几何尺寸与公差论坛------致力于产品几何量公差标准GD&T (GDT:ASME)|New GPS(ISO)研究/CAD设计/CAM加工/CMM测量  


返回   几何尺寸与公差论坛------致力于产品几何量公差标准GD&T (GDT:ASME)|New GPS(ISO)研究/CAD设计/CAM加工/CMM测量 » Norm Space: Product Automatic Standards - 范数空间:产品自动化标准 » National Standards » American standards
用户名
密码
注册 帮助 会员 日历 银行 搜索 今日新帖 标记论坛为已读


回复
 
主题工具 搜索本主题 显示模式
旧 2009-04-29, 09:23 PM   #1
yang686526
高级会员
 
注册日期: 06-11
帖子: 14579
精华: 1
现金: 224494 标准币
资产: 234494 标准币
yang686526 向着好的方向发展
默认 【转帖】positional tolerancing of symmetrical features

positional tolerancing of symmetrical features
folks-
i do a lot of sheetmetal design for electronics and often have a need to apply tolerances to symmetrical features. one such example is the panel cutout for a 25-pin "d" connector. i've seen examples where slots are controlled with a bilateral geometric positional tolerance feature control frame applied to the length dimension (tangent-tangent) and where a second bilateral fcf is applied to the width dimension. but what about the panel cutout for the "d" connector? we'd like to functionally link the two mounting holes with the cutout. can a central width datum be created by the tangent-to-tangent dimension of the cutout? technically speaking, the two tangents are not parallel opposing surfaces which seems to be a requirement for a width datum. tia for your help!
tunalover
yes it could be. however i would tend to question the need for positional tolerancing of a d hole on a panel.
ringman-
thanks for the input but i wasn't talking about a d-hole. i was talking about a panel detail for a d connector. these are two distinctly different things.

tunalover
i think ringman meant that. i also agree with him.
chris
sr. mechanical designer, cad
solidworks 05 sp2.0 / pdmworks 05
ringman and ctopher,
a d hole consists of the d shaped hole, plus two more holes for the jack screws.
when i do a d hole, i dimension to one of the jackscrew holes on the main view and i do a detail. the detail shows the d hole and the jackscrews dimensioned symmetrically. i just use the +/- tolerances, since these are adequate, and since asme y14.5m-1994 states that if the holes are shown symmetric, they are symmetric.
the big hole does not have to be accurate. since the jackscrew is two screws, a +/-.005" tolerance is adequate assuming a .125" hole and 4-40unc jackscrews (.112"dia).
jhg
yang686526离线中   回复时引用此帖
GDT自动化论坛(仅游客可见)
回复


主题工具 搜索本主题
搜索本主题:

高级搜索
显示模式

发帖规则
不可以发表新主题
不可以回复主题
不可以上传附件
不可以编辑您的帖子

vB 代码开启
[IMG]代码开启
HTML代码关闭

相似的主题
主题 主题发起者 论坛 回复 最后发表
【转帖】physical identification of datum features yang686526 American standards 0 2009-04-29 09:16 PM
【转帖】gdt 9gps0 per iso 1101, 8015, 2768 yang686526 American standards 0 2009-04-29 08:03 PM
【转帖】fully employing positional tolerancing over rectangular tole yang686526 American standards 0 2009-04-29 08:02 PM
【转帖】asme - where to star yang686526 American standards 0 2009-04-29 07:28 PM


所有的时间均为北京时间。 现在的时间是 05:44 PM.


于2004年创办,几何尺寸与公差论坛"致力于产品几何量公差标准GD&T | GPS研究/CAD设计/CAM加工/CMM测量"。免责声明:论坛严禁发布色情反动言论及有关违反国家法律法规内容!情节严重者提供其IP,并配合相关部门进行严厉查处,若內容有涉及侵权,请立即联系我们QQ:44671734。注:此论坛须管理员验证方可发帖。
沪ICP备06057009号-2
更多