Din 16742 - Tg5

You do not need TG5 on a cosmetic snap-dome button. Apply TG5 only to critical features (bearing diameters, mating bosses, gear centers). Use TG4 for all other dimensions.

DIN 16742 defines four tolerance grades for plastics: din 16742 - tg5

The key feature of TG5 is that it is the highest (strictest) precision grade in the standard, requiring the most accurate molds and stable processing conditions. You do not need TG5 on a cosmetic snap-dome button

A part with a single edge gate will have shrinkage variation along the flow path. Under TG5, you must simulate this (Moldex3D, Cadmould) and adjust the nominal dimension asymmetrically (e.g., +0.10 mm / -0.18 mm instead of ±0.14 mm). The key feature of TG5 is that it

TG5 represents the widest range of permissible tolerances defined in the standard tables. It is designated for applications where high precision is not critical to the function of the part, or where the material properties make tighter tolerances economically unviable.

Key characteristics include:

The tolerance value depends on the part’s nominal dimension (longest overall length or specific feature size). Common ranges include: