1. Copper clad board
This is available in different sizes. Select a suitable size to accommodate all the components. If the copper clad board is large in size, cut it to the required size using a Hacksaw blade. The copper clad board has a copper coated side which forms the soldering side. The other side is the component side on which the components are placed.

Copper clad board

2. Ferric chloride solution
This is the Etching solution of Ferric chloride. It removes the unwanted copper layers from the copper clad board. The Etching solution can be prepared by dissolving 50 gms Ferric chloride powder in 100 ml Luke warm water.

3. PCB drill and bits

PCB drill is used to drill holes in the PCB. A hand drill with suitable bits is sufficient for the purpose. Use drill bits of the following size to make holes for different components

A. 1mm – for IC pins
B. 1.2mm – for Resistor, capacitor, transistor etc.
C. 1.5mm – for diode, LED pins, presets etc.
D. 5mm – for LED, nuts, screws etc.
E. 8mm – for switches, pots etc.

4. OHP Permanent Marker Pen, Tracing / Butter paper, Pencil Carbon paper, Varnish etc.

PCB Making

PCB making involves the following stages

1. Draw the circuit diagram as compact as possible on a paper. Mark the points (component pins) to be drilled. This diagram is used for Pattern drawing on the copper clad board.

2. Draw the same diagram in the tracing / butter paper using the OHP marker pen. Draw the diagram carefully without any overlapping or shorting of tracks or components. The neatness of the PCB lies in the Pattern drawing. After drawing, see the other side of the paper. There is a Mirror Sketch of the tracks. This is the actual pattern of the PCB.

Mirror Sketch of PCB tracks

3. Place the Pencil carbon on the copper side of the copper clad board. The ink side of the carbon paper should face the copper layer.

4. Place the tracing paper with diagram over the carbon paper. The diagram should be in the middle part of the copper clad board. Fold the sides of the tracing and carbon papers and stick it using cello tape. This prevents the movement while drawing.

5. Once again redraw the diagram using the OHP marker pen so that the carbon ink will create a mirror sketch on the copper clad board.

6. Remove the tracing paper and carbon paper. Using the OHP marker pen, redraw the carbon pattern of the mirror sketch on the copper laminate. So that the tracks will be created using the permanent marker ink. Keep it for 10 minutes to dry the ink.

7. Mark points to be drilled.

8. Take a Plastic or Porcelain tray and place the copper clad board with the track side facing upwards. Carefully pour the Ferric chloride solution over the copper clad till the copper clad immerse in the ferric chloride solution. Keep the tray in sunlight and shake occasionally. Etching will be completed in one to two hours.

Etched PCB

9. After etching, thoroughly clean the copper clad using tap water. This will remove the dissolved copper from the copper laminate except the copper beneath the OHP pen markings.

10. Drill holes using appropriate drill bits.

11. Remove the OHP pen markings using Petrol or Thinner so that the tracks will appear as copper lines.

12. If required, tin the tracks carefully using solder lead. Dip in varnish to prevent copper oxidation in tracks.

Tinned PCB

Caution: Ferric chloride solution is toxic. It can cause skin burning or irritation. Use hand gloves during etching. Do not spill the ferric chloride on the skin. If this happens accidently, wash with water. Do not keep ferric chloride in places accessible to children.

D.Mohankumar

Photo-etching printed circuit board Video

Create Your PCB Layout Design

Start out by laying out the PCB traces & pads with your favorite CAD or PCB design program. I used Pad2Pad, mainly because I found that program pretty easy to use, and it’s free for download. You’re supposed to use Pad2Pad to design a board, then send the file to the company for manufacture. Instead, I use this design to create my own etching mask.

Unfortunately, you can’t export p2p files into other formats. So, I printed the board layout to a PDF, then opened the PDF into Illustrator, which allowed me to clean up & fine-tune the design and separate it into layers. This technique is for creating single-sided PCBs, so I made two masks: One for the copper traces & pads, the other for the silkscreen. You need to print out a mirror image of your masks — you’ll see why soon — but because the traces go on the back of the board, you can print those out normally. The silkscreen mask should be printed out in reverse.

Print the masks

This is a tricky step. You need to print the masks onto special paper, and make them as dark as possible. Here’s how I did it. I used Jet Print Multi-Project glossy photo paper. I had to order it online, but it might be available at larger office supply stores. Tom Gootee recommends Staples “Picture Paper”; that seems easier to obtain. Unfortunately I didn’t read Gootee’s article until AFTER I’d already gotten the Jet Print paper. So the Staples paper might be better.

