Printed circuit board PCB, is also known as printed wiring board PWB. The board enables the wiring to the electronic circuit to be contain on a board. This is a far more efficient method of manufacturing a larger quantity of electronics circuit.

Thinking about doing yourself a PCB board at home for your electronics project. Building these fabricated circuit board to hold all your electronics components. Yes, you have come to the right site. This is a step by step guide to building your own PCB board with lots of photos and video illustration.

Home DIY PCB board finished product

1. PCB board design
2. Printing Artwork
3. Exposure
4. Developing
5. Etching
6. Cuting and Drilling
7. Tinning and Masking
8. Other method of PCB making

The project introduce you to the basic steps in fabricating circuit board at home. If you want to fabricate the circuit board at low volume, this will be an attractive alternative to meet your budget.

For a less complex prototype circuit, I would recommend point to point wire solder. The process is tedious and slow, but the project cycle would be shorter. Modification can be done quickly and easily.

Looks like spaghetti, an example of point to point solder using wire wrapping wire.

Come, join me, as we walk through the process of doing DIY PCB fabrication, step by step, as easy as ABC.

PCB fabricating machine is more efficiency for mass production. For professional looking PCB board, you may outsource the task to a PCB design house or manufacturer. Well establiashed PCB manufacturer normally ask for higher fabrication volume. There are manufacturer that can do PCB fabrication in lower volume for your prototype. Some accept a few pieces, and even provide you with software for drawing your PCB design. Leadtime is typically a week or 2, while some manufacturer may offer express PCB fabrication service. If you are looking into high volume professional PCB board, China can offer a more competitive price. More reference to these manufacturer and PCB fabricating machines is available on this website.

Various professional PCB manufacturer.

If you want to fabricate the professional looking green board for a smaller quantity, you can try PIC-CONTROL. I usually send my gerber design to them for a reasonable price. However the delivery lead time is about 2 times longer as compare to the rest of the manufacturer of about 1-2 weeks.

1.   PCB board design

Material and Equipment

• electronics schematic design

• computer

• Protel DXP or PCB design software

software for

drawing PCB board.

Protel DXP software enviroment.

component layout & traces diagram.

new Protel DXP version (2005).

1.1 PCB design introduction

Before any PCB fabrication can be done, we need to design PCB electrical pads for component placing and trace for component connectivity. It can be draw by hand but if your design is very complex, the PCB software will be very helpful. The software have ready to use components footprint, and modification can be easy done, saving you a lot of time and effort as compare to manual drawing.

There are various brand of software for designing and drawing PCB, and most of them can generate gerber file (*.gbr) which is a common file format used for PCB fabrication in the local industries.

Professional PCB software such as CADSTAR and PROTEL can easy cost above thousand of dollars. Simple and basic PCB software such as Eagle or Easy-PC is slightly lower in cost, in the range of about $500 to $1200. They are cheaper in cost, but features can be limited. Limitation can be in the form of limited board size, number of board layer or the number of component's pin allowed in the design. Professional PCB software has a lot more sophisticated features to make the PCB design process more efficient. Software trials are available from most of these PCB vendors, for user to evaluate.

Various electronics schematic & PCB design tools.

Easy-PC from Number One Systems

CADSTAR from Zuken	Eagle from Cadsoft

Alternative you can engage professional help for the PCB design work, to relieve yourself from the extensive software training. With the experience and expertise from a PCB design specialist like Quantum CAD, you can be sure that your project can be in time and well taken care of. Demanding layout design for analog or any high frequency circuitry, would seems like a breeze in your development work.

In this fabrication trial, Protel DXP is used to aid schematic design and PCB layout. It is quite user friendly and technical support is strong in terms of user group and tutorial documentation.

Gerber file is not used in this home fabrication, instead a pictorial format save in *.pdf file. *.gbr gerber file is normally use in local fabrication house. The component layout and traces generated are save onto the *.pdf file.

The PCB artwork is now in *.pdf format and is ready for printing.

For more information on Protel DXP, you may refer to the following website, http://www.altium.com/

I have also started a website to document some common surface mount component footprint for references.

More PCB footprint references here. Footprint

Here is a reference on PCB design guideline that I got it from a website. Quite a useful information to guide you into design a proper PCB board.

