After prototyping a circuit on a breadboard or dot board it is always better to make a PCB for added stability and compactness.
PCB fabrication can be fit into any one of the following 2 categories,
* Non Chemical methods such as milling ( CNC )
The copper clad sheet is fed to the CNC which engraves the required tracks as fed to it by a computer .It is as simple as that and you get your PCB done.
* Chemical Methods
The parts of the copper clad sheet where tracks or signal traces need to be present are covered through either toner, permanent marker ink or sticker sheet etc (This transfer of toner or ink in most cases is done through heat ) .Then the copper sheet is dipped into etching solution ( combo of H2O2 and HCl or combo of FeCl3 and HCl) by which the uncovered portion gets etched into the solution. Now the toner or marker present on the tracks can be removed by abrasion and the PCB is ready to be drilled and used.
The chemical methods are suitable for hobbyists as it is cheap but it needs work to do. In this instructable i give you 2 different methods of PCB fabrication i generally use,
# Method of Toner Transfer
# Method of Stickers
The former is common and is a well tested method which can be used at home with very little expense and requires less resources.
The latter is a way i found out recently and it has proven to be both effective and simple but it requires a sticker cutting machine ( which is used in the sticker shops) .
Step 1: EAGLE CAD Tutorial and an Intro to EagleUp
With this tool you will be able to create the Schematic and Board File for your PCB Which needs to be printed out for Toner Transfer method.
See the attached pdf file for the detailed process of creation. It is a tutorial written by our department's technical club.
I have also attached a pdf on Introduction to PCB, written by the Electrical Research Fraternity of our college.
In case you would like to visualize the PCB that you have just designed there is a very good plugin for eagle termed EagleUp . This plugin along with the 3d modeling software, Sketchup can turn your design into a 3d model helping you visually ensure the PCB you have just designed is worth proceeding.
The steps for installing and running the plugin in Eagle Cad is mentioned with sufficient clarity in the website of EagleUp.Following the steps and if the paths are configured properly the plugin would work without a glitch.
# Owing to the lack of all the components in the database of EagleUp some of the components might not show up in the created 3d model , But these missing components can be found in the 3D Warehouse of Sketchup; These can be downloaded into the models folder of EagleUp ( but the names of the downloaded components should match with those names of it in eaglecad ) and reopening the plugin would fill up the missing components.
I have used EagleUp and Sketchup combo for many of my projects and it has proved to be of great help to me, some of my projects can be seen here.
Step 2: Toner Transfer Method
Below is the process of realizing it using toner transfer method.
Single sided copper clad sheet ( size depends on your circuit )
A laser print out of the circuit ( Only the tracks, pads and vias need to be printed out )
Gloves and a mask ( HCl produces an irritating smell and the etching solution is corrosive )
Etching solution ( Either HCl + H2O2 or FeCl3 + HCl .. well these are the combos i have used; while there are many others as shown here ; The proportions vary according to the concentration of the solution )
PCB drilling machine
This is a very easy method and most hobbyists use this method to create PCB's at home.
The process is described in the video below,
Step 3: Sticker Method
Compared to the PCB's made by Toner transfer these PCB's are tidy, less prone to shorting of nearby tracks, less debugging requirement, less time to fabricate.
But the cost involved increases due to the requirement of a cutting machine and the sticker.
- Software :
EAGLE Cad , Corel Draw
Access to a Sticker cutting machine, Sticker, Single or double sided copper clad sheet,Etching solution( same as toner transfer method),gloves,mask and PCB driller for making holes.
Most sticker cutting machines run from the print commands through corel draw, Thus the following steps will guide through exporting the eagle file to a coral draw file. ( from .brd to .crd )
* Create the board file of the required circuit in EAGLE Cad following the steps in the pdf attached to step1.
* In the Board file window of EAGLE go to file -> run -> dxf.ulp ; selecting and running the dxf.ulp will lead you to a new window with a couple of check boxes, uncheck the fill areas check-box and click ok.
* Open the created dxf file ( depends on you present board file location) in corel draw.
* Select the whole image using the pick tool of corel draw.
* Go to arrange->shaping->weld.
* Save the resulting file as a corel draw (.crd) file
Note : After using weld option make sure you get an image as shown.
The created corel draw file maybe sent to print in the sticker cutting machine and please take care to note if the dimensions are correct before print.
The unwanted portions of the sticker are removed and the tracks are stuck onto the PCB ( Ensure the PCB is cleaned with sandpaper/ acetone before hand).
Drop the PCB into etching solution and after the etching is complete drill the holes and thus the PCB is fabricated.
Using this method double sided boards can also be etched.
# This is a very new experiment of mine and it worked for me .. take precaution and i cannot assure you it works on all sticker cutting machines. I suggest you start with a very small board file. And in case you are planning to take print at a local sticker shop confirm with the shop keeper that he/she takes print out with a coreldraw file that includes small sized objects.
Since this is something new i tried, i would like to hear your feedback's about this.