Device Reliability: PCB Design for Functionality and Manufacturability

Tempo Automation

May 17, 2018 , in Blog

A conscientious man who also happened to be a great leader once said, “he who represents himself has a fool for a client.” Yes, he was a lawyer, referring to situations where people find their life or liberty at stake; however, President Abraham Lincoln’s advice applies to non-legal professionals as well. The point he was making is that in critical situations, you should rely on experts to receive the best chance of success. President Lincoln certainly put his words into practice by relying on more experienced military minds during the struggle for the preservation of the United States. His words and actions are great examples for PCB designers to follow as they should rely on their manufacturer’s expertise to ensure board quality.

When your client receives an electronic circuit board, system or product from you, their main concern is device reliability. Reliability can be measured in terms of functionality or durability, but actually encompasses both of these quantifiers. For example, a mobile phone contains electronic circuitry that is designed to make and receive phone calls, text messages, imagery and video, and the circuitry should be durable enough to consistently perform these functions for some time, provided the phone is operated correctly. The PCB manufacturer is primarily responsible for board durability, while the responsibility for PCB functionality rests with the designer. Yet, just as the expertise of your lawyer can significantly influence your legal outcome, reliance on a skilled contract manufacturer (CM) can greatly impact PCB quality, which is a key factor that contributes to overall device reliability. Let’s define the respective roles for you and your CM that can influence the reliability of your device.

Device Reliability: Designer’s Role

Your device’s reliability level may be a critical consideration, depending on where it will be implemented. Sensitive systems such as those used for aerospace, medical, military and automotive applications have strict durability requirements. For example, electronics in pacemakers must be extremely reliable with a lifetime of twenty years. But even if your PCB isn’t intended for one of these highly sensitive industries, device reliability should still be a high priority because it directly influences client retention.

PCB design schematic

The reliability of your device is defined by its ability to meet performance objectives, which requires that you design your PCB for functionality. However, in order to perform reliably, the board must be well-manufactured. Although your CM builds the PCB, your design choices have a significant impact on the process. Your design choices can be viewed as falling into one of the following categories:

  • Electrical design considerations – This relates to component quality and the overall functionality of the electrical system.
  • Mechanical design considerations – These are the physical specifications, tolerances and restrictions that define your board and its layout.
  • Environmental design considerations – These include the board’s operating temperature range; ability to withstand vibration, physical stress or flexibility needs; and resistance to oxidation and any emissions.

As the designer, you are responsible for instituting these considerations into your PCB design. In most cases, your CM is only involved with the mechanical design considerations. However, your board’s electrical performance, mechanical construction and environmental interaction all depend on manufacture quality. In fact, your choice of CM and the degree of your reliance upon their expertise may impact the turnaround time, cost and device reliability. To achieve maximum device reliability, it is advisable to partner with your CM during the design process and help them assume the manufacturer’s role.

Device Reliability: Manufacturer’s Role

The basic role of a CM is to build a board that implements your electrical design. However, if you choose to engage your CM as a partner from the design stage, they can assume a much broader role. This includes helping you incorporate electrical, mechanical and environmental manufacturing considerations into your design to maximize device reliability. These manufacturing considerations include:

  • Electrical manufacturing considerations
    • Trace widths and lengths
    • Copper weights
    • Component placement
    • Component signal routing
  • Mechanical manufacturing considerations
    • Clearances
    • Board material
    • Solder reliefs
    • Pad locations
    • Drill holes
  • Environmental manufacturing considerations
    • Thermal dissipation
    • Solder masking
    • Bend (for flex and rigid-flex boards)
    • Finish (if used)

A critical part of your relationship with your CM is the coordination between your design and the CM’s equipment and processes, known as design for manufacturing (DFM). By following DFM and synchronizing design specifications with the CM’s capabilities and restrictions, you can ensure that your board is built to last. A well-manufactured board is designed to function as desired and minimizing electrical, mechanical and environmental stresses helps maximize device reliability.

Knowing your CM's QC practices is also important for device reliability

Tempo Automation is the industry leader in fast turnkey custom PCB manufacturing. We will complete your boards quickly while ensuring high-quality PCBs that meet all design specifications. As your partner from day 1 of your design, Tempo will help you incorporate fundamental electrical, mechanical and environmental manufacturing considerations into your design so your PCBs provide the device reliability you require.

Tempo‘s Custom PCB Manufacturing Service

  • Performs entire turnkey process in as fast as 3 days.
  • Emphasizes DFM to eliminate time-consuming back-and-forth design corrections.
  • Performs BOM verifications to reduce possibility of component obsolescence issues.
  • Sources components from the most reputable suppliers in the industry to reduce procurement time.
  • Performs multiple automated inspections during assembly to ensure PCB quality for prototyping.
  • Provides support throughout the PCB manufacturing process, beginning with design.
  • Smooth transition from prototyping to production.

And to help you get started on the best path, we furnish information for your DFM 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 device reliability or how your design decisions impact the dependability of your boards, contact us.

The latest PCB news delivered to your inbox.

12051 users are already waiting.