Getting the Balance Right: Silk-Screening and Glass Strength
Trying to get infrared (IR) heating just right during the tempering process is a bit of a tightrope walk. You’re basically fighting a battle between fusing the ink and keeping the glass from warping. If you don’t hit the temperature, the ink just won’t stick. But if you go too far? You’re looking at distorted graphics or, worse, thermal shock that ruins the whole piece.
The Trick to Heat and Wavelength
Shortwave IR lamps are usually the way to go. They hit the glass surface fast and dump that energy straight into the ink. We stick with high-wattage quartz tubes because the ramp-up needs to be quick. When it happens fast, the ink doesn’t have time to wander or bleed across the glass. That’s how you keep your lines crisp. But you’ve got to keep an eye on the power density. A high-output tube can bake ink in a heartbeat. If your conveyor is crawling, you’ll end up burning the ink or stressing the glass from the inside out.
The Gear That Actually Lasts
We usually lean toward halogen-filled quartz tubes. Why? Because halogen lets the lamp run hotter without the tungsten filament giving up the ghost so quickly. It just lasts longer. The wiring side of things is pretty simple. Most of these setups use R7s or SK15 connectors, so when a lamp finally dies, you just pop a new one in and keep moving. One tip: use high-temp silicone wiring. You don’t want your insulation melting because it’s sitting too close to the heater bank.
The Trade-offs
Here’s the thing: high-density IR heating works great, but it puts a massive load on your cooling system. When you’re cranking these lamps to hit those tempering temps, the whole machine starts to soak in heat. If your exhaust fans and blowers aren’t up to the task, that heat will creep into your electronic controllers and start causing headaches. Plus, bad ventilation is a fast track to killing your lamps early. Keep it cool, and your gear will actually last.