Homemade Printed Circuit Boards
6/22/2015
Jonathan Weaver, KM4FIK
With special thanks to Paul (WA7ZVY)
Overview
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Creating PCB Artwork
Getting the PCB Artwork to copper
Preparation before Etching
Etching
Work after Etching
Supplies and Suppliers
Creating PCB Artwork: Circuit Design
Find and use
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Magazines, books, and references
Online
Component datasheets
Find and modify
Use specialized tools (logic tools, filter
tools, etc)
Create from Scratch
More Knowledge
and Experience
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Creating PCB Artwork: Circuit Simulation
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Verify that it “works”
Tool: LTSpice (freeware downloadable at
www.linear.com/ltspice)
Alternative: Pspice Student, OrCAD Lite (free
versions of production software with
limitations)
Creating PCB Artwork: Schematic
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Easy to read
Incorporates notes
Generates a bill of materials (list of parts)
Generates a net list (how the parts are connected)
Tools: TinyCAD
(http://sourceforge.net/projects/tinycad/)
Alternative Tools:
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ExpressPCB (easiest to learn)
Eagle (freeware has limitations, but very popular)
KiCAD
GEDA (Linux only)
DesignSpark PCB
Creating PCB Artwork: PCB Layout
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Physical Layout
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600 dpi printing limits the minimum sizes
15 to 20 mil (1/1000 inch) trace width where possible. 5 mil
trace width minimum (3 dots)
Similar on spacing
30 to 40 mil holes on 55 to 60 mil pads
Use copper “fill” areas to minimize etching
Imports net list (parts and hookups)
Includes an auto router (I usually never use)
Generates manufacturing files (usually
Gerbers)
Creating PCB Artwork: PCB Layout Cont.d
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Free PCB plus ViewMate Gerber Viewer
Alternatives:
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ExpressPCB (easiest to learn but tied to vendor if you want
PCB's manufactured)
Eagle (freeware has limitations)
KiCAD
GEDA (Linux only)
DesignSpark PCB
At this point you can send the PCB files to a
manufacturer or etch a board yourself
Printing a PCB
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Print to verify size, etc.
Print for etching (to PDF using PDF Creator)
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Keep the PDF file for easy printing later on
Print using LASER printer on magazine paper
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Mirror the top side
Bottom side is already mirrored
Alternative papers include
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Epson Glossy Ink Jet Photo Paper P/N S041141
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Pulsar Toner Transfer System (http://pulsarprofx.com). Digikey P/N
182-1003-ND and P/N 182-1021-ND.
Line up top and bottom using light under glass table
or light table
Tape two sides down
Getting the PCB Artwork to Copper
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Clean the copper clad board with a scotchbrite pad
Insert the board in the print out “pocket”
Iron on high. Cover entire board with iron. About a
minute. Apply good pressure (I usually iron on a
counter top).
Let board “sandwich” cool (sets the ink to the copper).
Soak the “sandwich” in a sink of cool water
Gently remove paper. Use toothbrush or sponge to
remove small bits of paper stuck to the ink.
Board Prep before Etching
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Inspect!!!!
Use an Exacto knife to cut any "shorted" traces or
pins apart.
Use a fine point sharpie marker to draw in traces that
may have been lifted with the paper removal.
If it is unrepairable, clean off failed transfer with
Acetone, and start over.
Cut out the board with a Dremel tool (SAFETY
GLASSES). Use care not to scratch the design.
Etching
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Bath of hot water
Float bath of etchant (Ferrious Chloride)
SAFETY TOOLS: Latex gloves, safety glasses,
apron or disposable clothes (etchant stains)
Submerge PCBs. Agitate Etchant. Flip PCBs.
Repeat until all exposed copper is removed.
Submerge PCBs in cold water to remove
etchant and stop chemical reaction
Dry PCBs.
After Etching
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CLEAN UP – I store used etchant and reuse. Etchant
can be neutralized with wash powder, dilluted, and
disposed down the drain.
Clean ink off the PCB using acetone (nail polish
remover) and scotchbrite pad.
Drill holes with drill press (etched holes in pads help
line up the bit)
Solder vias through holes (use bare bus wire)
Solder components and jumpers (soldering would be
a whole other presentation)
Suppliers
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Parts
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Digikey (www.digikey.com)
Jameco (www.jameco.com)
Mouser (www.mouser.com)
Others (Radioshack, Element 44, Allied, etc)
Copper Clad boards and drill bits
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Far Circuits (www.farcircuits.net) operated by
KF9GX
He will also etch your boards for you
He accepts ExpressPCB files