Getting the Distance Right: IR Heating for Glass Printing and Tempering
Here is the struggle when you’re combining screen-printing with tempering: you’re fighting a constant battle with heat. You need it hot enough to fuse the ink, but if you go overboard, you’ll burn the pattern or create thermal stress that just snaps the glass. It’s a delicate balance. And the secret weapon to getting it right? The distance between your IR lamps and the glass.
The “Hot Spot” Problem
Short-wave IR lamps pack a serious punch. If they’re sitting too close to the glass, the surface temperature doesn’t just rise—it spikes. Before the heat even has a chance to soak into the core of the glass, you’ll see the ink start to bubble or change color. It’s frustrating to watch a good print go to waste because of a “hot spot.” The fix is simple: give the lamps some breathing room. By increasing that gap, the radiation spreads out. You get a much smoother heat distribution, which protects the print while still getting the glass up to tempering temperature.
The Speed Trap
Now, you might think, “Great, I’ll just push the lamps way back and call it a day.” But there’s a catch. When you move the lamps further away, the heat transfer slows down. To compensate, you have to slow your conveyor belt. And if you’re running a business, slowing down your throughput is the last thing you want. The trick is to use zoned heating. Start with lower-power lamps or a wider gap during the pre-heat stage. This lets the ink stabilize without panicking. Once that’s handled, you can hit the glass with the high-intensity heat in the final tempering zone. It keeps the line moving fast without ruining the art.
The Nitty-Gritty Details
Don’t forget about the gear itself. High-wattage IR arrays get incredibly hot—not just the glass, but the whole system. If you’re pushing for maximum heat, make sure your cooling fans and housing can actually handle the load. If the ventilation is sloppy, your lamps will burn out way faster than they should, and you’ll get weird temperature swings across the glass. One last thing: check your alignment. Seriously. Even a tiny 5mm slip in distance can leave visible streaks across your finished print. It’s a small detail, but it’s the difference between a professional job and a scrap pile.