BS EN ISO 20753:2014 pdf free
BS EN ISO 20753:2014 pdf free.Plastics – Test specimens
Test specimens shall be prepared in accordance with the relevant material specification. When none exists,specimens shall be either directly compression or injection moulded from the material in accordance with ISO 293, ISO 294-1, ISO 295 or ISO 10724-1, as appropriate, or machined in accordance with ISO 2818 from sheets that have been compression or injection moulded from the compound, extruded from the compound or polymerized and cast.
Strict control of all the specimen preparation conditions is essential to ensure that all test specimens in a set are in the same state.
All surfaces of the test specimens shall be free from visible flaws, scratches or other imperfections. With moulded specimens, any flash present shall be completely removed, taking care not to damage the moulded surface.
The broad sides of multipurpose test specimens shall be suitably marked (see Note), for injection-moulded specimens to distinguish between the sides formed by the cavity plate and the fixed plate of the mould (see ISO 294-1 or ISO 10724-1)，for compression-moulded and machined specimens to identify any asymmetry resulting from the underlying moulding process.
For injection-moulded specimens, the sides can be identified by the impressions of the ejection pins and by the draft angle. Compression-moulded and machined specimens shall be marked at their shoulders. ISO bars taken from the central section of multipurpose test specimens shall be marked outside their central 64 mm section, which is loaded during flexural testing.
NOTE Asymmetry with respect to thickness may influence the flexural properties, including the temperature of deflection under load (see Annex A).
Test specimens shall be injection moulded as specified in ISO 294-1 or ISO 10724-1, as appropriate, and under the conditions defined in the relevant International Standard for the material under examination or, if no such standard exists, as recommended by the manufacturer of the material or as agreed upon between the interested parties.BS EN ISO 20753 pdf download.
