Short answer: There is no single static "ISO 20457 tolerance table PDF" like you would find for ISO 2768 (general tolerances). Instead, ISO 20457 gives you the method to create your own tolerance tables.
If you are looking for a ready-made PDF of standard tolerance classes (fine, medium, coarse) with numerical values for linear dimensions, angles, or GD&T — you might be thinking of ISO 2768-1 or ISO 286.
Let’s break down what ISO 20457 really is, and where to get the correct tolerance information for your drawings.
To get the official ISO 20457 tolerance table PDF:
Would you also like a comparison table between ISO 20457 and the older DIN 16901, or a sample drawing note for applying these tolerances?
The ISO 20457 standard (formerly DIN 16742) defines the manufacturing tolerances and acceptance conditions for plastic molded parts. It is primarily used to align expectations between designers and manufacturers regarding dimensional accuracy in injection molding and other plastic processes. Key Tolerance Group: TG6
For general thermoplastics, the standard typically defaults to Tolerance Group 6 (TG6) unless otherwise specified.
Application: General tolerances (Series 1) apply to explicitly drawn dimensions that lack individual tolerance indications.
Typical Note: Engineering drawings often include the note: General tolerances ISO 20457 – TG6. ISO 20457 Tolerance Table Overview
The standard uses two main tables to determine the applicable tolerance: INTERNATIONAL STANDARD ISO 20457
ISO 20457 (and its German equivalent DIN 16742) is the definitive global standard for manufacturing tolerances and acceptance conditions of plastic molded parts
. It replaced older standards like ISO 8062 to better account for the unique properties of plastics—such as shrinkage and thermal expansion—which differ significantly from metals. www.makrolar.eu Core Function of ISO 20457
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
(and its German equivalent DIN ISO 20457 ) is the primary international standard for specifying manufacturing tolerances of plastic molded parts
. It replaces the withdrawn DIN 16901 and DIN 16742 standards, providing a modern framework based on Tolerance Groups (TG) rather than generic fixed values. Key Tolerance Classifications organizes tolerances into Tolerance Groups (TG)
ranging from TG1 to TG10. These groups are further divided into based on production effort: Series 1 (Standard Production):
General tolerances used when dimensional requirements are not the primary quality focus. Series 2 (Accurate Production):
Oriented toward higher dimensional accuracy, requiring more rigorous manufacturing and quality assurance. Series 3 (Precision Production):
For parts requiring extremely tight tolerances, often involving higher production costs and surcharges. Achievable General Tolerances
While exact values depend on material groups (shrinkage rates) and nominal dimensions, typical baseline performance for injection molding includes: Super-Ingenuity Standard Features: plus or minus 0.05 plus or minus 0.15 mm for small to medium parts. Critical Features: plus or minus 0.025 iso 20457 tolerance table pdf
mm, but only for specifically designated critical-to-quality (CTQ) features. Large Parts:
Wider tolerance bands are required due to potential warpage and shrinkage variations. Comparison with ISO 286 The standard correlates its Tolerance Groups (TG) International Tolerance (IT) grades defined in
Lower TG numbers (e.g., TG1–TG4) represent high-precision requirements.
Higher TG numbers (e.g., TG6–TG9) represent lower precision, standard industrial production. OKW Gehäusesysteme Necessary Callout Information
To properly use an ISO 20457 tolerance table, design documentation must specify:
The Tolcap Rough Guide to Tolerancing Plastic Mouldings - Tol
The ISO 20457 standard (which succeeded DIN 16742) provides a standardized framework for tolerances and acceptance conditions for plastic molded parts. It defines tolerance groups (TG) ranging from TG1 to TG9, where lower numbers indicate higher precision. For many standard industrial thermoplastics, TG6 is the commonly used baseline for general tolerances. Key Tolerance Tables and Documents
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:
PolTolerances Guide (Makrolar): A comprehensive 28-page PDF that includes detailed tolerance tables, explanations of dimensional deviations, and the relationship between ISO 20457 and DIN 16742.
OKW Gehäusesysteme Tolerance Overview: Provides a concise technical data sheet focusing on TG6 tolerances for various nominal dimensions.
ISO Official Store: The definitive source to purchase and download the official ISO 20457:2018 PDF for full compliance.
Super Ingenuity Template Library: Offers downloadable quality and tolerance templates, including Excel-based CTQ (Critical to Quality) feature tables and 2D note blocks for ISO 20457-TG6. Understanding the Tolerance Groups (TG)
The tolerance applied to a part depends on both the chosen Tolerance Group and the Nominal Dimension (the size of the feature). Nominal Dimension (mm) TG4 (High Precision) TG6 (Standard/Technical) TG8 (General Purpose) > 10 to 18 > 18 to 30
Note: These values are typical approximations for linear dimensions; refer to the official standard for the full matrix covering all dimensions and specific material groups. Selection Process
ISO 20457 is the current international standard for determining manufacturing tolerances of plastic molded parts. It replaces older standards like ISO 8062 and is closely aligned with the German DIN 16742. This standard is vital for designers and manufacturers to agree on achievable precision without driving up costs through unnecessary accuracy requirements. Key Tolerance Groups (TG)
Unlike metal parts, plastics have high shrinkage and warpage, requiring specific "Tolerance Groups" (TG) based on material properties and manufacturing effort.
TG4 (Fine): Used for high-precision components like internal gears or small medical parts. TG5 (Medium): Typical for functional housing parts.
