DIN 16742 TG5 refers to a specific "Tolerance Group" (TG) within the German standard for injection-molded plastic part tolerances. While is the most common standard for general industrial parts,
represents a more precise accuracy requirement typically used for high-quality technical components. Deep Mould Key Characteristics of TG5 Precision Level : TG5 is classified as an "Accurate" "Precision"
production level. It is tighter than the standard TG6 but less extreme than the tool-room limits of TG3 or TG4. Application
: It is often specified for "hard" plastic components or multi-component parts where a more accurate fit is needed (e.g., snap-fits or bearing housings). Cost vs. Accuracy
: Achieving TG5 requires more intensive process monitoring and higher-quality tooling, which generally increases production costs compared to TG6. www.makrolar.eu Factors Affecting TG5 Compliance
The ability to maintain TG5 tolerances depends on several manufacturing variables outlined in the standard: Material Shrinkage
: Tighter groups like TG5 are easier to achieve with amorphous resins (e.g., ABS, PC) that have low, predictable shrinkage than with semi-crystalline materials (e.g., PA66, POM). Dimension Type : DIN 16742 distinguishes between Tool-specific (W) Non-tool-specific (NW) dimensions: Tool-specific (W)
: Dimensions formed within a single mold half; these typically allow for tighter tolerances. Non-tool-specific (NW)
: Dimensions affected by the opening/closing of the mold or moving parts (like sliders), which require larger tolerance ranges. Super-Ingenuity Implementation Recommendations
For technical guidance on applying this standard, designers often use tools like the PolTolerances Software
, which helps calculate specific values based on material and part geometry. www.makrolar.eu Design Note
: When using TG5, it is recommended to define "steel-off" positions on drawings to allow for final mold adjustments after the first trial (FOT). Standard Updates : Note that was largely harmonized with the international standard
, so you may see both referenced on modern engineering drawings. specific ±mm values for TG5 across different nominal dimension ranges?
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
, 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:
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: din 16742 - tg5
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.
Structural frames, heavy industrial covers, non-mating surfaces. 5. Implementation Recommendations
To successfully utilize TG5 in a project, the following steps are recommended:
Feature Name: DIN 16742 - TG5 Tolerance Analysis and Calculation
Description: DIN 16742 is a German standard for tolerance analysis and calculation in engineering design. TG5 refers to a specific part of this standard, which deals with the calculation of tolerances for geometric dimensions. This feature provides a comprehensive solution for engineers to perform tolerance analysis and calculation according to DIN 16742 - TG5.
Key Features:
Benefits:
Target Audience: The feature is designed for engineers, designers, and technicians working in various industries, such as mechanical engineering, automotive, aerospace, and manufacturing, who need to perform tolerance analysis and calculation according to DIN 16742 - TG5.
Technical Requirements:
Title: Precision in Motion: An Analysis of DIN 16742 Tolerance Class TG5
Introduction
In the realm of modern manufacturing, injection molding stands as one of the most versatile and widely used processes for producing plastic components. However, the physical properties of polymers—such as shrinkage, thermal expansion, and moisture absorption—present unique challenges when it comes to dimensional accuracy. Unlike machined metal parts, which can often achieve exact specifications, plastic parts require standardized tolerance systems to ensure interchangeability and functional reliability. This is where DIN 16742 comes into play. As the German standard for dimensional tolerances and acceptance conditions for plastic molded parts, it provides a framework for engineers and suppliers to agree on quality. Specifically, Tolerance Class TG5 represents a critical balance within this standard, offering a mid-range level of precision that is applicable to a vast array of industrial applications.
The Framework of DIN 16742
To understand the significance of TG5, one must first understand the structure of DIN 16742. The standard categorizes tolerances into two main groups: dimensional tolerances (for length, width, height) and form tolerances (for flatness, straightness, etc.). These tolerances are not arbitrary; they are based on the nominal size of the dimension and are grouped into "Tolerance Groups."
The standard defines distinct tolerance groups—TG1 through TG7—each corresponding to the manufacturing precision required. This classification acknowledges that not all plastic parts are created equal; a simple cable clip does not require the same precision as an optical housing or a medical device component. By specifying a tolerance group, manufacturers can select the appropriate molding parameters, materials, and quality control measures.
