ISO 20753:2018

This document specifies dimensional requirements relating to test specimens prepared from plastics materials intended for processing by moulding, as well as to test specimens prepared by machining from sheets or shaped articles. It compiles the designations and dimensions of test specimens used for the acquisition of comparable data and also of other frequently used specimens.

The following types of test specimen are specified:

a) Type A1 and type A2 specimens (1 = injection moulded, 2 = machined from a sheet or shaped article)

These are tensile test specimens from which, with simple machining, specimens for a variety of other tests can be taken (see Annex A).

The type A1 specimen is a multipurpose test specimen. The principal advantage of a multipurpose test specimen is that it allows all the test methods mentioned in Annex A to be carried out by all test laboratories on the basis of comparable mouldings. Consequently, the properties measured are coherent as all are measured using similar specimens prepared in the same way. In other words, it can be expected that test results for a given set of specimens will not vary appreciably due to unintentionally different moulding conditions. On the other hand, if desired, the influence of moulding conditions and/or different states of the specimens can be assessed without difficulty for all of the properties measured.

Also described are reduced-scale test specimens designated type Axy, where x is the number indicating the method of specimen preparation (1 = injection moulded, 2 = machined from a sheet or shaped article) and y is a number indicating the scale factor (1:y). These can be used e.g. when full-sized test specimens are not convenient or when sample material exists in small quantities only.

b) Type B specimens

These are bar specimens which can be directly moulded or can be machined from the central section of type A1 specimens or from sheets or shaped articles.

c) Type C specimens

These are small tensile test specimens which can be directly moulded or machined, e.g. from plates (Type D or type F specimens), from the central section of type A1 specimens or from sheets or shaped articles.

d) Type D1 and type D2 specimens

These are square plates of thickness 1 mm and 2 mm, respectively.

e) Type F specimens

These are rectangular plates intended for use in the analysis of mechanical anisotropy.

If a particular type of test specimen is not mentioned in this document, this does not mean that there is any intention to exclude the use of the specimen. Additional specimen types can be added in future if they are commonly used.