SMTA Tech Expo Panel Session: It Takes a Village to Discuss Proper Cleaning Solutions
Recently, I attended the SMTA Tech Expo in Long Beach, California. I was delighted to meet with the unflappable Barbara Kanegsberg, of BFK Solutions Consulting. An expert in cleaning processes, Barbara is also known as “The Cleaning Lady.” She moderated a group of panelists for a technical session entitled “Ask the Experts: Meeting the Challenges of Effective Cleaning, Defluxing in Southern California.” Here Barbara discusses the myriad of challenges regarding cleaning PCBs (particularly in the heavily regulated state of California) and what transpired during the open forum technical session.
Judy Warner: Barbara, it’s a pleasure to be with you. I understand that you hosted a technical panel session today. Tell me a little bit about yourself and the members who were on your panel today.
Barbara Kanegsberg: Absolutely. We did a totally unscripted “ask the experts” panel. What I love about this format is that it's not death by PowerPoint. It's focused on the audience and the questions that they have about manufacturing, the challenges that they have, and not what I think I want to tell them, or any of the other panelists.
For panelists, we had Gilbert Roberge from Inventec Performance Chemicals, Julie Fields from Technical Devices, Paul Petruna from Sirco Industrial, and Naveen Ravindran from ZESTRON High Precision Cleaning. Basically, what we had were people representing manufacturers of cleaning agents, cleaning equipment, fluxes, water purification systems, etc. It's a lot of what people need to know about in California, where we have very strict air regulations and do very high-end manufacturing.
We asked people to bring their questions about cleaning, minimizing costs, maximizing quality, avoiding regulatory hassles, and we just introduced everybody and got right to it. There were a lot of good questions. Globally, we have issues in electronics assembly of miniaturization and population of the electronics assemblies, high-end performance requirements, and increasing environmental regulations. What I was impressed with in this particular program is that there were many, many questions about how to get the board assembled technically and how to do a good job in the assembly. I think one question, if I could paraphrase it, discussed the issue of meeting customer requirements which were above and beyond the usual test requirements.
Warner: When you say test requirements. does that include IPC standards that are in place, or do you mean issues that exceed the standards that are in place?
Kanegsberg: Actually, you have it there, Judy. They're exceeding IPC's standards, and there are standards that we may not have thought about classically at IPC. I've been involved in helping to put together the cleaning and coating handbook, so I realized that there were so many issues even a few years ago. Those issues have only grown.
Warner: Do you think that is because of miniaturization? My understanding is that miniaturization and the failure to get boards pristinely clean at the micron level can cause issues, right?
Kanegsberg: You can have all kinds of issues. Let's start with soil. Soil is matter out of place. It's often stuff that we needed for manufacturing, but we don't want to have in the final product. In the case of electronics assembly, the first thing everyone thinks about is flux. You want the flux to either go away or be encapsulated in a form that it doesn't interfere anymore. Critical cleaning is removing matter out of place in the right way at the right point in the process. With electronics assemblies if we just consider standoff, when you get below I would say three to 5 mil standoffs, there will be cleaning problems. That has to do with the chemistry and physics of molecules, cleaning agents, and soils.
If you have closely spaced components, it's very hard to get wettability and to get the cleaning agents in contact with the soil so that the soil can be removed. You have these very small, densely populated assemblies, and you have customers that are using those assemblies in ways that maybe the suppliers never anticipated and maybe the IPC never planned for.
Warner: Let's talk about what some of those applications are, because technology waits for no one. Are we talking military, medical, RF? Are we talking applications with heat or thermal concerns? What stressors and what applications are really driving these issues?
Kanegsberg: We see a lot of applications in military/aerospace, NASA, medical devices, and sensors.
Sometimes the client explains that the customer rejects the product even though the standards have been met. Classically in IPC the issue is ionics. We don't want ionics, that's obvious. What we're gradually realizing is that residues of concern are not just ionics. For example, residue of metal working fluid and residue of particles can interfere with the performance of the assembly. Sometimes there's a problem right away and the assembly is rejected. That’s annoying. However, what’s worse is when you see the problem later. Depending on the product, field failures can be catastrophic.
Warner: So, what do we need to do in testing?
Kanegsberg: That's the challenge. We can do ionics testing on the electronics assembly. We can look at the electronics assembly using ion chromatography. Are those the right tests? It depends on the how the final product is used. The electronics assembly is usually not an end in itself; the assembly goes into the final product. Selecting the right tests depends on what soils can damage the final product. In addition to ionic contamination, you can have non-ionic or fat-like contamination. You might have particles. Contamination can lead to all sorts of performance problems. For example, suppose you have non-ionic contamination or particles and then do conformal coating. If you have a high-value product or a product that has to last a long time, even non-ionic contamination or particles can spell trouble. The conformal coating protects the electronics from the outside environment, but it also traps residual soil. Soil that’s trapped under the conformal coating can damage the assembly and compromise product performance. So back to testing. The tests depend on what the customer needs. Maybe at IPC we need to take a fresh look at application-specific requirements.
Warner: Let’s get back to the panel discussion. What other questions did you get?
Kanegsberg: People asked about how to save money on cleaning equipment. My answer was that the best way to save money on cleaning equipment was to purchase quality equipment. Several of the panelists expressed similar sentiments.
Another questioned complained that the company had purchased cleaning equipment that was supposed to be good enough, and it wasn't. One panelist opined that, in the future, testing the equipment before purchasing could be time well spent. Other suggestions included modifying the fixturing and perhaps adding another dryer. It becomes a matter of optimizing and managing the cleaning system.
I thought the question about drying was interesting; and the answer involves purchasing the correct quality of cleaning equipment. In cleaning, be it water-based or organic solvent-based cleaning, you have washing, rinsing, and drying. It's just like when you take a shower only it's an electronics assembly. When you wash, you bring the cleaning agent, the cleaning chemistry, in contact with the part. You remove the soil, and keep it away from the part. When you rinse, you remove the cleaning agent. When you dry, you remove the residual water or solvent. I’ve noticed that some manufacturers sort of run out of steam in terms of process design and money for capital equipment when they get to the drying step.
Several people asked the panel about the right water quality for the process. Water quality is important. Generally, tap water is not good enough. I
Warner: Well, isn't that why most cleaning systems use deionized water? I thought removing ions was a good thing.
Kanegsberg: Deionized water contains very few ions, so that's the point. You want the deionized water in one sense. You must have clean water to achieve good cleaning, but if you have total deionized water that water is looking for ions. Where is it going to find the ions? From the part you're trying to clean. That can then cause destructive surface modification.
Warner: What else did they ask about?
Kanegsberg: People asked questions about using organic acid flux versus no clean. That's a complex answer. It depends on what you're trying to accomplish, on what kind of assembly you are working with, and on the soldering process. All fluxes leave some sort of residue; no clean means low residue. Sometimes, you have to remove the residue left by no-clean fluxes. OA flux can be rinsed with water, but the OA residue tends to be more active. So, in hand-soldering work or under close spacing, you must plan the flux removal process carefully.
Warner: How refreshing it must have been for the attendees to go into a technical session and participate in a conversation with experts, that directly addressed their real-world concerns.
Kanegsberg: I think they enjoyed it, because the lunch was set out, and no one left! I kept saying, "Would people like to leave and go get some food?" They didn't want to leave. I finally said, "Go away and have lunch!" That was really refreshing. We live in an age of not communicating, but pontificating. I speak a lot. Sometimes improv is the right way to go. I love it. I personally like it because it's a great way to find out what people are interested in, which is not necessarily what we the panelists want to talk about.
We're consultants. BFK Solutions is a consulting company, and we help people either fix, improve, or setup better and more effective cleaning processes. One that lets them make high quality product and make lots of money. That's how we get paid. But we also teach. We do a lot of courses both for individual clients and sometimes for professional conferences and professional programs, that kind of thing. It's nice to know what people want to learn instead of just guessing what they want. The spontaneity of just having the audience speak up is fun. I think in this election year I was really happy that everyone was very well behaved. That was a relief.
Warner: Yes, because the EPA issues here in California can be a chokehold for EMS companies to sort out, right?
Kanegsberg: I would be really happy to do an entire separate interview with you at another point other than to say yes, you're absolutely right. Certainly, it's very confusing, and each air district uses its own approach to regulation. I must say that's always bothered me, because we all live in the same world, so I would love to see more standardization.
Warner: Wouldn’t that be nice? Going back to current market conditions, in the electronics manufacturing industry we see increasing demand for complexity and reliability from OEMs with a concurrent demand to lower costs. I assume you see that as well?
Kanegsberg: Of course.
Warner: From a cleaning standpoint, how do you encourage manufacturers to buy the best equipment when you know that they're being so hard pressed from their customers to keep their costs down? There's a huge tension there.
