FAQ - emco IBT Internal Bond Tester

General information

ISO 16260:2016 defines the internal bond strength as follows: “average potential energy expressed as J/m2 relative to the surface area required to delaminate a specimen under test conditions.”

Further above, the standard describes the Scott Bond method as “a method for determining the internal bond strength […] but in this method the delamination force is applied very rapidly (abruptly) which is much higher than in other methods. This method can therefore be used primarily to assess the performance of a sheet under printing and processing conditions.”

  • Fibre bonding
  • Layer bonding
  • Refining (fibre structure and fibrillation)
  • Sizing
  • Wet strength bonding
  • Fibre composition
  • Test climate
  • Sample cutting
  • Adhesive tape
  • Alloy (i.a. modulus of elasticity), surface and manufacturing accuracy of the angles
  • Alloy, surface (e.g. roughness) and manufacturing accuracy of the anvils
  • Contact pressure
  • Pressing time
  • Measuring range


In ISO 16260:2016 Paper and Board – Determination of Internal Bond Strength, the physical properties of the pendulum impact tester have been updated and extended to provide the basis for comparable measurements. In addition, specimen preparation, accessories and testing capabilities have been described in more detail.

Yes, the emco IBT meets the technical requirements of the standard. If you are unsure whether your model meets the standard, please contact our customer service.

The standard describes a test method that can be used to perform an objective test.

Sample preparation

The sample is prepared according to TAPPI T 569 and ISO 16260. A material sample is fixed between the sample holder and the aluminum angle so that the sample is fixed on both sides with double-sided adhesive tape.


For more detailed instructions, please refer to the Sample Preparation section (5.1.) of the operating manual for the individual steps.

Historically, 5 samples can be prepared simultaneously.

However, according to ISO 16260:2016, 10 pieces belong to a test cycle.

No, the emco IBT contains everything for sample preparation of up to 5 samples at the same time. A test strip with the dimensions 25.4 mm (1 inch) width and approx. 150 mm length must be available. Here the well-known principle applies, the test is only as good as the sampling.

Due to the American origin of the measurement method, the single sample is 25.4 mm x 25.4 mm (1.0 inch x 1.0 inch).

The test strip must be cut externally to 25.4 mm (1 inch) width and approx. 150 mm length.

Measurement result

Splitting strength according to Scott-Bond as energy per surface. The output is optionally in: J/m2, ft-lb/sq.in. or mJ/sq.in.

Older devices partly display the result in an energy unit. To compare the measured values, a conversion from square inches to square meters must first be done.

The emco device determines the internal bond strength using two methods: the potential energy Epot and the kinetic energy Ekin. The method of potential energy is historically known. The determination of the measured value via the kinetic energy is included so that measurement errors can be detected.

  • The traditional method of measuring potential energy is to measure the angular deflection that the pendulum reaches after impact. The angle difference to the maximum deflection of the pendulum at an empty stroke (zero measurement) is a measure of the energy used to split the sample.
  • The dynamic method (kinetic energy), on the other hand, measures the pendulum speed. The change in the pendulum speed is measured before and after the knock-off of the test angle and the energy used to split the sample is determined from the difference.

Differences between the two measured values indicate measuring errors. From a difference of 5 to 10 % of the measured value, the cause should be investigated.

For example, an additional strike of the lower leg of the angle against the pendulum can reduce the measured gap energy. The potential value would be lower than the kinetic value.

If the kinetic value is clearly scattered within a measurement series, this indicates a mechanical loosening of the pendulum. Then please contact the manufacturer.

If the paper is not split correctly, there is a measuring error and an exact analysis should follow.

Check the surfaces of the anvils and angles for cleanliness. If necessary, increase the contact pressure or the pressing time. Generally pay attention to a correct sample preparation and contact the manufacturer in case of further questions. If the sample surface is special, a different type of adhesive tape may have to be used.

  • The sample was not completely split.
  • The adhesive tape has come loose from the angle and/or anvil.
  • After splitting, the adhesive tape is partially visible. The adhesive tape was plucked and the sample was not split.
  • Kinetic and potential values differ more than 5 to 10 % from the measured value.
  • The standard deviation is a measure of the inhomogeneity of the sample.
  • The adhesive tape should be checked for age.
  • The sample preparation was inaccurate.
  • Incorrect measurements must be removed/deleted from the measurement series.

The materials show very different internal bond strengths. The increase of the splitting energy of the pendulum is realized with additional weights.

Four measuring ranges have developed historically with the emco IBT Internal Bond Tester. Recommended splitting strengths are assigned to the measuring ranges from the instructions. The exact ranges result from the almost linear behaviour within a measuring range.

An even higher splitting capability was achieved by introducing the measuring range 4 over a smaller measuring area with additional accessories. This is the fifth measuring range, which is only available as an option.

The measuring range extension is designed for particularly split-resistant papers such as pre-impregnated papers. These are additional accessories which reduce the measuring area and thus increase the splitting capacity of the pendulum impact tester.

No, the measurement results between the individual measuring ranges are not comparable. This means that if you want to compare the measured values between two different materials, you must select a measuring range that is adequate for both.

Five measured values are always combined into one measurement series in the device display. After data transmission, any number of measured values can be determined for a measurement series.

Yes, the emco IBT Internal Bond Tester includes software that ensures easy data transfer and implementation of customer needs.

