Overview
ISO 11093-5:2016 - Paper and board - Testing of cores - Part 5: Determination of characteristics of concentric rotation specifies a laboratory method to measure the rotational geometry of cylindrical board cores (mandrins). The standard applies to cores with a minimum wall thickness of 5 mm, minimum external diameter of 60 mm and maximum sample length of 3 200 mm. It defines apparatus, sampling/conditioning references, measurement procedures and reporting requirements for circularity and rectitude (concentric rotation characteristics).
Key topics and technical requirements
- Scope limits: wall thickness ≥ 5 mm; external diameter ≥ 60 mm; sample length ≤ 3 200 mm (full core or extracted specimen 1 200–3 200 mm where applicable).
- Measurement principles:
- Circularity (three-point method): measure between three points in a plane perpendicular to the core axis where two points are fixed and the third is the measurement point. Rotate the core 360° and record minimum and maximum dial-indicator readings; difference = circularity f_R (mm).
- Rectitude (five-point method): measure between five points in perpendicular planes where four points are fixed (two pairs) and the fifth is in the mid plane. Rotate core 360°, record min/max; rectitude f_S = (x/2) where x is the measured difference (mm). Convert to mm/m using f' = f_S × 1000 / S_l (S_l = distance between supports in mm).
- Apparatus requirements:
- Two supports (pairs of free-rotating rollers) and a sliding frame with two measurement heads.
- Roller diameter (85 ± 1) mm, width (19 ± 1) mm (example: bearing 6209).
- Measurement feet: flat 10 mm diameter, load ≈ 1.2 N; dial indicators graduated 0.01 mm with accuracy at least 0.005 mm.
- Support geometry: tangents between roller supports form 120° ± 5°; support spacing equals core length minus (200 ± 10) mm.
- Sampling & conditioning: sampling per ISO 11093-1; conditioning per ISO 11093-2.
- Quality data: calculate mean and standard deviation of circularity and rectitude to 0.01 mm precision. Measurement fidelity is adequate for rectitude ≥ 0.3 mm/m.
- Reporting: include ISO reference, core type, sampling/test dates and locations, specimen count and dimensions, test length, mean and SD for f_R and f_S, signature, and any deviations.
Applications and users
ISO 11093-5 is used for quality control, supplier acceptance, production process control and R&D for manufacturers and users of paperboard cores and mandrins. Typical users include:
- Core and tube manufacturers
- Converters and rewinders (winding paper, film, foil, nonwovens)
- Independent test laboratories and QA departments
- Product engineers validating core geometry and concentric rotation
Related standards
- ISO 11093-1 - Sampling
- ISO 11093-2 - Conditioning of samples for test
- Other parts of ISO 11093 series (dimensions, moisture, bending, compression, modal analysis) provide complementary test methods for cores.
Keywords: ISO 11093-5, testing of cores, concentric rotation, circularity, rectitude, paper and board, mandrins, core testing, measurement apparatus.
Open preview (PDF)Paper and board — Testing of cores — Part 5: Determination of characteristics of concentric rotation