June 18, 2006
June 18, 2006
June 21, 2006
11.1146.1 - 11.1146.7
Standardization Learning from Past; Preparing for the Future Abstract
This paper will look at the importance of standardization on manufacturing. The paper will compare and contrast ANSI B4.1 Preferred Limits and Fits for Cylindrical Parts and ANSI B4.2 Preferred Metric Limits and Fits and provide a practical example of how of to utilize these standards in a freshman technical graphics course to show how standardization can reduce cost through simplifying design and part reduction.
ANSI B4.1 and B4.2
ANSI B4.1-1967 (R1974), Reaffirmed in 1999 – Preferred Limits and Fits for Cylindrical Parts has been the historical standard for designing the relationship between shafts and holes and is based upon work which began in 1920. The Scope and Application of the standard states, “The recommendations are presented for guidance and for use where they might serve to improve and simplify products, practices, and facilities.
ANSI B4.2-1978, Reaffirmed in 1999 – Preferred Metric Limits and Fits describes the ISO system of limits and fits for mating parts. Notice that this standard does not include the words, “Cylindrical Parts” in its title. This standard expanded its scope by redefining “the general terms “hole” and “shaft” to also refer to the space containing or contained by two parallel faces of any part, such as the width of a slot, the thickness of a key, etc.” There are other important improvements in this standard over B4.1 that will be discussed in the balance of this paper.
Standardization and Design for Manufacturability
Standardization in the context related to technologies and industries, is the process of establishing a technical standard among competing entities in a market, that will bring benefits without hurting competition.3 Standards can be de facto, which means they are followed for convenience, or de jure, which means they are used because of (more or less) legally binding contracts and documents.3 In the case of ANSI B4.1 and B4.2 the titles includes the word Preferred and are therefore generally considered to be de facto.
Design for Manufacturability (DFM) is the practice of designing products with manufacturing in mind, so they can 4: • Be designed in the least time with the least development cost. • Make the quickest and smoothest transition into production. • Be assembled and tested with the minimum cost in the minimum amount of time. • Have the desired levels of quality and reliability. • Satisfy customers’ needs and compete well in the marketplace.
At the basis of DFM are the concepts of fewer parts and simpler designs.
Leduc, A. (2006, June), Standardization – Learning From The Past; Preparing For The Future Paper presented at 2006 Annual Conference & Exposition, Chicago, Illinois. 10.18260/1-2--879
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