Stop the Chips: Why we preheat glass with Infrared
Glass is a pain. It’s brittle, stubborn, and the second you hit it with a cutting wheel, it loves to shatter or chip—especially around those annoying corners. It usually happens because of internal tension. The glass is basically fighting the tool. To stop that, we use infrared (IR) preheating. By warming up the surface before the cut, you relax the material. It makes the glass less “angry,” which means the fracture goes exactly where you want it to. The secret is in the heat When glass is cold, it fights back. The cracks jump around and get erratic. We use shortwave IR lamps because they hit the surface fast. It’s not just about making the sheet warm to the touch. The heat actually softens those molecular bonds. When the cutter finally hits, the glass almost “flows.” You get a clean, crisp break. No more staring at a pile of wasted corners. Setting up the gear To get the heat right, we usually go with high-wattage quartz halogen tubes. You want a fast ramp-up. If the glass sits under the lamps for too long, it can warp, and then you’ve just traded one problem for another. The best way to do this is to mount the lamps in a bridge over the cutting line. But here’s the tricky part: you have to balance your wattage with how fast your line is moving. Too hot? You’ll get thermal shock. Too cold? You’re still chipping. We use a PID controller to keep things steady—usually between 60°C and 120°C, depending on how thick your glass is. The real-world trade-offs Look, IR preheating isn’t some magic wand. It comes with a few headaches. First, these heating banks pull a lot of power. Plus, they turn your shop floor into an oven. You’re going to need some decent cooling fans or ventilation so your electronics don’t fry. And if you decide to speed up your production line, remember that you’ll need more heat to keep up. That means cranking the wattage or adding more tubes to make sure the glass gets that necessary soak before the blade hits.