Wavelength-Control System


NGK’s proprietary Wavelength Control System uses a new drying technology based on infrared light. By irradiating materials with infrared radiation of specific wavelengths, this system performs drying at low temperatures difficult to achieve with conventional systems. Providing effective drying for the coating and drying process with minimal resulting damage to the base material, this innovative system has drawn significant interest from industrial circles. It’s also ideal for drying aqueous solvents, a challenging application for conventional hot air drying methods, making it easier for facilities to switch from organic to aqueous solvents and thereby promoting carbon neutrality.

Wavelength-Control System

Problems with conventional systems in the coating and drying process

The conventional hot air drying method in the coating and drying process has the following issues:

  • Heat damage caused by drying

    Hot air drying results in significant heat damage to films and applied materials. The method cannot be used with materials that are susceptible to the effects of heat.

  • Cost of drying product interiors

    A vacuum system is used to remove moisture from within the product, a step with adverse effects on productivity and cost.

  • Problems drying thick films

    Hot air drying generates webbing and foaming on the surface of materials applied in thick layers, making uniform drying difficult to achieve.

  • Time required to dry aqueous solvents

    Aqueous solvents are less likely to volatilize than organic solvents and take longer to dry.

Benefits of the Wavelength Control System in the coating and drying process

1. Low-temperature drying

Can dry solvents while reducing heat damage to the components or resin base material.
Ex.: Can dry moisture at 40°C.

Can now use components and materials that previously could not be used due to temperature restrictions during drying.

2. Internal drying

Can dry the remaining moisture inside the products.
Ex.: Complete drying to the ppm order is possible at atmospheric pressure.

A vacuum system is not necessary, making it possible to reduce production cost and time.

3. Drying of thick films

Prevents webbing of the surface and promotes drying on the inside of thick films, a location that cannot be dried by hot air.
Ex: Can dry thick films with a dry thickness of 300 μm. Hot air limit: 100 μm

Can increase the amounts of active components contained, shortening the production process.

4. Fast drying

Compared to hot air and heaters, drying with infrared rays of specific wavelengths halves drying times.
Example: Wet 500 μm, dry 100 μm aqueous paste dries in 200 seconds.

Switching from organic to aqueous solvents toward carbon neutrality

In addition, following benefits can be expected:

  • Reduction of power consumption by 30 to 50%
  • Possible reduction of binder segregation by 30 to 40%
  • All comparisons are with hot air.

Illustrations of conventional system (hot air method) and wavelength-control system

Illustration of Wavelength-Control System

Illustration of Wavelength-Control System for coating and drying process

Illustration of Wavelength-Control System for coating and drying process

Relationship between Wavelength Control heater radiation spectrum and wavelength absorbed by industrial materials

NGK has a lineup of wavelength-control heaters that selectively emit infrared rays in two different wavelength bands. For example, infrared rays with a wavelength of less than 3.5μm are suitable for drying aqueous solvents because they have a high water absorption rate.

Illustration of Heater radiation spectrum /  Illustration of Examples of wavelength ranges absorbed by industrial materials

Example of aqueous solvent drying

The NGK Wavelength Control System achieves faster drying at lower temperatures than hot air drying. It cuts costs by allowing use of base materials that are sensitive to heat and previously could not be considered. Lastly, it cuts CO2 emissions by allowing use of aqueous solvents.

Example of aqueous solvent drying

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