This International Standard specifies methods for the determination of puncture-impact properties of rigid plastics in the form of flat test specimens, such as discs or square pieces, under defined conditions. Specimens may be moulded directly, cut from sheets or taken from finished products. Different types of test specimens and test conditions are defined.
These falling-dart methods are used to investigate the behaviour of plastic sheeting or mouldings under the impact of a striker applied perpendicular to the plane of the specimen.
This part of ISO 6603 can be used if it is sufficient to characterize the impact behaviour of plastics by a threshold value of impact-failure energy based on many test specimens. ISO 6603-2 is used if a force-deflection or force-time diagram, recorded at nominally constant striker velocity, is necessary for detailed characterization of the impact behaviour.
These test methods are applicable to specimens with a thickness between 1 mm and 4 mm.
NOTE For thicknesses less than 1 mm, ISO 7765 should preferably be used. Thicknesses greater than 4 mm may be tested if the equipment is suitable, but the test falls outside the scope of ISO 6603-1 and ISO 6603-2.
These methods are suitable for use with the following types of material: rigid thermoplastic moulding and extrusion materials, including filled, unfilled and reinforced compounds and sheets; rigid thermosetting moulding and extrusion materials, including filled and reinforced compounds, sheets and laminates; fibre-reinforced thermoset and thermoplastic composites incorporating unidirectional or non-unidirectional reinforcements such as mats, woven fabrics, woven rovings, chopped strands, combination and hybrid reinforcements, rovings, milled fibres and sheets made from pre-impregnated materials (prepregs).
These methods are also applicable to specimens which are either moulded or machined from finished products, laminates and extruded or cast sheet.
The test results are comparable only if the conditions of preparation of the specimens, their dimensions and surfaces as well as the test conditions are the same. In particular, results determined on specimens of different thickness cannot be compared with one another (see annex E of ISO 6603-2:—). Comprehensive evaluation of the reaction to impact stress requires that determinations be made as a function of impact velocity and temperature for different material variables, such as crystallinity and moisture content.
The impact behaviour of finished products cannot be predicted directly from this test, but specimens may be taken from finished products (see above) for test by these methods.
Test data developed by these methods should not be used for design calculations. However, information on the typical behaviour of the material can be obtained by testing at different temperatures and impact velocities (see annex D of ISO 6603-2:—), by varying the thickness (see annex E of ISO 6603-2:—) and by testing specimens prepared under different conditions.
Two statistical methods of test are described in this part of ISO 6603:
Method A: staircase method (individual) (preferred)
In this method, a uniform energy increment is employed during testing. The energy is decreased or increased by the uniform increment after testing each specimen, depending upon the observed result (pass or fail) for the preceding test.
Method B: group method (optional)
In this method, successive groups of at least ten test specimens are tested. The impact failure energy is calculated by statistics.