TG6 (Coarse): Standard for non-critical consumer products or packaging. ISO 20457 Tolerance Table Overview
The following table provides general capability ranges based on the part's nominal dimensions (size) and the selected tolerance grade: Nominal Dimension (mm) TG4 (Fine) TG5 (Medium) TG6 (Coarse) Up to 1 mm 1 to 3 mm 3 to 6 mm 6 to 10 mm 10 to 18 mm 18 to 30 mm 30 to 50 mm 50 to 80 mm 80 to 120 mm 120 to 180 mm 180 to 250 mm Critical Requirements for ISO 20457 Callouts ISO 20457 Tolerance Table PDF: What You Actually
Simply stating "ISO 20457" on a drawing is insufficient. For a tolerance to be enforceable, the design documentation must include:
Tolerance Grade (TGx): Specifying the exact group (e.g., TG6).
Conditioning: Standard measurement temperature (usually 23°C) and humidity (50% RH).
Measurement Method: Specifying tools like a CMM (Coordinate Measuring Machine) or Optical Measurement Systems.
Datum System: Clear reference points to ensure repeatable results. Why ISO 20457 vs. ISO 2768?
The tolerances vary depending on the material, as different plastics shrink and mold differently. The standard generally divides materials into groups:
As we move toward Industry 4.0 and Model-Based Definition (MBD), the ISO 20457 tolerance table PDF is evolving into a machine-readable format. Future revisions may come as XML or JSON files that CAD systems read automatically. However, for the next decade, the PDF will remain the universal backup—the human-readable master key.
In the world of plastics engineering and injection moulding, tolerances determine whether a part snaps together perfectly or fails catastrophically. For decades, engineers defaulted to the ISO 286 system for metal parts—only to find that plastics behave differently due to shrinkage, warpage, and creep.
Enter ISO 20457:2020 – Plastics moulded parts – Tolerances and acceptance conditions. If you have been searching for the “iso 20457 tolerance table pdf” , you are likely facing the challenge of specifying realistic, cost-effective tolerances for injection-moulded components. This article provides a complete breakdown of the standard, explains how to interpret its tolerance tables, and guides you on obtaining and using the official PDF.
Purpose and scope
Key structure of the tolerance table (typical elements)
Interpretation nuances
Practical application guidance
Common pitfalls
When to consult the PDF/standard directly
Concise recommendation
ISO 20457:2018 is the primary international standard for determining manufacturing tolerances and acceptance conditions for non-porous plastic molded parts. It replaces the older DIN 16742 standard and provides a systematic way to calculate achievable tolerances based on material properties and manufacturing processes. Unlike metal machining standards, ISO 20457 accounts for the unique behavior of plastics, such as mold shrinkage and environmental sensitivity. Key Components of ISO 20457
The standard uses a tiered system to assign tolerance groups (TG) based on the material's complexity and the required precision:
Title: Download ISO 20457 Tolerance Table PDF for Precision Engineering Purchase from ISO
Introduction: ISO 20457 is an international standard that specifies tolerances for linear and angular dimensions, as well as geometric tolerances, for features on parts and products. The standard provides a comprehensive tolerance table that engineers and manufacturers can use to ensure precision and accuracy in their designs and manufacturing processes.
What is ISO 20457? ISO 20457 is a widely adopted standard that defines a set of tolerances for various features, including:
The standard provides a framework for specifying tolerances that balance the need for precision with the practical limitations of manufacturing processes.
ISO 20457 Tolerance Table PDF: The ISO 20457 tolerance table provides a detailed list of tolerances for various features, including:
By using the ISO 20457 tolerance table, engineers and manufacturers can:
Benefits of Using ISO 20457:
Download ISO 20457 Tolerance Table PDF: You can download the ISO 20457 tolerance table PDF from various sources, including:
Make sure to verify the authenticity and accuracy of the PDF document before using it for design or manufacturing purposes.
Conclusion: The ISO 20457 tolerance table PDF is a valuable resource for engineers, manufacturers, and designers who need to specify tolerances for linear and angular dimensions, as well as geometric tolerances. By using this standard, you can ensure precision, accuracy, and interchangeability of parts and components, ultimately leading to improved product quality and reliability.
Let’s walk through a real-world example to solidify your understanding of the ISO 20457 tolerance table PDF.
Scenario: A company is designing a mounting bracket for an electric motor. The bracket is a sheet metal part (2mm thick, 200mm long). The motor has a shaft that aligns to a hole.
Result: The machinist reads the PDF, applies the correct deviations, and the bracket is cheap to produce (not over-toleranced) but still fits the motor.
The most sought-after component of this standard is the tolerance table. Typically, the PDF version of ISO 20457 contains several critical tables, but one stands out: the table linking nominal sizes to permissible deviations for linear dimensions and angles.
Because ISO 20457 is a classification standard, its tables do not provide the raw numbers for every single dimension (that is the job of ISO 286, ISO 2768, etc.). Instead, it provides a decision matrix.
Here is a conceptual breakdown of what you will find inside the ISO 20457 tolerance table PDF:
Angles are treated differently because the deviation is measured as a length over a given length (mm/m) or directly in degrees/minutes.
| Tolerance Class | Permissible Deviation (mm per 100mm length) | | :--- | :--- | | Fine (f) | ± 0.3 mm/m | | Medium (m) | ± 0.5 mm/m | | Coarse (c) | ± 1.0 mm/m |
For shorter legs (< 10mm), the deviation is often given as a fixed value (e.g., ± 30 minutes for coarse, ± 10 minutes for fine).