Board Design Guidelines 2003 Rev-A.pdf

2.   Printing Artwork

Material and Equipment

• PCB artwork

• paper

• printer

• transparency

• laser printer or photo copier

material for the making of the transparency film.

a closer view of a printed PCB pad and traces photocopied onto a transparency.

2.1 Artwork introduction

The PCB layout can be printed from a normal home printer onto a white piece of paper. The printing will be photocopied to a transparency. The transparency will be use for photo-resist PCB board exposure in the next stage.

A laser printer is prefer for sharper trace, especially if the traces are very close to each other. The laser printer can also print directly to transparency.

The transparency is cut to PCB size 15x10cm. Five PCB artwork are squeeze and arranged to maximize board usage.

There is also another popular DIY call the tone transfer method. Basically, it is using a laser printer to print your art work on a piece of paper. The toner print out is then iron onto a piece of copper plated board. This forms the etch resist layer on top of the board which can be send to the etching process.

The following link provide further information on this method. http://www.fullnet.com/~tomg/gooteepc.htm

The advantage of tone transfer is that it is simple, fast and does not require special positive acting presensitized (photo sensitive) PCB board.

The following step presents the traditional photo exposure method. The etch resistance layer can be formed on the photo sensitive board after the exposure.

3.   Exposure

Material and Equipment

• ultra violet lamp

• a box

• Positive Acting Presensitized PCB board

• transparency with PCB artwork printed

• scotch tape

ultra-violet lamp (left) to expose the photo-resist coated Kinsten PCB board (right).

3.1 Exposure introduction

A typical Ultra Violet UV lamp for exposure on a Positive Acting Presensitized Kinsten PCB board.

   Where to buy them locally???

The ultra violet UV lamp is available in most lightings shop. I brought it at a electrical shop along kelantan lane (near Sim Lim Tower). The Kinsten PCB board, I brought in from Bell System, #03-12, Sim Lim Tower. It is also available in another shop Sunlight.

peeling off the protective film from the PCB board.

3.2 Preparing PCB board for exposure

Tear off the white/black protective film on the board. Place the transparency artwork on top of the PCB board. Secure the artwork position with scotch tape.

Video: laying film on PCB.avi

3.3 Exposure setup

If you have a piece of glass, place it on top, to make a good contact between the artwork and the PCB board. Close proximity should be maintain to make sure that trace are not expose to the UV light. I actually make this box out of a shoes box to prevent over UV exposure to the PCB board.

Video: PCB setup in the exposure box.avi

ultra-violet exposure

3.4 PCB exposure

Turn on and expose the PCB board for 90 seconds for ultra violet lamp, or 6-10 minutes for normal fluorescent lamp.

The above reference is base on the guideline of the lamp of about 5cm distance away from the artwork PCB. If the distance is far from the typical one, the exposure time should increase proportionally.

Video: exposure to ultra violet light.avi

4.   Developing

Material and Equipment

• Sodium Hydroxide or Developer solution

• distill or plain water

• gloove

• glass, plastic, wooden rod or old chopstick

• container slightly bigger than the PCB board

• exposed PCB board

• container with water for washing

Sodium Hydroxide NaOH, and a pair of Gloves.

4.1 Developer introduction

Sodium Hydroxide is used as a developer. Correct proportion is necessary as too much will destroy the photo-resist coating instantly, while too little will have no effect in developing the PCB.

Commercial developer solution (pre-mixed with distill water) might work better since mixture is in the correct ratio for PCB developing.

Silicate Based Product make a better developer as less likely to be over-developed. Higher concentration will increase the developing speed.

   Where to buy them locally???

I got my sodium hydroxide from my friend. You can actually buy these pcb developing solution from Bell System, #03-12, Sim Lim Tower.

mixing solution, NaOH chemical with water.

4.2 Developer mixture

I have used a old ice-cream container to mix the solvent. The solvent composite for making the developer consist ratio of about

1unit of Sodium Hydroxide is to

20 unit of Water.

The solution must be of uniform concentration. Stir the mixture until NaOH is fully dissolved in the water. If the chemical is not fully dissolved, the region with concentrated NaOH can destroy the photo-resist coating instantly.

