor drying, and various other drying methods with different systems.
-Blow Drying
Blow drying is a method of blowing strong wind onto the cleaned items to remove adhering water droplets and dry them. It is usually used as a pre-treatment before hot air drying.
-Hot Air Drying
Hot air drying is a drying method that sends heated air to the cleaned items to evaporate moisture. When the cleaned items have heat resistance, wind at as high a temperature as possible is used to promote vaporization of moisture. However, depending on the cleaned items, drying at high temperatures may cause discoloration such as oxidation, so temperature adjustment according to the cleaned items is important.
-Suction Drying
Suction drying applies hot air to the cleaned items to evaporate moisture and cleaning liquid on the surface. This evaporated moisture and cleaning liquid components are discharged to the outside through an exhaust device, thereby drying.
-Spin Drying
Spin drying is a drying method that rotates the cleaned items at high speed and removes moisture by centrifugal force. When performing spin drying on smooth plate-shaped substrates, consideration of the center of gravity is necessary. 
-Vapor Drying
Vapor drying is a drying method that can perform cleaning and drying simultaneously. The cleaned items are placed into a dryer filled with high-temperature steam of low-flammability cleaning liquid. Through this process, the steam adheres to the surface of the cleaned items as water droplets, and finish cleaning is performed. After that, the cleaned items gradually increase in temperature, and the adhering water droplets evaporate and dry. Vapor drying is generally used for finish cleaning and drying of precision parts such as camera lenses.
For Cleaning Challenges, Contact JFE Electronics
For cleaning challenges, JFE Shoji Electronics has specialized staff knowledgeable about your on-site cleaning processes who will make proposals according to your needs.
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