Week 8 Hardware Manufacturing

Week 8 Presentation: Here

Class Notes

PCB Fabrication Process

Acid Etching

  • Best for single layer, small batch prototyping
  • Flexible PCB Options
  • Risk of injury caused by chemicals
  • Waste disposal problems
  • Takes time an effort to get it correct

Milling

  • Best for single/double layer, small batch prototyping
  • Easier with thick PCBs
  • Risk of damaging milling bits

PCB Assembly Process

Apply solder paste with stencil

Pick and Place

  • Manual usage: easy for placing SMD parts
  • Auto usage: take time to setup

SMD Soldering

  • Hot Air Gun: quick, better for small number of parts
  • Reflow Oven: slow, better soldering quality, better for larger quantity of boards

Conductive Ink/Paste Printing

Order Components

  • Digikey
  • Mouser

Information needed:

  • MPN (Manufacture part numbers)
  • Package: 0402, 0603, 0805(imperial)
  • Value
  • Tolerance

Source Components

  • Octopart

Order PCB

  • OSH Park (expensive, slow)
  • PCBWay(cheap, fast but shipping takes time)

PCB Fabrication + Assembly

Options

  • MacroFab (affordable US based service)
  • Advanced Assembly (fast, very expensive)
  • Chinese manufacturers (cheap, shipping takes time)

Files:

  • Eagle / Gerber files
  • BOM (Bill of Materials)
  • Centroids (optional)

Eagle Basics

Eagle (student license)

Eagle Setup

  • Library Manager
    • Sparkfun Libraries
    • Lilypad Wearable Libraries
    • Adafruit Libraries
  • Electrical Rule CheckĀ (ERC)
  • Design Rule Check (DRC)

Eagle File Setup

  • Schematic File .sch
  • Board File .brd
  • Naming
  • Version Control

Eagle Schematic

  • Command
    • Add: adding components
    • Move: move components
    • Net: wire components
  • Drawing tools: dividers, names, notes, etc

Eagle Board Setup

  • Grid Setup:
    • Metric for PCB design
    • 0.5mm ~ 1mm for outline design
    • 0.1mm ~ 0.5mm for part placements
    • 0.01 ~ 0.1mm for routing
  • Layer Setup:
    • Single side or double side boards

Eagle Board Design

  • Command
    • Move: move parts
    • Route: route wires
    • Ripup: rip up wires
  • Drawing tool on layer 20 Dimensions: draw PCB outline
  • Ratsnet: flood the GND
  • Via: connect top layer to bottom layer
  • Manufacturing Review
  • Apply DRC