When I was a kid and learned to solder, I had a mentor that kept an old coffee can on his soldering bench labeled “Lead Waste - DO NOT THROW IN TRASH.” Wire snippings, solder bits, and the random metal detritus that accumulates on a soldering mat all went in there. Apparently, it got full every few years and he took it to a local electronics recycling place to make sure he wasn’t adding any lead or heavy metals to the environment. I was shocked when I got to college, and we just threw everything in the trash like savages. Since then, I’ve tried to do what I can to minimize the waste that comes from my designs, from minimizing respins with good design, to planning for disposal when a product dies or is replaced. While it’s good for all the warm fuzzies, it also helps prevent legal surprises when dealing with electronic waste.
Why you should recycle waste PCBs
Electronic waste, of course abbreviated to “e-waste,” can also cause some pretty serious environmental impacts. Some PCBs still contain lead solder, or a multitude of heavy metals. If they aren’t disposed of safely, those materials will leach into the environment and cause problems for generations. There are now laws almost everywhere about how to safely dispose of electronic products and violations are heavily fined.
There are heavy fines imposed in nearly every country (and in local municipalities) for throwing electronics in the trash instead of disposing of them safely.
PCB recycling isn’t only a matter of obligation. It’s also possible to recoup some processing cost be reclaiming materials. Many precious metals, like silver, gold, palladium, and copper, are used in PCB fabrication. They are usually found in substrate material, or plating on plugs and connectors. Often, they can be reclaimed and sold. The value of precious metals fluctuates significantly, so the financial incentive to recycling varies with the metals used in assembly on your specific boards, and the total value that can be reclaimed at any given time. Some circuits and connectors are also reusable and will be redistributed by recyclers.
Many connectors are gold plated, and the gold can be reclaimed during recycling.
How PCB recycling works
While shipping or dropping off your PCBs (or your coffee can of solder bits) is probably the most involved you’ll get in recycling your boards, it’s actually a fairly complicated process. PCBs contain a variety of materials, metal, ceramic, and organics, that need different processing through the stages of the recycling process.
Disassembly: Most PCB recycling and disposal starts with disassembly to recover any components that can be reused. Later recycling steps are also easier if cables, components, and casings have been removed from the PCB. Disassembly is usually done manually, so if you’ve ever done a lot of rework, you can appreciate how frustrating a job that is. There’s lots of research on image processing and part recognition, but because so many types of PCBs and components pass through a facility, the technology hasn’t scaled yet.
Removal of hazardous materials: Ideally, anything hazardous gets removed early in the recycling process. That way it can be disposed of safely, and isn’t spread around later. However, this doesn’t occur reliably, and many handlers leave those materials behind.
Crushing: The components of laminates, like resins, glass, and ceramics, and metal layers undergo “size reduction” to make them easier to handle. This is performed by a mechanical process like crushing or shredding. It also makes it easier to sort out the metallic elements from the PCB itself.
Separation: After crushing, a variety of sorting and separation methods, like sieves and magnetic separators, are used to remove different metals from the laminate material.
Chemistry: Chemical recycling is used to break down polymers, and helps separate metallic, organic, and glass components in the waste PCB material.
PCBs are crushed and the tiny pieces are sorted to recover the highest value metal scraps.
How to plan for disposal in your design
Ideally, you’ll start planning for your products “end of life” when you are designing and fabricating your board. Make sure to communicate with your manufacturer and understand if there are heavy metals or hazardous materials being used in your PCB. If so, you’ll likely have legal obligations to dispose of the products safely, or inform your customers that they must. If products aren’t getting returned to you, make sure they are labeled so your users understand what to do.
In some cases, you may have security considerations around disposal. If your design has ITAR or other export restrictions, you need to plan for the entire lifecycle of your product, including “end-of-life” disposal methods. Again, make sure to communicate with your customer, and label everything with the appropriate restrictions.
You should establish a relationship with a refinery. If you want to make any money from recycling PCBs, the best value will come from the refinery doing the work. If you don’t have a high enough volume to work with a refinery directly, then it is better to find a broker who will collect PCBs from multiple sources.
Once you’re in production, you need a much more robust system than an old coffee can with duct tape labels. Managing the lifecycle of your PCBs is much easier when you have good version control and can easily review parts and materials long after the initial design and manufacture. Using PCB software that integrates with your supply chain, like Altium Designer and it’s BOM management tools, is a good way to keep track. Especially when your designers change projects or move to new roles.
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