Free PDF of DIN EN ISO 8062-3:2008 - General dimensional and geometrical tolerances for castings
ISO 8062-3: A Guide to General Dimensional and Geometrical Tolerances for Castings
If you are involved in the design, manufacture, or purchase of castings, you may have heard of ISO 8062-3, a standard that specifies general dimensional and geometrical tolerances as well as machining allowance grades for castings using tolerances for indicated dimensions. But what exactly is ISO 8062-3 and how can it help you achieve more accurate and consistent castings? In this article, we will explain the scope, purpose, benefits, and application of ISO 8062-3, as well as the main changes from the previous edition. We will also provide some examples and recommendations for using ISO 8062-3 in different situations.
iso 8062-3 pdf free download
What is ISO 8062-3 and why is it important?
The scope and purpose of ISO 8062-3
ISO 8062-3 is a part of the ISO 8062 series, which covers geometrical product specifications (GPS) for moulded parts. GPS is a system of standards that defines the concepts, principles, rules, and methods for specifying and verifying the dimensional and geometrical characteristics of products. GPS helps to ensure that products meet the requirements and expectations of customers and users in terms of functionality, quality, reliability, and safety.
ISO 8062-3 is applicable for tolerancing of dimensions and geometry of castings in all cast metals and their alloys produced by various casting manufacturing processes. Castings are products obtained by pouring molten metal into a mould cavity and allowing it to solidify. Casting is one of the oldest and most widely used methods of producing metal parts with complex shapes and sizes.
The purpose of ISO 8062-3 is to provide a system of tolerance grades and machining allowance grades for castings as delivered to the purchaser according to ISO/TS 8062-2. Tolerance grades are groups of tolerances that define the permissible deviations from nominal dimensions or geometry. Machining allowance grades are groups of allowances that define the minimum amount of material to be removed from the casting surface by machining operations. ISO/TS 8062-2 is a technical specification that defines the requirements for specifying moulded parts using model-based definition (MBD), which is a method of using 3D models without indicated dimensions as the basis for product definition.
The benefits of using ISO 8062-3 for castings
Using ISO 8062-3 for castings can bring several benefits for designers, manufacturers, purchasers, and users, such as:
Reducing ambiguity and misunderstanding in communication and documentation
Improving compatibility and interoperability between different parts and systems
Enhancing efficiency and productivity in design, manufacturing, inspection, and verification
Optimizing quality and performance of castings
Reducing costs and waste by minimizing rework, scrap, and non-conformity
The main changes from the previous edition of ISO 8062-3
ISO 8062-3 was first published in 2007 and revised in 2019. The main changes from the previous edition are:
The introduction of MBD as the preferred method for specifying castings, which eliminates the need for indicated dimensions on drawings and simplifies the application of tolerances
The alignment of the tolerance grades and values with ISO 8062-4, which covers general dimensional and geometrical tolerances for castings using geometrical tolerancing in accordance with ISO 1101
The addition of examples and recommendations for applying ISO 8062-3 to different types of castings, such as sand castings, investment castings, die castings, and centrifugal castings
The clarification of some terms and definitions, such as nominal size, envelope requirement, and datum feature
The update of some references and normative annexes, such as ISO/TS 8062-2, ISO 1101, and ISO 14405-1
How to apply ISO 8062-3 to castings?
