ISO 7263-2:2018

Overview

ISO 7263-2:2018 specifies a laboratory test method to determine the flat crush resistance of a corrugating medium after laboratory fluting using a B‑flute geometry. The standard applies to any corrugating medium intended for manufacture into corrugated board and is part of the ISO 7263 series (ISO 7263‑1 covers A‑flute). Results indicate the potential flat crush performance of corrugated fibreboard and support quality control, material specification and comparative assessment.

Key topics and technical requirements

• Test principle: Laboratory fluting of single-faced corrugating medium between heated matched rolls, facing with pressure‑sensitive tape, then compression perpendicular to flute direction to measure maximum force before flute collapse (flat crush resistance).
• Fluter / roll geometry (B‑flute):
  • Roll temperature: 175 °C ± 8 °C
  • Roll speed: 4.5 r/min ± 1.0 r/min
  • Force between rolls: 100 N ± 10 N
  • Typical roll dimensions: diameter 226 ± 0.5 mm, 112 teeth (full roll), tooth depth 2.5 ± 0.05 mm, tooth spacing 6.45 ± 0.05 mm, peak/base radii 1.2 ± 0.1 mm / 1.6 ± 0.1 mm.
• Specimen preparation: At least 10 test pieces, 12.7 mm ± 0.1 mm wide, length 100–110 mm cut in the machine direction; free from defects.
• Conditioning and timing: Conditioning per ISO 187. Two procedures: immediate testing (15–25 s after fluting) or testing after reconditioning (30–35 min), with known differences in results.
• Compression test: Motor‑driven fixed‑platen flat crush tester per ISO 13820, platen surfaces with 400‑grit sandpaper, compression rate 12.5 mm/min.
• Results: Report flat crush resistance (N) and flat crush resistance index (flat crush divided by paper grammage, Nm2/g). Precision data available in informative Annex B.

Applications

• Quality control in corrugating mills and paper mills - compare batches, monitor process changes, validate roll maintenance.
• Material specification and supplier comparison - determine suitability of corrugating medium for B‑flute board construction.
• Research and development - assess effects of paper grammage, moisture and fluting parameters on flute stability.
• Packaging engineering - predict flat crush performance of corrugated board based on medium properties.

Who uses this standard

• Packaging engineers, quality managers and lab technicians in corrugated board and paper production.
• Raw material suppliers and converters specifying corrugating medium for B‑flute applications.
• Test laboratories performing comparative or compliance testing.

Related standards

• ISO 7263‑1 (A‑flute method)
• ISO 187 (conditioning)
• ISO 13820 (compression tester)
• ISO 536 (grammage)
• ISO 3035 (flat crush on manufactured corrugated board)
• ISO/TR 24498 and TAPPI T 1200 (precision information referenced in Annex B)

Keywords: ISO 7263-2, flat crush resistance, corrugating medium, B-flute, laboratory fluting, corrugated board, fluting rolls, flat crush tester, grammage, ISO standard.