Life Cycle Cost Analysis for Better PCB Design
The 1996 movie “That Thing You Do,” was a brilliantly made snapshot of the rise and fall of pop music groups that are often referred to as “one hit wonders.” The movie did a great job portraying the birth, development, popularity, and eventual demise of a 1960’s rock and roll band called “The Wonders.” Another phrase that is often used to describe this pattern of growth and decline is “life cycle.” We often think about life cycles in reference to people that we know or read about, but it’s actually a lot more. Just about everything that you can think of, from businesses and neighborhoods and even to musical groups, have some sort of life cycle.
Printed circuit boards and the components used on them also have a life cycle. It is very important to understand what impacts the life cycle of a PCB in order to predict its usable life. With a better understanding of this, PCB design engineers can employ design best practices to get the maximum life out of the board. Factors such as vibration, thermal shock, and even manufacturing stresses have a great impact on the life of a PCB, and they must be analyzed and accounted for in the design. Here are some considerations on conducting life cycle cost analysis on your next design to better help you create a longer lasting circuit board.
The Importance of Printed Circuit Board Life Cycle Cost Analysis
The last thing that anyone wants is a circuit board that fails prematurely. It causes embarrassment for the design group, headaches for the service department, a black eye for the parent company, and frustration for the end user. To avoid this, PCB design engineers are spending more and more time with their designs looking at them from a life cycle perspective. This can influence what components are selected for use, and what kind of design for manufacturability (DFM) standards followed. Not only will this help define how long the useable life of the board is, but it also helps with design decisions that can increase that life.
Life cycle cost analysis will also help designers to develop a more realistic project budget as they can target specific component prices and manufacturing processes instead of generic costs. All to often parts get changed after the design has been finalized for reliability reasons, or the board configuration changes for performance reasons. Both of these factors, along with many others can end up altering the expected manufacturing costs. With cost analysis being conducted first however, actual component and manufacturing prices can be calculated.
Another advantage to PCB life cycle cost analysis is to meet the requirements of circuit boards that are used in high stress environments such as aerospace or military applications. These boards can be mission critical where failure is not an option, and therefore careful analysis of the design to make sure that it will meet and exceed its projected life cycle is essential. In the same way, life cycle cost analysis can also help designers to meet different industry standards by identifying unacceptable component or design details before going to manufacturing.
Let’s take a closer look at some of the different factors that you should be looking for in your PCB life cycle cost analysis.
Analysis of your board while still in design will help you to build longer life into it
Factors that Impact the Life Cycle of a Printed Circuit Board
Here are some of the areas that you should be looking at when considering the life cycle of the printed circuit board that you are designing:
Components: The chief concern with components is their reliability. Some component vendors may not create as robust a part as others, while you should also be cautious about using parts from unreliable sources. In some cases parts get returned and restocked, while others are left exposed to undesirable environmental conditions, while others may be counterfeit parts. One of the best ways to guard yourself here is to deal with component vendors, distributors, or PCB assemblers that have a reputation for high quality and workmanship.
Manufacturing: Many PCB failures can be traced back to bad solder joints that weaken and eventually break while in service. A lot of these can be attributed to design flaws that could be avoided by following design for manufacturing (DFM) guidelines so that the board goes through assembly and soldering correctly.
Normal Wear and Tear: Circuit boards operate in harsh environments where they can be subjected to vibration, thermal shock, and moisture. As such they may need additional design considerations including mounting hardware, conformal coatings, and extra cooling to extend their serviceable life.
User Interaction: Circuit boards may also be used in applications where they suffer user abuse. Children playing with electronic toys, drones that fly (and crash), and even frustrated users that smack their computers when the internet is slow all fit into this category. These forces must also be taken into account and designed for as well in order to extend the life of the board.
There is a lot to consider here as you analyze the cost life cycle of your design. Fortunately, your design tools can help.
The ability to export and import design data with IPC-2581 is very helpful with cost analysis
Putting Your Design Tools to Work to Help with Cost Analysis
A lot of design tools today have useful features that can help you with your PCB life cycle cost analysis. Starting off with your components, you can often get part costs and availability from vendors while working in your schematic.
Another useful feature is the bi-directional file transfer capabilities that you can use with your manufacturers to set up the board materials and layer configuration of your design. The IPC-2581 file format will give you an industry-wide open standard of communication with many PCB fabricators and vendors so that they can input the correct layer configuration directly into your design tools.
Don’t forget also to maximize the use of your design rules to help you maintain the correct clearances between components and metal in order to ensure that your board can be manufactured without any problems.
That may sound like a tall order for a CAD system to do, but there is a PCB design tool system that already contains all of these capabilities. Allegro PCB Designer from the Cadence line of high performance EDA tools has all of these abilities built into it plus much more. Not only will these tools help you to analyze the life cycle cost of your design, but the different rules and design features will ensure that you create the most robust design possible.
If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts.