Overview
ISO 2577:2007 specifies a standardized method for determining moulding shrinkage and post-shrinkage of thermosetting moulding materials. The method applies to moulded test specimens produced by compression or injection moulding and provides reproducible procedures and reporting requirements useful for production control, mould design and assessment of dimensional accuracy for finished mouldings.
Key topics and requirements
- Scope: Measurement of initial shrinkage (difference between mould cavity and moulding at normal temperature) and shrinkage after heat treatment (post-shrinkage).
- Test specimens:
- Compression-moulded bars: 120 mm × 15 mm × 10 mm.
- Injection-moulded plates: ~60 mm × 60 mm × 2 mm (ISO D2 mould per ISO 10724-2).
- Moulding conditions: Follow ISO 295 for compression moulding and ISO 10724-1/2 for injection moulding procedures and parameters.
- Measurement accuracy and environment: Lengths measured to 0.02 mm at 23 °C ± 2 °C (relative humidity 45–55 % for storage). Mould and specimens must be measured under the same temperature conditions.
- Post-shrinkage heat treatment: Oven temperatures - 80 °C ± 2 °C for urea‑formaldehyde materials; 110 °C ± 3 °C for other thermosets. Exposure times: 48 h (rapid) or 168 h (normal).
- Acceptance and data handling: Discard specimens with warp > 1 % of length. Calculate moulding shrinkage (MS) and post-shrinkage (PS) as percentage differences between mould cavity and specimen dimensions; report individual values and arithmetic means.
- Required measurements and reporting: Include mould identification, material grade, moulding method and conditions, number of discarded specimens, heat‑treatment conditions, MS and PS values, measurement directions (for injection-moulded plates), dates of moulding and measurements.
Applications and users
ISO 2577:2007 is used by:
- Material manufacturers for production control and batch uniformity checks of thermosetting compounds.
- Quality control and testing laboratories performing standardized shrinkage testing and documenting results for specifications.
- Mould and tool designers who need accurate initial shrinkage data to dimension cavities and allow for compensation.
- Product engineers and OEMs assessing suitability of a thermosetting material for producing components with tight dimensional tolerances.
- Procurement and compliance teams specifying shrinkage performance in material or supplier contracts.
Practical benefits include improved mould design, reduced rejects, and reliable data for tolerance calculations when using thermosetting moulding materials.
Related standards
- ISO 295 - Compression moulding of test specimens of thermosetting materials.
- ISO 10724-1 - Injection moulding of thermosetting powder moulding compounds - General principles.
- ISO 10724-2 - Injection moulding - Small plates (D2 mould).
