ISO 20457 differentiates between dimensions formed by a single mold element and those affected by moving tool components:
“That’s a million dollars in scrapped fuselage brackets for Airbus,” Kenji said. “And for this?” He tapped the femur. “That’s a six-month surgical delay for a seven-year-old in Osaka.” Iso 20457 Tg5
: The environmental state (typically 23°C and 50% relative humidity) at which the part must be measured. Datum Scheme : The reference points used for measurement. ISO 20457 differentiates between dimensions formed by a
In injection molding, dimensions are split into tool-specific (dimensions formed within a single mold half or core) and non-tool-specific (dimensions crossing a moving mold parting line or slider). Tg5 explicitly dictates the permissible symmetrical limit deviation based on the nominal dimension size of the part. Nominal Dimension Range (mm) Tg5 Symmetrical Limit Deviation (± mm)* Typical IT Grade Mapping ± 0.05 mm to ± 0.08 mm IT11 / IT12 6 mm to 30 mm ± 0.10 mm to ± 0.15 mm IT12 / IT13 30 mm to 120 mm ± 0.18 mm to ± 0.25 mm IT13 / IT14 120 mm to 400 mm ± 0.30 mm to ± 0.50 mm IT14 / IT15 Datum Scheme : The reference points used for measurement
B -->|Rubber Molding| ERefer to ISO 3302 E -->|Most tech. parts| F[M3 is typical]
Molding material characteristics (amorphous vs. semi-crystalline polymers). Tooling design and manufacturing accuracy. Process stability during injection molding. Decoding the "TG5" Classification