Notch Impact Strength Testing Service for Cantilever Beams – Comprehensive Izod Impact Characterisation for Polymers, Composites and Advanced Materials
As an ISO/IEC 17025 accredited independent testing laboratory, we offer specialised notch impact strength testing services for cantilever beams – commonly known as Izod impact testing – to manufacturers, quality assurance teams, and material developers across the plastics, composites, automotive, aerospace, electronics, and consumer goods sectors. The Izod impact test measures the resistance of a material to fracture under a high‑strain‑rate, single‑impact load applied to a notched cantilever beam specimen. This test is essential for assessing the toughness, ductility, and brittle‑fracture susceptibility of polymeric and composite materials, and is widely used for quality control, material comparison, and product certification. Our test protocols are executed in accordance with ASTM D256 (Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics), ISO 180 (Plastics – Determination of Izod impact strength), EN ISO 180, and GB/T 1843 (Plastics – Determination of Izod impact strength). Our inspection and test reports are recognised by the National Medical Products Administration (NMPA), the State Administration for Market Regulation (SAMR), the Ministry of Industry and Information Technology (MIIT), and international certification bodies for product registration, type approval, and quality assurance.
Materials and Products We Regularly Test
Our Izod impact test facilities accommodate a wide range of material types and product forms. Typical test articles include:
- Thermoplastics – ABS, polycarbonate (PC), polyamide (PA, nylon), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyoxymethylene (POM), and polymethyl methacrylate (PMMA)
- Thermosets and engineering plastics – epoxy, phenolic, polyester, and polyurethane materials
- Fibre‑reinforced composites – glass fibre reinforced plastics (GFRP), carbon fibre reinforced plastics (CFRP), and hybrid composites
- Laminated and sheet materials – laminated plastics, sheet moulding compounds (SMC), and bulk moulding compounds (BMC)
- Elastomers and impact‑modified polymers – rubber‑modified plastics, thermoplastic elastomers (TPEs), and impact copolymers
- Additively manufactured and 3D‑printed materials – for process optimisation and material qualification
- Finished plastic components – moulded parts, extruded profiles, and machined components
- Recycled and filled plastics – for evaluating the effect of recycled content and filler materials on impact performance
Test Principle – Izod Pendulum Impact Test for Cantilever Beams
- Test specimen and notch geometry – standardised for reproducibility – We prepare test specimens from the supplied material, with standard dimensions of 64 mm × 12.7 mm × thickness (typically 3.2 mm, 6.4 mm, or 12.7 mm, depending on the material and the application). A V‑notch (45° included angle, 2.5 mm depth, 0.25 mm root radius) is machined into the specimen using a calibrated notch cutter. The notch is positioned so that the pendulum strikes the specimen on the side opposite the notch.
- Pendulum impact tester – capacity 0.5‑50 J, with a calibrated hammer and anvil – We use a calibrated Izod pendulum impact tester with a specified hammer mass and a specified impact velocity (typically 3.5 m/s). The specimen is clamped vertically in a vice, and the pendulum is released from a specified height to strike the specimen at the top (the notch side is facing the pendulum). The energy absorbed during the fracture is measured by the difference in the pendulum's height before and after the impact.
- Impact energy and impact strength – the primary output of the test – The impact energy (in J) is the energy absorbed by the specimen during fracture. The Izod impact strength (in J/m or kJ/m²) is calculated by dividing the impact energy by the width of the specimen (or by the cross‑sectional area at the notch). A high impact strength indicates good toughness and resistance to brittle fracture.
- Environmental conditioning – for consistent and reproducible results – The specimens are conditioned at 23 °C and 50 % RH (for 48 hours) before testing, in accordance with ISO 291 or ASTM D618. The test is also performed at the specified temperature (e.g., 23 °C, -20 °C, or -40 °C) for temperature‑conditioned testing.
Specimen Preparation – Notching and Conditioning
- Notch preparation – using a calibrated notch cutter – ASTM D256 / ISO 180 / GB/T 1843 – We prepare the V‑notch using a precision notch cutter with a specified notch angle (45° ± 0.5°) and root radius (0.25 mm ± 0.025 mm). The notch is machined to a depth of 2.5 mm ± 0.05 mm. For materials with a high impact strength, we may prepare a standardised notch (e.g., a 0.25 mm radius notch) and, for a more severe test, a 1.0 mm radius notch.
- Notch verification – using a profile projector or optical microscope – We inspect the notch geometry (depth, angle, and root radius) using a profile projector or an optical microscope. The notch dimensions must be within the specified tolerances to ensure consistent and reproducible test results.
