Assembly Reliability

With PCBs becoming increasingly complex, not only have the number of layers increased, but so also their manufacturing processes, and the importance of PCB assembly reliability. Although a single PCB assembly can have tens of thousands of soldered joints, just one faulty joint can cause an entire board failure. Even minor failures can affect the performance of a product in the field, risking warranty issues, recalls, extended design revisions, and more.

While functionality tests may be adequate to demonstrate overall board performance, they alone may not be sufficient to understand the wear and tear on the PCB assembly during use or when it is exposed to environmental factors. There may also be errors in process design, wave-soldering, or reflow-soldering, and these could result in product failure.

To prevent defects in PCBA, we, as manufacturers, build quality in it early in the design phase, thereby mitigating the quality, reliability, and thermal issues that could impact performance.

Below, we have explored selected technical insights, including common failures, challenges, and best practices, from Rush PCB Inc.’s work with PCBAs.

• Insufficient consideration of structural and process designs, leading to excessive loads and failure, is a common vulnerability of PCBA components. For instance, thin-film ceramic resistors and multilayer ceramic capacitors are extremely fragile and are vulnerable to assembly stresses that soldering may cause.
• Care must also be taken when reworking the PCBA, for instance, when repairing or modifying it. Heating the solder joint to remove a PTH component during repair can potentially damage the joint, specifically between the annular ring and the barrel.
• With lead-free solder, soldering temperatures are critical. Tighter temperature settings are necessary because the lead-free solder has a higher melting temperature. The operator needs to set the process temperature properly to ensure the solder will not bond well, or the high temperature may damage the components and even the board.

Soldering Considerations

We solder electronic components onto the PCB with solder alloy and flux, forming solder joints. During the assembly process, we perform surface mounting, PTH insertion, wave-soldering, and reflow soldering processes, with precisely controlled process parameters to mitigate possible reliability and product safety issues. There can be several failure modes related to soldering:

Thermal Considerations

With electronics becoming faster, smaller, and more complex, PCBAs require more power and this occasionally raises their operating temperature. Designing the PCB with an effective thermal performance is a critical factor, as more than half of all electronic components fail due to heat stress, a mismatch of CTE, or heat-induced material degradation. Some best practices we follow to address thermal considerations are:

Rush PCB Inc. has extensive experience in helping our customers review their design processes to improve product quality and reliability. We have multidisciplinary teams to evaluate the degradation of PCB materials, assess their impact on product lifecycle, and identify potential quality and defect issues while providing solutions and mitigation methods. We have inline AOI to detect the defect. Offline X-ray machine to detect solder wettability and adequate solder joint.

RUSH PCB Inc is familiar with all aspects of Plate-Through-Hole technology. The engineers at RUSH PCB Inc work with you on engineering and design of your Plate-Through-Hole print circuit.
Let our engineers assist with your design for manufacturability (DFM) issues relate to PTH technology in your assemblies. Contact us at [email protected], or call us at 1 408-496-6013