Plastics behave differently based on their molecular structure.
Key structure of the tolerance table (typical elements)
ISO 20457 splits deviations into two distinct categories, which are combined to create the final total tolerance: Mold Making Tolerances ( AWcap A sub cap W iso 20457 tolerance table pdf
The most common tolerance group for standard industrial injection molding.
Transitioning from metal design to plastic injection molding requires a shift in how you approach tolerances. Utilizing ISO 20457 ensures that your production team, mold maker, and quality control inspectors are operating under the same realistic, globally accepted baseline. Utilizing ISO 20457 ensures that your production team,
Read the corresponding plus/minus ( ±plus or minus ) value in millimeters. Simplified ISO 20457 Tolerance Lookup
| Standard | Material Focus | Key Feature | |----------|----------------|--------------| | ISO 20457 | Plastics (moulded) | PT grades, parting line allowances | | ISO 286 | Metals / machined | IT grades, very tight | | ISO 2768 (general tolerances) | Metals & plastics (vague) | Often too tight for plastics | | DIN 16901 | Old German standard for plastics | Replaced by ISO 20457 in 2020 | Instead, it categorizes tolerances based on two primary
An ISO 20457 tolerance table does not just give a single flat rate for deviations. Instead, it categorizes tolerances based on two primary factors: and Nominal Dimensions . 1. Tolerance Groups (TG)
The standard helps engineers and manufacturers align on realistic dimensional expectations, preventing the over-specification of tight tolerances that unnecessarily drive up tooling and production costs. 2. Key Factors Determining Plastic Tolerances