Polarized stress meter is suitable for measuring internal stress of various types of glass bottles such as medicinal glass containers and glass bottles. Polarized stress meter is designed and manufactured according to "GB/T 12415-2015 Inspection Method for Internal Stress of Medicinal Glass Containers", "YBB00162003-2015 Internal Stress Measurement Method", "GB/T 4545-2007 Test Method for Internal Stress of Glass Bottles and Cans". It is a testing instrument required by pharmaceutical enterprises, glass product factories, quality inspection units and other units.

Working principle of polarization stress meter

Polarization stress meter works based on the principle of polarized light interference: natural light is filtered by a polarizer to form linearly polarized light; When light passes through the tested material (such as glass or plastic), internal stress causes birefringence, and the light is decomposed into fast axis light and slow axis light perpendicular to the vibration direction, resulting in an optical path difference (Δ). The optical path difference is detected by a polarizer and compensation element (such as a 1/4 waveplate), and is manifested as interference fringes or color patterns; Finally, the stress value is calculated based on the formula σ=Δ × F/d (where σ is the stress, F is the material's stress optical constant, and d is the sample thickness). This process can qualitatively observe stress distribution or quantitatively analyze stress magnitude to ensure measurement accuracy.

Process flow of polarization stress meter

The process flow covers three stages: sample preparation, instrument operation, and data analysis:

Sample pretreatment: After annealing, the sample should be kept at room temperature for at least 30 minutes to avoid direct contact (such as wearing gloves) and ensure the stability of the material state.

Instrument calibration and setting: After turning on, input parameters (such as sample thickness) through the touch screen, rotate the eyepiece to adjust to the dark field state, and select quantitative or qualitative testing mode.

Test execution: Place the sample on the observation platform and rotate the analyzer to the clearest position of the interference fringes; Quantitative mode collects optical path difference data from multiple points, while qualitative mode observes dark cross features to determine the presence of stress.

Result processing: The system automatically records the rotation angle or optical path difference, calculates the stress value based on the thickness, and outputs the maximum, minimum, and average value reports.