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Stencil Printing - The Essentials

Presenter: Chrys Shea
Company: Shea Engineering Services
Date Published: 3/29/2016

Description: Presented by: Chrys Shea, Shea Engineering Services

Chrys Shea Overview:
Session 1, March 29, 2016
This introductory course on SMT solder paste stencil printing gives the attendees a solid foundation in the basic elements of printing to help them reduce defects and improve yields on the production line. Topics include the flow behavior of solder pastes, the mechanics of the process and the key role of tooling in successful printing.

After understanding the basic elements of the process and their influence on yields, attendees then review troubleshooting tactics, including the 5-minute check that reveals the source of most problems. A more detailed review of the most probable causes of defects follows, discussing reasons for solder bridges, peaking, insufficient deposits, and gasketing and alignment issues.

Session 2, March 31, 2016
All about stencils! This session focuses on stencil design, stencil materials, stencil manufacturing processes and stencil nanocoatings. The session begins with optimizing stencil design and construction based on PCB layout and component type. It discusses approaches for BTCs, miniaturized, and through-hole components by using aperture designs, multi-level stencils and solder preforms.

It then reviews materials and manufacturing processes, discussing the different options for stainless steel and nickel, and the state of the market on electroforming, laser cutting and elecropolishing. Nanocoatings are quickly gaining popularity. An overview of the types of nanocoatings available, the benefits and drawbacks of each, and user-generated data on the process improvement they offer are discussed in detail. Additionally, a spreadsheet to help calculate the cost of defects, printer consumables, and payback periods on nanocoatings is demonstrated and the download link is provided. Attendees are encouraged to ask questions or bring specific problems to the class for suggestions and inputs.


Session 1, March 29, 2016
1. Solder Paste Behavior
1.1. Properties & characteristics
1.2. Behaviors during the printing process
1.3. Printability differences between no-clean and water wash, tin-lead and lead-free
2. Mechanics of the Printing Process
2.1. Alignment and gasketing
2.2. PCB support
2.3. Squeegee or direct print head motion
2.4. Paste setup & release
2.5. Area ratios and transfer efficiencies
3. Troubleshooting Process Problems
3.1. 5-minute system check
3.2. Typical defects and likely root causes to investigate

Session 2, March 31, 2016
4. Stencil Technology
4.1. Optimizing design and materials based on PCB layout
4.2. Stencil Stepping
4.3. BTC and QFN aperture design
4.4. Preforms
4.5. Pin-in-Paste
5. Stencil Materials and Manufacturing Processes
5.1. Nickel – Electroformed and plated over stainless steel
5.2. Stainless Steel – stress relieved, fine grain and high-tension capable new materials
5.3. Electroforming
5.4. Laser Cutting
5.5. High tension foils and frames
5.6. Stencil Inspection & verification for production
6. Nanocoatings
6.1. Purpose
6.2. Types
6.3. Benefits
6.4. Quantifying costs and ROI spreadsheet

Who Will Benefit from this Course:

  • SMT assembly process engineers, technicians and advanced-level operators who are responsible for production or new product introductions processes
  • Engineers and technicians just entering the SMT field who want to quickly learn the science and art of stencil printing
  • SMT quality personnel interested in helping improve print and end-of-line yields and identifying root causes of failures
  • OEM supply chain engineers who assess and/or support SMT assembly contractors

  • Pricing:
      Members: $200.00 (Log on to receive the member rate)
      Non-Members: $300.00

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