ISO 179

ISO 179 provides guidelines on how to measure the impact resistance of plastic materials using the Charpy pendulum impact test. This test determines how much energy a material can absorb before breaking when struck by a swinging pendulum, with the specimen supported horizontally at both ends.

Purpose of ISO 179 Testing:

• It establishes a consistent methodology for assessing how plastic materials behave when subjected to sudden impact forces.
• The test involves placing a notched or unnotched specimen horizontally on two supports and striking it at the center with a calibrated pendulum hammer, measuring the energy absorbed during fracture.
• The Charpy impact strength indicates the material's toughness and ability to resist shock loading, with higher values indicating better impact resistance and ductility.
• The test differs from Izod (ISO 180) in specimen orientation: Charpy supports the specimen horizontally as a simply supported beam, while Izod holds it vertically like a cantilever beam.
• Having a standardized test method ensures results are reproducible and comparable across different laboratories and manufacturers.

Application to 3D Printing Filament:

• Many 3D printing filaments are made of plastics (like PLA, ABS, PETG, and others). Understanding impact resistance is crucial for applications where parts might experience sudden forces, drops, or collisions.
• Manufacturers can use ISO 179 testing to verify that their filament can withstand impact loads without brittle failure, ensuring consistent performance in applications requiring toughness and energy absorption.
• Designers and engineers might test 3D printed parts (or the filament itself) according to ISO 179 standards to validate performance in applications where impact resistance is critical, such as protective enclosures, consumer products, or structural components subject to shock loads.
• The standardized nature of ISO 179 testing helps in comparing different filament brands or formulations, ensuring that the material's behavior under impact is predictable, which is especially important for parts that must survive accidental impacts, rough handling, or operational shocks.

Benefits for 3D Printing and End Users:

• Quality Control: It allows filament producers to verify that their material can absorb impact energy effectively, distinguishing between brittle materials that shatter and tough materials that deform or bend without breaking.
• Material Selection: Users can review ISO 179 results (if available) to choose a filament with adequate impact resistance for their specific application, whether it's a consumer product, protective housing, or mechanical assembly.
• Predictable Performance: Understanding the Charpy impact strength ensures that 3D printed parts will resist sudden impacts and maintain structural integrity under shock loads, which is critical for durable goods, safety equipment, and parts subject to dynamic loading.

References

Read more about ISO 179 on the ISO's website.