The purpose of cleaning is to make the aluminum profile processing parts reach a certain degree of cleanliness. How to detect and evaluate the cleanliness of the surface of aluminum profile processing parts, different workpieces, because of the different cleaning purposes, have different performance and reliability requirements, therefore, the requirements for cleanliness are also different, the content of cleanliness detection and evaluation, The method is also different.
Some pollutants on the workpiece surface can be detected directly, while others need to be detected indirectly. For example, the cleanliness of parts and system cavities in machinery is usually determined by indirect methods, based on the contamination of the working fluid or process fluid (cleaning fluid) used.
Introduction to detection methods:
1. Visual observation method:
Whether the cleaning is clean or not, it can be observed directly with the naked eye or with a 5x magnifying glass. This is a fairly simple and convenient method, but it is difficult to judge trace pollutants.
2. Wiping method:
Use white paper, filter paper, and white silk cloth to wipe the surface of the aluminum profile, and use the naked eye to observe the degree of pollution on the white paper, filter paper, and white silk cloth to determine the degree of cleanliness. It is applicable to the production site, but it can only make a rough qualitative judgment, not precise judgment and quantitative analysis.
3. Water spray method:
After cleaning, spray water on the surface of the processed aluminum profile to see if the water film on the surface is continuous. If the water film is discontinuous and broken, it means that the cleaning is not clean and there is still oil. Because metal surfaces are all hydrophilic surfaces, if there is no oil stain, water will wet the surface well, and the water film will be continuous; if it is not cleaned and there is oil stain on the surface, the water film will be broken. This is also a method for judging the cleanliness of the production site. If there is surfactant remaining on the surface of this method, the judgment may be affected.
4. Contact angle method:
Drop a drop of water on the surface of the aluminum profile parts after cleaning, and use a contact angle meter to measure the contact angle of the water film. If the contact angle is large, it means that there is oil stains and the surface wetting is not good; if the contact angle is small, it means oil stains was washed clean. This needs to be carried out in a laboratory, and the detection is relatively simple, but the surface to be tested must be representative.
5. Water drop method:
Drop a drop of water on the surface to be tested at a certain height, and measure the diameter of the water drop on the surface. A large diameter indicates good wetting and cleansing of oil stains; a small diameter indicates poor wetting and cleaning is not clean.
