Category Archives: Process


Jul18
Introduction to Process Capability – Three Common Indicators: Cp, Ck, and Cpk

Cpk is commonly used as an overall indicator of a factory’s manufacturing process capability. However, it can also be applied across different industries to measure the ability to meet a target. A popular analogy is how well you can hit … Continue reading

Jul10
Customer Complaint About Oil Contamination on PCB: Who’s the Real Culprit? (FTIR Analysis)

In the previous article, Workingbear mentioned a serious DOA (Dead on Arrival) customer complaint involving one of the company’s products. Most of the defective units had unresponsive keypads—specifically the 3, 6, and 9 buttons—and it was eventually traced back to … Continue reading

Jul03
[Case Study] Troubleshooting a Customer Complaint – Keypad Malfunction Caused by Oil & Powder Contamination on the PCB

This article shares a real case from Workingbear’s past experience dealing with an urgent customer complaint. One day, Workingbear was suddenly assigned to fly to a factory in China to “hunt for oil.” My manager even warned, “If you don’t … Continue reading

Jun26
What is Environmental Stress Screening (ESS)?

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 … Continue reading

Jun05
Tumble Test: How to Prevent PCB and BGA Failures in Electronics Manufacturing

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, … Continue reading