Shortwave vs. Medium-Wave: Which IR Lamp Actually Works for Your SMT Setup?
When you’re setting up SMT preheating, you’ve basically got two choices for your IR lamps: shortwave (SW) or medium-wave (MW). It sounds like a technicality, but it’s the difference between a board that’s perfectly prepped and one that’s scorched. Both use high-purity quartz glass—because anything else would just melt or warp under the heat—but they behave very differently once you flip the switch. Let’s talk about penetration. Shortwave lamps run hot. Really hot. That heat doesn’t just sit on the surface; it sinks deep into the PCB substrate. If you’re dealing with thick boards or heavy components that act like heat sinks, SW is your best friend. It gets the core of the board up to temp without making you wait forever. Medium-wave is a different story. It hugs the surface. This is great for those thin PCBs where you need to melt the solder paste but don’t want to cook the internal layers. It’s a gentler touch. The “hidden” side of the hardware. Since we use quartz to keep things stable, you might think it’s all the same. But SW lamps need a ton of power density to keep that wavelength consistent. Here’s the catch: if you cram a high-wattage SW tube into a tiny space, you better have your cooling sorted. If you don’t, you’ll end up warping your housing or, worse, frying your wiring. MW lamps are a bit more relaxed. They run cooler and spread the heat more evenly, so you don’t have to worry as much about those annoying hot spots. Speed vs. Control SW is all about raw speed. You can get a board to temperature in a few seconds. It’s an adrenaline rush for your production line. But it’s a tightrope walk. If your conveyor belt lags for even a couple of seconds, you’re risking a scorched board. MW takes its time. It’s slower to react, but it gives you a thermal profile that’s way more stable. It’s much more forgiving. One last tip from the trenches: check your connectors. Make sure they’re rated for the actual amperage you’re pulling. A loose connection at the lamp head causes arcing, and that’s a fast track to a dead tube. Basically, if you need to move fast and have the cooling to handle it, go with SW. If you need precision and a bit more breathing room, stick with MW.