Use a glass rod when working with chemical if possible. Glass material is less reactive with most chemical.

Video: mixing NaOH developer solution.avi

When mixing NaOH to water, heat will be produce. Stir the water solution constantly while adding in NaOH slowly.

 

Various Developing Chemical
- Sodium Metasilicate	(msds)
- Sodium Hydroxide NaOH	(msds)

PCB developing. washing away photo-resist coating that are expose to the ultra-violet in the earlier stage.

4.3 Developing PCB board

Developing PCB board by dipping into the chemical solution. For this setup, I am also using ice-container.

During the developing process, the chemical board should be agitate constantly until the board is developed.

Video: developing PCB board.avi

The board is fully developed when the PCB traces appear green in color. This green layer is the photo resist layer which protect the copper surface underneath during the etching process. The region to be etched away later will be expose and is brown in color. The brown color is the actual color of the copper. There is no photo-resist coating to protect the surface.

Rinse the developed PCB board with running water after developing.

picture of a developed PCB board.

4.4 Over and under developed board

The left portion of the board is developed fairly. Notice that there are still some unwanted fade green coating on the copper surface. The board has been soaking in the developer solution for quite some time but the green photo-resist coating is still not remove. This is probably due to inadequate UV exposure time. The UV exposure for this board is exactly 60 seconds. The UV exposure should be 90 seconds instead. It is better to over exposed during the UV lighting process.

There is no attempt to dip the board for a longer period or using stronger solution to remove the fade green coating. It may just cause the dark green pattern to be washed away as well.

The photo-resist layer on the right portion of the board is being washed away. The board is dipped into the solution, without dissolving the NaOH chemical completely. The strong concentration of the chemical have wash away the coating instantly. This example serve as a reminder to stir and dissolve the mixture well before any attempt to develop the PCB board.

mending the circuit trace that are over developed.

This is the marker use in the demonstration. A fine tip oil base black marker from "ZEBRA NAME PEN" made in Japan.

4.5 Repairing over developed board

Sometimes, thin traces on the board may be over-developed. The required trace is not protected by the photo-resist coating after soaking for too long in the developer. The trace has to be protected or it will be etch away in the etching process. These broken or missing circuit trace pattern can be corrected and repaired by drawing over the copper surface with a Etch resist marker. The marker ink will cover up the copper region and acts as etch resistance during the etching process.

There are commercial etch resist marker available, however a general purpose oil base marker will be just as good for use as a etch resist coating. It is a commonly available permanent marker, meant for general use.

   Where to buy them locally???

I am fortunate to test out my zebra name pen marker can actually work as an etch resist shield. You can easy get this type of marker in our local stationary shop. For example, Popular Book shop. If you are looking for a professional etch resist marker, you can buy them from Farnell. They should have it. The tray is actually also a old ice-cream box.

over developed PCB board, with all traces wiped away. The NaOH mixture is too strong. The photo-resist layer got wipe out instantly.

4.6 Over developed board

The photos show the results of a over developed board. Too much chemical was mix in the solution, resulting in a very strong developer solution. The green photo-resist coating on the board was wiped away instantly. The clear and sharp printed pattern appear immediately when the board is dipped into the solution. When the board is lifted up, the whole photo-resist layer is being wash down from the surface of the solution. Leaving away nothing but bare copper on the board surface.

When PCB trace appear instanly when it is dip into the developer, it can indicate that the solution is too strong. Start off with low NaOH concentration, and increase a bit at a time. Experiment and obtain the correct mixture for the developer. Remember to dissolve the chemical fully when adding more chemical, before dipping the board into the solution.

5.   Etching

Material and Equipment

• Ferric Chloride powder

• distill or plain water

• gloove

• glass, plastic, wooden rod or old chopstick

• long container for the etchant

• a boarder container for boiling hot water below

• 3 litre of boiling water

• drilling machine

• plastic string

• developed PCB board

• container with water for washing

• detergent

Ferric Chloride FeCl3,

SENO 3200 (hexahydrate type)

Translated Instruction from German Language found on SENO 3200 iron iii-Chloride.

