The cleaning of metal components during mechanical processing is to remove various pollutants generated during the use, production, and storage of mechanical equipment through physical and chemical means, obtaining a certain degree of cleanliness, thereby improving the appearance quality and performance of the product, reliability, and meeting the requirements of the next processing process. Cleaning work is an important part of the mechanical processing process.

Most mechanical parts require cleaning before, during, and after assembly, and some parts are also cleaned after trial operation as needed. The purpose of cleaning parts is to remove residual casting sand, iron filings, rust, abrasives, oil stains, dust, and other pollutants from their surfaces. The cleanliness level of parts after cleaning will directly affect the assembly quality and the service life of construction machinery, so the cleaning of parts is a very important link in the assembly of construction machinery. To do a good job in cleaning parts, the correct selection of cleaning agents and methods should be based on their material, structural characteristics, pollution situation, and cleanliness requirements.

There are three main pollutants in the processing of mechanical parts: water-soluble pollutants, saponifiable oily pollutants, and non saponifiable oily pollutants.

Water soluble pollutants: Hand sweat, dust, and fingerprints on the surface of workpieces during processing and storage and transportation; Polymer, inorganic salt, polyol, soluble emulsifier, etc. evaporated from metal working fluid.

Saponifiable oily pollutants: lubricating materials used in metal cutting and forming process contain a large amount of animal vegetable oil or modified products. This kind of animal vegetable oil is a mixture of various esters composed of fatty acids and glycerol, which can be dissolved in various organic solvents. At the same time, this kind of oil can react saponification with alkali.

Unsaponifiable oily pollutants: cutting fluid, forming lubricant, pickling passivation paste, metal antirust oil, quenching oil, etc. used in metal processing contain a large amount of mineral oil, high molecular polymer, oily additives and sintering dirt. During the machining process, equipment oil such as guide rail oil and hydraulic oil leaked from the machine tool can also cause pollution to the workpiece.

Five common cleaning methods for mechanical parts:
1. Scrub.
Place the parts in a container containing diesel, kerosene, or other cleaning fluids, and wipe with cotton yarn or brush with a brush. This method is easy to operate and has simple equipment, but it has low efficiency and is suitable for single small batch small parts. In general, gasoline should not be used as it has fat solubility, which can harm human health and easily cause fires.

2. Boiling and washing
Place the prepared solution and the cleaned parts together in a cleaning pool welded with steel plates of appropriate size. Use a stove under the pool to heat it to 80-90 ℃, and boil for 3-5 minutes.

3. Spray washing
Spray cleaning solution with a certain pressure and temperature onto the surface of the parts to remove oil stains. This method has good cleaning effect and high production efficiency, but the equipment is complex and suitable for cleaning parts with less complex shapes and severe oil stains on the surface.

4. Vibration cleaning
Place the parts to be cleaned on the cleaning basket or rack of the vibration cleaning machine and immerse them in the cleaning solution. Simulate the manual rinsing action and chemical action of the cleaning solution to remove oil stains through the vibration generated by the cleaning machine.

5. Ultrasonic cleaning

By combining the chemical action of cleaning agents with the "ultrasonic cavitation effect" that occurs in ultrasonic cleaning machines, oil stains are removed.