Overview
ISO 3616:2022 specifies a standardized test method for measuring the average thickness, thickness under load, and recovery after compression of textile glass reinforcement mats - specifically chopped‑strand mats and continuous‑filament mats. The procedure defines specimen preparation, conditioning, measurement apparatus (dial micrometer and two calibrated steel plates), and calculation rules so results are reproducible and suitable for process and quality control in composite manufacturing.
Key Topics
- Scope: Method applies to chopped‑strand and continuous‑filament textile‑glass mats used as reinforcement in polymer matrix composites.
- Specimen preparation: Cut test samples and specimens using templates (e.g., 316×316 mm or 400×250 mm samples; specimens 158×158 mm or 200×125 mm) following ISO 3374 sampling guidance.
- Conditioning: Condition specimens for at least 2 hours in a standard atmosphere per ISO 291; testing atmosphere must match conditioning.
- Apparatus:
- Dial micrometer readable to 0.01 mm with ≥70 mm stem.
- Polished steel plate A (light plate) and plate B (heavy plate) with specified areas and masses to apply nominal light and heavy pressures (or equivalent hydraulic system).
- Positioning jig and stand for repeatable alignment.
- Procedure: Measure stack thickness under light pressure (plate A), under heavy pressure (plate A + plate B), and after specified recovery interval following removal of heavy load.
- Calculations & expression:
- Average thickness (mm) = (h1 − h2) / n; express to three significant figures.
- Thickness under load and recovery after compression expressed as percentages of average thickness; express to two significant figures.
- Test report requirements: Include reference to ISO 3616:2022, material ID, specimen dimensions, conditioning, apparatus details, and averaged results.
Applications
- Quality control and acceptance testing of textile glass mats used as reinforcement in composite parts.
- Process design and tooling specification in composite manufacturing (hand lay‑up, resin infusion, molding) to predict final laminate thickness and part dimensions.
- Supplier specification and comparison: ensures consistent reporting of average thickness, thickness under load, and recovery after compression.
- Relevant to industries using glass‑fiber reinforcements: marine, automotive, aerospace, wind energy, and construction.
Related Standards
- ISO 291 - Standard atmospheres for conditioning and testing (conditioning requirements).
- ISO 3374 - Reinforcement products - Mats and fabrics - Determination of mass per unit area.
- Prepared by ISO/TC 61 (Plastics), SC 13 (Composites and reinforcement fibres).
Keywords: ISO 3616, textile glass, chopped‑strand mats, continuous‑filament mats, average thickness, thickness under load, recovery after compression, composite manufacturing, test method.