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"How Can I Become a Cleaning Lady...
By Barbara Kanegsberg, BFK Solutions LLC
… I mean, is there a course of study I can follow?” While this particular question was a bit droll (the questioner was a male engineer), similar inquiries were posed at a number of recent conferences and workshops. Although custom majors can sometimes be designed, we are not aware of formalized, standardized university courses of study related to cleaning. The interest in cleaning as a formalized, respected area of expertise reflects an important trend and a need. Specifically, more cleaning processes are considered critical cleaning; cleaning processes are considered value-added to the overall manufacturing process. There are a number of symptoms of this upswing in interest; and a number of root causes – all of which indicate that it’s profitable to clean products and sub-assemblies in an effective, efficient manner.
The symptoms
People want to learn about critical cleaning. For example, at the recent Process Cleaning Expo (PCx) in Louisville, our introductory cleaning programs were pretty much SRO. We saw similar high levels of interest at other conferences: among electronics assemblers at a local SMTA symposium, among those involved in thermal spray at ITSA, and among materials scientists concerned with materials compatibility of composites at a national SME program.
People are asking the incisive questions. They are demanding more from experts; and that’s a good thing. We had active participation at our “Panel of Experts” at PCx. They asked us questions during the programs, at random moments during the conferences (even at dinner), and via follow-up calls and emails.
The word of the vendor, of the supplier of cleaning agents or cleaning equipment is no longer enough. Based on recent phone calls and emails to us, manufacturers are demanding that rationality replace hype; they are demanding proof that the products will work in their particular application.
So why are more manufacturers concerned with critical cleaning?
New people
There’s a new generation of engineers and production people. This means we have to go back to the basics. For example, the function of washing, rinsing, and drying, while simple on the surface, have to be redefined and reviewed. The washing step (or soil removal or depainting or deblocking step – pick your favorite euphemism) removes the soil from the surface while avoiding redeposition. The rinse step removes residual cleaning agent and may continue the wash step. Drying removes residual rinse agent and may actually have some washing function. At all stages, we have to avoid product damage. The basic concepts are simple; but it is essential to be aware of the function of each step to optimize the cleaning process.
More surfaces
Product integrity depends on cleaning. Components are getting smaller; the surface-to volume ratio gets larger. In moving from miniature devices to micro to nano, the surface becomes the product.
Better performance
Performance requirements are increasing. A consumer electronics device may have to last only until the next gizmo comes along; and therefore some manufacturers may be able to cut corners, get away with not cleaning, or, in the case of defluxing, clean with water alone. Frankly, they may be able to tolerate a level of consumer complaints about mobile phones that don’t work reliably or even (gasp!) TV remotes with “gremlins.” At the same time, given the availability of instant communication and the proliferation of blogs, if the competition provides a more reliable product, word gets around quickly. In other cases long-term and/or reliable performance is a must. Examples include aerospace components, military hardware, not to mention pharmaceuticals and medical devices. Public and personal safety may depend on products that have been properly cleaned. Weapons must not miss-fire. No one wants to have their implanted tooth, hip, or knee recalled.
Demand for cleaning metrics
How clean is clean enough must be redefined for the next decade, or at least for the next five years. Defining what clean means; defining the attributes of surfaces is application dependent. Traditionally, the cleanliness of an electronics assembly is considered to be a function of the level of conductive residue. However, post-defluxing processes such as application of conformal coating may require successful removal of non-ionic residue. Further, manufacturers of electronics assemblies are themselves a link in a larger supply chain. The assemblies have to be integrated into the final product; so more effective cleaning may be required, along with new tests to judge cleanliness.
Regulations
Regulatory requirements impel new, often more complex, cleaning requirements. Requirements to use lead-freesolders mean higher operating temperatures; that translates to more defluxing (cleaning) challenges. Safety and environmental restrictions on halogenated solvents has lead to process change. Those changes may involve adoption of non-halogenated organic solvents (or of blends with the chlorinated solvent trans-1,2,-dichloroethylene), of aqueous processes, of non-chemical processes, and/or of airless/airtight solvent cleaning systems. Some alternative processes have been, at best, semi-beautiful. Others have resulted in higher productivity, lower releases of chemicals, and higher throughput/efficiency. The successful companies have developed “cleaning lady” expertise.
Déjà vu all over again
Problems have “sequels.” Problems are rarely solved forever. Organic acid or no-clean (low residue) flux was a great solution to most of the cleaning problems for electronics assembly of the 1990’s. Now, changes in regulations and performance requirements have resulted in a re-evaluation of the defluxing process. We are active in the IPC revision and consolidation of the defluxing handbook as well as in planning an upcoming IPC/SMTA cleaning conference. People who adopted HCFC 225 as an interim solution to cleaning problems now need to plan for the 2015 phaseout. While some may stockpile solvent, process change is a more realistic approach.
Money
Money changes everything. Good cleaning processes cost money. Sub-optimal cleaning processes cost even more money. A high reject rate and customer dissatisfaction is not tolerable, particularly in a challenging business climate. If you want to build it right, you have to clean it right.
Folklore to science
A cleaning process should not occur because mom said it was a good idea. Critical cleaning processes, value-added processes, are a must for manufacturing to survive and ultimately to prosper. There are good, well-functioning cleaning processes that were put in place based on pragmatic experience. However, successful companies are looking to understand
• What cleaning processes work
• Why those processes work
• What processes are no longer needed
Successful manufacturers are on a journey to develop their own expertise as “cleaning ladies, cleaning gentlemen, or cleaning people.” Someday, there may very well be a formalized courses in critical cleaning.In the meantime, we’re always happy expedite that journey.