These papers are marketed as ink-jet papers. But for this process, you need to run them through a laser printer. The toner creates the mask. And, you want the toner to be as dark and dense as possible. I found that if you tell the printer that you’re printing a transparency, it’ll apply more toner. I also adjust various settings on the printer menus (e.g., toner density, optimization, etc.) to get the densest possible print — your printer settings will vary. Experiment to see what works best, and take notes as you go so you’ll be able to duplicate your best efforts later. I burned through quite a bit of paper before I got it right, but now I get it right the first time.

If your PCB design has long vertical traces, you might orient the design on the page so that the long traces are angled. Because of the direction that paper travles through laser printers, long vertical traces might lose toner density near the bottom. Angling the long traces helps keep the toner dense on the full length.

Remember to print the copper mask “right-reading” — i.e. NOT a mirror image — but the “silkscreen” mask shold be printed in reverse.

Make a print or two and find a mask that is uniformly dense with a minimum of pinholes. Make sure all the traces and pads are complete.

Prepare the blank PCB board

Cut your board to size, leaving a little extra room around the edges. I use a hacksaw, which leaves some burrs. Smooth any burrs off with a dremel or small file. You want the copper surface to be as flat as possible. Sand the surface of the blank board with 400-600 grit sandpaper in both diagonal directions in a crosshatch pattern. Then, use acetone on a paper towel to clean the board as thoroughly as possible. Grease spots are your enemy! Scrub the board really well.

Attach the mask to the blank PCB board

Carefully cut out the mask for the copper side from your printout. Place it face-down onto your board, so that the toner faces the copper. I use tiny bits of scotch tape on each edge to hold the mask in place. That might not be necessary if your blank is somewhat larger than your mask. I found that the mask tends to slide if it’s not securely taped; you want to avoid that when working with tight tolerances.

Use an Iron!

This is the trickiest step. You need to set your iron to its highest setting, no steam. Lay a paper towel over the board & mask; otherwise, the sticky melted plastic that oozes out from under the edges of the mask will cause the whole thing to stick to your iron.

When first applying the iron, press straight down and try not to wiggle or slide the mask. The plastic surface layer of the paper will melt instantly, forming a temporarily slippery layer, which will tend to slide around if you’re not careful. This is where it’s easiest to screw up, I think.

Start by applying steady, firm pressure to the whole board for one minute, moving the iron occasionally to make sure that the whole board is heated thoroughly. After that, the mask is pretty much stuck to the board, so now you can go over the whole board with the edge of the iron, a little at a time.

I use the edge of the iron & lean on it some, putting good heavy pressure lengthwise along the board. Then I move the iron a quarter inch or so and repeat until the whole board is covered. Then I do the same series of “pressure lines” widthwise across the board. Finally, I finish with overall pressure for a few more seconds. The total ironing time is maybe 3 minutes, tops.

Soak off the paper

Drop the hot board immediately into a pan of hot water, along with any of the paper towel that might be attached. Some of the paper will start to come off right away. Help it along! After a few minutes, more paper can be pulled off. Also peel off any scotch tape you used to hold the mask to the board. After 10-20 minutes, you’ll be down to the last layer, which is more like plastic than paper. The traces will be clearly visible though it. Get a corner started, and the plastic should peel off easily, leaving you with a nicely masked board. If you’ve ironed well enough, the toner will be fused to the board solidly; it can’t be scraped off with a fingernail.

If the traces are messed up in any way — for example, if the iron slipped — you can clean off the fused toner with acetone and start over with a fresh mask.

PCB Etching

Drop the board into your etch solution. Don’t let the etch chemical get onto anything made of metal! I use a large plastic containter. Etch the board until the remaining copper is gone. Depending on how fresh & warm the etch chemical is, it could take 10-30 minutes.

Clean off the mask

Use acetone to clean off the toner. You’ll be left with a nice shiny circuit board!

Apply the silkscreen layer

Now it’s time to add the “silkscreen” to the other side of the board. It’s not really a silkscreen; it’s actually the same process as described above, except that you leave the fused toner on the board and don’t do the etch and cleanoff.

To align the “silk”, I drill a hole in the four cornermost pads. After cutting out the silk mask, I place it toner-side-down against the side of the board opposite the traces. Holding it up to the light, you should be able to see the four corner holes through the mask. Use these to line up the silk mask properly, then tape it to the board with scotch tape. Next, iron the board the same way you did the copper side, and finally soak off the paper.

Drill the holes in the PCB

This is a little tricky, but can be done without requiring a drill press or other fancy equipment. I use a dremel tool with a #60 bit. That’s the smallest bit I can find at the local hardware store. The bit is clamped into a collet, which in turn is held in the dremel’s chuck.

