Getting Your IR Heating Right for Silk-Screened Glass
If you’re trying to handle annealing right after silk-screening, you know it’s a bit of a balancing act. You’ve got to cure the ink and get rid of those internal stresses, but you can’t just blast it with heat. Do it wrong, and you’ll end up with warped glass or blurry lines that look like a mess. That’s why shortwave infrared (IR) lamps are the way to go. Keeping Your Lines Sharp You can’t just throw the glass in a slow, ambient oven and hope for the best. That’s a recipe for ink bleed. Instead, we use high-wattage IR lamps to punch concentrated energy straight into the surface. It all comes down to how you set them up. By tweaking the wattage and moving the lamps closer or further from the glass, you control exactly how deep that heat goes. Here’s the tricky part: if you go too aggressive, you’ll fry the ink before the glass even gets warm enough to anneal. But if you’re too timid? The glass stays brittle and breaks. You’re looking for that “sweet spot” where the ink sets and the stress disappears at the exact same time. The Gear You Actually Need Most of the time, we use quartz halogen tubes. They’re tough. They can take a beating in a shop that never stops running. We usually wire them into R7s or SK15 sockets because when a tube finally burns out, you want to be able to swap it in seconds, not minutes. We stick with shortwave emitters because they hit the glass faster than medium-wave options. It’s simple: faster heating means you can speed up your conveyor and save a ton of floor space. The Catch High-density IR heating isn’t some magic wand. When you’re pushing high wattage into a tight space to keep the line moving, things get hot. I mean really hot. Your fans and ventilation have to be up to the task. If your exhaust is weak, heat just builds up in the tunnel. Before you know it, your ink is blistering and your glass is overheating. Just make sure your cooling can keep up with your speed. Otherwise, you’re just making expensive scrap.