Even experienced designers misuse TG5. Avoid these errors:
Dimensional tolerances depend on the nominal size range (mm) of the feature. Below is a simplified table for TG5 (based on DIN 16742, general tolerances for non-critical dimensions):
| Nominal dimension (mm) | Tolerance ± (mm) | |------------------------|------------------| | 0 – 3 | ±0.08 | | 3 – 6 | ±0.12 | | 6 – 10 | ±0.15 | | 10 – 18 | ±0.20 | | 18 – 30 | ±0.25 | | 30 – 50 | ±0.30 | | 50 – 80 | ±0.40 | | 80 – 120 | ±0.50 | | 120 – 180 | ±0.65 | | 180 – 250 | ±0.80 | | 250 – 315 | ±1.00 | | 315 – 400 | ±1.20 |
⚠️ These are general linear tolerances. For functional features (e.g., fits with metal parts), tighter TG3 or TG4 is recommended.
DIN 16742 - TG5 is not merely a number on a drawing. It is an engineering contract between designer, toolmaker, and molder. Specifying TG5 says: “I need functional fit, but I respect the physics of plastics.”
When used correctly—on selective features, with appropriate materials, and validated by simulation—TG5 delivers reliable assemblies without bankrupting the project. For the 80% of industrial plastic parts that require precise assembly (automotive, medical devices, industrial controls), TG5 is the gold standard.
Final recommendation: Always add a note to your drawing: "All dimensions per DIN 16742 - TG5 unless otherwise noted. Material group B (POM). Shrinkage pre-settlement required." This single line has saved countless tooling reworks.
Need to implement DIN 16742 - TG5 in your next project? Consult with your molder before freezing the tooling design. The TG5 tolerance class works best when the molder participates in the DFM (Design for Manufacturability) review.
Technical Report: DIN 16742 – Tolerance Group TG5 Evaluation of specifically regarding Tolerance Group 5 (TG5) for plastic molded parts. 1. Executive Summary standard (often paired with din 16742 - tg5
) provides a systematic framework for determining achievable tolerances in plastic injection molding. Tolerance Group 5 (TG5)
is characterized as a "high-standard" or "accurate" production grade. While TG6 is often the baseline for standard commercial plastics, TG5 represents a step toward Precision Production
, typically requiring more controlled manufacturing environments or materials with low shrinkage. 2. Defining TG5 within DIN 16742
The standard classifies tolerances into groups (TG1 through TG9) based on material characteristics and production requirements. Production Level: TG5 is generally associated with Accurate Production
. This means production and quality assurance are oriented toward higher dimensional stability than standard "normal" production. Application: It is frequently cited as the standard for Injection Moulding
by precision-focused suppliers (compared to TG7 or TG8, which are used for looser processes like Structural Foam Moulding). Achievability:
For materials like ABS, TG5 is considered a "standard" achievable grade, whereas reaching TG4 would require special measures or highly optimized geometry. 3. Key Variables Affecting TG5 Compliance
Achieving TG5 tolerances is not purely a matter of machine settings; it depends on the complex interplay of several factors: Material Shrinkage: Even experienced designers misuse TG5
Materials are classified by shrinkage rates (e.g., <0.5%, 0.5–1%, etc.). Low-shrinkage materials make TG5 easier to maintain. Mold-Fixed vs. Non-Mold-Fixed:
Dimensions formed by a single mold part (mold-fixed) are easier to control than those affected by moving mold elements (non-mold-fixed). "Steel Off" Optimization:
To reach the tight requirements of TG5, engineers often use a "Steel Off"
strategy—designing the mold slightly "small" so that plastic can be added later by removing small amounts of metal after initial testing. 4. Comparison to Other Tolerance Groups
The following table highlights how TG5 sits within the hierarchy of DIN 16742: Tolerance Group Production Type Typical Usage/Requirements
Medical connectors, high-speed gears; requires low anisotropy.
Standard high-quality injection molding; high dimensional stability
Baseline for many automotive interior trims and consumer tech. ⚠️ These are general linear tolerances
Structural frames, heavy industrial covers, non-mating surfaces. 5. Implementation Recommendations
To successfully utilize TG5 in a project, the following steps are recommended:
The Significance of DIN 16742 - TG5: A Comprehensive Guide
In the realm of industrial standards, precision, and quality are paramount. Among the numerous standards that govern various industries, DIN 16742 - TG5 stands out due to its specific relevance to tool holders and their critical role in ensuring the accuracy and efficiency of machining processes. This article aims to provide an in-depth look at DIN 16742 - TG5, its implications, and the significance it holds in manufacturing, particularly in the context of tool holders.
The primary technical feature of TG5 is that it does not use a single percentage for all dimensions. Instead, it splits tolerances into Functional Dimensions (F) and Non-Functional Dimensions (N) :
| Feature | TG5 Requirement | | :--- | :--- | | Functional (F) (e.g., fits, mating surfaces) | Very tight (e.g., ±0.03 mm up to 50mm, then increasing). Requires mold design to account for shrinkage precisely. | | Non-Functional (N) (e.g., free edges, bosses) | Standard tight (e.g., ±0.10 mm up to 50mm). |
The TG5 specification within DIN 16742 refers to a particular type of tool holder interface. The nomenclature can vary, but TG5 typically denotes a specific design or performance criterion that tool holders must meet. This could involve the geometric accuracy of the tool holder, its balancing class, or its material composition. The exact requirements of TG5 are detailed within the DIN 16742 standard and are designed to ensure compatibility, precision, and reliability in high-speed machining applications.
Most injection molders will warn against specifying TG7 or TG8 for mass production. While they are mathematically possible, they drive tooling costs up by 40–60% and scrap rates through the roof. TG5 offers a balance:
