If you have ever immersed yourself in the fitness culture for any period of time, you have undoubtedly heard the mantra “no pain, no gain.” There is truth in this saying because some gains, such as tighter muscles or physical stamina, do require suffering through weight training and cardio exercises. Once you achieve your goal of increased strength, better tone, improved endurance, and reduced weight, the pains become worth it. The key to the best results, however, is keeping the pain within acceptable limits.
This same philosophy is applicable to PCB development risk management. Managing the risks, whether inherent to the design and manufacturing process or derived from external sources, requires the determination of acceptable levels of impact and ensuring they are not exceeded. The key to controlling the impact of risks is to develop a risk analysis plan, and the best results can be obtained if your plan includes the essentials for ensuring the quality and reliability of your boards. First, let’s define a risk analysis plan and then refine it by defining the essentials for a PCB risk analysis plan.
What is a Risk Analysis Plan?
It is helpful for us to distinguish between some common terms associated with risks that are sometimes not clearly defined. These include:
Risk management - The process of identifying potential sources that may negatively impact or pose a risk to a project or product; quantifying the degree of impact of the risk; devising a means to offset or mitigate the impact of the risk; and implementing and monitoring the results so that the process can be improved.
Risk assessment - A tenet of risk management where risks that have been identified as potential threats to some aspect of a project are evaluated. This involves categorizing the risks and assigning parameters that can be used to quantify the impact of the risks.
Risk analysis - Also a tenet of risk management. Specifically, it is the review of the impact of risks that have been identified and for which a control strategy has been defined and implemented. The results of the analysis are the basis for refining or modifying the control strategy so that it will be more effective in the future.
Risk analysis may be quite complicated, especially when there are many possible outcomes or results that may occur depending on the degree of impact of the risk. Therefore, a means of quantifying the varying risk impact and the action(s) to be taken, or a risk analysis plan, is needed. Let’s take a look at the essential elements for a plan applied to PCB development in the next section.
The PCB Risk Analysis Plan Essentials
Good PCB design means creating your PCB layout such that your manufactured boards will meet your operational requirements reliably throughout the intended operational lifecycle. This means achieving the best yield rate during board production, which depends upon the quality of the PCB development process and management of potential risks. Effective risk management is predicated upon a good risk analysis plan, which should include the essential elements listed below.
Essential #1: The List of Risks
For your risk analysis plan to be most effective, it should include all potential risks to your PCB development. Some risks may be specific to your design or product, but common risks that should be included are: mechanical breakdown, unobtainable components due to shortages or obsolescence, and environmental hazards. As an example, for aerospace deployment you may have the following list of risks:
- Short circuit due to excessive current.
- Warping due to temperature exposure beyond material limits.
- Delayed assembly due to component(s) being unavailable.
- Increased costs due to low yield rate.
Essential #2: Parameters for Measuring Risk Impact
An action or response strategy should be created for every risk. Doing so first requires assigning parameters such that the severity of risk impact can be quantified. For example, the following parameters may be used to rank or scale risk severity for the list of Essential #1.
- Short Circuit
- Low impact - high current
- Mid impact - pin or trace discoloration
- high impact - component burned
- Low impact - ≤ 10°
- Mid impact - > 10° and ≤ 30°
- High impact - > 30°
- Delayed Assembly
- Low impact - 50 components available
- Mid impact - from 15 to 49 components available
- High impact - from 0 to 14 components available
- Increased costs
- Low impact - yield rate is 80% to 90%
- Mid impact - yield rate is 60% to 79%
- High impact - yield rate is 59% or less
The Engineer's Guide to PCBA Manufacturing Complexity
Essential #3: Controls for Each Risk Impact Level
Your plan should also include a response or control to be applied for each impact level for each risk. This will guide the implementation of your risk management strategy and provide for the assessment of its effectiveness. The results of this analysis can then be used to improve your risk management. If your process was found to produce an unacceptable yield rate, you may opt to add or modify board testing to address this risk.
In order to maximize the results of your PCB production, you need to optimize all phases of your development process. An important aspect of this is risk management, which should be based upon actual results obtained by implementing your risk analysis plan. For this plan to be the most effective, it should be adaptable and include the essentials listed above. As these essentials include actions to be taken during board fabrication and PCB assembly (PCBA), it is also advisable to involve your contract manufacturer (CM) in the creation of your risk analysis plan.
|Tempo‘s Custom PCB Manufacturing Service
Tempo Automation is the industry leader in building high-quality boards quickly and will partner with you, beginning with design, to ensure that the manufacture of your PCBs is in accordance with your design intent. We will also provide you with the necessary information and specifications for you to optimize your design for fabrication and assembly and minimize the likelihood of the occurrence of risks that may affect reliability.
And to help you get started on the best path, we furnish information for your DFM checks and enable you to easily view and download DRC files. If you’re an Altium user, you can simply add these files to your PCB design software.
If you are ready to have your design manufactured, try our quote tool to upload your CAD and BOM files. If you want more information on risk analysis or ensuring your plan includes the essentials for quality PCB development, contact us.