
Due to the rapid growth of mobile phone technology, the Electronic Manufacturing Service (EMS) in mainland China sometimes faces serious labor shortages. Additionally, Industry 4.0 promotes the need for factory automation in EMS. As a result, certain parts that cannot undergo SMT reflow process must fulfill the Paste-In-Hole (PIH) process, including type-A USB connectors, Ethernet connectors, power supply sockets, transformers, and others. Previously, most of these devices were touch-up soldered after SMT processing.
One day, my manager asked me a question: “Will changing the components from SMDs (Surface Mount Devices) to THDs (Through Hole Devices) and using the PIH (Paste-In-Hole) process affect the process and design?”
The trend in the electronics industry is toward smaller and smaller SMD components, with sizes such as 0402, 0201, and even 01005 becoming common (Note 1). Additionally, the pitch between pins on ICs has decreased to a fine pitch of 0.5mm, and even 0.3mm, posing a challenge for the SMT process.
