计算焊锡膏的使用

{0>Many people try to determine the volume of solder paste that they will use on a given circuit board or during a full production run.  Calculating the exact amount of solder paste needed can be difficult to achieve because of the print deposit variations, the paste left on the stencil and squeegees after the build is complete, and the bead size needed for the build, which will depend on the squeegee size.  The theoretical volume of solder paste can be calculated for each board using the Greely Formula and a simple volume calculation.<}0{>许多人想确定他们在某个电路板或者在整个生产流程过程中将使用的焊锡膏用量。计算确切数量的焊锡膏是困难的，因为印刷沉积量有变化,建设完成后在模版或橡胶滚轴留有焊锡膏,建设需要的珠粒取决于橡胶滚轴的大小。利用Greely公式和简单的体积计算可以计算出焊锡膏的理论量。<0}

{0>The Greely Formula allow for the calculation of the specific gravity of the particular solder paste being used. <}0{>Greely可以计算被使用具体焊锡膏的比重。<0}

{0>The Greely Formula:<}100{>Greely公式:

{0>Specific Gravity of the Flux vehicle is generalized to 1. <}97{>助焊剂载体的比重被概括成1。 <0}

{0>Example:<}100{>示例：<0}

·         {0>Solder Paste:<}100{>焊锡膏:<0} {0>SAC305 Indium8.9HFA Type 4.5 87.75%<}88{>SAC305 Indium8.9HFA, 类型 4.5, 87.75%<0}

·         {0>Aperture Size:<}100{>孔径尺寸:<0} {0>0.012” Square<}100{>0.012” 平方<0}

·         {0>Stencil Thickness:<}100{>蜡板厚度:<0} 0.004”

{0>Solder Paste Specific Gravity = 4.14<}100{>焊锡膏比重 = 4.14<0}

{0>Volume for this aperture can be calculated using the following formula:<}100{>该孔径的体积可以使用下列公式计算:<0}

{0>Length x Width x Height<}100{>长 x 宽 x 高<0}

{0>0.012” x 0.012” x 0.004” = 0.000000576 inches³<}98{>0.012” x 0.012” x 0.004” = 0.000000576 英寸³<0}

{0>To get the theoretical weight of the solder paste for the 0.012” square aperture you must multiply the solder paste theoretical volume by the solder paste density. <}100{>为了得到 0.012”平方孔径的理论重量的焊锡膏，你必须用焊锡膏的密度乘以焊锡膏的理论体积。 <0}

{0> 0.000000576 inches³ * 4.14gm/cm³ = 0.000009439cm³ * 4.14gm/cm³ = 0.0000391gm<}90{> 0.000000576 英寸³ * 4.14gm/cm³ = 0.000009439cm³ * 4.14gm/cm³ = 0.0000391gm<0}

{0>To calculate the theoretical amount of solder paste that will be used for each board the weight of solder paste for each aperture on the board will need to be calculated.  Once all of the weights have been calculated they can be added together which will result in the amount of solder paste per board. <}99{>为了计算每块板使用的理论量的焊锡膏, 电路板上每个孔径的焊锡膏的重量都需要计算。一旦所有的重量经过计算，它们可以加在一起，从而得出每块板的焊锡膏用量。 <0}

{0>Of course this is the theoretical value and not an actual value.  The easiest way to determine the actual paste weight per board is to weigh a board before the paste has been printed and then again after the paste has been printed.  The difference is the actual solder paste weight or consumption of solder paste per board.<}100{>当然，这是理论值，不是实际值。测定每块板的实际焊锡膏 重量就是在电路板被印刷之前称重电路板，然后在电路板刷 之后再称重。 差距就是每块块实际的焊锡膏重量或焊锡膏的消耗量。<0}{0>Of course, there will be some amount of error even in this calculation which will depend on the weight tolerances of the board and the variations in solder paste deposits from print to print.  <}85{>当然, 即使这种计算也有差异，原因在于电路板的砝码允差和印刷期间焊锡膏的沉积量不同。

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