SPI stands for Solder Paste Inspection. If we’re talking about the actual inspection equipment, people usually add “machine” after SPI. But in most cases, when you mention SPI in an SMT factory, everyone just assumes you’re talking about the inspection machine.
So what’s the real purpose of SPI? What exactly can it do for us? And why are more and more SMT lines adding SPI machines these days?
Over the past few days, Workingbear came across an issue I hadn’t really considered before. Here’s the story: an EMS (electronics manufacturing service) factory reported that during SMT production, they were seeing solder shorts under BGA components. After digging into it, the root cause turned out to be excessive solder paste. And why was there too much solder paste? The PCB’s solder mask (the green layer) and silkscreen (the white ink) were printed too thick.
When you think about it, this makes sense. If the solder mask or silkscreen is unevenly thick, it can affect the solder paste thickness during solder paste printing through stencil aperture. A thicker layer lifts the stencil slightly, increasing the gap between the stencil and the PCB. With all other printing conditions unchanged, that small gap leads to extra solder paste being deposited.
If you ask Workingbear, “As an engineer, would you prefer working in R&D or in manufacturing?”
(This article may not apply to the semiconductor wafer foundry industry. Rumor has it that wafer fabs in Taiwan are notorious for their brutal work hours—engineers often sacrifice their health to keep operations running. Many parents feel proud if their kids land jobs at a major integrated circuit company because of the high pay, without realizing it can also become a career trap.)
Workingbear started out as a product and process engineer, always dealing with products and processes. If I had to answer this question, I’d probably lean toward being a design engineer. But I put a question mark there—because people often complain most about the job they know too well. Since I’ve seen firsthand how tough manufacturing can be, I naturally hesitate. But once you really understand how tough design work is, my answer might not be “design engineer” anymore.
For many people, the first time they hear the term NPI, it feels a bit confusing. NPI stands for New Product Introduction, but just reading the name doesn’t make it much clearer. Is it some kind of sales role that introduces new products to customers? Not at all!
In reality, NPI is a bridge between the manufacturing plant and the R&D department. The core responsibility is to take a product designed by R&D and “introduce” or more accurately, drive it into mass production at the assembly factory.
In the previous articles, we talked about “The Responsibilities and Roles of an MPE (Manufacturing Process Engineer)” and “The Main Job Responsibilies of an MPE.” Now, let’s look at how an MPE’s job differs from other related roles, and what possible career paths an MPE might have.