Long-proven etching agent for printed circuits, copper and high-grade steel, which already corrodes at ambient temperature and is almost for an unlimited period storable also in used condition. In the temperature range of 20-40 it is characterised by a good etching rate and a small under etching. With increase temperature increases both. Copper admission on the average 40-50g/Litre, etching rate 40-3µ/min

Caution: Injurious to health when swallowing. Far of children and food store. Rinse off immediately during contact with the eyes thoroughly with much water and physician consult. Marks with difficulty removable.

Content: 230g per pack for 0.5 to 1 Litre of etchant.

mixing FeCl3 with water

5.1 Etching introduction

Ferric Chloride is use to etch away copper surface on the PCB board. It is a very toxin chemical and is harmful to the environment. Please handle and dispose the chemical waste with care. It is dark yellowish in color and can stain your clothing.

Remember to wear protective gloves while handling FeCl3. Chemical is toxin and will cause skin irritation Wash skin with running water immediately when in contact with skin.

Stronger FeCl3 solution enables etching process to be faster.

When design PCB board, it may be a good idea to fill up with regions of copper. This is to minimise the area of copper surface to be etched away. With less copper to etched, it will also means that the solution can be effectively use to etch more PCB board.

   Where to buy them locally???

You can buy Ferric Chloride from Bell System, #03-12, Sim Lim Tower. Please do take care of our environment when disposing this chemical. The etching tray is again an old ice-cream box.

5.2 Etchant mixture

The solvent composite for making the etchant consist of

about 1 unit of Ferric Chloride FeCl3 is to

3 unit of water.

or about 1 unit of Ammonium Persulphate is to

5 unit of water.

Stir the mixture until FeCl3 is fully dissolved with the water.

Video: mixing FeCl3 etching solution.avi

 

Various Etching chemical
- Ferric Chloride FeCl3	(msds)
- Ammonium Persulphate	(msds)
- Sodium Persulphate	(msds)
- Peroxy Sulfuric (recyclable chemical)
- Ammonium Persulfate	(msds)

warming up the FeCl3 solution

5.3 Warming up etchant

Warm up the FeCl3 solution on a tray (blue) filled with hot water. Temperature range from about 50°C to 60°C will be suitable to speed up etching process.

Video: warming up the etchant solution.avi

secure PCB board with string

or use scotch tape to secure string to the PCB board.

5.4 Board preparation for etching

Drill a small hole on the PCB board so that a string can be secure to the board. The string is use to position or pull out the PCB in the toxin solution.

or

A scotch tape can be used to secure the string to the PCB board.

PCB board etching until the unwanted copper is remove completely by the chemical.

5.5 Etching PCB

Immerse the PCB board slowly into the FeCl3 solution. Agitate the PCB by tilting the container to and fro gently, until the unwanted copper layer are properly etched away, leaving only the required region on the PCB. The process may take 15 - 60 minutes to complete. Process duration will depends on the concentration, temperature of the etchant solution.

 A video clip is available to help you visualise the process.

Video: etching process 1.avi

Video: etching process 2.avi

Video: etching process 3.avi

Etching method also plays a part in the etching speed. If you leave the board without any agitation, the process may takes hours. There are other method of agitation, for example by using bubble or spraying onto the copper surface. A good agitation equipment helps to speed up the process to merely a few minutes.

The etching effectiveness will be reduce if the solution is re-used for a number of times. Strong FeCl3 concentration and high temperature can increase the etching speed.

testing of different ways to resist copper from being etched by the chemical.

5.6 Testing various etch resist material

The photos simulate a developed PCB board masked with some scotch tape, masking tape, and text using oil based marker. The board is over-developed and is used for testing various etch resist materials.

The experiment shows that adhesive tapes and oil base marker can be implemented to perform as a mask to resist from the etchant.

washing PCB with detergent after etching.

5.7 Washing board condemned with FeCl3

Prepare a container of detergent solution to wash the PCB board condemned with chemical FeCl3. Detergent contain Sodium Carbonate or Sodium Hydroxide, which can neutralize FeCl3.

removing away the photo-resist green coating.

photo-resist coating removed, however the black marker writing is still on the board

contact cleaner is apply to tissue paper wiping away the marking.

washing chemical content on the board with running water.

PCB etching completed

5.8 Removing photo-resist coating and other stain

Photo-resist mask or marking of the traces can be removed using the NaOH developer. It is the same developer used during the developing process. Stronger solution can be use this time round as the etching is already completed. The protective coating is no more in use.

