The first step in developing an effective precision cleaning process for the product is to determine where cleaning can be avoided. Keeping the product clean, particularly during transfer and storage, is an important part of your contamination control program.

Much effort is expended in keeping the cleanroom clean, in monitoring the cleanroom. Much effort is expended in developing, validating, and monitoring cleaning processes for both so-called "high-end" products and for industrial applications. It is critical to manage three major sources of contamination for products fabricated within the cleanroom. These contamination sources are:

• People
• Equipment
• Transfer

EFFECTIVE TRANSFER
Many items such as raw materials for use in the manufacturing of the product are supplied double bagged or triple bagged depending on the manufacturing process. The outer packaging could potentially be highly contaminated so careful removal of this packaging is of utmost importance.

Sometimes pallet trucks of cardboard boxes are loaded into the transfer area. How do you remove contamination from those parts when going from the dirty side to the clean side? How do you avoid particle generation? In general, it is wise to remove all cardboard packaging outside of the controlled environment. As we explained in the previous column,¹ the material transfer room is a controlled environment that includes a 'dirty' side and a 'clean side.' However, contamination must be minimized even in the 'dirty side.' Therefore, remove the cardboard in an area outside of but proximal to the transfer area; then immediately move materials to the transfer area.