Factors influencing the measurement result

  • Yes, both Tappi T569 and ISO 16260:2016 indicate that a specific alloy and mass must be used. The dimensions also influence the measured value. Based on the experience of the users, the parameters alloy and surface quality of anvil and angle were included in the development of the new ISO 16260:2016.
  • The standards also state that only angles recommended by the manufacturer should be used.
  • According to ISO 16260, angles should be replaced every 10,000 measurements. Depending on the measuring range and wear, we recommend an exchange after 600 measuring cycles for accurate measurements.
  • Yes. Tappi T569 om-14 and ISO 16260:2016-06 recommend the following tapes:
    • – Tappi: 3MTM 410M*
    • ISO: Nitto P-50TM*, Tesa tesafix 4961TM, 3MTM 410M*.

*These tapes are available from emco.

  • Within the supply chain, you should agree on the use of one adhesive tape. In addition to the adhesive strength and thickness, the elastic deformation also influences the measurement result.
  • It is essential to check the width of the adhesive tape at 25.4 mm ±0.2 mm and to store it correctly before use (to avoid ageing).
  • Yes, a strip that is too narrow (<25.4 mm) has a serious influence. This can result in a connection between the upper and lower adhesive tape strips. This incorrectly increases the measured value.
  • Yes, strips that are too wide make handling more difficult and also falsify the measurement result upwards. More material has to be split.
  • Yes. If the contact pressure is too high, the sample may be unnecessarily compressed, causing a change in the material.
  • Yes. If the contact pressure is too low, the adhesive bond may not be sufficiently formed.
  • The rule is: As high as necessary, as low as possible. The contact pressure should be adjusted within the supplier chain.
  • Yes. Too long a pressing time can unnecessarily strain the sample and cause a change in the material.
  • Yes. If the pressing time is too short, the adhesive bond may not be sufficiently formed.
  • The rule is: As long as necessary, as short as possible. The pressing time should be coordinated within the supplier chain.

The position of the additional weight is essential for the measuring system. The choice of the additional weight determines the measuring range. The measuring instrument is only calibrated if the additional weight is attached correctly. Push the additional weight onto the pendulum as far as it will go. The serial number on the weight should point towards the pendulum joint. Fix it at this point with the set screws installed. A deviating position has a direct influence on the splitting energy of the system as well as additional undesired natural oscillations.

Expendable items

  • Adhesive tape is consumed with each measurement.
  • Aluminium accuracy angles, exchange after about 600 measurements each.
  • Knife blades. A clean cut without crushing is a prerequisite.

The consumption of adhesive tape for a preparation (corresponds to a test of five) is about 40 cm.

  • It is recommended to check the weights of the angles after approx. 300 measuring cycles. It is recommended to change the angles after 600 measuring cycles at the latest.
  • Check the angles regularly. Damage to the measuring surface in size and roughness will influence the measurement result.

All expendable items and spare parts are available from emco.

Contact us for a quote.

We offer two common types of adhesive tape. For special adhesive tapes, please contact other suppliers. Please pay attention to and check the width of the tape. ISO 16260 requires a tolerance of ±0.2 mm.

Inspection and calibration

  • The alignment of the instrument and the calibration should be checked at the beginning of the measuring day and after changing the measuring range.
  • If the instrument is moved, it is absolutely necessary to check the alignment and the calibration.

The calibration value (AVG) displayed during calibration must not fall below the minimum splitting capacity permitted in the corresponding factory certificate. If this is still the case, the alignment of the emco IBT must be checked.

  • Yes. The menu item (“Test”) offers the user three facets of testing:
    • Alignment of the device (important for the correct zero point of the pendulum swing)
    • Counting of pendulum swings total and in DIN range (<5 °) (important for pendulum function and friction control)
    • Adjustment of the current calibration value (important for the correct measured value)
  • Yes. A check of all materials and positioning is absolutely necessary. Preparation errors are not detected by the menu.

Repair and service

  • E-mail: emco@emco-leipzig.de
  • Phone: + 49 341 27146-0
  • Transport packaging (It is recommended to keep the special packaging used for delivery and to use it in case of shipping.)
  • Secure the pendulum carefully: Remove additional weights, fix pendulum to stand plate
  • The additional weights are necessary for a check.
  • Transport with pallet
  • The device must be installed on a flat, stable surface that is free of vibrations.
  • Alignment of the device to ensure error-free operation of the pendulum impact tester.
  • Before switching on, make sure that the pendulum is in the zero position.
  • Store the device in climatic conditions that do not damage electronics or mechanics (free of corrosion and electrostatics).
  • Check the alignment and calibration.
  • Test laboratory with standard climate
  • Vibration-free table
  • Power connection
  • Compressed air

Yes, compressed air (6 bar, oil and water free) is required to operate the device. A 1.5 m compressed-air hose is included in the scope of delivery.


The classic Scott Bond devices can no longer be maintained and repaired by the manufacturer. Nevertheless, there are many old devices in circulation. The new ISO states that these devices are correctly calibrated only with the original angles.

ISO 16260:2016 provides a way to compare different devices by defining the pendulum characteristics. However, differences may exist between different manufacturers due to the tolerance ranges of the properties. We recommend using the same type of construction within the supply chain.

With the emco Scott Bond Pendulum Check it is possible to check the pendulum functionality of the classic Scott Bond type and between different device types. The test provides a statement as to whether the tested device conforms to the Scott Bond master device of PTS Heidenau. The emco test set for Scott Bond IBT is the ideal complement to round robin tests.


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