Vacuum system pretreatment and cleaning methods during spare parts processing

The ultimate pressure at which a vacuum system can be achieved is greatly affected by the amount of gas or vapor contained in the system. To improve initial pumping efficiency after parts machining, assembly or maintenance activities, outgassing can be reduced by properly pre-conditioning the components in the system. The higher the ultimate pressure specification, the more cleaning is required, but all systems will benefit from proper preconditioning.

In vacuum systems, surface porosity is an excellent choice for trapping gases and vapors. The first step is to smooth the surface of the part to remove thick oxide layers such as rust or aluminum oxide. The most effective ways to remove surface pores are by mechanical grinding, brushing or sandblasting with glass or ceramic beads.

Cleaning to reduce surface contamination, once the physical surface is prepared, the next step is to reduce oil and coolant contamination of hydrocarbons introduced by machining, pump contamination or improper operation.

Choose a soap or organic solvent that is compatible with the material:

1. Determine if the cleaning agent needs to be heated to increase its chemical activity

2. Apply enough mechanical force (ie ultrasonic bath or high pressure sprayer)

3. Determine how long the component will need to be exposed to the cleaning solution (eg, dipping takes more time than spraying)

4. Bake at the highest material temperature allowed to remove adsorbed gases and vapors

Parts Machining After removing surface contamination and thoroughly rinsing off cleaning agents, the final step in the pretreatment process is baking. For many parts processing, it can usually be carried out in a vacuum furnace. Baking helps to remove moisture adsorption from the surface of the material. Generally, the higher the furnace temperature, the faster the degassing.

Keep your system clean:

1. Always protect the open vacuum system from atmospheric and artificial pollution

2. Carefully choose packaging materials that will not transfer oily substances to the vacuum assembly, such as aluminum foil or plastic sheet with low outgassing rate

3. During the assembly process, please consider environmental factors and human factors to avoid introducing exhaust pollutants into the system

4. Environmental factors include factors such as humidity, dust particles and oil mist/vapor

5. Human factors include: special clothing to prevent contamination from fingerprints, dander, hair and sweat; and the use of stainless steel or aluminum cleaning tools

6. Taking appropriate steps to prevent contamination will reduce the need for cleaning and ultimately help achieve the required base pressure more efficiently. From assembly to final testing and packaging solutions, our dedicated engineering staff is proficient in the proper fabrication of custom vacuum chambers.