: For critical fits, designers often use a "steel-off" approach, designing the mold slightly smaller so that material can be removed from the tool later to achieve the exact TG5 requirement after first-article testing. Software Tools : Applications like PolTolerances
For a nominal dimension between 0 to 400 mm, TG5 tolerances are exceptionally tight. For example:
| Standard / Grade | Equivalent to TG5? | Key Difference | |----------------|--------------------|----------------| | DIN 16901 (110) | No – 110 is coarser (~TG8). TG5 is ~130-140 range in old standard. | Old 110 is general purpose; TG5 is precision. | | ISO 20457 (P3) | Roughly equivalent | ISO P3 is similar but less detailed on geometric tolerances. | | VW 13010 (Group 4) | Slightly tighter | TG5 is similar to VW13010’s higher precision group. |
To reference this standard on a technical drawing, use the labeling field as follows:
Placing the gate near a critical TG5 dimension. Solution: Locate gates at thickest sections, away from tight-tolerance features. Use multiple gates or sequential valve gating for large parts.
The group assignment is often linked to the material’s shrinkage rate. Materials with lower shrinkage (like ABS or PC) are easier to hold to TG5 than crystalline materials (like PP or POM) that warp more easily. Typical Tolerance Values (Estimation)
Tolerances depend on the nominal dimension and the material's shrinkage behavior. For "Accurate Production" (TG5), the deviations are roughly tighter by one grade compared to standard production.
Below is a technical summary (white paper format) for applying in your designs. Technical Summary: DIN 16742 Tolerance Group TG5 1. Scope and Application
