New-Tech Europe Magazine | Q1 2023

Credit: ipctraining.org

therefore are typically lightweight. Usually, PCB-level components are on side one of the PCB; the paste gets printed, the components are placed, and the board is run through the oven. After this pass, the board is inverted – meaning our connectors are now upside down. The larger devices and the heat-sensitive components are usually placed on side two, and the board goes through the oven the second time. So, our connectors go through two oven passes, and they are inverted on the second pass. Most customers are able to process almost all Samtec connectors in this manner, with no problems. As part of our product qualification testing, we send our connectors through the oven three times: once on a standard soldering pass, and then twice on inverted passes. Almost all of our connectors pass these tests because almost all of our products are small and symmetrical, so the surface tension of the molten solder will hold the connector to the PCB while it’s inverted, without the need for additional hold-downs, locking features, or glue. Connectors that are more challenging are generally larger with an offset center of gravity. Are the commonboardprocessing problems experienced in recent years different from those of 10 20 years ago?

is the recognized governing body for the inspection of solder joints in electronic assemblies. IPC separates solder joints into three classes. Class 1 is for “General Electronic Products,” meaning if these products fail, it’s a nuisance to the user or they experience an inconvenience. Children’s games and toys are an example of products with Class 1 solder joints. Class 2, or “Dedicated Service Electronic Products,” is a significant step up in terms of functionality and reliability. If this product fails, the user’s inconvenience and “annoyance factor” is much greater than Class 1, but the user does not face physical harm. Samtec connectors are IPC Class 2.

The short answer is yes, primarily due to miniaturization. Components are getting smaller, stencils are getting thinner, and designers are trying to squeeze more parts on smaller boards. All of this adds up to processing challenges. But, stenci l design technology continues to improve, solder pastes are getting better, and reflow ovens are more precise and reliable. In other words, the tools used to create and inspect solder joints seem to be keeping pace with the demand for miniaturization. What do the different IPC solder joint classes mean? IPC, the Institute for Interconnecting and Packaging Electronic Circuits,

Credit: pcbdirectory.com

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