Impacts up to 50 J to establish specimens resistance

13 April 2016

The range of instruments offered by Noselab ATS to perform physical-mechanical tests on plastics includes the Impact pendulum, available for impact energies up to 15, 25 and 50 J.

The method used by this machine is based on the determination of the necessary energy to break a specimen under given conditions. Given the potential energy of the hammer, which varies depending on its shape, weight and release angle, the energy absorbed by the broken specimen can be determined by measuring the ascent angle of the hammer after the impact. The methods commonly used to perform this test are the Charpy, Izod and Tensile Impact methods, and differ among themselves in the way the specimen is mounted and how it is impacted.

In the tests performed with the Charpy method, the rectangular-shaped specimen is positioned horizontally and is broken with one oscillation of the hammer only; the impact line is centred between the two specimen supports. According to the Izod method, the rectangular-shaped specimen is blocked at one end in vertical position and is broken with one oscillation of the hammer only; the impact line is at a fixed distance from the blocked end of the specimen. Finally, in the tensile impact tests, the usually dumb bell-shaped specimen is inserted in two blocking brackets and is broken with only one oscillation of the hammer, which stresses the specimen along its longitudinal axis.

The main features of this instrument include:

- a casting mainframe which contains all electric and mechanical devices

- electronic crosswise levelling system

- centring system for Charpy specimens

- safety systems: double “pull” type hammer release; side safety shield (polycarbonate); braking system for slowing down the descent of the hammer after the impact

- user interface with touch-screen display (7-inches) for entering test parameters and displaying the energy and resilience values after the impact

- auto-test of the main functions when switching on and troubleshooting coding

- USB port for connection to PC

- automatic display of the ascent angle and of both the potential energy and actual speed of the impact

Noselab ATS manufactures a wide range of hammers, in order to meet the standard requirements in force for the various test methods. Correct positioning of the hammers in their seat is guaranteed by a pin mounted on the top of them. A correct calibration makes the installation of mounting adapters on their upper part unnecessary. Standard hammers, regardless of the test method they are designed for, cover an impact energy range up to 25 Joules, while shoulders and spacers for Charpy impact tests can be positioned in their seats with no possibility of errors. The seats, designed in strict accordance with the standards, are manufactured directly from the pendulum’s structure, in order to guarantee the necessary rigidity during the impact, while the centring tool installed on the instrument guarantees the exact positioning of the Charpy specimen. The Izod tests can be performed with a standard or fast clamping vice; the latter is equipped for entering notched specimens, and guarantees a constant pressure on it, in accordance with the standards.