Introduction:
A plastic three-point bending fixture is a precision testing attachment designed for universal testing machines, used to determine the flexural properties (including flexural strength, flexural modulus, and strain) of rigid and semi-rigid plastic materials, composites, and electrical insulating materials. Operating on the principle of central loading, it securely supports a rectangular test specimen on two parallel, hardened steel rollers while a third, identical roller applies a controlled downward force at the midpoint, inducing controlled bending until fracture or a specified strain limit is reached. Fully compliant with international standards such as ASTM D790 and ISO 178, it features an adjustable support span to accommodate various sample sizes, ensuring accurate alignment and consistent, repeatable test data for quality control and material research in plastics engineering.