- Specimen conditioning – to eliminate moisture and thermal effects – The specimens are conditioned at 23 °C and 50 % RH for 48 hours (or until the mass is constant). For some materials, we also perform conditioning at elevated temperatures (e.g., 70 °C) for 24 hours to simulate the effect of heat exposure on the impact properties.
- Specimen conditioning at sub‑zero temperatures – for cold‑climate applications – For materials used in cold environments, we condition the specimens at the specified low temperature (e.g., -20 °C, -40 °C) for 2‑4 hours and then test them at that temperature using an environmental chamber integrated with the impact tester.
Test Procedure – Step‑by‑Step Execution and Monitoring
- Selection of the correct pendulum hammer – based on the expected impact energy – We select the pendulum hammer with the appropriate energy capacity (e.g., 0.5 J, 1 J, 2.75 J, 5.5 J, 11 J, 22 J, 50 J) so that the absorbed energy is between 10 % and 80 % of the full‑scale capacity. This ensures the accuracy of the measurement.
- Mounting the specimen – ensuring correct alignment in the vice – The specimen is mounted vertically in the vice with the notch facing the pendulum. The specimen is clamped securely to prevent movement during the impact. The alignment is checked to ensure that the pendulum strikes the specimen at the correct point (mid‑height).
- Pendulum release and impact – recording the impact energy – The pendulum is released from the specified height, swings down, and strikes the specimen. The energy absorbed by the specimen (in J) is read directly from the dial or the digital readout of the tester.
- Observation of the failure mode – for ductile, brittle, or mixed failure – After the test, we examine the broken specimen to classify the failure mode: (a) complete break – the specimen is broken into two or more pieces; (b) partial break – the specimen is cracked or hinged, but not fully separated; (c) no break – the specimen is not broken (this is typical for very tough materials). The failure mode is recorded and is an important indicator of the material's toughness.
- Number of specimens – for statistical significance – We test a minimum of five specimens per material (or per condition). The average impact strength and the standard deviation are reported.
Data Analysis and Interpretation – Quantifying Impact Strength
- Izod impact strength (notched) – the primary output of the test – The Izod impact strength (in J/m or kJ/m²) is calculated by dividing the impact energy (in J) by the width of the specimen (in m) or by the cross‑sectional area at the notch (in m²). The width is the distance from the notch to the opposite edge. A high impact strength indicates good toughness; a low impact strength indicates a brittle material.
- Statistical analysis – for batch‑to‑batch consistency – For multiple specimens, we report the mean impact strength, the standard deviation, and the coefficient of variation (CV). A CV of less than 10 % is considered acceptable for Izod testing.
- Temperature dependence – for assessing cold‑climate performance – We compare the impact strength at room temperature with the impact strength at sub‑zero temperatures (e.g., -20 °C, -40 °C). A significant reduction in impact strength (> 30 %) indicates a ductile‑to‑brittle transition and a risk of brittle failure in cold climates.
- Comparison with specified requirements – for material qualification – We compare the measured Izod impact strength with the specified minimum value (e.g., as per the material standard or the product specification). A clear pass/fail verdict is provided.
Regulatory Compliance and Product Certification – Supporting Industry Standards
Our notch impact strength testing services are performed in accordance with the most widely used international and national standards. The most commonly requested include:
- ASTM D256 – Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics – the primary North American standard for Izod impact testing
- ISO 180 – Plastics – Determination of Izod impact strength – the international standard for Izod impact testing
- EN ISO 180 – European standard for Izod impact testing – for European market access
- GB/T 1843 – Plastics – Determination of Izod impact strength – the Chinese national standard for Izod impact testing
- ASTM D618 – Standard Practice for Conditioning Plastics for Testing – for specimen conditioning
- ISO 291 – Plastics – Standard atmospheres for conditioning and testing – for specimen conditioning
Report Acceptance and Regulatory Recognition
All Izod impact tests are conducted under our ISO/IEC 17025 accreditation, using calibrated pendulum impact testers, notch cutters, and temperature chambers, all traceable to national and international reference standards. Our final test reports include: a complete description of the test article (material, dimensions, notch geometry, manufacturer), the test method and conditions (temperature, pendulum energy, conditioning), the measured parameters (impact energy, Izod impact strength, failure mode), a statistical summary (mean, standard deviation, coefficient of variation), and a clear pass/fail verdict against your specified acceptance criteria. These reports are accepted by the National Medical Products Administration (NMPA), the State Administration for Market Regulation (SAMR), the Ministry of Industry and Information Technology (MIIT), and international certification bodies for product registration, type approval, and quality assurance. Bilingual (English/Chinese) versions are available to facilitate submissions to domestic and international authorities and to support your global market access.
