如果说工程图，是工程师交流的语言；
那么，GD&T，就是语法。
在大学里学的GB机械制图，相当于学了四则运算；这在一般的日常生活里，是已经够用了，但效率不高，易出错。
本帖最后由 憨老马 于 2012-7-20 10:50 编辑
宝龙 发表于 2011-8-7 20:49 static/image/common/back.gif
其实 我想说的是这里怎么没有人讨论GD&T的话题? 是大家不重视吗?还是大家都是精通的行家了? 图纸都按照标 ...
啊！人人都如楼主这么认真的话，那该多好。
昨天我给单位的同事发了个电邮，内容是：
有关力学（以及其他）的计量单位，我国早在1986年就已经修订过，废除了一批国际上已经过时的名称与表示符号。请你们以后在工作中多注意，否则容易会被人有其他想法，起码觉得我们不规范！
电邮中我举出实例，但还有人不服气，说看到很多人（地方）还在用，那该怎么办！
这些文件是我当年在国企任职“标准计量室”时的，带了20多年了。当看到有不规范的，像吃了苍蝇般恶心啊！
这是否就是人家所厌恶的“固执”了呢：http://bbs.cmiw.cn/forum.php?mod=viewthread&tid=270309！？
本帖最后由 喀秋莎 于 2012-7-20 12:09 编辑
Geometric Dimensioning and Tolerancing (GD&T) is a language used on mechanical engineering drawings composed of symbols that are used to efficiently and accurately communicate geometry requirements for associated features on components and assemblies. GD&T is, and has been, successfully used for many years in the automotive, aerospace, electronic and the commercial design and manufacturing industries.In today's modern and technically advanced design, engineering and manufacturing world, effective and accurate communication is required to ensure successful end products. Currently, ASME Y14.5-2009 is the accepted geometric dimensioning and tolerancing standard superseding ANSI Y14.5M-1994 used within the USA and ISO 1101-2004 is used outside of the the USA.Success oriented industries and organizations which, require accurate and common lines of communications between engineering, design, manufacturing and quality should consider geometric dimensioning and tolerancing (GD&T) as their mechanical drawing standard. Some advantages of GD&T (geometric dimensioning and tolerancing) are;
1.Provides a clear and concise technique for defining a reference coordinate system (datum's) on a component or assembly to be used throughout the manufacturing and inspection processes.
2.Proper application of geometric dimensioning closely dovetails accepted and logical mechanical design process and design for manufacturing considerations.
3.Geometric dimensioning dramatically reduces the need for drawing notes to describe complex geometry requirements on a component or assembly by the use of standard symbology that accurately and quickly defines design, manufacturing and inspection requirements.
4.GD&T concepts such as MMC (maximum material condition) when applied properly will facilitate and simplify the design of cost saving functional check gages, manufacturing fixtures and jigs.
The following ar common reasons one should apply GD&T principles:
1.Part features are critical to function or interchangeability.
2.When functional gauging techniques are desired.
3.When a common reference (origin) or datum is required to ensure communication is consistent between design, manufacturing and inspection.
4.When a standard interpretation or tolerance is not already implied.
5.Simplify tolerance analysis.
6.Replace complex or long geometry requirement description notes with a single geometric symbol.
憨老马 发表于 2012-7-20 10:44 static/image/common/back.gif
啊！人人都如楼主这么认真的话，那该多好。
昨天我给单位的同事发了个电邮，内容是：
现在国内基本上整个行业都浮躁的一塌糊涂。一些最基本的准则都没人在意了。以前，我们只是技术上落后，但起码大家还是认认真真的按规范做事，现在，我们连标准和规范都落后了，没几个人考虑这些了。看看以前一些国企的图纸，再跟现在的比一下，感觉就是在倒退。从企业到个人，几乎都把工程设计的一些基本原则丢掉了。美国人的优势在于高速的创新，德国人的优势在于认真，我们呢？看看整个行业的现状，真让人伤心。
从图纸标注公差来看，公差标注确实很重要，GD&T确实解释得很清楚了，必威APP精装版下载不少版块都以后讨论，讨论了几年了。
我感觉是，GD&T懂60%就够了，再多就纯粹是玩数学了，是质检的人在玩设计的人。
从机械设计来说，图纸公差的标注的重要性应该不是最重要的的，原理设计，材料，功能实现远比他重要。当然，硬是较真，图纸公差也没有什么不重要的理由。
很多初始设计，是根本不标公差或者忽略公差的，机器造出来了，原理实验了，后续内容才是如何设定合理公差，或者补充或者根据实际调试结果。
无论如何，GD&T是非常重要的基础知识。
俺严重同意楼主的观点！GD&T很重要，很有用。
来看看学习一下
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