| Primary Measurement Purpose | Measurement of residual stress in glass, especially compressive stress near the edge or surface of processed glass. | Supports quality control for tempered, heat-strengthened, laminated, architectural, automotive, appliance, and specialty glass. | Confirm whether the instrument is designed for edge stress, surface stress, or both, because the optical configuration and calculation method may differ. |
| Measurement Principle | Optical photoelastic measurement using polarized light to evaluate stress-related optical retardation in transparent glass. | Provides a non-destructive method that can be used during production inspection and laboratory testing. | Request details about the optical path, polarization components, measurement algorithm, and applicable glass conditions. |
| Typical Measurement Unit | MPaN/mm² | MPa and N/mm² are numerically equivalent units and are commonly used for reporting stress in glass. | Check whether the display and exported reports support the units required by the customer’s quality system. |
| Applicable Glass Types | Commonly applicable to transparent flat glass, tempered glass, heat-strengthened glass, and selected glass components with suitable optical access. | Useful for verifying heat-treatment results and identifying insufficient or uneven stress distribution. | Confirm supported glass color, coating, curvature, thickness, edge finish, and transparency limitations. |
| Measurement Location | Glass edge, edge vicinity, or designated surface area, depending on the instrument design and test method. | Allows inspection of stress concentration in areas affected by cutting, grinding, polishing, drilling, or thermal processing. | Verify the minimum accessible edge width, probe clearance, measuring depth, and positioning repeatability. |
| Sample Condition | Clean, dry, transparent measurement areas with stable positioning and limited contamination or surface damage. | Reduces optical interference and improves repeatability between operators and production batches. | Ask for sample preparation instructions, allowable surface defects, and recommended cleaning procedures. |
| Instrument Configuration | Typical configurations include a handheld optical unit, bench-mounted tester, or integrated inspection system. | Handheld systems support mobile inspection, while bench and integrated systems are better suited to repeatable laboratory or line-side testing. | Compare portability, fixture design, working distance, measurement speed, operator interface, and installation requirements. |
| Data Output | Measurement value, test location, sampling record, operator information, time and date, and optional trend or report data. | Helps manufacturers trace quality results by batch, production line, glass size, and heat-treatment cycle. | Confirm support for local storage, USB or network transfer, spreadsheet-compatible export, printed reports, and data backup. |
| Calibration and Verification | Periodic calibration or verification using a qualified reference sample, certified standard, or documented manufacturer procedure. | Maintains measurement consistency and supports internal audits, customer inspections, and laboratory traceability. | Request calibration interval, certificate format, traceability information, adjustment procedure, and service availability. |
| Measurement Repeatability | Repeatability depends on optical stability, sample positioning, glass uniformity, operator technique, and instrument resolution. | Good repeatability is important when comparing production lots or verifying process changes. | Ask for repeatability test data using the customer’s actual glass type, thickness, edge finish, and measurement location. |
| Production Applications | Incoming inspection, in-process quality control, final inspection, laboratory testing, process verification, and failure analysis. | Supports monitoring of thermal strengthening, edge processing, cutting quality, and stress-related breakage risk. | Evaluate whether the supplier offers production fixtures, operator training, method validation, and application support. |
| Software and Reporting | Common functions include measurement recording, result review, statistical trend analysis, user permissions, and report generation. | Improves traceability and reduces manual transcription during repeated inspections. | Verify software language, operating-system compatibility, database capacity, update policy, and data ownership. |
| Environmental Requirements | Stable indoor conditions, controlled lighting, clean optical surfaces, and protection from excessive vibration generally improve measurement reliability. | Suitable environmental control helps prevent inconsistent readings in laboratories and production areas. | Request operating temperature, humidity limits, vibration requirements, lighting restrictions, and enclosure protection details. |
| Supplier Deliverables | Instrument, power supply, optical accessories, sample fixture, operating manual, software, calibration documentation, and packaging. | A complete delivery package reduces installation delays and supports immediate commissioning. | Obtain a detailed packing list and confirm whether installation, training, spare parts, and technical documentation are included. |
| Customization Capability | Possible customization areas include fixtures, measurement software, language interface, report templates, data interfaces, and production-line integration. | Useful for manufacturers with non-standard glass sizes, special edge geometries, or automated inspection requirements. | Ask for engineering lead time, prototype testing, interface specifications, acceptance criteria, and change-control procedures. |
| After-Sales Support | Technical consultation, remote troubleshooting, calibration service, repair support, replacement parts, and application training. | Reliable service reduces downtime and helps maintain consistent measurement performance over the instrument’s life cycle. | Confirm response time, service location, warranty terms, spare-parts availability, and the process for returning equipment for repair. |
| Export and Compliance Documents | Commercial invoice, packing list, user manual, calibration certificate, product specification, and applicable electrical safety documentation. | Complete documentation supports international purchasing, customs clearance, installation, and internal equipment approval. | Confirm required voltage, plug type, shipping terms, export packaging, certificates, and documentation language before ordering. |