Fixing Those Pesky Cold Spots in Your KHS Blow Molder
Ever look at your PET bottles and see those annoying streaks or “pearls”? Or maybe the walls are thin in some spots and thick in others. It’s frustrating. Usually, it comes down to one thing: your heating oven isn’t hitting the preforms evenly. Most of the time, you’re fighting old lamps that have just worn out or bulbs that aren’t putting out the right kind of heat. We make high-output IR lamps that slide right into your KHS system to plug those thermal gaps and get your bottles looking clean again. The trick to getting the heat right It all comes down to how the filament is wound inside the quartz tube. Cheap lamps often have a “center-heavy” problem—they blast heat in the middle but leave the ends cold. We keep our tolerances tight so the heat is spread evenly across the whole length. When the infrared emission is stable, your preforms get a consistent soak. No surprises. But here is the thing: you’ve got to get the voltage and wattage exactly right for your power supply. If the voltage is too low, the filament will burn out way faster than it should. On the flip side, if the wattage is too low, your preforms won’t get hot enough to stretch. You’ll just be fighting the machine all day. The nuts and bolts of the hardware We use high-purity quartz glass because these things take a beating with constant heating and cooling. Most of our lamps use R7s or Sk15 connectors. Now, a tight fit here is a big deal. If there’s even a tiny gap in the socket, you get electrical resistance. That creates heat in the wrong place, and before you know it, you’re looking at a melted socket. Not a fun way to spend a Tuesday. A quick heads-up on speed It’s tempting to just crank up the heat density to shave a few seconds off your cycle times. But that comes with a trade-off. More wattage means more energy in the oven, which puts a lot more pressure on your cooling blowers. If your ventilation can’t keep up, you might actually overheat the electronics inside the machine. Before you switch to higher-density tubes, just double-check your airflow. It’ll save you a massive headache down the road.