With the rapid advancement of mobile communication technology, EMS (Electronic Manufacturing Services) providers worldwide are facing severe labor shortages. Furthermore, the Industry 4.0 trend has heightened the demand for automation in EMS facilities. As a result, many components that were previously not suited for Surface Mount Technology (SMT) are now required to meet the Paste-In-Hole (PIH) process. These components include Type A USB connectors, RJ45 Ethernet connectors, power sockets, transformers, and other relatively bulky parts. In the past, these components were typically soldered after SMT using wave soldering equipment or manual touch-up.
Due to the scarcity of manual labor and the need to save on subsequent manufacturing costs, along with quality considerations, many system manufacturers and EMS companies are gradually transitioning these non-SMT components to at least meet the PIH process requirements. This enables all electronic components to be soldered to the printed circuit board through a reflow oven.
What is an SMT Reflow Carrier? Why is it sometimes necessary in SMT production? And when do we need an SMT Full Process Carrier? Are there situations where neither is required?
The so-called “SMT reflow carriers or reflow templates” are essentially trays or carriers used to hold PCB (Printed Circuit Board) during the reflow soldering process. These carriers often feature positioning pillars to secure the PCB, preventing misalignment or deformation. Some advanced carriers even come with a lid, typically designed for Flexible Printed Circuit (FPC) use to avoid it from floating or lifting, equipped with magnets on both the upper and lower carriers acting as suction cups to firmly hold the board. This ensures the prevention of board deformation. In the case of rigid PCBs, a cover plate may also be used to secure specific components during the reflow process, preventing sliding.
This is a query from a user regarding SMT (Surface Mount Technology) processes, focusing on topics such as stencils, determining component placement sequence, and explanations of DFM (Design for Manufacturability) and DFX (Design for Excellence). We believe these questions and terms might also be of interest to those working in roles such as Project Management (PM), New Product Introduction (NPI), or procurement guys within electronic companies.
Often, when attending meetings with engineers, you may hear these technical terms without a clear understanding of what they actually mean. Not to worry, in this brief guide, we’ll attempt to explain these engineering terms in simpler language. Feel free to check back for updates if you have more related questions in the future.
The “SMT dispensing” process, also known as the “SMT Red Glue” process in Asia, is a process where a glue is used to stick Surface Mount Device (SMD) parts to a Printed Circuit Board (PCB). The term “SMT Red Glue” is derived from the prevalent use of red adhesives in SMT processes, with a few instances of yellow adhesives. As seen in the illustration at the beginning of this article, beneath small chip components like resistors and capacitors, there is a red, glue-like substance in the center, commonly referred to as red glue.
The PIH (Paste-In-Hole) process involves directly printing solder paste onto the Plating Through Holes (PTHs) of a PCB (Printed Circuit Board). Subsequently, Through-Hole Devices (THDs) are inserted directly into these holes with pre-applied solder paste. At this point, some of the solder paste adheres to the leads of the component, while most remains on the PCB’s solder pads. When these assemblies pass through a high-temperature reflow oven, the solder paste on the leads and PCB pads melts, securely attaching the component to the circuit board. This method can effectively replace traditional processes like wave soldering or hand soldering.
This process is also known by other names such as “Pin-In-Paste (PIP),” “Intrusive Reflow Soldering (IRS),” and “Reflow Of Through-hole (ROT).”