File Name: asme y14 5 dimensioning and tolerancing 2009 .zip
Part 3 - Tips on creating and implementing an addendum Introduction Welcome to part three of the article on addendums. It covers a few tips on creating and implementing an addendum in your organization. How to implement an addendum is just as important as the creation process. This section covers a few tips on creating an addendum. The tips are divided into three parts; useful information, tips for creation, and typical pitfalls to avoid. The list below contains an example of useful information for creating an addendum.
All of the items may not apply to your organization. The list below contains common addendum pitfall. This section covers a few tips on implementing an addendum. All of these tips may not apply to your organization. Hopefully, some insights were gained with this brief look at addendums.
As you may have noticed, I am an advocate of using addendums in large corporations. Developing an addendum renews the focus on the importance of drawings. If you would like to see an example of an addendum, you can purchase a copy of the GM addendum by clicking the button below. Does your company use an addendum? Do you have any suggestions for items that should be in a Y If so, add a comment below.
If you would like assistance in creating a corporate addendum, contact me at Alex KrulikowskiConsulting. Introduction This part of the article on addendums to Y Throughout this article where a number appears between square brackets, e. There are five categories of content commonly found in corporate addendums. Allow the use of only one of several optional methods. Change a default condition. Clarify a concept, symbol, modifier, or definition for your companies' application. Document the use of a tolerancing practice that is not in the Y Examples of modifications in each content category are in the paragraphs below.
Corporate addendums may include many or just a few modifications. This article contains a few examples of modifications that are common in addendums. The format of an addendum varies in each company. The format shown here may not be optimal for your company.
The examples in this article are not arranged in the sequence of a typical addendum. The examples are grouped by category. This content category is popular in addendums. Selecting an option when several practices are permitted in the Y T he list below contains a few examples of selecting an option from the Y In most cases default conditions are not revised in an addendum; they are addressed on the face of a drawing.
What should be in an addendum is a list of which defaults should be overridden on your drawings and instructions on how to override them. Changing a default can be beneficial because the default may not be the best for your company. For a list of common defaults in the Y The advantage of revising standard defaults on the face of a drawing is that the requirement or condition is visible to the drawing users. The list below contains a few examples where clarifying a concept from the Y Each ASME standard contains a paragraph citing a list of additional standards it invokes and provides a method to determine which standards are partially invoked.
However, many companies have difficulty understanding exactly which standards, and which versions apply to their drawings. Discouraging or disallowing the use of a symbol or concept is important because it reduces the number of tolerancing tools available for use on drawings. There are many tolerancing tools in the Y There are also tolerancing tools that are not used often.
There are often discussions over which symbol is better for an application. The addendum focuses the discussions by disallowing or discouraging certain tolerancing tools leaving the tolerancing tools needed for defining your products.
Tolerancing tools can be disallowed for a variety of reasons. A few tolerance tools are overly restrictive for most applications or are not a good tool for your companies' applications.
A few tolerancing tools that are only used in rare applications may be disallowed or discouraged to prevent their widespread use. The list below contains a few examples of disallowing or discouraging a concept, symbol, or modifier. The Statistical Tolerance modifying symbol shall not be used.
The "alternative practice" to control parallel and perpendicular relationships shall not be used. Direct tolerancing often referred to as plus and minus or limit tolerancing methods shall not be used for location or orientation of features of size. The practice to override the degrees of freedom by reference of an order of precedence shall not be used.
Another area that I recommend companies to address is to discourage "extension of principle" on their drawings when a tolerance application is not in the Y Even though the extended principle may make sense to the drawing creator, since its interpretation is not documented, it can be interpreted differently by drawing users.
Documenting the use of a symbol or concept that is not covered in the Y It helps drawing users to have a consistent interpretation of the drawing requirements. If you add a new symbol or concept, it should be fully explained from a functional and inspection standpoint. The list below contains a few examples of tolerancing tools that are not in the Y In this section, only example topics are listed, the entire addendum text and figures to fully describe these items are too lengthy for this article.
Adding new tolerancing tools in your addendum should be used sparingly. Adding new tolerancing tools can cause problems for CAD, analysis, and inspection software. In part two, we looked at each of the five content categories of corporate addendums.
Each corporate addendum is different based on their unique situation. Every addendum will not address all five of the above categories. An addendum may also include additional information not discussed in this article. Part three of this article will be posted next week. In part three, you will learn a few tips on creating and implementing an addendum in your organization. About this article This article consists of three parts.
The first part discusses whether using an addendum to the Y The second part explains the five content categories typically found in an addendum. The third part provides tips on creating and implementing an addendum. If you answered yes to any of the questions above, then you should consider creating an addendum to the Y I can read your mind. Some of you are wondering "Why do I need to go through the expense of creating and implementing an addendum when I am getting along just fine using the Y However, have you considered the following?
T he Y Imagine you were in a contest and won a giant toolbox filled with hundreds of different tools. The tools could handle almost any kind of plumbing, electrical, or mechanical repair job that came along. This toolbox has so many tools that knowing how or when to use all the tools would be difficult. The giant toolbox is good because you could use the tools that you are familiar with to do many jobs.
It would also be bad because there would be tools that you were not familiar with and you might end up using them in the wrong places. The Y Having a standard that is like a giant toolbox is useful because it provides tolerancing tools that are needed for most applications in many companies.
It also can be confusing because it contains tolerancing tools that are not useful in a particular company. This toolbox approach requires users to choose from several tolerancing tools to select the one that is best suited for their application.
Which tolerancing tool is best for my application? In some cases, it provides multiple ways to communicate the same requirement. There are also cases where there are tolerancing tools that are needed in a particular industry but are not covered in the Y An addendum can improve the use of the Y An addendum is a document that supplements the Y It may also supplement other ASME standards as well. In some companies, an addendum exists under other names like corporate standard, engineering standard, or another name.
If your addendum documents a change to a default condition or adds a tolerancing tool, not in the standard, the addendum must be referenced on each drawing for interpretation. In this case, your addendum must also be accessible to all drawing users.
ASME Y In today's modern and technically advanced design, engineering and manufacturing world, effective communication is required to ensure the design and manufacture of successful products. A datum is just a fancy word for saying which specific feature on a part will be used as a reference zero for tolerance calculations, dimensional measurement, and most importantly, from where the feature s manufacturing should build from to ensure a consistent part. Without the use of a datum system zero reference on a part, it is not clear to manufacturing or quality where to manufacture or measure from. Additionally, the use of datums dramatically simplifies the design and specification of fixtures for use in manufacturing and quality verification steps. This means the derived center of each of the holes must fall within a square tolerance zone. In figure 2, there is a dimension attached to the top left and bottom right corners.
Part 3 - Tips on creating and implementing an addendum Introduction Welcome to part three of the article on addendums. It covers a few tips on creating and implementing an addendum in your organization. How to implement an addendum is just as important as the creation process. This section covers a few tips on creating an addendum. The tips are divided into three parts; useful information, tips for creation, and typical pitfalls to avoid.
ASME Y The Y standard is considered the authoritative guideline for the design language of geometric dimensioning and tolerancing (GD&T).
Asme y ASME Y It contains 12 sections which cover symbols and datums as well as tolerances of form, orientation, position, profile and runout. Zagad Faist.
In a general tolerance block.
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