Dealing with Heat Spots in Your KHS Blow Molding
Ever pull a batch of PET bottles off the line and see that annoying pearlescence or weird wall thickness? It’s frustrating. Usually, it happens because your thermal profile is drifting, and nine times out of ten, the infrared lamps are just worn out. That’s exactly why we built our replacement lamps for the SMI SR 12 blower. We wanted to fix those annoying heat gaps once and for all.
The Nitty-Gritty on Power
Getting the temperature just right on an SMI SR 12 is a balancing act. You need enough heat to prep the preform, but not so much that you scorch the plastic. Our tubes fit the original footprint perfectly. We use high-purity quartz glass because it lets the shortwave radiation actually get deep into the PET, rather than just heating the surface. Now, here is the tricky part: putting high wattage into a small tube creates intense heat. It’s great for high-speed lines because you ramp up fast, but it’s brutal on the lamp ends. To stop the filaments from burning out during those constant power cycles, we reinforced the electrodes. They just last longer.
Swapping Them Out
These are simple drop-in replacements. No hacking, no modifying the housing, no headaches. We used standard connectors, so you can wire them up and get back to work. We also treated the quartz envelope to sharpen the emission spectrum. Basically, the energy goes exactly where it belongs—on the preform—instead of wasting heat on the machine frame.
What Happens in the Real World
You don’t need to overpay for OEM parts to get a perfect heat field. These quartz lamps match or even beat the originals. You get a steady infrared output across the whole tube, which kills off those “cold spots” that cause blowing defects. But a quick heads-up: if you’re pushing for higher heat density, your reflectors are going to feel the stress. If your reflectors are pitted or oxidized, a brand-new lamp isn’t going to magically fix your uniformity. **Do yourself a favor: clean your reflectors before you pop the new tubes in.**That’s the only way to actually get the full output you’re paying for.