Crucial for dynamic parts like gears or fluid seals where deviations cause failure.
Initially specified TG5 for all dimensions. After mold flow analysis, only the pin grid array (PGA) zones were mapped to TG5. The outer shell was relaxed to TG4.
| Nominal size range (mm) | TG5 – W tolerance (± mm) | TG5 – NW tolerance (± mm) | |------------------------|-------------------------|--------------------------| | 1 to 3 | 0.05 | 0.08 | | > 3 to 6 | 0.08 | 0.11 | | > 6 to 10 | 0.11 | 0.14 | | > 10 to 18 | 0.14 | 0.17 | | > 18 to 30 | 0.17 | 0.20 | | > 30 to 50 | 0.20 | 0.23 | | > 50 to 80 | 0.23 | 0.36 | | > 80 to 120 | 0.36 | 0.50 | | > 120 to 180 | 0.50 | 0.58 | | > 180 to 250 | 0.58 | 0.65 | | > 250 to 315 | 0.65 | 0.70 | | > 315 to 400 | 0.70 | 1.00 | | > 400 to 500 | 1.00 | 1.40 |
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)?
(affected by the movement of mold components), allowing for more realistic tolerance expectations based on tool mechanics. Supply Chain Alignment : Particularly in the European and German automotive supply chains din 16742 - tg5
: Reaching this group usually requires more rigorous process control and quality assurance than general-purpose molding. Comparison within the Standard Tolerance Group Typical Application Classification TG4 Critical interfaces, bearing seats High Precision TG5 Functional fits, standard precision parts Accurate Production TG6 General housings, enclosures Standard Production TG7/8 Large cosmetic covers, foam molding Reduced Precision Practical Application Tips
For small nominal dimensions (under 6 mm), TG5 tool-specified tolerances can be as tight as . As the nominal dimension increases to 100 mm, the allowed tolerance expands toward ±0.25 mm or higher to account for compound material shrinkage across larger surface areas. 4. Factors Influencing TG5 Feasibility
Wear on the mold over time will eventually push parts out of the TG5 threshold if maintenance is neglected. 3. Process Control and Environment
TG5 occupies the central range of the tolerance groups, balancing cost and precision. It corresponds to a point score of in the standard's classification system. The table below lists the nominal tolerance values for tool-bound dimensions: Crucial for dynamic parts like gears or fluid
Easiest materials to hit TG5 requirements consistently. Semi-Crystalline High, anisotropic shrinkage ( PP, PE, PA6, POM
When manufacturing injection-molded plastic parts, achieving absolute dimensional perfection is impossible. Factors like material shrinkage, tool design, and processing variables cause variations in final part dimensions. To manage these variations, engineers rely on the German standard . Within this standard, the TG5 tolerance group represents a highly precise classification used for demanding technical applications. What is DIN 16742?
DIN 16742 TG5 represents the standard of excellence for technical plastic parts. It provides engineers with a realistic guide to what can be achieved through disciplined manufacturing. By selecting TG5, designers ensure that their parts will function correctly in complex assemblies while avoiding the prohibitive costs of over-engineering the tolerance requirements.
Key characteristics include:
This guide breaks down , the primary German and European standard for plastic part tolerances, with a specific focus on Tolerance Group 5 (TG5) 1. What is DIN 16742?
Requires optimized cooling, precise processing, and often fiber reinforcement (e.g., PA6-GF30) to meet TG5. Production Impact of Specifying TG5
These have tighter tolerances because they are controlled entirely by the steel cavity.