Kanegsberg: That's a great question Judy. There is immense tension associated with equipment selection. In fact, there were quite a few questions for the panel about cleaning equipment costs. We ended up discussing cleaning process costs. It gets into issues of the cleaning agent, filtration, waste disposal, management, permitting and so on. It's quite complex.
Clients often ask me how to get really cheap cleaning equipment and the best way to do a really cheap process. I always just say buy quality, and they usually open their eyes and they're skeptical, but they're generally pretty accepting of it. I should add by the way that we're not reps, so we don't do commissions or fees.
Warner: Meaning you don't have a stake in the advice you’re giving?
Kanegsberg: Well we don't do consultant appreciation day and all that stuff, but we accept lattes and we treat people to lattes.
Because the client pays us, we don’t necessarily aim at recommending more and more cleaning. For example, one client was able to get away from doing very much cleaning in their own plant because they were able to verify that their supplier gave the assemblies to them in a condition that was clean enough for their application. They didn’t need the cleaning machine or the fairly expensive cleaning solvent; and they could avoid the costly environmental permits. Is that talking us out of a job? Sure, but that's okay. The goal is not to keep cleaning for its own sake, but to do critical cleaning, which is the right amount of cleaning in the right place at the right parts of the process.
Warner: So, how should electronics assemblers figure out what cleaning process to use?
It is important for customers of cleaning equipment companies and cleaning agent companies to figure out what they truly need. What I heard in several the questions for the panel was that electronics manufacturers had been sold a cleaning process without their ever really testing the solution. They were told that it was supposed to meet the specs, and maybe there was some data, but everybody needs to spend a little bit of time testing it out.
Warner: That's a little frightening when you think about it. Manufacturers depend heavily on empirical data provided
Kanegsberg: That’s true.
Warner: We trust that these equipment manufacturers have fastidiously measured and gathered reliable data. If that data is not accurate, that's very unnerving given the cost of the equipment.
Kanegsberg: Our panelists are all ethical, educated, concerned people. It’s a matter of perspective. Everybody works based on their own experience. Suppliers, vendors, and reps of cleaning agents and cleaning equipment tend to have the most complete understanding of their own product lines. It's great to look at every bit of data that comes in, but external studies are not going to exactly duplicate what you as a manufacturer must do.
Warner: Makes sense that in every plant, there are many variables and countless custom applications.
Kanegsberg: In your plant, your location, your workforce, and your customers are unique. What does the customer need? What does the customer really want in terms of the electronics assembly?
Warner: Are you saying then that the customers aren't being completely clear about what their requirements are?
Kanegsberg: Sometimes the customers don't really know what their requirements are. They want the product to work; they don’t want any assembly problems. With so many variables in complex products, it may be impossible for them to specify everything.
Warner: How do we resolve that, Barbara?
Kanegsberg: It's difficult Judy, because we live in an age of specifications. This is not to do with the panel, per se, but I think in a way it connects with some of the questions. I have clients saying to us, "Well the customer wants us to meet this spec." The spec may indicate not only ionics but also soil level, the particle level, thin film contamination; this goes way beyond typical electronics. The customer may not even know what they want—high reliability. They may not even know what they need to achieve that reliability. There really must be a bit of communication between the electronics assembler and the customer. Communication is important all the way through the supply chain.
When I get into the mode of doing electronics assembly, I think, “Oh, here's the perfect assembly. We've done a great job.” However, the assembly is not set on a shelf to be admired; generally, it goes into something else to make the final product. Just as the assemblers get the bare boards, the components, the fluxes and the solders from different places—that's the electronic supply chain, those assemblies themselves are become part of another supply chain. The communication is awfully important.
Warner: Can you talk about the different types of cleaning? I know there's aqueous, there's chemical cleaning, and there's also vapor cleaning, correct?
Kanegsberg: Yes, there is. First, I will get in a little plug that we have edited and contributed to the Handbook for Critical Cleaning from CRC Press. Let me just say that there are probably a gazillion cleaning techniques, give or a take a few million. Basically, most people who do electronics assemblies do aqueous cleaning. That means either water alone or water with some chemicals in it to improve the wettability and soil removal capability of the water. Fluxes have both organic compounds, meaning carbon containing compounds in it, and inorganic compounds. Inorganic compounds don’t contain carbon; they generally are more polar, so you can often remove them with water alone. Sometimes you need more than water. Even so-called no-clean fluxes need to be cleaned. Sometimes you clean them with water, or aqueous, or water with solvents in them.
