Iso 20457 Tolerance Table Pdf |link| < Original >
The tables are arranged in rows corresponding to the size of the feature being measured. Standard step ranges typically look like this: Up to 3 mm 3 mm to 6 mm 6 mm to 10 mm 10 mm to 18 mm 18 mm to 30 mm (And so on, up to 1000 mm)
when no individual tolerance is specified directly on the drawing.
Specifying the exact group (e.g., TG6).
Choosing the right tolerance grade is a balance between functional requirements and manufacturing cost. iso 20457 tolerance table pdf
(e.g., glass fibers) reduce shrinkage but introduce anisotropy (different shrinkage rates parallel and perpendicular to the flow). 4. Post-Molding Environmental Factors
The most common tolerance group for standard industrial injection molding.
: Cross-reference the category with the nominal dimension of the part to find the specific deviation (in mm). Implementation and Resources Official Standard : Detailed specifications are available directly from the ISO 20457:2018 Publication Page Working Templates : For practical engineering use, Super-Ingenuity The tables are arranged in rows corresponding to
The system categorizes tolerances using , ranging from TG1 to TG9.
A key concept within the ISO 20457 PDF is the distinction between two types of dimensions:
For general thermoplastics, the standard typically defaults to unless otherwise specified. Choosing the right tolerance grade is a balance
ISO 20457 is an indispensable tool for anyone involved in the design, molding, or sourcing of plastic parts. By using its tolerance tables and systematic approach, you can avoid costly rework, ensure proper assembly, and achieve reliable quality. The shift from experience-based guesswork to a structured system like ISO 20457 is a foundational step in professionalizing plastic parts engineering.
The appropriate TG depends on the specific plastic material used, its filler content, and the precision capabilities of the molding process. Tolerance Grade Process and Material Capability Cost Impact
The standard classifies tolerances into , typically ranging from TG1 to TG9. TG6 is the most common baseline for commercial plastic parts. Nominal Dimension (mm) TG4 (Precision) TG6 (General) TG8 (Coarse)
ISO 20457 is the direct international successor to the German national standard DIN 16901, and the two are closely related. However, there are key differences: