ISO 1302

ISO 1302. It is an international standard published by the International Organization for Standardization that specifies the rules for the indication of surface texture on technical drawings and related documentation. The standard provides a symbolic language for designers and engineers to communicate requirements for surface characteristics to manufacturing and quality control. It is a fundamental part of the Geometrical Product Specifications system, ensuring unambiguous interpretation across global supply chains.

Overview

The standard establishes a comprehensive system for specifying surface texture parameters on engineering drawings. It was first published in 1978, with subsequent revisions aligning it with evolving practices in metrology and manufacturing. The system defined is used globally in industries such as automotive manufacturing, aerospace engineering, and precision engineering. Compliance helps prevent misunderstandings between design offices in one country and production facilities in another, such as between General Motors and a component supplier in Germany.

Scope and purpose

The primary scope is to standardize the method of indicating surface texture requirements in technical product documentation. Its purpose is to provide clear, concise, and internationally recognized symbols to define characteristics like roughness, waviness, and lay. This eliminates ambiguity that could lead to manufacturing errors or disputes during inspection at facilities like Mitsubishi Heavy Industries. The standard is intended for use by design engineers, drafters, and quality assurance personnel involved in the production of mechanical parts.

Indication of surface texture

The standard details how to apply a graphical symbol, often called the "tick symbol," to drawing leader lines or feature outlines. This symbol acts as a pointer to a set of alphanumeric codes that specify the exact surface texture requirements. The codes can define various parameters, including the arithmetic mean roughness value, which is critical for parts functioning in assemblies like those in the International Space Station. The placement of the symbol relative to the surface line conveys additional information, such as whether material removal is permitted.

Symbols and designations

A core element is the library of standardized graphical symbols. The basic symbol resembles a check mark, and additional legs or circles can be added to modify its meaning, such as specifying a "material removal prohibited" condition. These symbols are combined with alphanumeric designations that call out specific numerical values for parameters standardized in other documents, like ISO 4287. For example, a designation might specify a maximum Ra value, guiding the use of instruments like those from Taylor Hobson for verification.

Related standards

It is part of a larger family of ISO standards under the umbrella of Geometrical Product Specifications. Key directly related standards include ISO 4287, which defines surface texture parameters, and ISO 4288, which provides rules for measuring them. Other relevant standards are ISO 13565 for stratified surfaces and ISO 3274 for contact stylus instrument characteristics. This network of standards is maintained by committee ISO/TC 213, ensuring consistency across the field of dimensional metrology.

Category:ISO standards Category:Engineering drawing Category:Metrology