Overview

Many factors in the injection-moulding process influence the properties of moulded test specimens and hence the measured values obtained when the specimens are used in a test method. The mechanical properties of such specimens are strongly dependent on the conditions of the moulding process used to prepare the specimens. Exact definition of each of the main parameters of the moulding process is a basic requirement for reproducible and comparable operating conditions. It is important in defining moulding conditions to consider any influence the conditions may have on the properties to be determined. Thermoplastics exhibit differences in molecular orientation in crystallization morphology (for crystalline and semicrystalline polymers), in phase morphology (for heterogeneous thermoplastics) as well as in the orientation of anisotropic fillers such as short fibres. Residual ("frozen-in") stresses in the moulded test specimens and thermal degradation of the polymer during moulding also influence properties. Each of these phenomena shall be controlled to minimize variability of the numerical values of the properties measured. This document specifies the general principles to be followed when injection moulding test specimens of thermoplastic materials and gives details of mould designs for preparing two types of specimen for use in acquiring reference data, that is type A1 and type B1 test specimens as specified in ISO 20753, and provides a basis for establishing reproducible moulding conditions. Its purpose is to provide consistent descriptions of the main parameters of the moulding process and to establish a uniform practice in reporting moulding conditions. The particular conditions required for the reproducible preparation of test specimens will vary for each material used and are given in the International Standard for the relevant material or are to be agreed upon between the interested parties. The responsible committee for this standard is NA 054-01-02 AA "Mechanische Eigenschaften und Probekörperherstellung" ("Mechanical properties and preparation of test specimens") at DIN Standards Committee Plastics (FNK).

Document: references other documents

Document: referenced in other documents

Responsible national committee

NA 054-01-02 AA - Mechanical properties and preparation of test specimens  

Responsible european committee

CEN/TC 249 - Plastics  

Responsible international committee

ISO/TC 61/SC 9/WG 18 - Preparation of test specimens