机械菜鸟90 发表于 2015-2-10 13:17:54

貌似大侠忽视了,这是个主视图,如果,要是加工成一边大一边小,是不是需要出个俯视图,看看

BULINGBULING 发表于 2015-2-10 14:12:57

大侠说的对啊

召唤师170 发表于 2015-2-10 14:22:33

机械菜鸟90 发表于 2015-2-10 13:17 static/image/common/back.gif
貌似大侠忽视了,这是个主视图,如果,要是加工成一边大一边小,是不是需要出个俯视图,看看

不是要加工成一边大一边小,而是按图上的标注的话即使加工成一边大一边小,按图纸验收你都没办法判别人不合格{:2_41:}

爱哭的CR7 发表于 2015-2-10 15:20:49

业精于勤荒于嬉,形成于思毁于随

seekfor 发表于 2015-2-10 19:40:28

本帖最后由 seekfor 于 2015-2-10 19:41 编辑

其实人家图纸根本没有错,你想歪了。
1、从这个视图看过去那根线就是表示的那个表面,注意(默认的basic dimension 90°)。并没有你所表述的、歪成那样的位置下(basic dimension 不为90°)再评价垂直度。我觉得你把这个垂直度理解为平面度了。
附上一些尺寸的基本原则:
a) Each dimension shall have a tolerance, except for those dimensions specifically identified as
reference, maximum, minimum, or stock (commercial stock size). The tolerance may be applied directly
to the dimension (or indirectly in the case of basic dimensions), indicated by a general note, or located in
a supplementary block of the drawing format. See ANSI Y14.1.
(b) Dimensioning and tolerancing shall be complete so there is full understanding of the characteristics of each feature. Neither scaling (measuring the size of a feature directly from an engineering
drawing) nor assumption of a distance or size is permitted, except as follows: Undimensioned drawings,
such as loft, printed wiring, templates, and master layouts prepared on stable material, are excluded
provided the necessary control dimensions are specified.
(c) Each necessary dimension of an end product shall be shown. No more dimensions than those
necessary for complete definition shall be given. The use of reference dimensions on a drawing should
be minimized.
(d) Dimensions shall be selected and arranged to suit the function and mating relationship of a part
and shall not be subject to more than one interpretation.
(e) The drawing should define a part without specifying manufacturing methods. Thus, only the
diameter of a hole is given without indicating whether it is to be drilled, reamed, punched, or made by any
other operation. However, in those instances where manufacturing, processing, quality assurance, or
environmental information is essential to the definition of engineering requirements, it shall be specified on the drawing or in a document referenced on the drawing.
(f) It is permissible to identify as nonmandatory certain processing dimensions that provide for
finish allowance, shrink allowance, and other requirements, provided the final dimensions are given on
the drawing. Nonmandatory processing dimensions shall be identified by an appropriate note, such as
NONMANDATORY (MFG DATA).
(g) Dimensions should be arranged to provide required information for optimum readability. Dimensions should be shown in true profile views and refer to visible outlines.
(h) Wires, cables, sheets, rods, and other materials manufactured to gage or code numbers shall be
specified by linear dimensions indicating the diameter or thickness. Gage or code numbers may be
shown in parentheses following the dimension.
(i) A 90° angle applies where center lines and lines depicting features are shown on a drawing at
right angles and no angle is specified.
(j) A 90° basic angle applies where center lines of features in a pattern or surfaces shown at right
angles on the drawing are located or defined by basic dimensions and no angle is specified.
(k) Unless otherwise specified, all dimensions are applicable at 20°C (68°F). Compensation may be
made for measurements made at other temperatures.
(l) All dimensions and tolerances apply in a free state condition. This principle does not apply to
nonrigid parts as defined in section 5.5.
(m) Unless otherwise specified, all geometric tolerances apply for full depth, length, and width of the
feature.
(n) Dimensions and tolerances apply only at the drawing level where they are specified. A dimension
specified for a given feature on one level of drawing, (for example, a detail drawing) is not mandatory for
that feature at any other level (for example, an assembly drawing)
一下是其中一个中文PPT中的,中文的仅供参考,翻译不全感觉,也感觉不是很贴切愿意。




