Overview
ISO 295:2004 - "Plastics - Compression moulding of test specimens of thermosetting materials" defines the general principles and procedures for preparing test specimens by compression moulding from thermosetting powder moulding compounds (PMCs). The standard covers specimen preparation, mould design guidance, equipment and measurement requirements, and the information to be recorded in the moulding report. It applies to PMCs based on phenolic resin, aminoplastic, melamine/phenol, epoxy and unsaturated polyester systems, and is intended to ensure reproducible, comparable test results across laboratories and suppliers.
Key topics and requirements
- Scope and applicability: Applies to heat- and pressure-moulded thermosetting PMCs; special methods for atypical materials must be agreed and recorded.
- Mould design: Guidance for single- and multi-cavity moulds (recommended “type E ISO 295” plate 120 × 120 mm), cavity finish and geometry (surface roughness Ra 0.4–0.8 µm, edge-taper ≤ 3°, clearance ≤ 0.1 mm).
- Apparatus and controls: Requirements for compression presses, heating devices and temperature adjustment with spatial/temporal uniformity within ±3 °C. Preferred press closing speeds (fast approach and slow final close) and ability to close within 15 s before pressurization are noted.
- Specimen preparation: Conditioning and storage of moulding powders, charge preparation (pelletizing if needed), pre-treatment and moulding conditions per material-specific ISO standards.
- Measurement and reporting: Use of calibrated devices (stopwatch 1 s, balance 0.1 g, pyrometers/fusible salts). The standard specifies the content of the moulding report to document conditions that affect test-property results.
- Cooling and handling: Use of a cooling fixture to prevent warping on removal; avoidance of specimen damage during ejection.
Practical applications - who uses it
- Quality control and materials laboratories performing mechanical, thermal or electrical testing of thermoset PMCs.
- R&D teams developing resin formulations and processing parameters.
- Manufacturers and suppliers specifying contract test methods to ensure comparable results.
- Certification and accreditation bodies that require standardized specimen preparation procedures.
Using ISO 295:2004 helps ensure consistent specimen quality, traceable moulding conditions and reliable inter-laboratory comparison of thermosetting material properties.
Related standards
- ISO 3167 - Multipurpose test specimens
- ISO 4287 - Surface texture (profile method)
- ISO 472, ISO 1183 - Plastics vocabulary and density methods
- Material-specific series: ISO 14526, 14527, 14528, 14529, 14530 and ISO 15252 (phenolic, aminoplastic, melamine/phenol, unsaturated-polyester, epoxy PMCs)
Keywords: ISO 295:2004, compression moulding, thermosetting materials, PMCs, test specimen preparation, mould design, moulding report.