Overview
EN ISO 294-2:2018 - Plastics - Injection moulding of test specimens of thermoplastic materials - Part 2: Small tensile bars specifies the design and use of a four‑cavity type C ISO mould for producing small tensile bars (type CW11 in ISO 20753). The standard covers mould geometry, dimensional tolerances and practical moulding guidance to ensure reproducible test specimens of at least 60 mm × 10 mm × 3 mm (thickness 3.0 mm ± 0.2 mm). It is intended for preparing indicative specimens used when assessing environmental effects (chemicals, heat, weathering) on thermoplastic materials.
Key topics and technical requirements
- Mould configuration: Four‑cavity type C ISO mould with a double‑T runner; main cavity geometry and features specified (see Figure in the standard).
- Specimen size and tolerance: CW11 specimen dimensions per ISO 20753; thickness specified as 3.0 mm ± 0.2 mm and cavity depth 3.0–3.2 mm.
- Runners and gates: Low critical cross‑sectional area (~9 mm²) affects melt flow behavior compared with larger type A moulds (~40 mm²).
- Injection parameters: Recommends choosing injection velocity so that the injection time is comparable to that used for a type A ISO mould; for the type C mould this typically requires a higher injection velocity (about twice that for type A) to avoid low melt speed and temperature in runners.
- Machine requirements: Minimum locking force guidance is provided (example: 440 kN for a maximum melt pressure of 80 MPa).
- Procedure and conditioning: Material conditioning, injection moulding procedure and reporting follow ISO 294‑1:2017 with the Part 2 additions.
- Reporting: Test‑specimen preparation report must reference ISO 294‑2:2018 and include information per ISO 294‑1 (moulding conditions, material conditioning, machine data, etc.).
Applications
- Producing standardized small tensile bars for mechanical testing and indicative property evaluations after environmental exposure (chemical resistance, ageing, weathering).
- Ensuring consistent specimen preparation for comparative studies, material qualification, R&D and quality control of thermoplastic materials.
- Useful in laboratories and production settings where reproducible specimen geometry and moulding practice are required for standardized testing.
Who should use this standard
- Materials test laboratories and quality control teams working with thermoplastics.
- Mold designers and tooling engineers producing ISO test moulds.
- R&D engineers conducting environmental exposure and comparative mechanical testing.
- Manufacturers and certification bodies requiring standardized specimen preparation.
Related standards
- ISO 294‑1:2017 - General principles and moulding of multipurpose and bar test specimens
- ISO 20753 - Test specimen types (defines CW11)
- ISO 11403‑3 - Environmental influences on properties (context for “indicative” testing)
Keywords: EN ISO 294-2:2018, injection moulding, small tensile bars, type C ISO mould, thermoplastic materials, CW11 specimen, ISO 20753, specimen preparation.
