Dimensions formed by moving parts of the mold, such as parting lines, slider mechanisms, or core pulls. These require wider tolerances to account for shifting or flexing during the high-pressure injection process. How to Apply ISO 20457 to Your Drawing
You can purchase the official standard from national bodies:
Because ISO 20457 is a copyrighted standard, full official tables are typically accessed through authorized distributors or summarized by manufacturers. You can find detailed overviews and downloadable PDF guides at the following sources:
For engineers, quality managers, and procurement professionals working with injection-molded plastic parts, precision is everything. However, the properties of plastics—from material shrinkage to thermal expansion—make them fundamentally different from machined metals. Applying metal tolerances to plastic parts inevitably leads to costly rework, rejected shipments, and strained supplier relationships. This is where comes into play. iso 20457 tolerance table pdf
It is important to note that ISO standards are proprietary documents. While you may find snippets or summaries online, obtaining the official, complete generally requires purchasing the standard from:
): Dimensions affected by moving parts of the mold, such as the parting line, sliders, lifters, or cores. They require larger tolerances due to tool shifting or clamping variations. ISO 20457 Tolerance Grades (TG1 to TG9)
ISO 20457 (and its German equivalent DIN 16742) is the definitive global standard for manufacturing tolerances and acceptance conditions of plastic molded parts Dimensions formed by moving parts of the mold,
The standard applies to non-porous molded parts made from thermoplastics, thermoplastic elastomers, and thermosets. If agreed upon by contractual parties, the standard can also be applied to other plastic processes.
The ISO 20457 tolerance table, found within the standard’s PDF, is a cornerstone of modern geometric product specification. It translates the abstract concept of “general tolerance” into specific, actionable numbers for linear dimensions, angles, flatness, straightness, perpendicularity, and runout. By organizing these values into four clear classes (f, m, c, v), the standard balances manufacturing economy with functional assurance. For any design engineer or manufacturing professional, understanding how to read and apply the tables in ISO 20457 is not a niche skill—it is a fundamental practice that turns a drawing into a reliable, producible product.
Used for highly flexible materials or parts where dimensional precision is not critical to function. You can find detailed overviews and downloadable PDF
Whether you are a veteran designer or new to plastic part manufacturing, gaining a thorough understanding of and access to the ISO 20457 tolerance table PDF is not just a best practice—it is a necessity for modern, competitive manufacturing.
As the nominal size of the part increases, the allowable tolerance window expands to accommodate the higher volume of material shrinkage. Simplified Preview of an ISO 20457 Tolerance Table