I have had many pets, mostly dogs, during my tenure on earth and the companionship, joy, and love that I received from them is immeasurable. Unfortunately, they have all departed, but the memories of all the fun we had remains vivid. Even so, the thing that sticks with me the most is how dependable they all were. Regardless of my disposition or state of mind, I could rely on them to be happy to see me. This type of reliability seems to be an inherent trait for dogs. So much so that we can rely on them to guide us when we cannot do so ourselves.
This type of unfailing reliability is the goal when designing PCBs. Although, it can be elusive in some cases, delivering boards to your client with a low failure rate is obtainable. However, this does require that reliability is made a priority, which is implemented through reliability engineering. Let’s define reliability engineering and why it is important for your PCB design. Then we explore what reliability engineers do to ensure the best products are delivered to your clients.
What is Reliability Engineering?
Engineering may be considered as the application of principles, techniques, tools and processes to achieve a defined result or objective. In many cases, the objective is a device, system or product with specific performance criteria and a defined operational lifecycle. The overriding measure of a product’s reliability is its tendency or ability to satisfy the performance criteria for the duration of the operational life cycle. Thus, reliability engineering can be defined as follows:
Reliability engineering is the application of principles, techniques, tools (hardware and/or software) and processes with the goal of ensuring that the resulting device, system or product meets or exceeds its specified performance criteria and operational lifecycle.
Achieving this goal requires attendance, not only throughout design and development but also during post-production when the product is in the field or in use. However, by understanding the importance of reliability and instituting good design practices the potential for PCB failure and its impact can be minimized.
Why Is Reliability Engineering Important for PCB Design?
Reliability engineering can be applied to any business endeavor; however, it is most often referred to for operations or activities that produce goods or manufacturing and production. For PCBs; however, manufacturing and production cannot easily be separated from design. In fact, every board that is manufactured has to first be designed. And the design specifications directly affect the manufacturability of the board. Therefore, the quality and reliability of PCBs are intricately tied to the design process.
Concept of reliability engineering
For this reason, there are regulations and standards that govern how PCBs should be designed, just as there are to ensure the process of manufacturing boards institute quality control standards.
For example, all PCBs must adhere to dimension specifications and performance reliability based upon their classification according to IPC-6011. And boards built for the aerospace, medical devices, and automobile industries have strict guidelines for design reliability and risk reduction in the form of quality management system (QMS) standards given in AS9100, ISO 13485 and IATF 16949, respectively. These standards and others are in place to ensure that reliability engineering is incorporated into the PCB design, manufacture and production processes.
What do Reliability Engineers do?
Obviously, reliability engineering is very important for PCB design and your company may have engineers dedicated to ensuring its implementation. On the other hand, making sure that the boards you develop are reliable for your clients may be one of the hats that you wear. In either case, your PCB development does employ a reliability engineer. And the reliability engineer is responsible for the following activities.
PCB Reliability Engineer Responsibilities
Risk management: This is probably the most important function of a reliability engineer as it directly impacts the other responsibilities. Typically, a formal risk management plan is put in place that provides a means or method for identifying potential risks and a list of controls or actions to be taken when a risk exceeds a predefined threshold. Risk matrices are one tool for organizing and monitoring risks.
Ensuring boards last for the defined lifecycle: In utopia, production yield rates are 100% and no board ever fails in the field. In the real world, there are times when your PCBs will need to be repaired or replaced. For these situations, the reliability engineer is usually tasked with managing the support needed to restore the client’s product functionality.
Minimizing product and resource losses: Loss can be generally defined as an outcome where the expected result was not attained. This includes the need to use previously unallocated resources, an excess of unusable materials and produced boards that do not meet performance and operational lifecycle expectations. Changes to processes, equipment and even predicted outcomes can be used to minimize losses, as well as incorporating principles such as lean manufacturing.
Although more specific activities can probably be added; such as making sure to incorporate accurate manufacturing overhead variance in time management estimations, the list above gives a good overview of what reliability engineers do or should do for your PCB development process. Essentially, it is the reliability engineer’s job to make sure that your boards do not prematurely wind up in the heap of failed and unusable PCBs.
Heap of failed and unusable PCBs
Reliability for PCB development begins with the design. Identifying and correcting potential errors that could render your design non-manufacturable is essential to risk management and enhances reliability. This is best done with the best PCB Design and Analysis tool, Cadence’s Allegro. This industry-leading software package includes DesignTrue DFM technology that enables you to incorporate your CM’s DFM in realtime as you design your board ensuring manufacturability of your PCB.
If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts.