Density Testing Protocols under ISO 1183 for Customs Classification
ISO 1183 density testing determines customs tariff lines under Chapter 39; accurate classification demands exact fluid temperature control and plaque molding.
ISO 293 Plaque Compression Molding
Meaning
A specimen preparation method uses heat and pressure to form plastic plaques from pellets or powder for subsequent physical testing. Utilizing iso 293 plaque compression molding creates samples with a known thermal history and minimal internal stress compared to injection moulding. It is the preferred technique for preparing specimens for density and crystallinity tests where a neutral baseline is required.
Thermal Cycle
The resin is heated between two metal plates until it reaches a fully molten state. Following the heating phase, iso 293 plaque compression molding requires a controlled cooling rate to ensure the polymer chains organize consistently. This cooling step is the most critical part of the process because it determines the final degree of crystallinity in the plaque.
Pressure Application
High force is applied to the mould to ensure that the material fills the cavity and that all air is expelled. During iso 293 plaque compression molding, the pressure must be maintained throughout the cooling phase to prevent the formation of sink marks or voids. This ensures that the resulting plaque has a uniform density and thickness across its entire surface.
Plaque Integrity
The absence of flow-induced orientation makes these samples ideal for measuring the inherent properties of the resin. Samples produced via iso 293 plaque compression molding provide a more accurate representation of the raw material than parts with complex flow paths. This method allows for a direct comparison of different polymer batches without the interference of the shear forces found in injection moulding.
Consistent plaque quality is the foundation of all reliable material characterisation in the plastics industry.