Stop the Chipping: Why Preheating Your Glass Actually Works
Cutting glass is basically just a game of controlled breaking. But when you hit a cold sheet with a cutting wheel, things get messy. The internal stress in the glass makes the cracks jump around, leaving you with those annoying jagged edges or corner breakouts. It’s frustrating, and it wastes material. The fix? Simple. We use single tube infrared lamps to warm up the surface right before the blade touches the glass. The secret is in the heat. Infrared doesn’t bother heating up the air around the glass; it goes straight for the molecules. This relaxes the tension in the surface layer and makes the glass a bit more “forgiving.” When the cutting head finally hits, the crack just follows a straight line. You get a clean, crisp break. No more jagged bits. Getting the setup right We usually go with short-wave quartz tubes. Why? Because they heat up in seconds. You can sync them perfectly with your conveyor speed so you aren’t wasting energy. But you have to find that sweet spot with the wattage. If you crank the heat too high, you’ll shock the glass and crack it. Too low, and you’re right back to square one with the chipping. A few things to watch out for Most of us mount these tubes in reflective housings to push all that energy downward. Just be careful with the spacing. If the lamp is too close, you’ll get “hot spots” that can warp thinner sheets. Too far away, and the heat just isn’t dense enough to do the job. On the electrical side, make sure you use fast-acting relays in your PLC. You don’t want a power surge frying your filaments. And do yourself a favor: keep a pyrometer handy. Monitoring the surface temperature in real-time is the only way to make sure you’re staying in that perfect preheat window.