The general principles and rules of ISO 8062-3
ISO 8062-3 is based on the following general principles and rules:
iso 8062-3 pdf free download geometrical product specifications
iso 8062-3 pdf free download dimensional and geometrical tolerances for moulded parts
iso 8062-3 pdf free download general dimensional and geometrical tolerances and machining allowances for castings
iso 8062-3 pdf free download gps standard
iso 8062-3 pdf free download complementary process-specific tolerance standard
iso 8062-3 pdf free download chain of standards on mouldings
iso 8062-3 pdf free download vocabulary part 1
iso 8062-3 pdf free download rules part 2 technical specification
iso 8062-3 pdf free download gps matrix model annex f
iso 8062-3 pdf free download cancels and replaces iso 8062:1994
iso 8062-3 pdf free download technical revision
iso 8062-3 pdf free download international standard
iso 8062-3 pdf free download international organization for standardization
iso 8062-3 pdf free download technical committee iso/tc 213
iso 8062-3 pdf free download dimensional and geometrical product specifications and verification
iso 8062-3 pdf free download patent rights
iso 8062-3 pdf free download approval by at least 75% of the member bodies casting a vote
iso 8062-3 pdf free download tolerance grades
iso 8062-3 pdf free download individual dimensional and geometrical tolerances
iso 8062-3 pdf free download relevant gps standards on dimensional and geometrical tolerancing
iso 8062-3 pdf free download general tolerances
iso 8062-3 pdf free download functional reasons or economical reasons
iso 8062-3 pdf free download individual tolerances shall be indicated
iso 8062-3 pdf free download drawings where the tolerances only apply under specified restricted conditions
iso 8062-3 pdf free download refer to iso 10579 on the drawing
iso 8062-3 pdf free download linear dimensional casting tolerance grades dctg
iso 8062-3 pdf free download defined and designated as dctg 1 to dctg 16
iso 8062-3 pdf free download table 2 linear dimensional casting tolerances dct
iso 8062-3 pdf free download wall thicknesses clause 7
iso 8062-3 pdf free download annex a gives recommendations for the application of the above tolerance grades
iso 8062-3 pdf free download default conditions for the dimensions
The use of tolerances for indicated dimensions
If indicated dimensions are used on drawings or models to specify the nominal size or location of features on castings, they shall be given with tolerances. The tolerances shall be derived from the tolerance grades specified in ISO 8062-3. The tolerances shall not be modified by any other means, such as maximum material condition (MMC) or least material condition (LMC) modifiers.
The use of general dimensional and geometrical tolerances
If indicated dimensions are not used on drawings or models to specify the nominal size or location of features on castings, general dimensional and geometrical tolerances shall be applied. General dimensional and geometrical tolerances are tolerances that apply to all dimensions or geometry of features on castings that are not individually indicated. General dimensional and geometrical tolerances shall be specified by using the symbols and indications given in ISO 8062-3. General dimensional and geometrical tolerances shall not be combined with any other type of tolerances, such as individual or geometrical tolerances.
The use of machining allowance grades
If machining operations are required to achieve the final dimensions or geometry of features on castings, machining allowance grades shall be specified. Machining allowance grades are grades that define the minimum amount of material to be removed from the casting surface by machining operations. Machining allowance grades shall be specified by using the symbols and indications given in ISO 8062-3. Machining allowance grades shall not be confused with roughness values or surface texture symbols.
The tolerance grades and values of ISO 8062-3
ISO 8062-3 provides four types of tolerance grades for castings: dimensional casting tolerance grades (DCTG), geometrical casting tolerance grades (GCTG), surface mismatch (SMI) tolerances, and wall thickness tolerances. It also provides four types of machining allowance grades for castings: required machining allowances (RMA), minimum local thickness (MLT), minimum remaining wall thickness (MRWT), and minimum distance to a hole (MDH). The tolerance grades and values are given in tables in ISO 8062-3.
The dimensional casting tolerance grades (DCTG)
The DCTG are groups of tolerances that define the permissible deviations from nominal dimensions for linear sizes, diameters, radii, angles, chamfers, fillets, grooves, slots, holes, bosses, ribs, webs, flanges, etc. The DCTG are designated by a letter from A to G followed by a number from 1 to 18. The letter indicates the type of feature (A for linear size, B for diameter, C for radius or angle, D for chamfer or fillet, E for groove or slot, F for hole or boss, G for rib or web) and the number indicates the level of accuracy (1 being the most accurate and 18 being the least accurate). For example, DCTG B6 means a diameter tolerance grade with a level of accuracy of 6.
The DCTG values depend on the nominal size range and the casting manufacturing process. The nominal size range is divided into six categories: up to 6 mm, over 6 mm up to surface alignment between two adjacent parts of a casting that are produced in separate moulds or cores. The SMI tolerances are designated by the letter L followed by a number from 1