Some people are afraid of spiders or snakes and I’m afraid of those too, but one of my worst fears is being audited. Now it’s time to start getting organized again and collect on all of my organization last year to make reviewing my notes and preparing for taxes easy. But, wait: my drawer full of notes and important receipts is also full of assorted shopping lists, grocery receipts, home repair goals, and that list I wrote in February for a workout routine that I stuck to for three days. I have a formal bookkeeping process, but, sometimes, I worry that it’s not enough. I wish I knew what the IRS was looking out for in their reviews process.
On the other hand, being the auditor isn’t just picking daisies. Especially if you’re auditing your manufacturing process for your PCB manufacturer, there are hordes of things to keep track of and pay attention to. While small batches of boards or simple PCBs with large tolerances probably don’t justify the time and travel for a full review, when you’re designing high density PCBs or large volumes of them, a thorough review should definitely be within your considerations.
Since the manufacturing facility may contribute to defects, it’s a good idea to audit your manufacturer’s facilities and practices. When you visit, you should be prepared with a list of items you want to review, like my checklist of tax forms and documentation. Everything from the equipment, the environmental controls, and the handling procedures should be considered. It may seem like a lot, but if you’re going to the effort to visit a manufacturing facility, especially if it’s overseas, it will be better to get it all done at once.
One of the first steps to any review will be looking at the available documentation. This can range from questions such as if temperatures and ramp times are recorded each the time the solder reflow oven is used if issues with etching are recorded, and how different products are tracked and kept separate during manufacturing. Having an understanding of your manufacturer’s documentation process will allow you to know what kind of information you’ll want from them, and what you’ll be able to have ready access to.
Just as important to understanding their documentation process, your manufacturer’s design security is incredibly valuable too. Horror stories like manufacturers using your design to start producing counterfeit versions themselves, or having unsecured computers where your proprietary designs could be easily accessed by unauthorized entities are as much a part of your review of your manufacturer’s process. Even if it seems redundant or insulting, it’s significantly better to ask the specific questions now instead of seeing a competitor learning your trade secrets.
When you get into checking the manufacturing facilities, you’ll be looking into how the manufacturer handles the materials and the environment. Here are some of the key methods to check in your handling reviews:
Process Controls: Make sure that everyone who enters the area is wearing proper protection. That should include hair nets to keep static discharge from building up, as well as keeping hair off the boards in case of shorts. People should also be wearing wrist, and possibly shoe straps that are plugged into the ground at each workstation.
Environmental Controls: Along with process controls, you want to see good environmental controls. Contamination is a huge concern, and a dirty manufacturing environment will be almost impossible to compensate for. There shouldn’t be dust collecting on any equipment. Any processes that produce dust, like CNC milling, should be separated from the rest of the production line and cleaned regularly. Chemical processes should be performed under hoods or appropriate ventilation. Operator contamination sources, like oil from your skin, hair, or clothing, should be minimized by gloves, goggles, hairnets, or other PPE.
ESD Protection: One of the largest concerns for your PCB design is ESD protection. Having environmental protections for ESD during manufacturing will keep components and boards from suffering discharge damage. As much as I’ve harped on paperwork, ESD areas shouldn’t have any loose paper or packaging materials around that could get pushed around and generate a static charge.
Packaging: Always ask to see the packaging that gets used. Make sure that it meets your requirements for the product their currently packing, and that they are familiar with the type of packaging that your product will need.
As a final step, check how the materials and products are actually unpacked and packed to make sure the handling processes are consistent throughout the production process. Consistency and manufacturing safety is vital to the overall health of your manufacturing process.
Your first and main concern with a manufacturer’s audit would most likely be the actual production capabilities of your manufacturer; skipping over their review would be like itemizing your deductions when you have no income to report: an awful lot of work to miss the main event. Here is a list of things to consider:
The most enlightening of a manufacturer audit might be in finding out that a manufacturer can produce one of your designs in a cheaper and more effective way than you had previously anticipated. Being able to know confidently what your manufacturer is capable of will give you a clearer gauge of the success of manufacturing any of the potential designs you come up with.
Unlike an IRS audit, manufacturing reviews should be informative and helpful for everyone involved. It’s an opportunity to learn more about the production line, and how to improve your designs.
After you learn what your manufacturer’s capabilities are, you can use those guidelines to help improve your PCB design process with assistance from your CAD system. When you need to access an easy-to-use PCB layout tool that includes everything needed to build high-quality manufacturable circuit boards, look no further than CircuitMaker. In addition to easy-to-use PCB design software, all CircuitMaker users have access to a personal workspace on the Altium 365 platform. You can upload and store your design data in the cloud, and you can easily view your projects via your web browser in a secure platform.