Fixing Those Annoying Cold Spots in Glass Annealing
If you’ve ever worked with glass containers that have weird shapes—deep recesses, narrow necks, or complex curves—you know the headache of “cold spots.” Standard IR lamps just throw heat in every direction. It’s a 360-degree spray. The problem? Half that energy is just vanishing into the air, while the hardest-to-reach parts of your glass stay cold. That’s how you end up with internal stress and, eventually, shattered product. We handle this by pairing shortwave IR lamps with custom reflectors. Instead of letting the heat wander, we force it exactly where it needs to go. The trick with directed heat Think of a lamp without a reflector as a lightbulb in a dark room. It’s bright, but it’s not a beam. By adding a polished aluminum or gold-coated reflector, we basically flip the switch. The reflector catches all that wasted energy heading backward and shoves it forward onto the glass. You get a much higher heat density on the surface, but here’s the best part: you aren’t cranking up the wattage. You’re just using the heat you already had, but smarter. Dealing with the “weird” shapes A generic curve doesn’t cut it when your containers change size or shape. That’s why we don’t do “one size fits all.” Depending on the footprint of your glass, we use parabolic or elliptical geometries. We make sure the IR waves bounce and overlap in just the right way. It fills in those dead zones that usually lead to breakage, giving you a much more consistent finish. A quick word of caution Now, there is a trade-off. When you concentrate heat this effectively, things get hot—fast. If your conveyor belt is moving too slowly, you risk creating “hot spots” that can actually deform the glass. It’s a balancing act. You have to tune the reflector angle to match your line speed so you don’t overdo it. Getting it on the floor We built these to be easy. They’re drop-in replacements for your existing heating banks, usually using R7s or SK15 connectors. You can swap them out quickly without a massive teardown. Since these reflectors live right next to the heat, we use materials that won’t warp or flake off after a few weeks of thermal cycling. One last thing: check your cooling fans. Because we’re reflecting so much energy toward the workpiece, the chassis can get toasted if your airflow isn’t up to the task. You don’t want to find out your wiring has melted mid-shift.