SMT StENCILS
Boston Engineering | Mechanical Engineering Co-op | Jul - Dec 2019
OBJECTIVE
Prove the feasibility of a non-planar printing system for a food-grade application. More specifically, develop 14 test stencils to use with the intended Surface Mount Technology (SMT) printer, and program Mathcad to calculate how much mass would be deposited through a variable stencil to determine that the client's mass deposition goals were being met.
SKILLS SNAPSHOT
MATHCAD
SOLIDWORKS
SHEET METAL DESIGN
VENDOR MANAGEMENT
ITERATIVE DESIGN
MECHANICAL DRAWINGS
DESIGN STEPS - SMT STENCILS
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Brainstormed parameters affecting mass deposition with the project manager and other engineers
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Identified aperture shape, aperture size, clearance between apertures​, and stencil thickness as the most important factors affecting mass deposition
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Developed stencil CAD using SolidWorks' Pattern and Fill features
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Used test prints to inform further iterations of stencils
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Identified a vendor able to produce unconventionally sized SMT stencils
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Learned to communicate effectively with electrical engineers, since SMT is traditionally used to design PCBs
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Posing with the first set of SMT test stencils!
A drawing of one of the stencils sent to the vendor for an initial RFQ
DESIGN STEPS - MATHCAD CALCULATOR
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Sought out resources to learn MathCAD's syntax and operators
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Developed psuedocode to think through the functionality needed
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Created sub-sections to focus on the geometry of hexagonal, triangular, square, and circular apertures
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Defined known parameters such as aperture width, ​clearance between apertures, and footprint size
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Calculated the dry mass deposited by defining the following:
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The height of two rows of apertures
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The number of two row units that fit in the desired footprint
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The length of a row that fit in the desired footprint
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Whether an one more or one less aperture fit in the offset second row
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Total number of hexes that fit in the desired footprint
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Dry mass deposited though the total number of apertures
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MathCAD code used to calculate the mass deposited through optimally packed hexagonal apertures on an SMT stencil.​ Note: variable subscripts are redacted for the client's confidentiality. They are color-coded for ease of navigation.
RESULTS
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Test stencils helped identify parameters that were important to produce an acceptable print
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​MathCAD program accurately calculated mass deposition through a variable stencil
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The vendor I identified and built a relationship with continued to be used past the end of my co-op
SKILLS DEMONSTRATED
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MathCAD programming
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SolidWorks modeling and drawing
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Iterative design
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Identifying and building relationships with vendors