Here’s my secret to drilling lots of tiny holes with a hand-held drill: use a scrap piece of acrylic as a drill guide. Drill a hole in the acrylic, then drill through that hole and through the board. The clear acrylic makes it easy to line up the drill bit correctly on the center of each pad. After a dozen holes or so, the “guide hole” in the acrylic will start to “loosen up” — just drill another guide hole & keep going.

Finished PCB

The board is ready to use.

I’ve made four boards using this method. The first one was perfect, but got ruined by sloppy soldering. The second and fourth were also perfect & worked great in projects. On the third board, I moved the iron when I first applied it, so the mask slipped and blurred some traces.

With a little practice, you can make a board in a couple hours (not counting design time).

• laser printer/photocopier & transparencies
• copper board
• scrubbing pads
• iron
• rubber gloves
• Ferric Chloride or Ammonium Persulphate
• drill and drill bits

1. PCB Design and print

Design your PCB. I use anything from Adobe Illustrator to Cadsoft Eagle.
Once you think everything is perfect, print it on a piece of paper and test it by placing your components over it. You have to ‘flip horizontal’ your final design so that the transfer from the transparency to the copper board ‘restores’ the intended design… Then print it on a transparency. It has to be a laser printer or a photocopier because we want toner on the transparency. If you can, ask the guy at the print shop to make it as dark as possible (more toner). I’ve noticed that I’ve had the best results at the worst print shops in town.

2. Transfer the toner

Now you want to transfer the toner (mostly made of molten plastic) onto the copper board. Set the iron to ‘silk’ (you’ll have to experiement with the temperature…it took me quite a while to consistently get good results).

Clean and rinse the board with the scrubbing pads and soap. Dry it up. Place the transparency on the copper board, place a piece of paper on top if it all and start ironing! Depending on the size of your circuit, it takes about 2-3 minutes for the copper board to get hot enough so the toner sticks to it. When you think you’re good, immerse the copper board (with the transparency stuck to it) in cold water. Then you should be able to peel off the transparency while the toner remains on the copper board.

If the toner did not transfer completely, you didn’t iron long enough and/or didn’t set the temperature high enough. If the toner transfered but is smudged on the copper board, the temperature was too high and/or you ironed for too long. You can use a Sharpie or any other permanent marker to fix parts of the circuit that did not transfer properly.

3. PCB Etch

You’re almost done. Put the gloves on, pour some etchant in a plastic or glass container and immerse the board. At room temperature, it can take up to half an hour. Mixing the solution as it’s etching can speed up the process. Another good way to dramatically decrease the etching time is to warm up the solution. Now I strongly discourage you to get creative with the microwave or your precious pots and pans. You can however dip the container in warm water poured from the tap. When it looks good, clean the board in running water.

4. Clean the PCB Board

Use the scrubbing pads to remove the toner from the board.
You can reuse the etching solution, so just pour it back in the original container. Do not pour it down the drain! It will corrode your copper pipes… Over time, the etching process will take longer and longer. When the solution becomes unusable, contact the waste management organisation in your community to know where to dispose of the chemical.

5. PCB Drill

For those of you who do not use surface mount components, you’ll need to drill holes in your circuit board. I use a Dremel (you can find generic versions for less than 40$). You’ll need tiny drill bits (#66-#60). Most places you’ll go to will rip you off with those tiny precise bits (10-15$ each). However, some places like Lee Valley sells them for ~$0.50 each.

Features of Golden Gate Graphics Design Services

• Designs Done Right the First Time
• Streamlined Design = Accuracy Plus Speed
• Knowledge, Teamwork and Manufacturability
• Electronic Circuit Schematics
• We Handle Any Type of Circuit Layout
• Engineering and Product Development Services
• Consulting Services

Golden Gate Graphics address:
2408 E. Nichols Circle
Centennial, Colorado 80122, USA

720-276-9127

SMT PCB test board

SMT (Surface-mount technology) is a method for constructing electronic circuits in which the components (SMC, or Surface Mounted Components) are mounted directly onto the surface of printed circuit boards (PCBs).
Electronic devices so made are called surface-mount devices or SMDs.

SMD soldering guide

Soldering SMD chips to the boards (surface mount soldering), you will need four things:

• A good soldering iron. It is much easier with a 60W like Weller W60P temperature-controlled iron.
• A suitable pair of tweezers is esential. Use a 4.5 inch curved pair.
• A head-mounted binocular magnifier, the kind you can flip up or down as needed.
• A board vise (or something similar) to hold the PCB securely while you are soldering on it.

