Iso 20457 Tg5 May 2026

ISO 20457 Tolerance Group 5 (TG5) is the industry-standard "baseline" precision level for plastic molded parts. It is typically used for general-purpose applications like housing parts and standard technical components where extreme precision is not required, but functionality must remain reliable. Key Characteristics of TG5

Baseline Precision: TG5 represents standard manufacturing accuracy for injection molding, sitting between high-precision groups (TG1–TG4) and coarse/loose groups (TG6–TG9).

Application Focus: Ideally suited for housing parts, enclosures, and general technical moldings.

Production Difficulty: Often classified under "Series 1" (Standard Production) or slightly tighter, meaning it can typically be achieved using standard injection molding processes without excessive specialized measures. How TG5 Fits into ISO 20457

ISO 20457:2018 (which replaced standards like DIN 16742) categorizes tolerances into nine groups (TGs) based on the required precision: Tolerance Group Description Typical Use Case TG1 - TG3 Extreme Precision Critical medical or optical components TG4 High Precision Gears, precision wheels, or high-speed impellers TG5 Baseline Precision Consumer electronics housings, standard covers TG6 Packaging, bottle caps, or simple pen barrels TG7 - TG9 Very Coarse High-shrinkage parts or rotational molding (e.g., TG9) Practical Considerations for Using TG5

Material Impact: Achieving TG5 is easier with low-shrinkage materials like ABS. For high-shrinkage materials like Polypropylene, reaching TG5 might require more precise process control.

Tooling Costs: Since TG5 is the baseline, it usually offers a good balance between part performance and manufacturing cost. Tighter groups like TG4 often incur a "significant surcharge" due to increased quality assurance and tooling precision.

Measurement Context: Tolerances in ISO 20457 are often defined as symmetrical limit dimensions (e.g., ±0.1 mm) rather than a total tolerance band.

Parting Lines: Be aware that dimensions crossing the tool's parting line (NW - Not tool-dependent) typically have wider tolerances than those contained within a single mold half (W - Tool-dependent). Iso 20457 Tg5

For Government Regulators

If you are building a "Smart City," you use TG5 standards (specifically ISO 14813) to ensure your investment isn't wasted on proprietary systems that can't talk to each other later. It provides a neutral, standardized blueprint for tenders.

1. Executive Summary

Technical Group 5 (TG5) is a working group within the ISO/TC 204 committee. Its primary mandate is to maintain and develop standards related to the Reference Architecture and Terminology for Intelligent Transport Systems (ITS).

While "ISO 20457" is often cited as the umbrella for the group's work, the output of this group consists of several critical ISO standards (most notably the ISO 14817 series and ISO 14813 series). TG5 is essentially the "city planner" of the ITS world—they design the blueprints before the systems are built.

Why TG5 Matters More Than Ever in 2024-2025

As global regulations tighten (e.g., the EU’s PPWR - Packaging and Packaging Waste Regulation), demand for high-quality recyclates has skyrocketed. However, the market is flooded with "recycled grades" that fail during injection molding due to poor filler dispersion or fiber breakage.

Step 3: Modified Melt Flow Rate (TG5.3)

Standard ISO 1133 uses a 2.16 kg weight. TG5 allows for 5kg or 10kg weights (Condition M).

2. The Glass Fiber Retention Nightmare

Glass-fiber reinforced plastic (GFRP) recycling is notoriously difficult. The extrusion process for recycling breaks long glass fibers into short stubs. A virgin GF-PA66 might have 3mm fibers; a recyclate might have 0.2mm fibers. TG5 mandates the "Thermal treatment + image analysis" method for measuring fiber length. This is non-negotiable for engineering applications like power tool housings or automotive fan shrouds.

7. Summary Checklist

Common Pitfalls Ignoring ISO 20457 TG5

Case Study: An automotive Tier 1 supplier switched to a "certified recycled talc-filled PP" for a non-visible bracket. The virgin material had an MFI of 12 g/10min. The recyclate arrived with an MFI of 45 g/10min (measured via standard ISO 1133). The molder assumed extreme degradation and scrapped the batch.

Analysis via TG5: When measured correctly using the TG5 high-load protocol, the recyclate actually had an MFI of 14 g/10min. The standard 2.16kg weight simply couldn't push the talc-heavy melt through the die, causing a false reading. The recyclate was viable; the test method was wrong. TG5 saved $50,000 in scrap. ISO 20457 Tolerance Group 5 (TG5) is the

Conclusion: Don't Overlook the Details

Searching for "ISO 20457 TG5" suggests you are moving beyond vague sustainability claims into the realm of hard engineering data. Whether you are a recycler trying to sell your talc-filled bumper regrind, or a manufacturer trying to avoid field failures, TG5 is your technical anchor.

Key Takeaways:

Ask your supplier: "Does your Certificate of Analysis follow ISO 20457 TG5?" If they look confused, you have found the gap in your quality chain.

Disclaimer: This article is for informational purposes. Always consult the official ISO 20457:2020 document for definitive testing requirements.

ISO 20457 is the international standard for dimensional and geometrical tolerances of plastic molded parts, replacing the older ISO 8062 and standardizing requirements for injection molding. Within this framework, Tolerance Group 5 (TG5) represents a specific "General" tolerance grade typically used for consumer goods and housing parts. Understanding ISO 20457 TG5

The standard categorizes tolerances into groups (TGs) ranging from TG1 (ultra-precision) to TG9 (coarse). TG5 is often the baseline for "standard" industrial production where extreme precision is not required, but assembly and function must remain consistent.

Application: Commonly used for housing parts, toys, and consumer goods packaging.

Permissible Range: For flatness and straightness, TG5 typically allows a variance between ±0.50plus or minus 0.50 ±1.00plus or minus 1.00 mm, depending on the length of the surface. Why TG5 Matters More Than Ever in 2024-2025

Material Influence: Achieving TG5 is considered "simple production" for stable materials like ABS. However, semi-crystalline materials with higher shrinkage, like Polypropylene (PP), may naturally track closer to TG6 unless the process is tightly controlled. Key Factors in Applying TG5

When specifying ISO 20457 TG5, designers and manufacturers must consider several environmental and mechanical factors:

Reference Conditions: Tolerance values are only valid at specific environmental settings—typically and 50% relative humidity.

Tool-Specific vs. Non-Tool-Specific: Dimensions formed by the same mold half (tool-specific) are generally easier to control than those formed across different mold parts or moving sliders.

Processing Shrinkage: The final size of a part depends heavily on its shrinkage rate. TG5 accounts for standard fluctuations in shrinkage during the cooling process.

Cost Efficiency: Selecting TG5 is often a strategic choice to balance quality and cost. Striving for tighter grades (like TG4 or TG3) significantly increases the cost of tools and quality assurance. Comparison of Tolerance Groups Accuracy Level Typical Examples TG3 Medical devices, aerospace components TG4 Automotive interiors, electronics TG5 General/Standard Toys, household housings, packaging TG6 Large shipping containers, basic structural parts

For more detailed technical data, you can consult the official ISO 20457:2018 page or review comprehensive guides from manufacturers like Makrolar and Hoka.

tolerance values for different nominal dimensions under TG5?