Environmental Stress Screening (ESS) is a method used to apply certain environmental and operational stresses—such as power on/off cycles, bias voltage, pressure, thermal cycling, and vibration—to new or repaired products (usually electronics or components). The idea is to expose hidden early-failure issues that normal testing might miss. This helps weed out defective units and ensures better product quality.
Energy-Dispersive X-ray Spectroscopy (EDS or EDX) is a common, non-destructive technique used in the industry to quickly identify the elemental composition of a sample’s surface. In electronics manufacturing and material analysis, knowing what elements are present is critical for quality control and surface-level failure analysis.
Although EDX is considered non-destructive, there are some limitations. Most EDX equipment has size restrictions, so it’s a good idea to check with the lab beforehand to make sure your sample fits. Also, in many cases, the sample needs to be cross-sectioned before analysis. That’s because EDX can only detect elements within about 5 microns (µm) from the surface, so it’s best suited for surface-level analysis.
During the design and verification phase of electronic products, an Impact Drop Test is a standard procedure. This test is generally divided into two phases:
(Note: This article is based on personal experience and is for reference only. If you have different opinions, feel free to discuss with us. Also, the test methods mentioned are not industry standards, so please use discretion when referring to them.)
From what I remember, one of the earliest and most frequent requests for tumble testing came from Motorola. Since some of Motorola’s mobile phones and products were designed for military use, their reliability and quality standards were exceptionally strict. However, this also meant higher design and production costs. I can’t help but wonder if this was one of the reasons Motorola eventually lost its competitive edge.
Workingbear strongly believes in maintaining high-quality standards, but over-engineering beyond practical use (over quality) can be a waste of resources. Take smartphones as an example—most people replace their phones every two years. Designing a phone to last five years is already impressive. Insisting on a 10- or 20-year lifespan might only make sense if it doesn’t significantly increase costs. Otherwise, companies need to seriously consider whether the extra investment is worth it.
Workingbear’s company was having a tough time with a strange issue: intermittent micro-short circuits inside the layers of the PCB. Since the shorts didn’t show up near any components, it was really hard to figure out what was wrong.
Recently, we made a breakthrough. We finally got a faulty PCB that consistently showed the issue. After working with the PCB manufacturer to analyze it, we found the likely cause: CAF (Conductive Anodic Filament)—a type of metallic filament caused by electrochemical migration (ECM), which is known to cause failures in PCBs.
At last, we had a clear direction to investigage. Before that, our customer was getting very frustrated because we couldn’t find the root cause.
