Stop Fighting with “Cold Cores”: A Better Way to Heat Your PET Preforms
If you’ve spent any real time on a high-speed blowing line, you know the struggle. You’re fighting a constant battle to get the heat just right. Too often, you end up with “cold cores”—that frustrating spot where the outside of the preform is practically scorching, but the center is still cold. It’s a nightmare for consistency. That’s exactly why we built our 380V replacement bulbs for Sidel SBO and Husky HyPET systems. We wanted to fix that gap. The secret is in the heat density. By running at 380V, we can pack more wattage into every centimeter than you get with standard tubes. It’s not just about “more heat,” though. It’s about the kind of heat. We’ve tuned the filament temperature to push shortwave infrared (IR) energy deeper into the plastic. The result? The heat actually penetrates the material instead of just sitting on the surface. You can spend less time in the oven and stop worrying about burning the outer skin. No headaches during installation. We used high-purity quartz glass so the bulbs won’t warp when things get hot. And we kept them simple. These are drop-in replacements. You won’t need to rewire your racks or call in a specialist to figure out the fit. We also paid a lot of attention to the connectors. They’re built to handle high current without pitting or oxidizing. No one wants a bulb to burn out early just because of a bad contact point. A quick reality check from the shop floor. Now, here’s the thing: when you push more IR energy into a preform, your oven’s cooling blowers have to work harder. If your cooling system is clogged or just can’t keep up, the ambient temperature inside the oven will climb. That’s when you start seeing preforms deform. It’s a trade-off you need to watch. And please, keep your reflectors polished. A dirty reflector basically kills all the gains you get from a high-penetration bulb. One last tip? Swap the lamps across the entire zone at once. It’s the only way to make sure your heating is uniform across the whole batch.