Medical connectors, high-speed gears; requires low anisotropy.
standard is a critical German guideline for determining tolerances for plastic moulded parts, and the TG5 (Tolerance Group 5)
| Tolerance Group (TG) | TG1 | TG2 | TG3 | TG4 | | TG6 | TG7 | TG8 | TG9 | |----------------------|-----|-----|-----|-----|--------|-----|-----|-----|-----| | Point sum | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
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
The primary technical feature of TG5 is that it does not use a single percentage for all dimensions. Instead, it splits tolerances into and Non-Functional Dimensions (N) : din 16742 - tg5
DIN 16742-TG5 is the designated tolerance group for . It is the default choice for general tolerances on engineering drawings and is the standard applied by many manufacturers for their standard injection moulding processes. The specification "DIN 16742 – TG5" in a drawing's title block defines the permissible general tolerances for all features not explicitly dimensioned.
For TG5, the standard explicitly notes that are often insufficient. The feature requires statistical process control (SPC) and frequent CMM (Coordinate Measuring Machine) verification due to the elastic recovery and warpage potential of plastics.
by precision-focused suppliers (compared to TG7 or TG8, which are used for looser processes like Structural Foam Moulding). Achievability:
The selection of a tolerance group is not arbitrary. The standard provides a structured, point-based scoring system that evaluates five individual influence factors. The sum of these points directly determines which TG is achievable for a given part in a given production environment. Those five factors are: For TG5, the standard explicitly notes that are
DIN 16742 is the German national standard for tolerances and acceptance conditions of plastic moulded parts, officially titled “Plastics moulded parts — Tolerances and acceptance conditions.” Published in October 2013, it replaces the withdrawn DIN 16901 (last issued in 1982) and serves as a completely revised and updated successor. The standard is aimed at moulded part designers, moulded part manufacturers, and the designers and manufacturers of the required tools.
To reach the tight requirements of TG5, engineers often use a "Steel Off"
(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
It classifies materials into different accuracy groups, which then determine the applicable Tolerance Group. Deep Dive into Tolerance Group 5 (TG5) In the world of injection molding
is often described as the "Standard" or "Fine" tolerance class for technical injection-molded parts. It sits in a sweet spot where high precision is achieved without the exponential cost increases associated with ultra-tight groups like TG1 or TG2.
In the world of injection molding, achieving the right balance between functionality, manufacturability, and cost is critical. As plastic components replace metal parts in demanding applications, the need for standardized, precise tolerances has grown. (often used alongside or replaced by the newer DIN ISO 20457 ) is the definitive German standard for determining tolerances for plastic moulded parts.
for a specific material like ABS or POM.