General description

To stabilize the cleaning quality using automation technologies, it is essential to select an appropriate cleaning basket and a proper structure for the cleaning fixtures. They should be designed exclusively for respective usage upon understanding the characteristics (e.g. shapes, strength, and materials) of the workpieces to be cleaned and satisfying the quality requirements.

Explanation

(1) Cleaning and quality problems

- The required cleaning quality has become higher than before due to the trend of making the parts and units more compact and integrated, in addition to complying with the upgraded label requirements.
- The quality problems related to cleaning include the following: (1) Degraded adhesion strength, (2) Reliability problems related to surface alteration/corrosion by attachment of foreign materials, (3) Aesthetic quality problems due to external defects.

(2) Cleaning basket structure for stable cleaning quality

- One of the important measures to stabilize the cleaning quality is to adopt an appropriate cleaning basket structure.
- The following five requirements must be met for the cleaning basket structure to be appropriate:

1. To prevent leaving the residual cleaning solution in the area where the cleaning basket contacts the workpiece, it is important to design the cleaning basket so that it contacts the workpiece at multiple points without touching the whole surface (Fig.1).
2. To prevent the quality deterioration of the workpiece during cleaning, be sure to avoid the important surface of the workpiece to be in contact with the basket.
3. Oscillation by ultrasound may cause the workpiece to chip if the workpiece is in contact with the cleaning basket and/or the cleaning fixtures. Therefore, the R-shape design is recommended for the corner area and the contact point of the cleaning basket and fixtures (Fig.2).
4. For ultrasonic cleaning, a mesh should be selected for improving the circulation and drainage of the cleaning solution on both the bottom and side faces of the cleaning basket, as well as for minimizing the degradation of cleaning energy distribution efficiency.
5. The cleaning basket and fixtures should be made of materials that will not be corroded by the cleaning solution and that will not react with the workpiece.