solomoon 发表于 2015-2-10 23:07:47

楼主大侠,要说一个图纸有没有问题先看是不是满足功能,功能不清楚的情况下不好说是否不合理。

从原图上看,两个端面是允许倾斜的,符合自由的形位公差就可以了,

但是标注垂直度的两端面,平面度必然在0.02的范围内,要不然就超差了,无法保证垂直度的要求。

图纸在不明白功能时,不能说有问题

zerowing 发表于 2015-2-10 23:20:33

solomoon 发表于 2015-2-10 23:07 static/image/common/back.gif
楼主大侠,要说一个图纸有没有问题先看是不是满足功能,功能不清楚的情况下不好说是否不合理。

从原图上 ...


还是拿这个图说。图中左右两个图的黑线就是所谓的垂直度限定面。
你可以明显看到,无论左右都肯定跟底面或者说背景面垂直的。对吧。
但是右图明显和左图是不平行的。
里面的红线是可能的加工后实际面。绿线是你检测的基准面。
所以很明显,如果出现右图的倾斜情况,你再用绿线基准面检查那个平面度的时候,就不可能控制0.02的精度要求。


这个图的问题在于缺失了一个相对左端面的限定要求。导致你的实际加工面和实际测量面的偏差变大。那个默认的平面度就很难说了。


zerowing 发表于 2015-2-10 23:43:09

seekfor 发表于 2015-2-10 19:40 static/image/common/back.gif
其实人家图纸根本没有错,你想歪了。
1、从这个视图看过去那根线就是表示的那个表面,注意(默认的basic d ...


借前面三纬图说好了。你可能更容易理解。
你看图中的斜面,他和底面肯定是严格垂直的吧。你单去测他自己的平面度,也一定是小于0.02的吧。

那现在问题就出来了。如果这个斜面达不到让你一眼看出来的程度,你怎么打他表面的平面度?或者说你打表的基准是什么?肯定是底面和左端面或者底面和侧面。那这个斜面自身的偏差可能就足够吃掉你假象中的垂直度自带平面度要求了。你再验收就没法说了。所以,同样的问题,你拿这张图找人家,人家打平面度给你转个偏角,一打,在0.02之内。你说你怎么要求呢。

seekfor 发表于 2015-2-10 23:44:34

seekfor 发表于 2015-2-10 19:40 static/image/common/back.gif
其实人家图纸根本没有错,你想歪了。
1、从这个视图看过去那根线就是表示的那个表面,注意(默认的basic d ...


仅考虑图纸,我个人是这样理解的。
如果真要你那样理解的话,很多图纸都没法标了。
你的理解我也理解,就是只看那个垂直度标注,0.02|A,不考虑整张图纸去计量;这种情况下我完全同意;
但是,我不赞成这种方式。
我还是坚持我的理解:


zerowing 发表于 2015-2-11 01:42:48

seekfor 发表于 2015-2-10 23:44 static/image/common/back.gif
仅考虑图纸,我个人是这样理解的。
如果真要你那样理解的话,很多图纸都没法标了。
你的理解我也理解 ...

比如这个情况吧。

哈哈。有点扣定义的意思。
实际中测定的时候,如果平面度和垂直度是分别测量的,那么,原则上说,只要人们都是那么理解,自然最后的结果很喜人。
如果是一同测量的,那么很大程度上,就是找两个基准面,把标架好,沿着被测面打一圈。那就成了我之前说的那种情况了。
但是从定义要求上来说,垂直度并没有要求说类似上图中的波动是不允许的。所以,这种情况下,你可以说超差了。但是他不垂直吗?所以来说,垂直度实际上只是界定了倾斜状态下对于偏差的要求。并未实际要求或包含平面度的要求。
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