ISO 5628

Testing Standard

International standardization defines laboratory methods for determining the bending stiffness of paper and board by static bending methods. Technical testing protocols published under ISO 5628 establish standardized procedures for measuring flexural resistance in rigid paperboard substrates. The standard specifies specimen dimensions, bending angles, load application rates, and force measurement tolerances required to produce comparable test data.

Bending resistance testing identifies structural strength properties essential for packaging performance under vertical stacking loads. Test procedures apply across paperboard and corrugated board materials, excluding tissue products and flexible film laminates.

Measurement Principle

Two-point bending methods clamp one end of a test specimen while applying force to the free end at a fixed distance from the clamp. Multi-point arrangements support specimens at outer points while applying loads across central span lengths to measure deflection forces. The standard mandates controlled test atmospheres of twenty-three degrees Celsius and fifty percent relative humidity to eliminate moisture variability during testing.

Quality Compliance

Mill laboratories utilize standardized testing procedures to verify compliance with customer stiffness specifications on commercial board grades. Instrument calibration against certified reference materials ensures data interchangeability between paper mills and packaging converting facilities. Deviations from standard specimen cutting dimensions introduce significant errors in calculated stiffness values due to cubic thickness relationships.

Certified testing according to published methods provides defensible structural data for packaging design calculations and material claims.

A digital render features a mechanical testing frame alongside stacked corrugated board sheets and geometric blocks inside a dark studio.

ISO 5628 Water Vapour Transmission Rate Cobb Test

Hygral Stress Dynamics and Edge Waving Mechanics in Recycled Paperboard Skids

Hygral edge waving in recycled paperboard skids results from perimeter moisture absorption driving compressive buckling against a dry, rigid core.

An illustrative render displays a cross-section of a composite panel featuring a paperboard honeycomb core, intermediate substrate, and external facing.

BCT Degradation Solid Bleached Sulphate Ultrasonic Polar Scan

Quantifying Mechanical Core Shear Modulus Shifts during Ultra High Speed Platen Converting Passes

Dynamic platen converting above 7,500 sph degrades board core shear modulus by up to 60 percent, demanding calibrated matrix tooling to prevent carton collapse.

A teardrop shaped sample of white paper substrate rests balanced upon a narrow metal straight edge within a testing laboratory environment.

Shear Yield Point ISO 5628 Aqueous Dispersion Barrier

Dynamic Crease Stiffness Analysis in Water Based Dispersion Barrier Coated Cartonboard

Dynamic crease stiffness analysis measures real-time polymer film relaxation during high-speed board folding to prevent barrier fracturing and line jams.

A large circular paper roll stands centrally mounted between two vertical mechanical towers inside a dimly lit industrial facility with clean concrete floors.

Platen Bed Deflection Counter Plate Creasing Rule

Platen Bed Deflection Correction and Real-Time Impression Adjustments for High-Speed Packaging Lines

Real-time platen bed deflection correction eliminates crease depth variance across wide formats, preventing high-speed packaging jams and cutting tooling wear.

A gloved technician operates a mechanical creasing device on a heavy white paper substrate positioned atop an industrial workstation.

Counter Matrix Creasing Rule Height Carton Springback Force

Creasing Channel Selection for Laminated Folding Boxboard Conversion

Select creasing channels for laminated folding boxboard using wider channel factors to protect surface polymer films from tensile rupture during folding.

$A fractured black grooved mandrel lies beside a heavy cream paperboard sheet on a polished steel production table surface.$

ISO 534 Out of Plane Swelling Shear Modulus

Chemithermomechanical Core Viscoelastic Compliance Modeling for Packaging Substrates

Chemithermomechanical core compliance modeling predicts time-dependent box compression decay under changing humidity by coupling viscoelastic Prony series with shear kinematics.

Smart eyewear rests atop layered brown cardstock sheets and folded dark blue specialty paper next to a black rigid box.

Crow-Footing Multi-Ply Folding Boxboard Dye Penetration Test

Coated Folding Boxboard Crease Quality Audit Procedures

Crease audits verify internal mechanical ply shear through moment ratios between thirty and fifty percent without top coating fracture under dye staining.

Digital render displays several white folding paperboard cartons arranged on a dark surface alongside an open box revealing fibrous padding.

Pertinax Counter Dies Polyethylene Terephthalate Lamination Internal Bond Strength

Designing Counter Die Relief Profiles for Laminated Folding Boxboard

Counter die relief profiles for film laminated folding boxboard require expanding channel widths by twenty percent to prevent outer film shear tearing.

Heavy industrial machinery compresses corrugated waste cardboard into dense rectangular bales positioned beside wooden pallets inside a commercial recycling warehouse.

Solid Bleached Board Solid Bleached Sulfate Poisson Ratio

Dynamic Viscoelastic Crease Recovery and Orthotropic Panel Deflection Limits in High Speed Packaging

Dynamic viscoelastic springback coupled with orthotropic panel deflection governs cartoning line efficiency and side-wall structural limits under high speeds.

A digital render displays an accordion folded sheet of thick white paperboard extending from a dark gray storage box on a desk.

Chemical Pulp Board Downgauging Machine Direction

Evaluating Machine Direction Stiffness Anisotropy in High Speed Folding Boxboard Converting

Folding boxboard machine direction stiffness anisotropy governs carton opening force and high-speed feeder reliability, demanding strict ratio limits on orders.

A rendered image shows a multi-axis robotic arm positioned above a specialized flatbed machine, processing a substrate in a controlled industrial setting.

ISO 5628 Sheet Flatness Interlaminar Shear

Quantifying Structural Flexural Modulus Loss in Recycled Paperboard Subjected to Dual-Axis Mechanical Decurling and Fluid Rehydration

Mechanical decurling and fluid rehydration permanently degrade recycled paperboard flexural modulus by shear micro-delamination and fiber plasticization.

A handheld electronic testing device rests on corrugated board upon a metal workbench inside a material evaluation facility with stacked substrate samples.

Acoustic Impedance Time of Flight Paperboard Creasing