In temperature measurement, selecting the measurement location is extremely important for ensuring measurement accuracy and applying controlled temperature. Even for the same object, different measurement locations can yield varying temperatures. Therefore, it is necessary to minimize variations in measurements and maintain consistent temperature control.
In particular, to achieve proper temperature control in manufacturing processes, it is essential to accurately understand the effects of heating and cooling and identify the optimal measurement location for the target object. Choosing an inappropriate measurement location can result in discrepancies between the set temperature and the actual temperature, leading to reduced quality and process instability.
This chapter explains how the selection of temperature measurement locations affects temperature control and provides a detailed discussion on how to determine appropriate measurement locations based on controlled temperature principles. Additionally, it focuses on optimizing actual measurement locations by considering the factors contributing to temperature measurement errors, such as heat conduction, heat convection, and thermal radiation, as discussed in Chapters 3 and 4.

6.1 Determining Measurement Locations Using the Concept of Controlled Temperature

“Controlled temperature refers to the reference temperature that ensures stable temperature management while considering measurement errors and environmental variations.
The purpose of temperature measurement is not merely to “”measure temperature”” but to maintain optimal process control and product quality. Therefore, selecting measurement locations requires considering the manufacturing process and quality standards of the target object and measuring the most critical areas.”

Benefits of Selecting Appropriate Measurement Locations:
1. Reduces variations in temperature measurements and ensures stable controlled temperature.
2. Enables temperature management that aligns with actual manufacturing conditions.
3. Prevents quality issues and improves yield.
4. Supports manufacturing condition optimization and reduces energy costs.

6.2 Measuring the Most Critical Locations in the Manufacturing Process

To properly manage temperature in manufacturing, it is necessary to consider how heating and cooling affect products and measure the areas with the most critical temperatures.
Incorrect measurement locations can lead to discrepancies between the set temperature and the actual product temperature, increasing the risk of quality degradation and defects in the manufacturing process. Below are specific examples of important measurement locations across different industries.

6.2.1 Examples of Temperature Measurement for Heated Objects

1. Heat Treatment of Metal Parts
Issue: In heat treatment, surface and internal temperatures differ. Measuring internal temperature is essential to ensure proper hardness.
Measurement Location: The center of the part or a stable temperature area (where a thermocouple is embedded).

2. Plastic Molding
Issue: If the material does not melt and cool evenly during molding, it can cause defects or insufficient strength.
Measurement Location: Internal temperature of the molten resin, mold surface temperature.

3. Food Processing (Oven Heating)
Issue: Even if the oven air temperature is correct, insufficient heating inside the food can lead to safety concerns.
Measurement Location: The center of the food (with a probe inserted), multiple locations to check oven temperature distribution.

4. Semiconductor Manufacturing
Issue: In wafer heating processes, uniform temperature control is necessary. Verifying whether the set temperature matches the actual wafer temperature is crucial.
Measurement Location: Measure the temperature at both the center and edges of the wafer to evaluate uniformity.

6.3 Supplementary Measures to Minimize Measurement Errors

When selecting appropriate measurement locations, it is crucial to choose positions that are less affected by external environmental factors and ensure consistency.
Due to material properties, shape, and surrounding environment, the temperature readings at different measurement locations can vary even for the same object. Ensuring measurement location stability enhances the reliability of controlled temperature.

6.4 Standardizing Measurement Criteria for Consistency

To improve measurement accuracy, it is essential to standardize measurement locations and collect consistent data based on controlled temperature principles.
If measurement locations vary each time, data inconsistency arises, reducing the reliability of controlled temperature.

6.4.1 Examples of Standardized Measurement Criteria

1. Heat Treatment of Metal Parts
Standardization: Always place a thermocouple at the center of the part to obtain consistent data.
Purpose: Prevent temperature inconsistencies and standardize measurement locations.

2. Plastic Molding
Standardization: Record not only nozzle temperature but also the internal temperature of the molten resin and cooling process at a unified measurement location.
Purpose: Stabilize product quality.

3. Food Processing (Oven Heating)
Standardization: Always insert a temperature probe at the center of the same food sample and collect internal temperature data.
Purpose: Evaluate heating uniformity and ensure food safety.

4. Semiconductor Manufacturing
Standardization: Always collect data from the same measurement points (center and edges of the wafer).
Purpose: Verify heating uniformity and improve manufacturing precision.

6.5 Conclusion

By standardizing measurement criteria and selecting appropriate measurement locations, it is possible to enhance the accuracy of temperature measurements and improve the reliability of temperature control.
Applying the concept of controlled temperature and minimizing environmental influences enables consistent temperature management, contributing to process optimization and quality improvement in manufacturing.