Sometimes people use what's a called a semi-aqueous process. That is a process where you wash in primarily solvents, meaning organic solvents. I know water is a great solvent for sugar, but in my world solvents means organic solvents. Then with semi-aqueous you then rinse with water. Sometimes people use what are called co-solvent, bi-solvent, or sequential solvent cleaning. That's where you wash with one organic solvent and you displace with another, or you vapor clean or vapor rinse with another.
You mentioned vapor cleaning and vapor degreasing. That's usually using an organic solvent. What's fun about degreasers is that you can clean in the liquid phase and do the final cleaning or final rinsing (the line blurs here—it’s self-rinsing), in the vapor phase. That means you have freshly distilled solvent. It's completely clean, or almost completely clean. We won't get into azeotropes in this discussion, but there are lots of techniques. There is so-called non-chemical cleaning. This includes processes like steam, CO2, dry ice, plasma, and UV ozone. There's lots of ways to skin a cat. How long do you have, Judy? (Laughs)
Warner: That is why this panel was so relevant to the local market here, correct?
Kanegsberg: Well the local market's interesting, because the air districts are very restrictive in what you can use. I would say that most manufacturers have not spoken up to their ‘friendly’ air district because they’re afraid. Many of them have quietly left Southern California, which gets me a lot of frequent flyer miles. And that's fine, but I would love to see manufacturers as neighbors right here in Southern California where I'm located. I think we ought to be able to have regulations that are practical for industry and that keep things safe for the workers and safe for the environment.
Right now, we need a general cross-cultural education of people in the regulatory world as to what is possible in terms of cleaning. I think that locally manufacturers are being forced to use cleaning processes that are not tenable and really do not work very well for densely-populated electronics assemblies. I have seen companies that shall not be named for obvious reasons refuse projects in California, because they don't think they can get permits for the cleaning process. They'll ship the process out of state. That's just silly. We all live in the same world. The air has to be clean everywhere. That gets into the Ozone Transport Commission and work that IPC did with them; that’s a separate topic in itself.
Warner: Let's talk about IPC for a moment. Is IPC looking at revising or updating standards relevant to cleaning and testing in the future?
Kanegsberg: I would love them to do it. I'm always open to assisting and to helping, but I don't know what they will do. I think with IPC, we are still hung up on ionics. Don't get me wrong, we have to minimize ionics, but we need to look a little bit more at what the levels ought to be relative to the application in question. Part of it is that really, we need to look at what customers for electronics assemblies are looking for, and that's difficult.
IPC, historically, has maybe been a little bit more involved in aerospace, and maybe ASTM a little bit more in medical. I don't know that it should be that way, because we really need to get those standards to be a little bit more global and a little bit more encompassing.
Warner: Isn't aerospace and medical usually at the top of the technological food chain, so to speak? Wouldn't that flow down to cover other applications?
Kanegsberg: Well, yes, they are near the top, but they don't always talk with each other. I'm not sure that either of them is necessarily speaking as clearly with their suppliers of electronics assemblies as they need to be. In other words saying “meet the spec,” or “do what I want,” or “make it good enough that the FDA won't yell at us,” or “make it so that we pass Nadcap.”
Warner: Are you saying what the customer requirements aren’t well defined inside of some of those certifications?
Kanegsberg: It is very difficult to put together complete standards and guidance documents that encompass all desirable aspects of the product. It's a matter of working with the people who are using the product. Just the way the five of us panelists were answering questions from the audience.
Warner: Would you be supportive of an industry consortium around cleaning to foster high-level conversations to more clearly define what is needed?
Kanegsberg: Oh, talk to each other? Yikes! That's a dangerous idea. I like your style Judy; I think that would be wonderful. There needs to be more communication and we need to teach cleaning. You don't learn to be a cleaning lady in school. I'm working on that now and I think that has to happen.
Warner: It's very interesting to me that it's become so complex.
Kanegsberg: I think it always was. We had some tried and true approaches, but the world has changed. When I started my company in ‘94 I had been in charge of phasing out those other cleaning chemicals and replacing Freon and 1,1,1-trichloroethane, and I actually received an EPA ozone protection award. It was upper ozone that I was trying to protect, and I realized gradually that the solutions that looked so good were actually creating their own problems.
We saw devices, components, and widgets becoming much more complex with more different sorts of materials of construction. When we get into additive manufacturing and 3D printing, will it make electronics simpler? I don't know.
Warner: In addition to more complex materials, the environmental regulations have completely changed in my lifetime. When I started in this industry back in the ‘80s, we had lots of really toxic stuff that worked really well!
