SMT Bootcamp

This class is designed to introduce the student to the basics of automated SMT and PTH assembly. The student will be given an overview of the print, placement, reflow, inspection, test, and wave/selective soldering processes. In depth discussion of process parameters associated with each process, typical defects and how to correct them. Curriculum includes classroom and practical lab working on the equipment. The successful students will be awarded a Circuit Technology Certification of Completion.

Module 1

• Introduction and overview of the SMT assembly process.

• “Basics of Soldering” including alloys, fluxes, solder paste, rheology and intermetallic bond.  Hands on lab included.

• RoHS

Module 2

• SMT component Identification using samples and concentrating on industry recognized standards and terminology.  Component handling, ESD, MSD and contamination/solderability included.

• IPC-J-standard 001 and supporting documents 002-006, T-50 review

• IPC-610 review

Module 3

• Analysis of bare board design, types and workmanship standards and inspection criteria.

• IPC-600 and 6012 review

Module 4

• Analysis of the stencil printing process including using Gerber data to manufacture stencils, different stencil considerations, squeegee selection and considerations, etc.  Paste deposition will be discussed along with common defects found during the stenciling process and the best resolution.  Hands on at the printer.

• US vs Japanese printing standards-stencil size

• Stencil design

  • Chem-etch, laser cut, e-form
  • Aperture designs
  • IPC-7525 stencil design guidelines

• Printing parameters

  • Squeegee speed and pressure
  • On contact vs off contact printing
  • Under stencil wiping-wet and dry
  • Paste inspection
  • Defects typically associated with the printing process
    • Shorts/insufficient solder/excess solder/misaligned solder

Module 5

• Analysis of component placement process, machine types, where typical defects can occur and the best resolution.  Hands on at the placement machines.

• Machine architecture

  • Turret-Fuji, Hitachi and Panasonic
  • Modular-all manufacturers now
  • Hybrid machines-Juki and Universal

Module 6

• Analysis of the reflow process and profiling.  How to build a robust SMT profile, typical defects and the best resolution.  Hands on at the reflow oven.

  • Straight ramp vs ramp/soak/spike, cooling
  • Effects of N2
  • Defects causes by improper profile
    • Component shock
    • Solder balls/solder beads/graping
    • Tombstone
    • Head in pillow
    • Bridges
    • Insufficient reflow
    • Over cure
    • Bare board delamination

Module 7

• Analysis of the wave solder and selective solder process including profile generation, flux application and defect recognition/root cause analysis.  Hands on at the wave solder machine.

• Flux application-spray, foam, drop jet

• Effects of N2

• Defects at the wave

  • Poor topside fill
  • Insufficient circumferential fill
  • Solder balls
  • Skips
  • Part float
  • Missing parts-SMT
  • Bare board delamination
  • Non wetting/de-wetting
  • Copper dissolution
  • Excessive flux, pallet “gasketing”
  • dross

Module 8

• Analysis of the assembled PCB inspection process including automated and manual techniques.  Hands on lab included.

• IPC-610 criterion

• Manual vs automated inspection

• 3D inspection

Module 9

Overview of the test process including ICT, flying probe and functional.

Module 10

• Cleaning

  • Why Clean
  • Cleaning Chemistries
  • Manual Cleaning
  • Cleaning Equipment – Automated Cleaning
    • Vapor Degreaser
    • Aqueous/Semi Aqueous-Batch and In-Line
    • Stencil Cleaning

Module 11

• PCB Transport and  Handling

  • Conveyors
  • Loaders and Unloaders – Bare Board and Magazine
  • Buffers
  • Cooling Towers

Module 12

• Analysis of the PCB rework process including TH, SMT, BGA and pad repair.  Hands on lab included.

• IPC-7711 overview