The ISO 1133-1 standard specifies methods for determining the flow properties of thermoplastic materials under defined conditions of temperature and load. These tests are conducted using a melt flow tester, where polymer granules are heated and extruded through a die. The primary goal is to measure the material’s melt viscosity and assess its processability. These tests are essential for R&D and quality control in polymer processing, providing critical data on melt and processing behavior that influences extrusion, injection molding, and other manufacturing techniques.