Temperature Measurement System Calibration: The Lifeline for Process Accuracy
I once saw a situation that was both laughable and frustrating. A factory's graphitization degree was consistently unstable. After a thorough investigation, it was finally discovered that the infrared thermometer reading was nearly 300 degrees Celsius lower than the actual temperature. Because of this one deviation, all the automatic controls went awry. The holding time was sufficient, but the actual temperature wasn't reached, and the product wasn't fully heated. Inaccurate temperature measurement is like the **bad apple that spoils the whole barrel**.
Regular Calibration: Every 1-2 years
The dual-color infrared thermometer is a high-precision optical instrument, and drift may occur after a period of use. It is recommended to send it to the manufacturer or a nationally authorized metrology institution every 1 to 2 years for calibration using a blackbody furnace as the standard temperature source. A calibration certificate will be issued after calibration, specifying whether the accuracy of each temperature point meets the standard. This certificate serves as proof of the equipment's condition and is also a document required by the quality management system.
On-site Comparison Verification Method
Between two formal calibrations, basic verification can be performed on-site:
- Place a calibrated type B or type C thermocouple inside the furnace
- After the furnace temperature rises to approximately 1500℃ and stabilizes (too low a temperature is not representative, too high a temperature poses a high operational risk)
- Compare the thermocouple reading with the infrared thermometer reading
- If the deviation is within the allowable range → continue normal use; if the deviation exceeds the limit → send for inspection immediately
Calibration Service
We can provide customers with contact services for calibration institutions and assist in arranging inspections. The temperature control accuracy of the entire machine is also verified using calibrated standard temperature measuring equipment when the equipment leaves the factory, ensuring accuracy from the moment it leaves the factory.
Lesson learned: That factory suffered huge losses because it hadn't performed calibration for two years, resulting in a nearly 300-degree temperature drift without its knowledge. Furthermore, the operators lacked experience and couldn't judge the approximate temperature by the color of the light emitted from the furnace. This led to several batches of products failing to meet graphitization standards. Calibration is an essential expense that shouldn't be skimped on.