If you’re seeing cans bulge, you’ve probably already checked the seamer. But here’s the thing: the machine is usually fine. The real problem is almost always the gasket. If it hasn’t softened enough, you aren’t getting that tight, airtight seal you need. Usually, this happens because of “cold spots” in your IR preheating lamps. If the heat isn’t hitting every inch of that gasket, you’re asking for trouble. The heat struggle We spent a lot of time figuring out how to kill those dead zones. See, when the heat is uneven, the gasket gets soft in some spots and stays stiff in others. That creates tiny micro-leaks. You won’t see them at first, but once those cans hit sterilization, the gas builds up and—boom—you’ve got a bulge. We use shortwave IR because it actually digs deep into the material. Longwave IR tends to just scorch the surface, but shortwave hits the core. It’s the difference between searing a steak and actually cooking it through. Getting it right on the line This is where most people trip up: matching the lamp’s power and length to how fast the conveyor is moving. If the lamp is too weak, the can just zips through the heat zone without getting warm enough. We build our radiators for high heat density, but you have to be careful. If your focal point is off, you’ll end up overheating the can body. You want that energy concentrated strictly on the rim. No more, no less. Stopping the waste When the heat is uniform, everything just works. The gasket softens perfectly, the seaming roll does its job, and you get a clean, solid weld. Your scrap rate drops, and those bulging cans basically disappear. One last tip: these high-intensity lamps pull a lot of power. Make sure your wiring can actually handle the peak current. If you get a voltage drop, your heating spectrum shifts, and suddenly your consistency is gone. It’s a small detail, but it’s the kind of thing that can ruin a whole batch.