Roller Hearth Kiln


The Roller Hearth Kiln is a continuous fast firing kiln that transports products on rollers inside the kiln. It offers excellent temperature uniformity, cleanliness, and thermal efficiency.
The system provides firing conditions that meet customer needs through atmosphere controls for air, N2, O2, N2 + H2, and other gases, as well as precision temperature controls for each of the preheating, firing, and cooling zones. The system contributes to the production of all solid-state batteries (solid electrolyte) and cathode and anode materials for lithium-ion batteries, essential for applications targeting carbon neutrality, for a carbon-zero society, and for MLCC and other electronic components that support our digital society.

Roller Hearth Kiln

According to the powder material type, NGK adds the following processes and offers proposals for improving production efficiency and product quality.

Material powder feeding and compression

  • Powder compression increases production volume.
  • Optimization of the feeding shape minimizes temperature unevenness and improves product quality.

Powder collection system

  • This system cools the powder as it is collected. (Allows the cooling area to be shortened.)


Improvement in production performance

Atmosphere control technology

NGK offers atmosphere control technologies compatible with O2 concentrations from below 50 ppm to 99% or higher. NGK products are backed by extensive experience in firing, from old ceramics such as sanitary ware and tiles to the latest cathode and anode electrode materials for lithium-ion batteries and MLCCs which support the decarbonized and digital.

Flow of air supply/exhaust Lateral cross section
Flow of air supply/exhaust
Lateral cross section
Flow of air supply/exhaust Longitudinal cross section
Flow of air supply/exhaust
Longitudinal cross section

Rapid warm-up, Atmosphere switching technology

The kiln’s special internal structure combined with a sensing gas supply and exhaust system achieve atmosphere switching within the same furnace and fast warm-up. This, in turn, allows use with MLCCs that require different materials to be sintered at different temperatures.

Illustration of rapid warm-up, atmosphere switching technology

Boosting productivity while conserving energy

Multi-row/multi-stage tray transport to improve area productivity

NGK’s high-strength rollers achieve multi-row/multi-stage tray transport for efficient production in limited site areas, typically yielding three-fold improvements in productivity.

4-row standard insulator
4-row standard insulator
6-row, 2-level high-performance insulator
6-row, 2-level high-performance insulator
Productivity per area / 300%
Power consumption / Approximate 40% reduction*

For the same production volume

Wide Rollers and Multi-Row Tray Transport

Energy saving

The combination of low thermal conductivity insulators and six-row, two-level tray transport cuts energy consumption by 40% or more. This reduces not just operating costs, but CO2 emissions, helping us move closer to carbon neutrality and the carbon-free society ideal.

Atmosphere gas saving

A special seal structure in the drive section and flat ceiling cuts atmosphere gas volumes by 20%, reducing operating costs still further.

Promises stable operation.

Reduced contamination

Ceramic components eliminate metal contact. NGK’s Roller Hearth Kiln has won high marks and is backed by a solid track record of achievements in the battery and electronic component industries—industries where significant efforts are focused on inclusion of metallic foreign substances.

Total engineering for preceding and following systems

NGK also provides total customer support in aspects ranging from product supply and collection to stacking and unstacking of tools, which helps reduce factory labor requirements.

Stable product transport

A Universal Joint system, a proprietary NGK technology, achieves high precision transport on both sides of the rollers, enabling stable product transportation even in long furnaces.

Universal Joint
Universal Joint

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