The standard provides a systematic way to determine achievable tolerances based on the combination of material properties, molding processes, and part geometry. It primarily covers: Dimensional Tolerances : General tolerances for linear and angular dimensions. Geometrical Tolerances : Surface profile and position deviations. Acceptance Conditions : Specific environment requirements, such as measuring at 23 raised to the composed with power cap C 50% relative humidity , to ensure consistency across different facilities. ISO - International Organization for Standardization Tolerance Groups (TG) Breakdown The ISO 20457 tolerance table is organized into Tolerance Groups (TG) , typically ranging from TG1 to TG9 . These groups correlate to the ISO 286 IT grades used in metal machining. ResearchGate ISO 20457:2018(en), Plastics moulded parts
Searching for an typically means you want immediate access to these numerical values without purchasing the full 30-page document. However, understanding the logic behind the table is essential before applying any numbers. iso 20457 tolerance table pdf