With each new PCB design, there comes a time when you must make decisions based on more than performance alone. Physical space is easily overlooked in the world of equations, schematics, and oscilloscopes—we'll often focus on signal integrity over such mundanities as component volume. In the days of room-filling computers, we didn’t have to be deliberate with our space. However, cost, time and space requirements have obviously changed. There is now a point in every designer’s journey where the reality of their budget (or lack thereof) smacks them square in the face, and we must turn to assessing the cost implications of our decisions—particularly how our board layout affects manufacturing costs. We've come a long way in both scalability of components and our knowledge of component placement. Learning from our mistakes, we can identify some key areas that can help keep your design to a more budget-friendly range.
With the technology available to factories, it might seem like anything is possible on a small budget. While this might mostly hold true, each step added in the manufacturing process is a step that will certainly be billed. The idea of a simplistic design should always be in the back of your head, since manufacturers will look to charge for any extra work they must do. This includes rapid pick and place machines placing the components on the board, machine-guided soldering steps, flipping of the board, factory worker touch times, and so on. The more they have to finagle with your board, the greater the cost to you.
There are hundreds of tips and tricks that you will undoubtedly encounter and learn from throughout your design. However, the following three tactics are your low-hanging, budget-friendly fruit that you should always keep in mind.
With the varied technology in mounting components these days, we'll likely find ourselves mixing and matching through-hole with surface-mount components. This poses a slight issue for manufacturers, as there are unique ways to install and solder each component to the PCB. This will certainly add a plethora of additional steps and touch time required to produce the board—thus adding more cost to your overall manufacturing budget. If keeping to one mounting technology is out of the design question, then grouping similarly mounted components together on either side of the board will limit the number of steps taken to solder such groups successfully.
Throughout your life, you may have been told to keep your ducks in a row. Regardless of how you've kept your ducks (or other poultry) over all these years, I must bring you back the same old adage in regards to your PCB design. Keeping components scattered all over the board isn't a wrong practice, but your machine manufacturing costs will soar to new heights. Keeping your components oriented with each other and in a nice neat row will decrease the amount of time spent on soldering as well as minimize errors and extra steps needed in manufacturing.
When working with a simplistic two layer board, we suggest keeping your components on the top side of the board. Depending on your physical limitations, you may be thinking to yourself "Hey, I bet I could take half of the components on one side, and place them on the bottom. I'd save plenty of room!" Tread lightly, however, as this could serve to become a manufacturing nightmare. In the assembly stage of PCB manufacturing, a rapid pick and place machine can make quick work of a single PCB side. If, however, your board requires a second side to pick and place, your costs may just break the bank.