Overview
ISO 11093-4:2022 - "Paper and board - Testing of cores - Part 4: Measurement of dimensions" specifies standardized test methods to determine the internal diameter, external diameter, wall thickness and length of paper and board cores. It is part of the ISO 11093 series and is intended for consistent, repeatable dimensional measurement in laboratory and production environments.
Key topics and technical requirements
- Scope & references
- Sampling and conditioning
- Test pieces must be taken and conditioned per the ISO 11093 series prior to measurement.
- Internal diameter measurement (four methods)
- Method A - internal tri-point micrometer: instrument accurate to at least 0.025 mm, with specified measuring forces; limited to cores with internal diameter ≤ 180 mm and wall thickness ≥ 3 mm.
- Method B - internal vernier calliper: calliper accurate to at least 0.1 mm.
- Method C - calibrated step mandrel: stepped mandrel graduated in 0.1 mm increments with tolerance ±0.01 mm; each step ≥50 mm. For diameters >70 mm a mandrel with a maximum of five levels is recommended.
- Method D - calculated: derive internal diameter from measured external diameter and wall thickness (d = D − 2s).
- External diameter measurement (three methods)
- Method E - external micrometer: accuracy at least 0.025 mm; anvil/spindle face dimensions and measuring-force ranges are specified.
- Method F - external vernier calliper
- Method G - flexible tape
- Wall thickness and length
- Methods for wall thickness are designated H, I, J (see standard for apparatus and procedures). Length measurement procedures and apparatus are given in Clause 9.
- Reporting
- Test report contents are specified (see Clause 10).
Applications and users
- Practical uses:
- Quality control for paper/board core production
- Incoming inspection for converters and rewinders
- Supplier acceptance testing and procurement specifications
- R&D and failure analysis where core dimensions affect winding, runnability or material usage
- Primary users:
- Paper and board manufacturers, converters, tissue and towel producers, industrial rewinders, testing laboratories, and procurement/quality engineers.
Related standards
- ISO 11093 series (Parts 1 and 2 are normative for sampling and conditioning)
- Instrument standards referenced: ISO 13385-1 (vernier callipers), ISO 3611 (micrometers)
Keywords: ISO 11093-4, paper cores, core measurement, internal diameter, external diameter, wall thickness, core length, calibrated mandrel, tri-point micrometer, vernier calliper, testing standard.