If you could know the future, would you want to? Let’s suppose this is not a rhetorical question. If you were aware of events before they happened, you would likely find yourself changing plans to achieve a better outcome. For this clairvoyant skill to be useful, it would need to be accompanied by some constraints—for example, a fixed objective or target outcome.
While designing and building circuit boards may not depend on clairvoyance, it will require PCB reliability prediction. And for these predictions, your target outcome for any future production will include an expectation of reliability. This requirement is especially true for critical PCBA development areas such as aerospace, medical devices and automotive systems; however, it applies to all board development to some extent. The ability to meet reliability requirements is directly related to the quality of your CM’s board-building process. With adequate quality controls in place, your CM will not only build the best PCBAs for your project but also aid in PCB reliability prediction.
What Is PCB Reliability Prediction?
PCB reliability prediction can be viewed as an extension of board yield calculations. The latter provides an estimate of how many boards will be usable relative to the number of manufactured boards. The former, however, estimates whether the usable boards will perform as intended over their projected lifetimes.
Mathematically calculating yield is a complicated task due to the number of factors that may contribute to or cause failure modes. This complexity increases for reliability prediction quantification; however, it is not typically necessary to explicitly define a specific number of failures in the field. Instead, it is more effective to institute quality management procedures to reduce the risk of any type of failure.
Using Quality Management to Improve PCBA Reliability
For critical system PCBA development, standards define the quality management system (QMS) characteristics that are acceptable. A good example is ISO 13485, which provides information on establishing a QMS, including the following considerations: who should be involved; how the system should be managed; what documentation is necessary; how to use data; and how the system can be improved. This standard, along with similar publications, defines quality management attributes that designers and CMs can use as a foundation to ensure a quality-focused process. To specifically target finished product reliability, you should additionally institute the following.
QMS Attributes for PCB Reliability Predictions
- Establish a culture of quality.
- Establish training requirements for individual roles.
- Incorporate an emphasis on customer needs.
- Establish transparency, open communication and collaboration with your CM.
- Engage your CM early to ensure design intent is understood.
- Make sure your CM shares your commitment to quality.
- Develop and institute a strong risk management plan.
- Require documentation of and reaction to continuously collected quality data.
- Document processes for material inspection and disposition of non-conforming materials.
Quality can seem hard to qualify, but it is not difficult to quantify. Meeting or exceeding the performance and operational expectations of your customers supplies the best example of attainable quality. By ensuring that the attributes listed above are present in your board development and incorporated into your PCBA design checklist, this goal can be consistently reached. And you can feel confident in predicting that your PCBAs will reliably meet your objectives.
The PCB Design Development Checklist
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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 Designer or Cadence Allegro user, you can simply add these files to your PCB design software. For Mentor Pads or other design packages, we furnish DRC information in other CAD formats and Excel.
If you are ready to have your design manufactured, try our quote tool to upload your CAD and BOM files. If you would like more information on using quality management for PCB reliability prediction, contact us.