Model-based definition (MBD), sometimes called digital product definition (DPD), is the practice of using
3D models (such as
solid models, 3D
PMI and associated metadata) within 3D
CAD
Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve co ...
software to define (provide specifications for) individual components and product assemblies. The types of information included are
geometric dimensioning and tolerancing
Geometric Dimensioning and Tolerancing (GD&T) is a system for defining and communicating engineering tolerances and relationships. It uses a symbolic language on engineering drawings and computer-generated three-dimensional solid models that exp ...
(GD&T), component level materials, assembly level
bills of materials, engineering configurations, design intent, etc. By contrast, other methodologies have historically required accompanying use of 2D
engineering drawing
An engineering drawing is a type of technical drawing that is used to convey information about an object. A common use is to specify the geometry necessary for the construction of a component and is called a detail drawing. Usually, a number of ...
s to provide such details.
Use of the 3D digital data set
Modern 3D CAD applications allow for the insertion of engineering information such as dimensions, GD&T, notes and other product details within the 3D digital data set for components and assemblies. MBD uses such capabilities to establish the 3D digital data set as the source of these specifications and design authority for the product. The 3D digital data set may contain enough information to manufacture and inspect product without the need for
engineering drawings
An engineering drawing is a type of technical drawing that is used to convey information about an object. A common use is to specify the geometry necessary for the construction of a component and is called a detail drawing. Usually, a number o ...
. Engineering drawings have traditionally contained such information.
In many instances, use of some information from 3D digital data set (e.g., the solid model) allows for
rapid prototyping
Rapid prototyping is a group of techniques used to quickly fabricate a scale model of a physical part or assembly using three-dimensional computer aided design (CAD) data.
Construction of the part or assembly is usually done using 3D printin ...
of product via various processes, such as
3D printing
3D printing or additive manufacturing is the Manufacturing, construction of a three-dimensional object from a computer-aided design, CAD model or a digital 3D modeling, 3D model. It can be done in a variety of processes in which material is ...
. A manufacturer may be able to feed 3D digital data directly to manufacturing devices such as
CNC machines to manufacture the final product.
Limited Dimension Drawing
Limited Dimension Drawing (LDD), sometimes Reduced Dimension Drawing, are 2D drawings that only contain critical information, noting that all missing information is to be taken from an associated 3D model. For companies in transition to MBD from traditional 2D documentation a Limited Dimension Drawing allows for referencing 3D geometry while retaining a 2D drawing that can be used in existing corporate procedures. Only limited information is placed on the 2D drawing and then a note is placed to notify manufactures they must build off the 3D model for any dimensions not found on the 2D drawing.
Standardization
In 2003,
ASME
The American Society of Mechanical Engineers (ASME) is an American professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing ...
published the
ASME Y14.41
ASME Y14.41 is a standard published by American Society of Mechanical Engineers (ASME) which establishes requirements and reference documents applicable to the preparation and revision
of digital product definition data (also known as model-based ...
''Digital Product Definition Data Practices'', which was revised in 2012 and again in 2019. The standard provides for the use of many MBD aspects, such as GD&T display and other annotation behaviors within 3D modelling environment. ISO 16792
standardizes MBD within the ISO standards, sharing many similarities with the ASME standard. Other standards, such as ISO 1101 and of AS9100 also make use of MBD.
In 2013, the
United States Department of Defense
The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government charged with coordinating and supervising all agencies and functions of the government directly related to national secu ...
released
MIL-STD-31000 Revision A to codify the use of MBD as a requirement for
technical data packages (TDP).
See also
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ASME Y14.41
ASME Y14.41 is a standard published by American Society of Mechanical Engineers (ASME) which establishes requirements and reference documents applicable to the preparation and revision
of digital product definition data (also known as model-based ...
*
CAD standards
are a set of guidelines for the way Computer-aided drafting (CAD), or (CADD) Computer Aided Design and Drawing, drawings should appear, to improve productivity and interchange of CAD documents between different offices and CAD programs, especiall ...
References
External links
Model-centric Design, Design World, 2008*
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{{DEFAULTSORT:Model Based Definition
Computer-aided design
Computer-aided engineering
Product lifecycle management
Computer-aided manufacturing software