We all want manufacturing processes that are reliable, that don’t cost an arm and a leg, that meet or exceed customer or regulatory requirements. To achieve high-performance cleaning processes, use the 4Ds—define, develop, document, defend.
Know your target before you select a weapon, aim, or fire. What is the cleaning process supposed to accomplish? What specific factors are needed to get there? It is important to define the overall process as well as the sub-processes that are used to accomplish the goal. A process flow diagram can outline what comes before and what will ensue next in the process, but a flow diagram itself is not enough. It is also important to know what equipment and/or chemicals are needed, as well as how much time and labor will be required. You have to know where cleaning occurs, both in-house and by your suppliers. That can be easier said than done. Cleaning processes are not always recognized as being cleaning. Your suppliers may incorrectly assume that you have the responsibility for cleaning.
Process definition includes the methods and metrics that determine that the process step has been completed. For instance, if this is a cleaning process, how will the cleanliness be measured? Purely visual? Via an analytical method?
It takes a village, often a global village, to develop a world-class cleaning process. This includes working collaboratively and critically with vendors who supply cleaning equipment and chemicals. Define your plan to find and evaluate these vendors.1 Develop your supply chain. Is it a good idea to use an inexpensive supplier who supplies partially cleaned or inconsistently cleaned parts? Does your supplier pass all the cleaning on to you? It may help to be reminded that the longer a soil resides on a part, the harder it is to remove.
Developing a process means planning for actual production conditions. Processes that are quite acceptable during R&D may be inadequate for production. How will you manage a surge in production?2 Add shifts? Pull retired equipment out of the warehouse? Outsource?
Consider the safety and environmental aspects of the cleaning process. Will you need to consider equipment for containment or personal protection? Consider the certifications you either need or would like to have. Even if a process is perfectly legal, will it meet resistance by the employees who perform it (for example, due to unpleasant odors)?
Once a process has been defined and developed, it is necessary to have clear, executable instructions for implementing, duplicating, and performing the process. Employees need instructions they can follow. If another employee undertakes the task, will they be able to get the same result? A scientific research result will usually not be accepted until others can duplicate the findings. The same should be true for day-to-day production.
Documenting also includes training. How will the process be taught to employees? Step-by-step recipes have more value if rationales for process steps are provided. Technicians can become innovators to make processes better when they understand why a step is being done, rather than being simply ordered to follow directions.
Documentation also means adequate monitoring. This includes monitoring process conditions such as temperatures and the status of a cleaning bath. Periodically audit the cleaning process, whether it is in-house or outsourced. This includes auditing the cleaning processes of your supply chain.
Processes can and most likely will evolve. Sometimes this is because someone comes up with a better mousetrap, an improved or more cost effective way of performing the process. Maybe the process step really isn’t needed and its functions can be accomplished somewhere else in the overall process. Or perhaps the process is not accomplishing its aims and needs to be made more robust. At times, change is dictated from outside, by a customer requirement or by a new regulatory restriction. When the inevitable change occurs, have a procedure for evaluating proposed changes and amending the process instructions. If questions should arise due to product performance, it can be invaluable to be able to pinpoint what processes were in place in the manufacture of that product.
For a process to be useful in a manufacturing environment, it must be defensible. Does the process actually accomplish the goal? How does it reduce risks of product failure? These are questions that must be answered to validate a process. They may be needed to prove (unfortunately sometimes in court) that a process does what is expected and was performed properly. This is analogous to Performance Qualification (PQ) that is part of validation procedures utilized in medical device and pharmaceutical industries.3 If a change is suggested or required, will the change reduce the likelihood of product failure?
The 4Ds have to be defensible to company management. Justify the expense of developing, performing, and maintaining a particular process. Is the process needed? How does it increase value? Increasing value is a paramount principle of lean manufacturing. Sometimes the increased value of including a particular process is reflected in the costs associated with not including it. Would product failure increase? Will the product be less reliable and therefore less competitive?
A multi-dimensional world
Manufacturing has more than four dimensions. We cannot always anticipate the unexpected; we can be nearly certain that the unexpected will happen. Plan for the unexpected as part of each of the 4Ds.
1. B. Kanegsberg, “Evaluating, Choosing, and Implementing the Process: How to Get Vendors to Work with You,” Handbook for Critical Cleaning (Second Edition): Applications, Processes, and Controls, CRC Press (2011).
2. B. Kanegsberg, “Process Flow,” Clean Source, Dec. 2013 http://bfksolutions.com/index.php/newsletter/77-clean-source-newsletter/227-process-flow#FeatureArticle.
3. B. Kanegsberg and E. Kanegsberg, “Contamination Control in and out of the Cleanroom: Contamination Control and cGMP,” Controlled Environments Magazine, Feb. 2008.
Barbara Kanegsberg and Ed Kanegsberg (the Cleaning Lady and the Rocket Scientist) are experienced consultants and educators in critical and precision cleaning, surface preparation, and contamination control. Their diverse projects include medical device manufacturing, microelectronics, optics, and aerospace. Contact: firstname.lastname@example.org
This article appeared in the January 2014 issue of Controlled Environments.