How to determine if the stress of glass products exceeds the standard?

The core of determining whether the stress of glass products exceeds the standard is through Polarized stress meter detection Combined with Standard comparison ：

1. Place the product in a polarized stress meter and observe the interference color fringes under polarized light (the greater the stress, the more significant the change in stripe color/density);

2. Compare with stress standard slices or industry specifications (such as glass for food ≤40MPa) to convert the stress value corresponding to the fringes;

3. If the standard threshold is exceeded, it is judged as exceeding the standard. If necessary, a laser stress meter can be used for accurate quantification or cold and hot shock tests for auxiliary verification.

A concise explanation of how to handle common quality defects

1. Prevention and Control (Reduce Defect Generation)

For Bubbles / Stones: Strictly control the purity of raw materials (screen impurities, dry raw materials), optimize kiln temperature and clarification time, and regularly overhaul kiln refractory materials.

For Cracks / Stress: Precisely control the annealing process (slow cooling to release stress), ensure uniform wall thickness during molding, and avoid local rapid cooling.

For Surface Defects (Scratches, Spots): Maintain a clean production environment, regularly maintain molds (polishing, applying mold release agent), and add buffer protection to product contact points.

2. Detection and Screening (Reject Defective Products)

Internal Defects (Bubbles, Stones): Use laser scanning or microscopy to detect and reject products with excessive defects (e.g., bubbles with a diameter > 0.3mm).

Stress / Cracks: Use a polarizing stress meter or thermal shock test to screen out products with excessive stress or that are prone to cracking.

Surface Defects: Machine vision systems quickly identify scratches and spots, and manual sampling is performed for decorative products.

3. Classification and Disposal (Repair or Scrap)

Irreparable Defects (Bubbles, Stones, Cracks): Scrap directly to avoid safety risks (such as products used in the food and pharmaceutical fields).

Repairable Defects (Slight Scratches): Polish and repair non-critical surfaces with polishing paste to ensure that the function and appearance are not affected.

Common Security Risks

　　Equipment operation risks: The kiln temperature reaches 1600℃, contact can easily cause burns; molding machines, cutting machines and other mechanical devices, if not properly protected, may cause sprains and cuts; lifting equipment (such as lifting glass sheets) operational errors may lead to injuries.

　　Fire and explosion: Fuel (natural gas, heavy oil) leaks may cause fire; accumulation of broken glass that is not cleaned up in time may trip employees or damage equipment.