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The content of this presentation is confidential and the copyright of DEK. It is intended for the exclusive use of the recipient.
The content may not be copied in whole or part without the prior written permission of an authorised officer of DEK.
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The content of this presentation is confidential and the copyright of DEK. It is intended for the exclusive use of the recipient.
The content may not be copied in whole or part without the prior written permission of an authorised officer of DEK.
Thank you!
Area Ratio Calculator For Rectangular aperturesAperture Width Aperture Length Foil Thickness Ratio
7.24 6.53 3 0.572224642947.2772 27.54
82.62
Area Ratio Calculator for Circular AperturesAperture Diameter Foil Thickness Ratio
9.4 4 0.58754.7 118.1238837904
22.0969.39778172686
Industry Standards Aspect Ratio Foil Selection Area Ratio FormulaMinimum webPb-Free Design Ind. Std. Calculator Reduction in X & Y
Reduction of Area
Helps for determining the correct aperture design
Aperture Width
Aperture Length
Foil Thickness
When considering the printability of a stencil design, the Area Ratio for optimum paste release should be >0.66.
To use this calculator, simply enter the values in the rows indicated by the red arrow, and enter. The area ratio will display in the yellow cell.
Substrate
Area Ratio = Wall Surface Area
Aperture Open Area
Next
Ind. Stds ReductionsThis Calculator represents Industry Standard ReductionsEnter the pad pitch, pad width, Land Pattern Sizeand pad length under Land Pattern Size. Under Stencil Design enter the Foil Pad PitchThickness, and the 25recommended aperturesize will be shown with the area ratio. Pad
Length60
PadWidth
14
Solder Volume 1:1 with pad footprint 5040Solder Volume with Ind. Std Reduction 4350
Return to Area Ratio Page
Ind. Stds Reductions = 690 cubic mil of solder
Stencil Design
FoilThickness 6
ApertureLength
58
Aperture 12.5Width
Area Ratio 0.856974
725846
Return to Area Ratio Page
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This Calculator represents reductions Percentage of area reductionin total area. 20 0.20 0.80 20
0.894427
Enter the pad pitch, pad width, Land Pattern Sizeand pad length under Land Pattern Size. Under Stencil Design enter the Foil Pad PitchThickness. Enter the 20desired percentageof area reduction. Aperture size with Padarea ratio will be Lengthshown. 65
PadWidth
10
Solder Volume Without Reduction Solder Volume With Reduction
2 13
520 0.77517134.1641 670.8204
Return to Area Ratio Page
Next
Percent Reduction = 650 cubic mil of solder
Stencil Design
FoilThickness 5
ApertureLength58.13777
Area Ratio0.77517
Aperture 8.9442719Width
Solder Volume Without Reduction 3250 Solder Volume With Reduction 2600
520 520 5 650670.82039
Return to Area Ratio Page
This Calculator represents reductions Percentage of reductionin X and Y. 12 12
Enter the pad pitch, pad width, Land Pattern Sizeand pad length under Land Pattern Size. Under Stencil Design enter the Foil Pad PitchThickness. Enter the 20desired percentageof reduction in X & Y. Aperture size with Padarea ratio will be Lengthshown. 50
PadWidth
12
Solder Volume Without Reduction Solder Volume With Reduction
1.44 6
464.64 0.709677109.12 654.72
Return to Area Ratio Page
Next
Percent Reduction = 812.16 cubic mil of solder
Stencil Design
FoilThickness 6
ApertureLength
44
Area Ratio0.709677
Aperture 10.56Width
Solder Volume Without Reduction 3600 Solder Volume With Reduction 2787.84
464.64 464.64 6 600654.72
Return to Area Ratio Page
Return to Area Ratio Page
Pb-Free Stencil Design
Typical SMT stencil design for lead rich solder reduces the stencil aperture so that the paste brick is not 1:1 to the pad footprint. The Stencil aperture is reduced 1-3 mils per side depending on the pad size and pitch.
Paste Brick
Pad Footprint
Pb-Free aperture design is closer to a 1:1 to the pad footprint, with a minimal reduction. The reason for this is the wetting characteristics for Pb-free solder will, in most cases, not allow the typical and familiar reductions since the migration of molten solder, and capillary action are less robust than with Pb-rich solder.
Pb-Free Stencil Design
Typical SMT stencil design for lead rich solder reduces the stencil aperture so that the paste brick is not 1:1 to the pad footprint. The Stencil aperture is reduced 1-3 mils per side depending on the pad size and pitch.
1-3 mil reductionper side is typical.