The principle of fast drying of glue by infrared short-wave heating tube

Infrared short-wave heating tube directly acts on the molecules in the glue by emitting electromagnetic waves of specific wavelengths (usually short-wave infrared of 0.9~1.4 μm), achieving efficient and rapid heating and curing. Its core principles are as follows:

1. Molecular resonance absorption

Polar molecules in the glue (such as chemical groups in water, solvents or resins) have strong absorption of short-wave infrared. When the energy of infrared photons matches the frequency of molecular vibration, the molecules vibrate violently and generate heat energy, directly heating the inside of the glue instead of relying on heat conduction.

2. Penetration and selective heating

Short-wave infrared has strong penetration (can reach several millimeters inside the material) and can directly heat the entire glue layer instead of just the surface. At the same time, different materials have different absorption rates of infrared (such as high reflectivity of metals and high absorption of non-metals), which can achieve precise heating of glue without overheating the substrate.

3. Rapid response and efficient energy conversion

After the short-wave infrared lamp is powered on, it heats up in milliseconds without preheating; the electrical energy is almost completely converted into radiation energy (efficiency>90%), avoiding the heat energy waste of traditional hot air drying.

4. Promote chemical reactions

For thermosetting adhesives (such as epoxy resins and polyurethanes), infrared heating accelerates the cross-linking reaction; for solvent-based glues, it accelerates the volatilization of solvents.

Application principle in filter manufacturing

Filter paper folding bonding: Spray hot melt adhesive at the joints of continuously folded filter paper, and infrared short wave instant curing ensures the stability of the folding structure.

Bonding of metal end caps and filter elements: Epoxy glue quickly cross-links at the interface between metal and filter material to avoid overheating and oxidation of metal.

Sealing ring installation: After the silicone sealing ring is pre-coated with glue, infrared heating realizes instant bonding between the elastomer and the shell.

The manufacturing of filters (such as air filters and fuel filters) often involves gluing processes (such as filter paper folding, end cap bonding, and sealing ring fixing). The advantages of infrared short-wave heating are reflected here:

1. High-speed continuous production

Shortening curing time: Traditional hot air curing takes several minutes to tens of minutes, while infrared short-wave can be completed in seconds (especially for thin layers of glue), matching the high-speed beat of the assembly line.

Instant start and stop: The infrared lamp can be turned on and off instantly with the start and stop of the production line to avoid no-load energy consumption.

2. Precise process control

Temperature and wavelength matching: By adjusting the infrared wavelength (such as selecting the 1.2 μm band for the glue absorption peak) and power density (such as 5~20 W/cm²), the curing effect is optimized.

Regional selective heating: Use a reflector or lens to focus infrared rays and only heat the glue-coated parts (such as the edge of the filter paper) to avoid deformation or aging of the filter material (such as cellulose, synthetic fiber) due to overall heat.

3.  Improve bonding quality

Uniform curing: Infrared penetration ensures synchronous curing of the glue layer inside and outside, avoiding surface crusting and internal bubbles (common in hot air heating).

Reduce thermal stress: Rapid heating shortens heat exposure time and reduces stress cracking caused by thermal expansion differences between metal/plastic end caps and filter paper.

4. Energy saving and environmental protection

Energy consumption is reduced by more than 70%: Compared with hot air furnaces, infrared systems directly radiate heat without heating air or conveyor belts.

Reduce VOC emissions: After the solvent-based glue evaporates quickly, an exhaust gas recovery device can be integrated to avoid diffusion pollution caused by long-term drying.