ISO 7263-1:2018

Overview

ISO 7263-1:2018 - Corrugating medium - Determination of the flat crush resistance after laboratory fluting - Part 1: A‑flute - specifies a laboratory test method to measure the flat crush resistance of a corrugating medium after it has been fluted using an A‑flute geometry. The procedure applies to any corrugating medium intended for use in corrugated board manufacture and provides repeatable test conditions for quality control, product development and supplier specification.

Key topics and technical requirements

• Scope and principle: Flute the paper between heated corrugating rolls, bond a facing strip, then apply a perpendicular crushing force to determine the maximum load before flute collapse (flat crush resistance).
• Two timing procedures:
  • Immediate testing: compress 15–25 s after fluting.
  • Reconditioned testing: compress after reconditioning 30–35 min in the standard atmosphere.
• Apparatus and settings:
  • Corrugating rolls heated to 175 °C ± 8 °C, one driven at 4.5 r/min ± 1.0 r/min; force between rolls approx. 100 N ± 10 N.
  • A‑flute roll geometry defined (roll diameter ~228.5 mm, tooth depth ≈4.75 mm, tooth spacing ≈8.55 mm); rack and comb to support test piece.
  • Pressure‑sensitive tape as facing (low stretch, non‑moisture transferring).
  • Flat crush tester: fixed‑platen motor‑driven per ISO 13820, using 400‑grit sandpaper on platens, compression rate 12.5 mm/min.
• Specimen preparation:
  • Cut at least 10 test pieces, 12.7 mm ± 0.1 mm width and 150–160 mm length (machine direction).
  • Condition samples per ISO 187; measure grammage per ISO 536 if calculating an index.
• Results:
  • Report flat crush resistance (force at failure) and, if required, the flat crush resistance index (flat crush resistance divided by paper grammage).
• Precision and maintenance: Annex B contains precision data; Annex A covers maintenance of fluting rolls.

Applications and users

• Quality control laboratories in paper mills and corrugating‑medium manufacturers
• Packaging engineers and converters specifying raw materials for corrugated board
• R&D teams developing fluting media or flute profiles (A‑flute performance)
• Suppliers and buyers using objective test data for supplier acceptance and performance comparison

Related standards

• ISO 7263-2 - same method for B‑flute geometry
• ISO 3035 - flat crush resistance testing of manufactured corrugated board
• ISO 13820, ISO 187, ISO 536 - referenced test‑equipment, conditioning and grammage methods

Keywords: ISO 7263-1:2018, corrugating medium, flat crush resistance, A‑flute, laboratory fluting, corrugated board testing, flat crush tester, packaging quality control.