钢网开孔面积计算公式

Calculations Recommendations: PW=1-3+ P/2 PitchPad WidthPW Rectangular Aperatures(P - mils)(PW - mils)OK? 5026TRUE 2515TRUE 2012TRUE 1610TRUE 128TRUE Recommendations: PW=0-2+ P/2 PitchPad DiaPad Dia Circular Aperatures(P - mils)(PD - mils)OK? 6032TRUE Aperture Width 4-5 particle diameters Aspect Ratio = W/t 1.5 Aspect Ratio t W Area Ratio D t Aopening=p pD2/4 Awall=p pDt = AR=D/4t W = PW - 2 to 3 AR= W/t 1.5 ApertureWStencilAspectAR (W -mils)OK?ThicknessRatioOK? (t - mils)(AR) 23TRUE63.833TRUE 12TRUE62.000TRUE 10TRUE52.000TRUE 8TRUE51.600TRUE 6TRUE41.500TRUE D = PW - 2 to 3 ArR=D/4t 0.66 ApertureDStencilArea ArR DiameterOK?ThicknessRatioOK? (D-mils)(t-mils)(ArR) 30TRUE51.5TRUE Aperture Width 4-5 particle diameters Aspect Ratio = W/t 1.5 Aspect Ratio t W Inputs: milsOutputs: mils L(min)75Aperture or Land L(max)85A23 T(max)26B69 W(max)53C115 X63 Y46 Aperture Only D34.5 F61 Home Plate Stencil Design: Minimizes Solder Balling Near Passives DefinitionsLand PatternsStencil Aperatures A=Lmin-2Tmax B=Pad Pitch=A+Y C=Lmax+30 D=0.75Y F=X-2 L=Passive length tolerances Tmax=Passive max thickness Wmax=Passive max width X=Wmax+10 Y=0.5(C-A) A B Y F X C D Y Home Plate Stencil Design: Minimizes Solder Balling Near Passives DefinitionsLand PatternsStencil Aperatures A=Lmin-2Tmax B=Pad Pitch=A+Y C=Lmax+30 D=0.75Y F=X-2 L=Passive length tolerances Tmax=Passive max thickness Wmax=Passive max width X=Wmax+10 Y=0.5(C-A) A B Y F X C D Y InputsOutputs Solder Pad Diameter (mils)76V = 2Vf +Vh-Vp Pin diameter mils18Vf PTH diameter mils30Vh PWB Barrel Length mils58Vp Paste Reduction Factor0.52V Solder Paste Volume Needed If Pin is Square.Stencil Metrics Length - mils18Stencil Thickness - mils Width - mils22Side: If Square Aperture - mils Equivalent Pin Dia mils22.454Radius: If Round Aperture - mils Rectangular? If First Side is (mils): Second Side should be (mils: V V Vh Vf= Solder fillet Vf= (0.21r 2)x (0.223r +a) x 2P(Pappu-Guldi) r = (solder pad -pin ) 2 a=Radius of (round ),(length x width/P)0.5(rectangular Vh= Solder volume of the Vh=Pd 2t d =Radius of plated through t=Length of the PTH Vp= PTH volume displaced by the Vp=Pa2t (for round ), length x width x t (for rectangular ) Cubic Mils 17585.147 40997.784 14759.202 61408.876 118093.992 7 129.887 73.281 80 210.882 Vsolder= 2Vf + Vh - Vp Vf= Fillet Volume (Pappus-Guldin) Vh= PWB Hole Volume Vp= Pin Volume V = 2Vf +Vh-Vp Solder Paste Volume Needed Stencil Metrics Stencil Thickness - mils Side: If Square Aperture - mils Radius: If Round Aperture - mils Rectangular? If First Side is (mils): Second Side should