2. 4 Cleaning Innovations
3. 4 Drying Innovations
4. Summary
1. The Troublesome Problem of Cleaning and Drying Blind Holes and Close Contact Parts
Among parts, blind holes and close contact configurations are conditions where cleaning and drying defects are likely to occur. The main cause is that the parts have complex shapes, making it difficult for cleaning agents and rinsing water to penetrate.
"Then why not use fluorinated solvents or chlorinated solvents that have high cleaning power and excellent drying properties?" you might think. However, unless the cleaning agent physically penetrates into the gaps of the parts, the effectiveness of the cleaning agent cannot be fully demonstrated. Therefore, as innovations beyond the cleaning agent itself, innovations in cleaning methods and drying methods are necessary.
2. 4 Cleaning Innovations
First, let's introduce innovations in cleaning methods.
There are mainly 4 innovations:
2-1．Reduced Pressure (Vacuum)
When the pressure inside the cleaning tank is reduced, gases trapped in the parts can be removed. Additionally, one key point is that the pressure difference makes it easier for the cleaning agent to penetrate into the interior of the parts. Furthermore, by repeating reduced pressure and atmospheric release states, gas removal between parts and penetration of cleaning agent can be further promoted.
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2-2. Rotating in Rotating Basket
Placing parts in a rotating basket and rotating them is also one effective method. The cleaning agent becomes easier to penetrate into the gaps of the parts due to centrifugal force. Also, the rotational motion makes it easier to separate parts, so it is also effective when thin parts are in close contact.
However, if rotated at high speed, parts may collide or rub against each other, potentially causing part defects such as "deformation" or "impact marks". Therefore, finding the appropriate rotation speed is important.
2-3. Shaking in Basket
Similar to "rotating", "shaking" is also effective. By giving motion to the parts, gaps are more likely to form between parts, making it easier for the cleaning agent to penetrate. It also enables liquid drainage from cleaning agent that has penetrated into blind holes. This cleaning method is called "oscillation cleaning" or "vibration cleaning".
2-4. Shower Cleaning × Ultrasonic Cleaning
Combining shower cleaning and ultrasonic cleaning is also effective for cleaning blind holes and close contact parts. With shower cleaning, cleaning agent and water are ejected at high pressure onto the parts, making it easier for the cleaning agent and water to penetrate into gaps in the parts. Additionally, with ultrasonic cleaning, it is possible to distribute the cleaning agent to detailed areas through both chemical and physical actions (※).
※Reference: [The Strong Ally of Cleaning: The Mechanism of Ultrasonic Cleaning]
3. 4 Drying Innovations
Similar to cleaning, drying defects can be avoided by innovating drying methods. There are mainly 4 innovations:
3-1. Vacuum Vapor Drying
Vacuum drying, which dries the basket containing parts in a vacuum state, is effective for drying blind holes and close contact parts. By creating a vacuum, gases are removed. This makes it possible to remove gases that have penetrated inside blind holes (non-through holes).
In addition to vacuum, the mainstream method is to combine vapor (steam) to raise the temperature of the parts and improve drying performance.
※Reference: [Typical Essential Drying Process - Effects of Vacuum Drying]
3-2. Barrel Rotation Hot Air Drying
Similar to cleaning, rotation is also effective for drying. Centrifugal force can expel liquid hidden inside holes, and rotation also releases the close contact state of parts. Additionally, applying hot air further promotes drying, which is another key point.
3-3. Suction Drying
Since liquids tend to remain inside holes and in detailed areas, suction-type drying is also effective. Non-through holes and items with many fine irregularities are particularly difficult to naturally dry. That's why suction drying, which dries the surface by applying hot air while sucking out water, is effective.
3-4. Solvent Water Removal Drying
When parts with water-soluble processing fluid are evaporatively dried, water marks occur. In such cases, pre-washing is performed with cleaning agents containing special surfactants to forcibly separate the water adhering to the parts - this method is solvent water removal drying. By combining with vapor cleaning and drying, water marks can be prevented and drying achieved.
4. Summary
For parts with shapes different from standard configurations, cleaning and drying defects can be prevented by devising innovations in cleaning and drying methods. It's good to select the appropriate method according to what kind of finish is anticipated and its intended use.
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