Glass tempering is a critical process in which precise temperature control directly determines the mechanical strength, safety, and optical quality of the final product. During heating and rapid cooling, even small temperature deviations can lead to internal stresses, distortions, or product defects.
Non-contact infrared measurement has become a key technology for ensuring stable and repeatable tempering processes in modern glass production lines.
Process Characteristics and Measurement Challenges
In a glass tempering line, glass sheets are heated to temperatures typically above 600 °C and then rapidly cooled using air quenching. The process requires strict temperature uniformity across the entire glass surface.
Key challenges include:
• varying emissivity of glass at different temperatures
• reflections from surrounding heat sources and furnace components
• rapid temperature changes during quenching
• need for full-surface monitoring rather than single-point measurement
These factors make conventional contact sensors unsuitable and limit the effectiveness of standard temperature measurement methods.
Role of Infrared Cameras in Tempering Processes
Infrared cameras enable continuous monitoring of the entire glass surface in real time. This allows operators to detect temperature variations early and adjust process parameters accordingly.
Typical monitoring points include:
• heating furnace zones
• glass exit temperature before quenching
• temperature distribution during cooling
By capturing full thermal images, IR systems provide significantly more process insight compared to single-point sensors.
Advantages of Non-contact Measurement
The use of infrared cameras in glass tempering lines provides several key benefits:
• real-time temperature distribution across the full glass surface
• improved process control and repeatability
• reduction of optical defects and internal stresses
• early detection of uneven heating or cooling
• increased product quality and yield
This enables manufacturers to maintain consistent tempering conditions and reduce scrap rates.
Optris Solutions for Glass Tempering
Optris infrared cameras are specifically developed for challenging industrial environments and offer high accuracy in glass processing applications.
Optris PI 640i G7
The PI 640i G7 is designed for high-precision temperature measurement of glass surfaces at elevated temperatures.
Key features:
• spectral range optimized for glass (around 7.9 µm)
• high resolution of 640 × 480 pixels for detailed thermal analysis
• excellent accuracy for glass emissivity conditions
• ideal for monitoring heating and tempering processes
The camera enables precise detection of temperature gradients and ensures uniform heating before quenching.
Optris PI 450i LT
The PI 450i LT is optimized for lower temperature ranges and is particularly effective in cooling and post-processing stages.
Key features:
• high sensitivity for lower temperature measurements
• resolution of 382 × 288 pixels
• real-time monitoring of cooling processes
• compact design for easy integration into production lines
This makes it suitable for analyzing temperature distribution after quenching and detecting residual thermal stresses.
Application Value in Industrial Production
Accurate temperature monitoring across the tempering line allows manufacturers to achieve better control over the entire process.
With infrared cameras, operators can:
• ensure uniform heating of glass sheets
• optimize quenching efficiency
• detect temperature deviations instantly
• minimize defects such as warping or breakage
The combination of cameras like PI 640i G7 and PI 450i LT provides a comprehensive solution covering both high-temperature and cooling stages.
