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The American National Standards Institute is a private nonprofit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that American products can be used worldwide.
A flange is a protruded ridge, lip or rim, either external or internal, that serves to increase strength ; for easy attachment/transfer of contact force with another object ; or for stabilizing and guiding the movements of a machine or its parts. Flanges are often attached using bolts in the pattern of a bolt circle.
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 drawings are necessary to completely specify even a simple component. These drawings are linked together by a "master drawing." This "master drawing" is more commonly known as an assembly drawing. The assembly drawing gives the drawing numbers of the subsequent detailed components, quantities required, construction materials and possibly 3D images that can be used to locate individual items. Although mostly consisting of pictographic representations, abbreviations and symbols are used for brevity and additional textual explanations may also be provided to convey the necessary information.
Geometric dimensioning and tolerancing (GD&T) is a system for defining and communicating engineering tolerances via a symbolic language on engineering drawings and computer-generated 3D models that describes a physical object's nominal geometry and the permissible variation thereof. GD&T is used to define the nominal geometry of parts and assemblies, the allowable variation in size, form, orientation, and location of individual features, and how features may vary in relation to one another such that a component is considered satisfactory for its intended use. Dimensional specifications define the nominal, as-modeled or as-intended geometry, while tolerance specifications define the allowable physical variation of individual features of a part or assembly.
The Unified Thread Standard (UTS) defines a standard thread form and series—along with allowances, tolerances, and designations—for screw threads commonly used in the United States and Canada. It is the main standard for bolts, nuts, and a wide variety of other threaded fasteners used in these countries. It has the same 60° profile as the ISO metric screw thread, but the characteristic dimensions of each UTS thread were chosen as an inch fraction rather than a millimeter value. The UTS is currently controlled by ASME/ANSI in the United States.
A datum reference or just datum is some important part of an object—such as a point, line, plane, hole, set of holes, or pair of surfaces—that serves as a reference in defining the geometry of the object and (often) in measuring aspects of the actual geometry to assess how closely they match with the nominal value, which may be an ideal, standard, average, or desired value. For example, on a car's wheel, the lug nut holes define a bolt circle that is a datum from which the location of the rim can be defined and measured. This matters because the hub and rim need to be concentric to within close limits. The concept of datums is used in many fields, including carpentry, metalworking, needlework, geometric dimensioning and tolerancing (GD&T), aviation, surveying, geodesy, and others.
The Initial Graphics Exchange Specification (IGES) is a vendor-neutral file format that allows the digital exchange of information among computer-aided design (CAD) systems. It is an ASCII-based textual format.
Product and manufacturing information, also abbreviated PMI, conveys non-geometric attributes in 3D computer-aided design (CAD) and Collaborative Product Development systems necessary for manufacturing product components and assemblies. PMI may include geometric dimensions and tolerances, 3D annotation (text) and dimensions, surface finish, and material specifications. PMI is used in conjunction with the 3D model within model-based definition to allow for the elimination of 2D drawings for data set utilization.
CAD standards are a set of guidelines for the appearance of computer-aided design (CAD) drawings should appear, to improve productivity and interchange of CAD documents between different offices and CAD programs, especially in architecture and engineering.
Nominal Pipe Size (NPS) is a North American set of standard sizes for pipes used for high or low pressures and temperatures. "Nominal" refers to pipe in non-specific terms and identifies the diameter of the hole with a non-dimensional number. Specific pipe is identified by pipe diameter and another non-dimensional number for wall thickness referred to as the Schedule. NPS is often incorrectly called National Pipe Size, due to confusion with the American standard for pipe threads, "national pipe straight", which also abbreviates as "NPS". The European and international designation equivalent to NPS is DN, in which sizes are measured in millimetres, see ISO 6708. The term NB is also frequently used interchangeably with DN.
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, which pertains to CAD software and those who use CAD software to create the product definition within the 3D model. ASME issued the first version of this industrial standard on Aug 15, 2003 as ASME Y14.41-2003. It was immediately adopted by several industrial organizations, as well as the Department of Defense (DOD). The latest revision of ASME Y14.41 was issued on Jan 23, 2019 as ASME Y14.41-2019.
Model-based definition (MBD), sometimes called digital product definition (DPD), is the practice of using 3D models within 3D CAD software to define individual components and product assemblies. The types of information included are geometric dimensioning and tolerancing (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 drawings to provide such details.
In a technical drawing, a basic dimension is a theoretically exact dimension, given from a datum to a feature of interest. In Geometric dimensioning and tolerancing, basic dimensions are defined as a numerical value used to describe the theoretically exact size, profile, orientation or location of a feature or datum target.
A reference designator unambiguously identifies the location of a component within an electrical schematic or on a printed circuit board. The reference designator usually consists of one or two letters followed by a number, e.g. C3, D1, R4, U15. The number is sometimes followed by a letter, indicating that components are grouped or matched with each other, e.g. R17A, R17B. The IEEE 315 standard contains a list of Class Designation Letters to use for electrical and electronic assemblies. For example, the letter R is a reference prefix for the resistors of an assembly, C for capacitors, K for relays.
Engineering drawing abbreviations and symbols are used to communicate and detail the characteristics of an engineering drawing. This list includes abbreviations common to the vocabulary of people who work with engineering drawings in the manufacture and inspection of parts and assemblies.
Tolerance analysis is the general term for activities related to the study of accumulated variation in mechanical parts and assemblies. Its methods may be used on other types of systems subject to accumulated variation, such as mechanical and electrical systems. Engineers analyze tolerances for the purpose of evaluating geometric dimensioning and tolerancing (GD&T). Methods include 2D tolerance stacks, 3D Monte Carlo simulations, and datum conversions.
In manufacturing and mechanical engineering, flatness is an important geometric condition for workpieces and tools. Flatness is the condition of a surface or derived median plane having all elements in one plane.
A reference dimension is a dimension on an engineering drawing provided for information only. Reference dimensions are provided for a variety of reasons and are often an accumulation of other dimensions that are defined elsewhere. These dimensions may also be used for convenience to identify a single dimension that is specified elsewhere.
Model-based enterprise (MBE) is a term used in manufacturing, to describe a strategy where an annotated digital three-dimensional (3D) model of a product serves as the authoritative information source for all activities in that product's lifecycle.
Geometrical Product Specification and Verification (GPS&V) is a set of ISO standards developed by ISO Technical Committee 213. The aim of those standards is to develop a common language to specify macro geometry and micro-geometry of products or parts of products so that the language can be used consistently worldwide.
References
- ↑ "Dimensioning and Tolerancing". ASME. Retrieved 5 May 2019.
- ↑ "SAI Webstore - ANSI Y14.5-1973". Archived from the original on 6 May 2019. Retrieved 5 May 2019.
- ↑ Dimensioning and Tolerancing - Table of Contents (PDF) (2018 ed.). The American Society of Mechanical Engineers.
- ↑ Morse, Edward (1 August 2016). "Tolerancing Standards: A Comparison". Quality Magazine. Archived from the original on 11 September 2017.
- ↑ MacMillan, David M.; Rollande, Krandall (2014). "History of Geometric Methods In Dimensioning and Tolerancing". Circuitous Root. Archived from the original on 25 November 2017. Retrieved 5 May 2019.
- 1 2 MacMillan, David M.; Rollande, Krandall (2014). "Bibliography for Dimensioning and Tolerancing With an Emphasis on Geometric Methods". Circuitous Root. Archived from the original on 27 March 2019. Retrieved 5 May 2019.
