Din 16742 - Tg5 【TOP ★】

Unlike standards for machined metal parts, DIN 16742 accounts for the unique behavior of plastics. The standard distinguishes between two types of dimensions:

The standard assigns tolerance values based on the nominal dimension and the selected Tolerance Group.

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). |

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

) 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 din 16742 - tg5

, 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: Unlike standards for machined metal parts, DIN 16742

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. The standard assigns tolerance values based on the

Standard high-quality injection molding; high dimensional stability

Baseline for many automotive interior trims and consumer tech.

Structural frames, heavy industrial covers, non-mating surfaces. 5. Implementation Recommendations

To successfully utilize TG5 in a project, the following steps are recommended:

DIN 16742 is a standard that specifically deals with tool holders and their interfaces. Tool holders are essential components in machine tools, serving as the bridge between the machine and the cutting tool. They are critical in ensuring that the cutting tool is accurately positioned and securely held during the machining process. The standard covers various aspects, including dimensions, materials, and performance requirements for tool holders.