Before you start soldering the SMD, make sure you’ve separated them intro groups and tagged each group with its value. You can use something like a hinged plastic box that is divided intro compartments, but make sure the compartments can’t leak into each other.
Once you’ve tinned the pads (remember one pad per chip), you pick up a chip with the tweezers and position it onto its set of pads. While holding it in place with the tweezers, you heat the tinned end until the solder melts and adheres to the chip. Let this cool. Remove the tweezers and solder the other end. The chips are small, so don’t use too much solder. Don’t hold the iron on the chip too long. With a good iron, it should take just seconds.

It helps soldering SMD is you use an iron with a steel-clad instead of a solid copper tip. Be sure to keep the tip clean. The traditional damp-sponge cools oof the tip and can fuls the tip if the sponge burs. I much prefer a brass-wool pad.
This is not the officially way to correctly apply SMD soldering but this worked for me.

Surface mount soldering videos

surface mount soldering no1
Instructions for Soldering and Desoldering SMDs featuring up-close shots of fine-pitch soldering.

SMT Soldering no2
Advanced surface mount, vertical drag soldering at Washburn Computer Group by John Gammell, Certified IPC Trainer.

Stripboard, Veroboard design software

• StripBoard Designer – Design your electronic circuits on stripboards. StripBoard Designer makes it easy to break strips, jump wires and place components on stripboards. You can even draw your own components and save them in a library for reuse.
  
• VeroDes – is an easy-to-use design program for those wishing to design circuits on veroboard, also known as stripboard. With VeroDes you can: create veroboard circuit designs with ease! Board sizes up to 70 holes by 70 tracks can easily be accomodated, view both sides of your circuit; with links, breaks, and component pins clearly marked in either view, print the circuit in a variety of ways and you can create your own components, up to 25 pins by 25 pins.
  
• LochMaster – is a developers tool for strip board projects. It has features like auto-generation of components lists, a connection test, an editable library with a large number of symbols and components. LochMaster displays views of both sides of the board and both sides are editable. All required functions, like wiring, splitting tracks, soldering, placing components, etc. are included and very realistic.
  
• VeeCAD Stripboard Editor – like a PCB layout program, VeeCAD takes a schematic generated netlist and assists you to build a layout – but on stripboard (Veroboard). The usual design tools are provided: netlist import, component footprint definition, component positioning, wiring and connectivity check.
  
• Stripboard Magic – is a Windows application for designing PCB layouts on stripboard (aka prototyping board). The interface is a quite primitive and a little strange but the program is functional even on Windows XP.
  

10 Free and Best PCB design software

1 ∴ ZenitPCB
Is an excellent pcb layout design software tool to create professional printed circuit board ( PCB ). It is a flexible easy to use CAD program, which allow you to realize your projects in a short time. With ZenitPCB Layout is possible to create the project starting both from the schematic capture or by the layout itself.

2 ∴ FreePCB
Is a free, open-source PCB design editor for Microsoft Windows. It was designed to be easy to learn and easy to use, yet capable of professional-quality work. Some of its features are: 1 to 16 copper layers, board size up to 60 inches by 60 inches, imports and exports PADS-PCB netlists and more

3 ∴ TinyCAD
Is a program to help you draw circuit diagrams. It comes complete with symbol libraries to get you started straight away. As well as being able to simply print your designs, you can use TinyCAD to publish your drawings by copying and pasting into a Word document or saving as a PNG bitmap for the web.

4 ∴ Osmond PCB
Is a flexible tool for designing printed circuit boards. It runs on Macintosh. Its many features include: virtually unlimited board sizes, number of board layers, number of parts, support for both through-hole and surface mount parts and more.

5 ∴ BSch3V
Is a schematic capture program for Windows. The name “BSch” is an abbreviation of “Basic Schematic”. It has only basic functions, in order to simplify operation.

6 ∴ ExpressPCB
Is a snap to learn and use. Laying out PCBs is easy, even for the first time user.

7 ∴ Kicad
Is an open source (GPL) software for the creation of electronic schematic diagrams and printed circuit board artwork. It is useful for everybody working in electronic design (schematic diagrams and Printed Board up to 16 layers).

8 ∴ gEDA
Runs on Linux and has produced tools which are used for electrical circuit design, schematic capture, simulation, prototyping, and production. Currently, the gEDA project offers a mature suite of free software applications for electronics design, including schematic capture, attribute management, bill of materials (BOM) generation, netlisting into over 20 netlist formats, analog and digital simulation, and printed circuit board (PCB) design layout.

9 ∴ Score
Free schematic capture software for Windows. Features: Features: ability to import OrCAD SDT and OrCAD Release IV schematics, can use directly either .LIB or .SRC libraries, no design size limitations, export EDIF netlist.

10 ∴ Eagle
Is a powerful and affordable schematic capture and PCB design software package. CadSoft offers user friendly, powerful and affordable solutions for PCB design, including Schematic Capture, Board Layout, and Autorouter.