Bursting Strength Tester for Linerboard and Fluting

What is the Bursting Strength Tester for Linerboard and Fluting?

A bursting strength tester configured for linerboard and fluting measures the bursting strength of the uncombined component papers used to make corrugated board. It supports the calculation of expected board strength and the control of base paper quality.

Overview

Linerboard and fluting are tested as single sheets using the paper aperture and pressure range, before they are combined into corrugated board, so the result describes the component rather than the structure. Corrugating plants use these values to predict the bursting strength of the finished board from the contributions of both component papers, and to verify incoming base paper against specification. Specimens are cut from the reel in the machine direction and cross direction because strength differs between directions, and the moisture condition at testing must be recorded, since linerboard picks up moisture during storage. Because the components are thin relative to corrugated board, the standard paper test area and clamping pressure apply, and the same diaphragm rules apply as for paper testing.

How does it work?

A circular specimen is clamped between two platens under a defined clamping pressure and a rubber diaphragm expands against it as hydraulic or pneumatic pressure increases at a controlled rate. The maximum pressure reached at rupture is recorded as the bursting strength, and the value is affected by clamping pressure, diaphragm condition, the rate of pressure rise and specimen conditioning. Standards define the clamping force, the free test area, the pressure rise rate and the diaphragm material and thickness, so the instrument must be configured exactly as the method specifies. Because the diaphragm stretches with every test, it must be replaced at defined intervals and its condition checked, since a stiff or hardened diaphragm gives high and erratic readings. Corrugated board requires a larger test area and a support plate to prevent local crushing.

What are the key features?

• Paper aperture and pressure range for thin sheets
• Consistent specimen cutting in machine and cross direction
• Digital display with statistics for lot evaluation
• Moisture record for stored reels
• Calculation support for predicted board strength
• Diaphragm counter per test count

What are the technical specifications?

A typical bursting strength tester for linerboard and fluting configuration offers measuring range of 0–1600 kPa, resolution of 1 kPa, test area diameter of 30.5 mm per paper method, clamping pressure of Per paper method, specimen orientation of Machine and cross direction and typical grade range of Linerboard 100–300 g/m². Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Bursting Strength Tester for Linerboard and Fluting is used in incoming inspection of linerboard and fluting reels, prediction of finished corrugated board strength, control of base paper quality between suppliers and process control in corrugating plants. Across the wider Burst Analysis class, laboratories also deploy it for bursting strength of packaging papers and boards, corrugated board quality control and paper bag and sack grade verification.

Which standards and certifications apply?

Relevant standards and methods include ISO 2758, ISO 2759, ISO 12625-11, ASTM D774, TAPPI T403, TAPPI T810 and IEC 61010-1. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Condition specimens to the standard atmosphere, since bursting strength changes markedly with moisture content. Clamp each specimen centrally and without creases, since edge positions and wrinkles cause premature rupture and low readings. Replace the diaphragm at the interval stated in the method or whenever it shows hardening, cracking or permanent deformation, and record the replacement in the instrument log. Verify the clamping pressure and the pressure rise rate periodically, and check the pressure gauge or transducer against a reference. After each test, inspect the rupture pattern: an off-centre or irregular burst usually indicates a clamping or centring problem rather than a material fault.

How do I select the right Bursting Strength Tester for Linerboard and Fluting?

Specify this configuration when base papers are tested before corrugating, for supplier verification or for predicting board strength. Confirm the pressure range covers the grade range and that the instrument is calibrated to the paper standard, not the board standard, and set up a procedure that records orientation and moisture with each result.

How does it compare with other Burst Analysis variants?

Choose the instrument from the standard and the product. Paper and tissue use the smaller hydraulic test area, board uses the larger area with a higher pressure range, and corrugated board needs a pneumatic or hydraulic instrument with a support plate and a sufficiently wide clamping ring. Confirm the pressure range covers the expected bursting strength with adequate headroom, since a range that is too low prevents reaching rupture and one that is too wide reduces resolution. Specify automatic clamping if many specimens are tested, and always choose an instrument whose diaphragm and pressure rise rate match the standard edition you follow, because values from different configurations are not interchangeable.