Defining Tolerance Class TG5
TG5 falls in the middle of the standard spectrum, situated between the highly precise lower groups (TG1–TG3) and the looser, general-purpose higher groups (TG6–TG7).
TG5 is often characterized as a "Fine" or "Medium-Precision" tolerance class. It is stricter than general commercial molding standards (like TG6 or TG7) but does not demand the extreme, costly controls required by High Precision (TG1–TG2). DIN 16742 TG5 refers to a specific "Tolerance
In the context of the standard’s tables, TG5 specifies a permissible deviation that is significantly tighter than what might be acceptable for a disposable item, yet achievable without exotic tooling or specialized environment controls. For example, on a nominal dimension of 100mm, the tolerance range in TG5 would be narrow enough to ensure good fitment with mating parts, but wide enough to account for the natural variability of the injection molding process.
Application and Suitability
The selection of TG5 is highly strategic. It is the default choice for functional components that require a degree of reliability and fitment but do not fall into the category of high-precision instrumentation.
Material Considerations
A unique aspect of DIN 16742 is that tolerance groups are often correlated with material behavior. TG5 implies the use of materials that offer moderate stability.
If a manufacturer were to specify TG1 for a semi-crystall
DIN 16742 is the German industrial standard used to define manufacturing tolerances and acceptance conditions for plastic moulded parts. It replaced the older DIN 16901 and is often used alongside or as a reference for the international standard ISO 20457. Tolerance Group 5 (TG5) Overview
TG5 is a specific accuracy class within this standard. In the hierarchy of tolerance groups (TG1–TG9), TG5 is considered a "precise" or "standard precision" class for high-quality injection moulding.
Application: It is typically used for functional parts with moderate to high dimensional accuracy requirements, such as precision mechanical components or mating interfaces.
Production Level: Generally falls under Series 2 (Accurate Production), meaning production and quality assurance are oriented toward higher dimensional stability than standard commercial grades (like TG6).
Material Influence: Achieving TG5 often requires materials with lower shrinkage rates (e.g., amorphous resins like PC or ABS) rather than high-shrinkage semi-crystalline materials. Key Tolerance Concepts
When applying TG5 under DIN 16742, dimensions are categorized based on how they are formed in the tool:
Tool-Specific Dimensions (W): Dimensions formed by a single, solid part of the mould. These typically have tighter tolerances because they are not affected by mould movement.
Non-Tool-Specific Dimensions (NW): Dimensions affected by moving mould parts (e.g., across the parting line, sliders, or lifters). These require larger tolerances to account for mechanical play in the mould. Standard Acceptance Conditions
For measurements to be valid under DIN 16742, parts must be conditioned according to DIN EN ISO 291: Temperature: Humidity: relative humidity.
Timing: Measurements should typically be taken between 16 and 72 hours after production to allow for shrinkage stabilization. Tolerance Comparisons
While specific values for TG5 vary by nominal dimension (e.g., 1–3mm vs. 500–630mm), it sits between the high-precision TG4 (used for medical devices/gears) and the standard industrial TG6 (used for general housings).
injection-moulding-tolerances-din16742-2013.pdf - Xometry Pro
Understanding DIN 16742 - TG5 DIN 16742 is the central German engineering standard for determining tolerances in plastic molded parts. Within this framework, TG5 (Tolerance Group 5) represents the "baseline" or "standard" precision level for modern injection molding.
Choosing the right tolerance group is critical because plastic behavior differs significantly from metal. Plastics are subject to high thermal expansion, moisture absorption, and shrinkage—factors that DIN 16742 addresses through its system of nine tolerance groups (TG1–TG9). What is Tolerance Group 5 (TG5)?
TG5 is widely regarded as the standard precision application. While groups like TG1 through TG3 are reserved for extreme precision (often requiring specialized high-stability materials and rigorous process control), TG5 is used for:
Standard Engineering Components: Parts where functional fit is important but doesn't require extreme sub-millimeter precision.
High-Quality Consumer Goods: Products that need a clean aesthetic and reliable assembly. Tolerance Calculation: The feature allows users to calculate
Industrial Enclosures: Cases and housings where dimensional stability is necessary for snap-fits or screw bosses.
