Iso 20457 Tolerance Table Pdf Jun 2026

Online technical documentation platforms like IHS Markit or SAI Global.

In the world of plastics engineering and injection moulding, tolerances determine whether a part snaps together perfectly or fails catastrophically. For decades, engineers defaulted to the ISO 286 system for metal parts—only to find that plastics behave differently due to shrinkage, warpage, and creep.

Note: This table is a representative summary. The official ISO 20457 PDF contains exact values and footnotes regarding chamfers, radii, and external/internal dimensions.

(e.g., glass fibers) reduce shrinkage but introduce anisotropy (different shrinkage rates parallel and perpendicular to the flow). 4. Post-Molding Environmental Factors iso 20457 tolerance table pdf

The accuracy of the mold cavity design and construction.

ISO 20457 provides:

Find the size row of your feature (e.g., 1–3mm, 10–18mm, 50–80mm). Online technical documentation platforms like IHS Markit or

Ana read until the shop lights hummed awake, and her mind stitched the dry numbers to the machines she knew best: a precision lathe, a column drill, a tiny vertical mill she had affection for. She began to rework an old coupling that had been slipping on a generator shaft. With the tolerance table open beside her, she adjusted diameters and chamfers, selected fits that would reduce vibration, and calculated clearances that would let thermal expansion breathe without sacrificing engagement. The first coupling she finished felt right in a way that was more than fit—it was a small piece of order restored.

So any PDF that claims to be a universal “ISO 20457 tolerance table” is likely a simplified summary from a textbook or company standard.

Plastics absorb moisture and have a high coefficient of thermal expansion, causing parts to expand or contract based on ambient air conditions. Note: This table is a representative summary

In practice, ISO 20457 defines based on:

ISO 20457 specifies different tolerance values for Code A and Code B dimensions, reflecting the higher difficulty of controlling the former.

When manufacturing plastic parts, achieving precise dimensions is significantly more challenging than working with metals. Shrinkage, material composition, and molding conditions all introduce variability. To standardize these variations, the International Organization for Standardization introduced ("Plastics molded parts — Tolerances and acceptance conditions"), which officially replaced the older DIN 16742 standard.

based on material properties (such as shrinkage and stiffness) and the manufacturing process used. www.makrolar.eu Tolerance Tables Overview

Using official tables protects both the OEM and the molding supplier from disputes regarding part rejection.