A cloth soak with the solution can be use to wipe on the PCB board surface to remove the coating.

For the marker stain, it can be remove using commercial available contact cleaner, alcohol, or thinner solution.

Rinse with water, clean and dry the PCB board.

Video: wiping marker ink away from the copper.avi

soaking FeCl3 in detergent before attempting to dispose this chemical waste.

5.9 Disposing toxin chemical

Ferric Chloride FeCl3 is a toxin chemical. Please consult your local authority for proper dispose of chemical waste product.

As recommended, detergent (or other baking soda) can be mixed to the FeCl3 solution. The mixture solution can easily produce bubble foam which can grow 10 times in volume. Lay waste paper under the container to prevent toxin overflowing out of the container onto the floor. Leave it to dry before disposing the waste.

Sodium carbonate (washing soda) or sodium hydroxide can be added to neutralize Ferric Chloride before proper disposal.

For information on the disposal of Ferric Chloride. Follow this link,

http://www.mgchemicals.com/techsupport/ferric_faq.html

one month after neutralizing FeCl3

semi-dry residue at the wall of the container.

6.   Cutting and Drilling

Material and Equipment

• dot punch or sharp tool

• drilling machine or hand drill

• 1mm, 1.5mm drill bits

• coping saw

• hand files

• penknife

• steel ruler

• bench clamp or support

Complete fabrication of smaller individual PCB board

6.1 Introduction to cutting and drilling

The etching is completed. The original artwork is arrange to maximise the use of the PCB board. 5 small PCB can be fabricated on the 15cm x 10cm board. 3 of the PCB pattern is not formed properly during the developing process, therefore only 2 PCB board can be extracted.

Hole is necessary to mount component (example: resistor, capacitor, inductor, board mount switch, DIP integrated circuit IC etc). Before drilling, a dot punch is used to mark the hole position. This serves as a shallow guide for the drill bit to align easily while drilling. Any other sharp pointed tool can be use to do the marking.

The drill is fitted with a 1mm drill bit. A typical hole size large enough for most components. A 1mm drill bit is thin and can break easily. Hold the drill steady and drill in straight slowly. The hole will be drilled with little force applied.

After the drilling is completed, the board outline is then marked with a steel ruler and a pen knife. Coping saw is used to cut the board out. The board will leave sharp bur edges after sawing the board. Use the hand file to de-bur the sharp edge.

The PCB board making is completed and is ready for use.

Video: drilling holes for components.avi

There is a market trend of shifting all electronics to surface mount type. Components are more compact and therefore reduces the overall size. Eventually it contributes to the reduce in cost in almost every aspect of the project. Cost reduce in component, PCB board, transportation, etc... . Although it is fairly difficult to solder, the convenience of making PCB board without the hazard of drilling holes make it very attractive to the home PCB fabrication. Soldering surface mount device (SMD) component is possible and requires some practices.

Talking about soldering SMD component, there is this interesting question I have once raised. Have you ever notice the perfect soldering in the industrial PCB? It took me quite an imaginary journey searching for machine to do a perfect soldered PCB board. In the PCB manufacturing industrial, they are using a grey solder paste/cream instead of the solder wire roll. Similar to a toothpaste it is actually a lot of tiny solid solder balls mixed with flux. The paste is spread onto the PCB soldering pad, where leads or SMD component will be later place on.

The whole PCB board is then taken on a conveyer belt ride through the hot oven to melt the solder paste and flowing solder will occur. After melting the paste on the PCB, it is then cool, and the solder harden which results in a perfect soldered PCB board. This re-melting process is know as reflow.

Reflow soldering is very fast, a method suitable for mass production. Unlike using a soldering iron, there is no need to aim on the soldering pad, typical heating through gases. SMD component will align automatic themselves during the reflow. You may be interested in getting a reflow station, or reflow machine for high volume production. For a cheaper reflow solution at home, you can click down to this highly recommended website,

 http://www.sparkfun.com/tutorial/ReflowToaster/reflow-hotplate.htm. They have demonstrated how surface mount component are soldered to PCB using industrial standard. It is a very interesting and educational website. Hope that you will enjoy.

The wave soldering process, is another method used for mass soldering of the circuit. Quite interesting.

http://www.ami.ac.uk/courses/topics/0225_wave/index.html

More article on Wave and reflow soldering.

http://www.ibselectronics.com/pdf/pa/walsin/smt_notes.pdf

www.zianet.com/erg/SMT_Soldering.html

Reference for smd equipment for soldering production.

- smt equip,emt reference.pdf

- http://www.faze.co.za/Products.html

7.   Tinning and Masking

Material and Equipment

• solder flux

• soldering iron (flat tip is available)

• soldering stand with wetted sponge

• solder sucker

tinned PCB board.

finish PCB product

DTMF decoder circuit using MT8870DE

LM2576 dc-dc converter circuit

7.1 Tinning the copper surface

Copper will oxidize when expose to oxygen environment. Oxidization should be avoided as soldering is difficult on oxidization surface.

A thin layer of solder is coated on the copper surface to prevent oxidization. Apply solder to the copper surface with hot soldering iron and spread the liquified solder across the surface. Covering the copper surface with solder helps protect the copper from oxidization.

Video: tinning PCB copper area.avi

7.2 Masking PCB board

Masking can be applied to non-soldering area to protect the board from potential short circuit, oxidization and overflow of solder during soldering. The soldering would also be easier and nicer

It is not really necessary in home PCB fabrication, however if you want to give your board the professional touch, there is masking spray available in the market to lacquer the PCB board.

7.   Other Method of PCB making

<This is an OLD ARTICLE>

Laser printing, iron transfer artwork

Use Etch-resist pen

PCB patter transfer film

Milling PCB

Using etching machines for mass production.

bubble etching equipment

bubble Tank accessories for PCB board fabrication.

container to hold the Etching chemical.

A flat plastic container is used for developing the photo-resist PCB. Glass rod should be used to stir and mixed the chemical in distill water, because glass material does not have chemical reaction with most chemical.

air pump to sort of stir the liquid to quicken the etching process.

long stone rod to disperse air bubble

water tank or fish tank heater to warm up the water during etching process.

photo-resist PCB board 15cm x 10cm from Kinsten

Old Article:

Written by Lim Siong Boon, dated 03 Dec 2005.

The fabrication process was a failure. Photos was taken on the fabrication process. Unfortunately the photos were lost in the borrowed digital camera. Damn it, the pictures are lost for no reason. Should have retrieve the photos immediately after the photo taking.

The first fabrication was done in a friend's company, selling and dealing with chemical stuff. He is Chee Keong, my good friend from Singapore Polytechnic. He is my very supportive of my project, and invited me to his company on a fine Saturday evening (Sep 2005) for my board fabrication. The place is great because he have all the chemical, tools and facilities I need to fabricate the PCB.

Sodium Hydroxide NaOH was used to developing the photo-resist board, and Sodium Persulphate was used to etch away the metal. Ferric Chloride is a more common chemical used for etching the board, it is a very toxin chemical and disposal needs careful attention. The chemical is a controlled item in Singapore and requires license to use the chemical. It is this reason that I insist to try something safer, like sodium persulphate. However after the trial, sodium persulphate doesn't seems to perform. I have not yet figure out the reason, but would like to try out Ferric Chloride for my next trial. It is a dangerous chemical, so some knowledge research or revision is recommended before any attempt to use the chemical.

There are other alternative chemical used in PCB fabrication after some research on the internet.

Bubble etching concept

Trying to heat up the solution with the heater. It is slow and very troublesome. The air pump has to be glue to the bottom as it will tends to float and is unable to keep still. Cleaning is very troublesome because a lot of equipment is required for the etching.

After trying for 2 times, a simpler idea pops out of my mind. Shortcuts are for lazy people like me.

New IDEA

A new and simple etching setup that pops up on my mind.

Hair Dryer will provide the heat and agitation to speed up the etching process.

The flat lying plastic tray will provide minimum amount of chemical to be mixed for etching the PCB board, through means less wastage.

In the end, I ended up using an even easier method by placing the container of etchant solution on a tray of boiling water.

It works and have less minimum setup. Etching quality is just as nice.

Bill Of Materials, estimate to be S$60.00