Printed Circuit Boards (PCBs) are without a doubt central to all electronics. As technology advances, however, PCBs must be made faster and smaller than ever before. Before you get busy, make sure you nip sloppy PCB production
in the bud, before it costs you big bucks. Read on to discover the 12 biggest PCB development mistakes and how to avoid them.
We divide them into 3 stages: Layout Stage, Building Stage and Manufacturing Stage.
In Layout Stage
1. Improper Planning
Have you ever heard “proper planning prevents poor performance?” It’s true. There’s a reason we consider poor planning the number one PCB development mistake. There is no substitute for proper PCB planning. It can save you time and energy. If you build it wrong, you will have to spend additional resources to go back and fix it. How do you plan properly? Consider numbers 2-6 on our list before you physically begin building. You’ll be thankful you did.
2. Incorrect Design
There is an infinite number of layout possibilities with PCBs. Keep function in-mind when designing the form. For example, if there’s a good change you’ll need to add on in the future, you may want to consider something like a ball grid array (BGA), which can help conserve space on an existing board to enable you to build upon that design in the future. If your design must incorporate copper, you’d be best going with a polygon-style design. Whatever your function, choose the right form.
3. Improper Board Size
It’s much easier to begin with the right size first. Although the portion of the project you’re working on now may only require a small board, if you’re going to have to add on in the future, you’re better off getting the larger board now. Stringing multiple boards together may be difficult due to potential circuitry and connectivity issues. Plan adequately not only for current function but future function so you save yourself time and money.
4. Failing to Group Like Items
Grouping your PCB is a critical part of production. Grouping like items will not only help you keep your trace lengths short (another important element of design), but it will also help you avoid circuitry issues, ease testing and make error correction much more simple.
5. Software, Software, Software
We know you can design a PCB from scratch, but why would you want to when you can use software? Software makes your life easier. Electronic Design Automation gives you recommendations for the best layout to choose and other programs may suggest the best materials to use, based on prospective board function. Software won’t do all of the thinking for you, but it sure does help.
6. Using the Silk Screen Improperly
A huge ally when creating a design for a PCB board is the silk screen. When used properly, it’s a great tool that allows you to map out all aspects of your PCB before construction, including circuitry planning. However, be careful and maintain best practices. When used improperly, the silk screen can make it difficult to know where connectors and components are supposed to go. Use full words as descriptors when possible, or keep a key of your symbols nearby.
In Building Stage
Once you’re done planning, you can begin building your board. You’re still not out of the water, however. Building is another area where people make costly mistakes. When done well, however, you can build PCBs faster than ever.
7. Poorly-Constructed Via-in-Pad
This issue is one of the biggest detriments to proper PCB development. Many boards now require via-in-pads, but when soldered incorrectly, vias can lead to breakouts in your ground plane. This creates a larger circuitry issue, as power travels between boards instead of connectors and components. Test your ground plane. If you suspect you have a shaky via-in-pad on your board, cap or mask it and test it again. It may slow down production now, but it’ll save you time in the long run.
8. Using the Wrong Materials
Although this mistake may seem like a novice move, it happens. PCBs can be constructed using various materials. Know the purpose for which you are building your board, and which materials are best for that design, before you start building. If you’re building an FR-2 grade, single-sided PCB, you can use phenolic or paper materials. Anything more complex, however, should use epoxy or glass cloth. Also, different materials have different temperaments. Keep this in mind. If you’re building a simple design that needs to hold up in an area with a lot of humidity, it may be worth it to go with epoxy.
9. Too Lazy to Test It
If there’s one habit you begin to change, it should be the frequency you test your prototype. Assuming your board is grounded and that circuits will function in perfect accordance with their potential ground paths and voltages is asking for trouble. We know it takes time to test your board, but it’ll take more time to find and correct an error as time goes on. Test it now. Every design has an issue, keep that thought in mind.
In Manufacturing Stage
So you properly planned and built your board. Things couldn’t still go wrong, could they? Wrong! They can and they do. These are the three mistakes to avoid.
10. Failing to Double Crunch the Numbers
We’ve all felt the pressure of an upcoming product deadline. You’re sweating, over-caffeinated and running on lack of sleep. We know you’re an engineer, but don’t let your ego cost your company huge amounts of money due to an error. Always double-check your numbers before sending your model to production. This includes testing your board, ensuring the size is in line with your client’s specifications and double-checking your design is ideal for the intended function. It’s always better to have one model that needs to be reworked than a thousand. Rewind to #1 in this list… proper planning. Never jump the gun when sending out the design.
11. Temperature Control
This step is often neglected, but it’s important. Even if you do everything right leading to the production process, you will ruin your boards if you neglect temperature during development and storage. Every step in the process must factor in temperature. Soldering in cold temperatures, for example, often leads to poor connections. Likewise, storing boards in extreme heat or humidity may damage components and the board itself. At every step in the process, consider temperature and ensure its working for you.
Building PCBs can be fun, if you create functional boards at the end of the grueling process. So you designed your board well and followed best practices during production – you’re in the clear, right? Not always. Ensure you properly communicate with your clients at all times. It sounds simple, but what’s said isn’t always what’s heard. Your finished product can be rejected. Save yourself a step by making sure you’re creating what your client wants at every step in the process, so you can move onto more fun things, like making a paper airplane machine gun.