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Without sounding like a broken record, the continuing trend of miniaturization in electronics devices remains to be among the key issues that assemblers must grapple with when it comes to electronics assembly. From paste printing, to the pick-and-place, and all the way to the reflow process and inspection, these smaller and smaller PCB assemblies—with their increasingly shrinking components and packages, not to mention board real estates—can have a very big impact in every step of the manufacturing process.
For the August issue of SMT007 Magazine, we focused on cleaning: the challenges, key considerations, and strategies to improve the cleaning process—and why every manufacturer should start considering cleaning their assemblies now, if they haven’t been doing so already.
But why clean? In our conversations, many assemblers said that cleaning is not a value add, that their customers are getting nothing out of it. It also means an added process, and as such, an additional production cost.
Meanwhile, no-clean fluxes have been in the industry for over 20 years now. So why do we even have an issue about cleaning the no-cleans?
Perhaps, clean is in the eye of the beholder. Yeah, it does sound corny. But consider this example/explanation given to me by Kyzen’s Tom Forsythe during an interview: Imagine you are going to have a pacemaker—an electronic device—installed in your body. Now, I am pretty sure that you would want to have a pacemaker that has undergone a cleaning process to remove whatever contaminant may have come in contact with it during its assembly process. Granted, such electronics are being assembled in cleanrooms anyway. But it still must be cleaned, as it will undergo the soldering/reflow process perhaps, and you want to make sure that it is in the most pristine condition before being put inside your body for a very long time.
Next, consider the mobile phone. I am sure that with the very short product lifecycles of mobile phones, cleaning is not a value add. I recently came across an article mentioning something about ‘time-delayed’ effect, wherein defects will not show up until a product has been used for a year or two. In products like mobile phones, such defects won’t show up because newer models are coming out every year, and people tend to get new phones every two years anyway. So, no need for cleaning there.
Therefore, I would say cleaning depends on the application. In mission-critical systems, contamination of boards could result in massive, even life-threatening issues later, if not dealt with early on. Reliability is a must, so cleaning the assemblies is important. These are just a few simple things I can come up with, as I am no cleaning expert.
To read the full article, which appeared in the August 2018 issue of SMT007 Magazine, click here.