Kanegsberg: We have always had lots of toxic stuff that worked well. I think that solvent substitution, where you stop using chemical A and start using chemical B or mixture C, is ridiculous. It’s not the answer; it’s not a box that we should not be trapped in. If the replacement works as well as what we tried to replace it with, there are potential environmental issues and there are potential toxicity issues.
Heinlein once said, "There ain't no such thing as a free lunch." If it cleans well there could be safety environmental problems, because we're all of this earth. We're all made of the same materials ultimately. There really has to be some process management rather than just chemical substitution. In terms of chemicals it's turned into chemical witch hunts, and that's kind of silly. It's almost analogous to the way we manage foods. It's kind of like for a while eggs were bad, now eggs are good.
Warner: Now GMOs and gluten are bad. It used to be fats were the problem.
Kanegsberg: A while back gluten was supposed to be great if you ate it in large muffins but left the butter off. Now, it seems to be forget the large bread and eat the butter separately. Just as we are beginning to look at our diet more holistically, we need to look at manufacturing processes using a risk/benefit approach.
Warner: This has been interesting. I've really enjoyed it. What do you think the people that attended your panel today walked away with, on a positive note?
Kanegsberg: Hopefully they walked away with some practical options and some information that they were interested in. Hopefully they walked away with the ability to look at their own cleaning process somewhat more critically, somewhat more incisively. Rather than to simply say, "Well we passed the test," or "Gee, the data sheet means we ought to pass the test." There really are no guarantees in life. It has to work well. Hopefully they're thinking a little bit more, and I mean that in a nice way. Not that they weren't thinking before. Everybody there had thought about cleaning a lot, but hopefully they're learning to learn a little bit more. I hope we'll see a little bit more communication between the customers and the suppliers.
Warner: Isn't that why we are here in Long Beach at the SMTA Tech Expo? We all get together face to face and we talk to each other.
Kanegsberg: That’s right.
Warner: To wrap up, just give me a little info about BFK, and how you ended up in this scientific discipline?
Kanegsberg: I'm the president, chief bottle washer, and technician for BFK Solutions. We're an independent consulting company. We are client-based rather than product-based. We work on projects in all sorts of areas to help people improve their cleaning processes. I've become known as the cleaning lady. My husband, Ed Kanegsberg, is the rocket scientist, because he is one. We work on product cleaning. It gets into electronic assemblies and medical devices; I've worked on the surface quality of coffin corners; some of those involve sophisticated vapor deposition techniques. We’ve had projects in optics, pharma, medical devices, food, oh golly. We've gotten involved in thermal spray, 3D printing of metals. We worked with NASA and in aerospace.
Warner: What is your education and how did you get to become the cleaning lady?
Kanegsberg: My education is in biology and biochemistry. I minored in English and economics and I switched to biochemistry because I saw too many of my classmates become secretaries. I thought, “Gee, I want to have a career.” I did research as a lab tech at UCLA. I designed blood tests and urine tests at a place called Bioscience Labs. That's where I learned a lot about automation, about managing decision issues and contamination issues.
I moved to aerospace after the clinical lab had three corporate takeovers in three years. I moved to Litton Industries. Analytical chemistry was not as much fun for me as designing clinical tests – probably not enough variety or suspense by comparison. Then, I was put in charge of the phase out of ozone depleting chemicals, because I didn't run away fast enough. My boss said that the guys didn't want to do it or talk to each other, I could do it in my spare time, and “that it wouldn't take much of your time, dear.” Yeah, sure! I ended up working with dozens of Litton divisions world-wide. I became an in-house consultant. I am so grateful for the opportunity. Then I started BFK Solutions in 1994, and have been doing that ever since. It's been fun. It is fun.
Warner: On the outset, cleaning doesn't seem like it would be that complex, but it clearly has a major impact on the electronic assemblies.
Kanegsberg: I figured I’d run BFK Solutions for a few years, solve all cleaning problems, then figure out what I’d do when I grow up. That was about 23 years ago, and I’m still trying to solve cleaning problems. You’re right! Cleaning has a major impact on electronics assemblies. On most products. As a biologist, I realize things happen at the cell membrane level. Of course, you must have the right structure, but the interactions are at the surface, at the interfaces, is where nice stuff can happen and evil stuff can happen. It’s analogous to what happens at the interfaces of electronics assemblies. With the right critical cleaning, you minimize the evil and maximize the good.
Warner: Well I really enjoyed this Barbara, thank you so much for your time.
Kanegsberg: Thank you so much, Judy.