How to detect surface cleanliness after aluminum profile processing

The purpose of cleaning is to ensure that the processed parts of aluminum production equipment reach a certain degree of cleanliness. How to detect and evaluate the cleanliness of the surface of aluminum profile processing parts? Different workpieces have different requirements for performance and reliability due to different cleaning purposes. Therefore, the requirements for cleanliness are also different. The content of cleanliness detection and evaluation, The methods are also different.

Some contaminants on the surface of workpieces can be detected directly, while others need to be detected indirectly. For example, the cleanliness of components and system cavities in machinery is usually determined by indirect methods based on the degree of contamination of the working fluid or process fluid (cleaning fluid) used.

Introduction to detection methods:

  1. Visual observation method:

Whether it is clean or not can be observed directly with the naked eye or with a 5x magnifying glass. This is a very simple and convenient method, but it is difficult to judge trace pollutants.

  1. 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 contamination on the white paper, filter paper, and white silk cloth to determine the degree of cleanliness. It is suitable for production sites, but it can only make rough qualitative judgments and cannot make precise judgments and quantitative analyses.

  1. Water spray method:

After cleaning, spray water on the surface of the aluminum profile workpiece of the aluminum profile extruder to see if the water film on the surface is continuous. If the water film is discontinuous and appears broken, it means the cleaning is not clean and there is still oil stains. 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 break. This is also a method for judging cleanliness at the production site. This method may affect the judgment if surfactant remains on the surface.

  1. Contact angle method:

After cleaning the aluminum profile parts, drop a drop of water on the surface and use a contact angle meter to measure the contact angle of the water film. If the contact angle is large, it indicates the presence of oil stains and poor surface wetting; if the contact angle is small, it indicates oil stains. Been washed clean. This needs to be done in a laboratory, and the detection is relatively simple, but the surface being tested must be representative.

  1. Water drop method:

Drop a water droplet on the surface to be measured at a certain height, and measure the diameter of the water droplet on the surface. A large diameter indicates good wetting and the oil stains are clean; a small diameter indicates poor wetting and unclean cleaning.