# Professional-Scale Testing

- Tensile strength is the maximum tensile force developed in a test specimen before rupture on a tensile tester carried to rupture under prescribed conditions. Tensile Tester "PARAM XLW(EC)" from LABTHINK is a vertical single-column tensile tester designed for testing of paper and low elongation films and foil. On this machine, we can change sample width, gauge length, and loading rate. Output results are paper strength in force units (standard or metric), elongation at break as a percent from the original gauge. Output results are paper strength in force units (standard or metric), elongation at break as a percent from the original gauge length. Tensile strength given is the force per the width of the test specimen, which is 1 inch, usually.
- Standard Method(s):
- TAPPI T494 - Tensile properties of paper and paperboard (using a constant rate of elongation apparatus)
- ASTM D828 - Tensile Properties of Paper and Paperboard Using Constant-Rate-of-Elongation Apparatus

- Bursting strength is the maximum pressure required to rupture the tested material. The sample is held at the perimeter while the hydrostatic pressure is increased at a controlled constant rate under a rubber diaphragm until sample rupture. The L&W Burst-o-matic is designed to measure the bursting strength of sheet materials. Output results are paper burst strength in pressure units (standard or metric), commonly psi.
- Standard Method(s):
- TAPPI T403 - Bursting strength of paper
- TAPPI T807 - Bursting strength of paperboard and linerboard
- TAPPI T810 - Bursting strength of corrugated and solid fiberboard
- ASTM D774/D774M – Bursting Strength of Paper

- The energy consumed to tear the test sample (usually 4 plies of the sheet material) a certain distance is used to calculate the average tearing force. The L&W Tearing Tester measures the tearing strength of paper, fabric, plastic foil, ect. The tearing energy is measured through positional change of machine’s pendulum. Output results is the paper tearing strength in force units standard or metric (usually pounds).
- Standard Method(s):
- TAPPI T414 - Internal Tearing resistance of Paper (Elmendorf type)
- ASTM D689 – Internal Tearing Resistance of Paper

- A strip of sheet (paper) under a standard tension is subjected to double folding oscillations until break. The logarithm to the base 10 of the number of double folds is considered as “Folding Endurance”. It measures the ability of a sheet of material (paper) to withstand repeated folding. It is also useful for indicating the deterioration of material upon aging.
- Standard Method(s):
- TAPPI T511 - Folding endurance of paper (MIT tester)
- ASTM D2176 – Folding Endurance of Paper by the M.I.T. Tester

- A strip of sheet (paper) is clamped in two pair of clamps 0.7 mm apart. moving towards each other, sample is compressed in the edge direction. The maximum force causing failure is measured and given in pound. The L&W Compression Strength Tester uses the STFI method of testing for edgewise compression strength of containerboard in the range of 100 – 400 g/m
^{2}. - Standard Method(s):
- TAPPI T826 - Short span compressive strength of containerboard

- The L&W Stiffness Tester is used to evaluate stiffness and resiliency properties using resonance length.
- Standard Method(s):
- TAPPI T535 - Bending stiffness of paper and paperboard-Resonance length method

- This instrument measures the bending moment required to deflect the free end of a 1.5 in wide vertically clamped specimen 15° from its center line when the load is applied 2 in. away from the clamp. The resistance to bending is calculated from the bending moment and given in Taber units.
- Standard Method(s):
- TAPPI T489 - Bending resistance (stiffness) of paper and paperboard (Taber-type tester in basic configuration)

- The Huygen Internal Bond Tester is designed to measure rapid “Z” directional ruptures of paper and paperboard samples. The unit uses Scott and American Sisal craft specimen technique.
- Standard Method(s):
- TAPPI T569 - Internal bond strength (Scott type)

- Gurley is the standard instrument for measuring porosity, air permeability, or the air resistance of paper products.
- Standard Method(s):
- TAPPI T460 - Air resistance of paper (Gurley method)

- The Hagerty Paper Smoothness Tester tests the surface smoothness of paper especially coated. This method is a measurement of the air flow between the specimen (backed by flat glass on the bottom side) and two pressurized, concentric annular lands that are impressed into the sample from the top side. The rate of air flow is related to the surface roughness of paper or paperboard. We use a Haggerty test device to measure Sheffield smoothness.
- Standard Method(s):
- TAPPI T538 - Roughness of paper and paperboard (Sheffield method)

- The Glossmeter provides 75° and 20° specular gloss measurements. Its primary application is for coated papers but the machine may also be used on uncoated papers, most ink films, and paper or paperboard.
- Standard Method(s):
- TAPPI T480 - Specular gloss of paper and paperboard at 75 degrees
- TAPPI T653 - Specular gloss of paper and paperboard at 20 degrees

- The Brightimeter Micro S5 measures brightness, opacity, color, and fluorescence.
- Standard Method(s):
- TAPPI T425 - Opacity of paper (15/d geometry, illuminant A/2°, 89% reflectance backing and paper backing)
- TAPPI T452 - Brightness of pulp, paper, and paperboard (directional reflectance at 457 nm)
- TAPPI T524 - Color of paper and paperboard (45/0, C/2)
- TAPPI T562 - Brightness of pulp, paper, and paperboard (directional reflectance at 457 nm) CIE whiteness and tint of paper and paperboard (using 45°/0° directional illumination and normal viewing)
- TAPPI T646 - Brightness of clay and other mineral pigments (45/0)
- ASTM D985 - Brightness of Pulp, Paper, and Paperboard (Directional Reflectance at 457 nm)

- The Electronic Micro Gauge measures specimen thickness within the 0 – 3 mm range.
- Standard Method(s):
- TAPPI T411 - Thickness (caliper) of paper, paperboard, and combined board
- ASTM D645/D645M - Thickness of Paper and Paperboard