Automation is touted as the “magic bullet” to preventing contamination problems. We often assume that automation improves the process by removing the people. We know that humans generate contamination, both particulate and thin-film. While removing the people may eliminate one contamination source and one source of variability, there is far more to automation than, well, automating. You may have removed the human factor from the operation, but notfrom the process design.

Automation typically requires a substantial investment in capital equipment and facilities modification. Therefore, automated critical cleaning is reserved for true, value-added applications, such as removal of process chemicals or achieving the desired surface characteristics. Because the automation process is designed by people, investing plenty of up-front time can result in a more effective automated assembly.

UNDERSTAND THE PROCESS
Automation brings consistency. Too often, processes are automated without fully grasping the nuances of the process in question and of the overall production environment. When this happens, the automated process may be consistent,but it can be consistently incorrect.

Process understanding has been divided into eight stages of knowledge.¹ In Stage 1, we know the product works, but have no idea of how to achieve the desired output. In Stages 2 through 5, we begin to recognize major variables, grasp the relevance of variables, engage in metrics, and then begin to exert local control over the variables. In Stages 6 and 7, we understand how the variables impact the output. Stage 8 is complete knowledge; a lofty goal rather than a status achieved by mere mortals. Table 1 describes the relationship of these stages to cleaning and contamination control processes.

Stage	Stage of Knowledge	Comments
1	Complete ignorance	Can be a pathway to innovation
2	Awareness of parameters, ignorance of relative importance	Assembly as art, process steps kept secret, not written
3	Understand parameters, can’t control them	Environmental or customer mandates can restrict options & advancement
4	Control of mean, uncontrolled parameters	Beginning of process control
5	Process capability	• Cleaning recipes • May reveal over-cleaning, over-purification of chemicals • Cost savings
6	Process characterization	• Understanding “how” process works • Fine-tune, optimize output • Reduce costs • Must reach this stage for successful automation
7	Understanding “why” the process works	Rarely achieved in surface preparation
8	Complete process understanding	A goal to approach
Table 1. Automation journey applied to surface cleaning and contamination control

OBSERVE THE PEOPLE
In our experience, the shortest route from Stage 1 to Stage 5 is to work directly with the technicians. In eliminating the human operator without good understanding of the cleaning process, primary sources of knowledge may be inadvertently ignored. Even if technicians follow every step of supposedly well-documented fabrication and cleaning processes, the first step in automation should be to determine what the process steps actually are, not how steps are written in the work instructions. Understanding people involves observing and questioningin a retribution-free environment.

EMBRACE CHANGE
Often, particularly for critical devices, the details of the desired surface characteristics or attributes are not known. There may be in-house or industry standards, sometimes related to unfortunate product failure, but they may not be complete. For aerospace, pharmaceutical, medical, and microelectronicapplications, performance requirements may shift and the desired surface quality may be even more elusive. For this reason, there is growing realization that automation must be based on a dynamic, interactive, knowledge-based model rather than on a static model. Automation is not a two-dimensional “as the crow flies” commute. As our understanding of product requirements changes, the journey through the stages of knowledge inherently needs tobe repeated.

Reference

1. Bohn, R. E. “Measuring and managing technological knowledge,” Sloan Management Review, 36(1), 61-73, (1994).

Barbara Kanegsberg and Ed Kanegsberg are independent consultants in critical and precision cleaning,surface preparation,and contamination control.They are the editors of The Handbook for Critical Cleaning,CRC Press. Contact them at BFK Solutions LLC.,310-459-3614; info@bfksolutions.com;www.bfksolutions.com.