For many manufacturers, TG5 is the default starting point. If a design requires tighter tolerances (TG4 or higher), production costs usually increase due to stricter process monitoring and potential tool modifications. Key Factors in DIN 16742
The standard doesn't just provide a table of numbers; it calculates tolerances based on several variables: 1. Mold-Fixed vs. Non-Mold-Fixed Dimensions
Mold-Fixed (W): Dimensions determined by a single part of the mold tool. These are typically more accurate.
Non-Mold-Fixed (NW): Dimensions affected by moving tool parts, such as sliders, cores, or the parting line. These usually have wider tolerances because they are subject to tool opening/closing variances. 2. Material Behavior
Plastics are categorized by their molding shrinkage (VS). Crystalline materials (like POM or PA) tend to shrink and warp more than amorphous materials (like ABS or PC), which can move a part out of a specific TG rating if not managed. 3. Production Environment
DIN 16742 requires that dimensions be measured under specific acceptance conditions, usually 16 to 24 hours after molding at a standard atmosphere of 23°C and 50% humidity.
The DIN 16742 standard is a widely used German engineering guideline for determining tolerances of plastic moulded parts. Within this standard, Tolerance Group 5 (TG5) represents the baseline or "standard" level of precision for industrial applications. Understanding DIN 16742 - TG5
Precision Level: TG5 is considered the standard precision category. It is often applied as a general tolerance across various plastic materials, such as ABS or PC+ABS, to ensure a balance between manufacturing cost and part quality.
Tolerance Range: While the exact numerical deviation depends on the nominal dimension of the part, TG5 typically allows for general tolerances in the range of ±0.1 mm to ±0.5%.
Purpose: Using TG5 allows engineers to define acceptable variations without having to specify tolerances for every single dimension on a drawing, simplifying the design process and setting clear expectations with manufacturers.
Status Update: Note that DIN 16742 was officially withdrawn and superseded by the international standard DIN ISO 20457:2020-03. Comparison of Tolerance Groups
Tolerances in DIN 16742 are categorized based on the required precision and manufacturing process: TG1 to TG3: Extreme precision parts. TG4: High-precision parts. TG5: Standard precision applications (baseline).
TG6: Coarse parts where looser tolerances are acceptable (often used for standard thermoplastics).
TG7 to TG9: Very coarse parts where shrinkage is high or unpredictable. Key Implementation Advice
Material Influence: Shrinkage properties of different polymers (e.g., PP vs. ABS) will affect how easily TG5 is achieved.
Mold-Fixed vs. Non-Mold-Fixed: When citing this standard, you should specify whether the dimension is mold-fixed (within one half of the tool) or non-mold-fixed (crossing the parting line), as this changes the expected tolerance.
Alternative Processes: While primarily for injection moulding, TG5 is also a common target for vacuum casting and some CNC post-processing workflows.
Are you looking to apply these tolerances to a specific material or a particular manufacturing process like injection moulding? Vacuum Casting | FACTUREE – The Online Manufacturer
Achieving TG5 is not automatic. It requires disciplined manufacturing protocols:
1. Dimensional Tolerances Under TG5, a 100 mm nominal dimension on a non-critical feature allows a deviation of approximately ±0.2 mm to ±0.3 mm, depending on the material (amorphous vs. semi-crystalline). For reference, TG1 would allow ±0.8 mm at the same length.
2. Surface Structure (The "5" in TG5) The standard strictly defines surface roughness based on comparator blocks. TG5 requires surfaces to be free from visible sink marks, flow lines, and ejector pin marks that exceed a depth of 0.02 mm. It aligns roughly with Rz 10–20 µm (average maximum height of the profile).
3. Form and Position TG5 enforces flatness, roundness, and parallelism. A TG5 part cannot simply have the right width; its side walls must be straight within 0.1 mm over 100 mm.
In 2025, DIN 16742 is undergoing a revision to align with Industry 4.0 and additive manufacturing. However, TG5 remains unchanged because it correlates directly with physical limits of melt flow. The upcoming changes include:
Even experienced designers misuse TG5. Avoid these errors: