BSC什么意思

封装尺寸图的 BSC

先查Google

一说BSC是指基本值(Basic),其它还有TYP(典型值),REF参考值,单位一般会在资料里说明。

二说是Basic Spacing between Centers，

三说BSC不是单位，意思是没有误差的，也就是说这间距必须符合前面的值，这个一般在指定两个脚之间的距离时出现，比如0.050BSC就是 说两脚间距必须是50mil也就是0.050英寸

Solution 1:
BSC means "Basic Space Between Center". 

The "Drawing Requirements Manual" by Jerome Lieblich (W/C is in compliance with Mil Std 100F) defines BSC as a numerical value that is used to describe the theoretically exact size, shape, or location of a feature or datum target; this is shown on drawings enclosed in a rectangle. It is the basis for determining which permissible variations are established by tolerances on other dimensions. 

Solution 2:
"BSC" is short for BASIC. It is a numerical value used to describe the theoretical exact size, shape or location of a feature or datum target. It is the basis on which permissible variations are established by tolerances on other dimensions, in notes, or by feature control symbols. Basic dimensions are displayed on the drawing enclosed in a rectangle. 

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实际上就是要求这个尺寸值，必须是准确的，不能有误差，所以不存在 typ, min和max值。