ISO 294-4:2018 PDF

Plastics — Injection moulding of test specimens of thermoplastic materials — Part 4: Determination of moulding shrinkage

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Title (English):

ISO 294-4:2018

Plastics — Injection moulding of test specimens of thermoplastic materials — Part 4: Determination of moulding shrinkage

Document status:: Active
Format:: Electronic (PDF)
Number of pages:: 9
Publication date:: December 20, 2018
Edition:: ISO IS 294 edition 3 version 1
ICS:: 83.080.20

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Description (English):

This document specifies a method of determining the moulding shrinkage and post-moulding shrinkage of injection-moulded test specimens of thermoplastic material in the directions parallel to and normal to the direction of melt flow. For the determination of shrinkage of thermosets, see ISO 2577[2]. Moulding shrinkage as defined in this document excludes the effects of humidity uptake. This is included in post-moulding shrinkage and thus in total shrinkage. For cases when post-moulding shrinkage is caused by the uptake of humidity only, see ISO 175[1]. Moulding shrinkage as defined in this document represents the so-called free shrinkage with unrestricted deformation of the cooling plates in the mould during the hold period. It is considered, therefore, as the maximum value of any restricted shrinkage.

Technical details

Technical committee: ISO/TC 61/SC 9 - Thermoplastic materials
SKU: ISO 294-4:2018

Abstract

Overview

ISO 294-4:2018 - Plastics - Injection moulding of test specimens of thermoplastic materials - Part 4: Determination of moulding shrinkage specifies a standardized method to measure moulding shrinkage, post‑moulding shrinkage and total shrinkage of injection‑moulded thermoplastic test specimens in directions parallel and normal to melt flow. The third edition (2018) updates referenced documents and integrates measurement, apparatus and procedural requirements for reproducible shrinkage data used in material comparison, process control and quality assurance.

Key topics and technical requirements

Scope and definitions: Clear definitions of moulding shrinkage (excludes humidity uptake), post‑moulding shrinkage (includes humidity effects), and total shrinkage.
Test specimen and mould: Uses a Type D2 ISO mould producing 60 × 60 × 2 mm plates (see ISO 294‑3). Reference marks may be engraved at (4 ± 1) mm from cavity edges; marks should be ≤ 5 µm deep to avoid restricting shrinkage.
Apparatus:
- Pressure sensor in the mould is mandatory (cavity pressure measurement).
- Measuring equipment must resolve dimensions to within 0.02 mm (measure between centre lines, edges or reference marks).
- Oven required only if post‑moulding shrinkage testing is agreed.
Injection and pressure control:
- Recommended cavity pressures at hold: 20, 40, 60, 80 and 100 MPa (intermediate values allowed).
- Tolerance for cavity pressure: ±5%.
- Hold pressure and change‑over point must be selected to avoid pressure peaks that exceed hold pressure by more than 10% during the first second after change‑over.
Procedure elements: Material conditioning, injection moulding parameters, measurement of mould and melt temperatures, specimen handling (cut from runner immediately) and storage at (23 ± 2) °C for 16–24 h before measurement.
Measurement notes: Include the 0.5 mm gate step when measuring length; ensure jaws of mechanical gauges do not indent specimens.
Reporting: Expression of results, precision, and test report requirements are specified (see Clauses 6–8).

Applications and users

ISO 294‑4:2018 is used by:

Polymer materials laboratories and test houses for material comparison (shrinkage behavior).
Injection‑moulding process engineers for process optimization (melt/mould temperature, hold pressure, change‑over timing).
Quality engineers and manufacturers for production control and verifying moulding consistency.
R&D and materials selection teams assessing suitability of thermoplastics for dimensionally accurate parts.

Note: the method measures free shrinkage (maximum unrestricted shrinkage) and is intended for comparison and process insight rather than direct design calculations.

Related standards

ISO 294‑1:2017 (general principles)
ISO 294‑3:2002 (small plates / Type D2 mould)
ISO 2577 (thermosets shrinkage)
ISO 175 (humidity‑induced dimensional changes)

Related standards

Standards mentioned in the description

Abstract

Overview

Key topics and technical requirements

Scope and definitions: Clear definitions of moulding shrinkage (excludes humidity uptake), post‑moulding shrinkage (includes humidity effects), and total shrinkage.
Test specimen and mould: Uses a Type D2 ISO mould producing 60 × 60 × 2 mm plates (see ISO 294‑3). Reference marks may be engraved at (4 ± 1) mm from cavity edges; marks should be ≤ 5 µm deep to avoid restricting shrinkage.
Apparatus:
- Pressure sensor in the mould is mandatory (cavity pressure measurement).
- Measuring equipment must resolve dimensions to within 0.02 mm (measure between centre lines, edges or reference marks).
- Oven required only if post‑moulding shrinkage testing is agreed.
Injection and pressure control:
- Recommended cavity pressures at hold: 20, 40, 60, 80 and 100 MPa (intermediate values allowed).
- Tolerance for cavity pressure: ±5%.
- Hold pressure and change‑over point must be selected to avoid pressure peaks that exceed hold pressure by more than 10% during the first second after change‑over.
Procedure elements: Material conditioning, injection moulding parameters, measurement of mould and melt temperatures, specimen handling (cut from runner immediately) and storage at (23 ± 2) °C for 16–24 h before measurement.
Measurement notes: Include the 0.5 mm gate step when measuring length; ensure jaws of mechanical gauges do not indent specimens.
Reporting: Expression of results, precision, and test report requirements are specified (see Clauses 6–8).

Applications and users

ISO 294‑4:2018 is used by:

Polymer materials laboratories and test houses for material comparison (shrinkage behavior).
Injection‑moulding process engineers for process optimization (melt/mould temperature, hold pressure, change‑over timing).
Quality engineers and manufacturers for production control and verifying moulding consistency.
R&D and materials selection teams assessing suitability of thermoplastics for dimensionally accurate parts.

Note: the method measures free shrinkage (maximum unrestricted shrinkage) and is intended for comparison and process insight rather than direct design calculations.

Related standards

ISO 294‑1:2017 (general principles)
ISO 294‑3:2002 (small plates / Type D2 mould)
ISO 2577 (thermosets shrinkage)
ISO 175 (humidity‑induced dimensional changes)

ISO 294-4:2018 PDF

Technical details

Abstract

Overview

Key topics and technical requirements

Applications and users

Related standards

Related standards

Abstract

Overview

Key topics and technical requirements

Applications and users

Related standards

Related standards

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