Why Your Can Lids Are Bloating (And How to Fix It)
If you’re seeing bloated can lids, you already know the deal: your seal is failing. Usually, it comes down to the gaskets. If they don’t soften up enough to create that vacuum-tight bond, air gets in. The real culprit? Your IR lamps are likely throwing out an uneven heat field. If the center of the lid is baking while the edges stay chilly, that gasket isn’t going to cure the way it should. The heat has to be flat. That’s the secret. You want a thermal profile that’s consistent across the whole surface. We use shortwave infrared emitters because they punch through the gasket material fast. You want that rapid soften—but you can’t scorch the coating. Here’s the thing: “hot spots” are the enemy. They create tiny micro-gaps. You can’t see them, but air finds them. That’s how you end up with bloated cans sitting in your warehouse. Getting the heat right It’s all about how those radiation cones overlap. If you tweak the spacing of the emitters and adjust how far they sit from the conveyor, those annoying cold zones just disappear. Now, high-wattage quartz tubes are great for keeping the line moving fast, but you have to balance that power with how long the lids actually spend under the lamps. If you just crank the power to 100% to fix a cold spot on the edge, you’ll probably burn the center of your lids to a crisp. The trade-off Getting that perfect, uniform heat usually costs a bit more in energy. Instead of running one lamp at full blast, we find it works better to run a few lamps at a lower percentage. It’s a smarter way to do it. Not only does it kill the hotspots, but it also stops your filaments from burning out prematurely. Just make sure your power supply can handle the extra load of a multi-lamp setup so your output stays steady all shift long. When the heat is flat, the gaskets soften evenly. The seal bites hard. And the bloating finally stops.