PCB design. PCB Design Software

Typically, an electronics or electrical engineer designs a circuit, and a layout specialist performs circuit board development. Their design is a specialized skill. There are many methods and standards used to design a printed circuit board, which is easy to manufacture but also small and inexpensive.

PPs are widely used in all electronic products, such as engineering, energy, transportation, wireless devices, robotic applications, and many other areas of science and technology. They provide fast operation, access, control, monitoring and accurate results compared to other connection devices.

Individual PCBs

A printed circuit board (PCB) mechanically supports and electrically connects electronic components using conductive tracks, connections, and other elements etched from copper sheets laminated on a non-conductive substrate. It has a pre-designed and copper track design on a conductive sheet. Thus, the development of the printed circuit board reduces the possibility of malfunctions arising from weak connections, while assembling the components is simple - the radio amateur can only place the components and solder them.

Many developers use individual PPs instead of the finished product due to the fact that the custom design makes them more compact, more convenient to use, since the radio amateur himself decides where to place the parts. And finally, the board is much stronger, unlike finished products, which are pierced by many holes that make the products weak.

PCB manufacturing technology is quite simple:

1. Layout development.
2. Printout of the circuit.
3. Thermal transfer of the circuit to a copper plate.
4. Etching of PP in a special solution of ferric chloride followed by washing it with water to remove residual reagents.
5. Remove the remaining ink with a solvent to expose the unpainted copper portion.
6. After removing ink, you will need holes to solder the components on the board.
7. According to the completed scheme, the components are soldered.

Tools and Reagents

Printed circuit boards are made from special materials that do not conduct electricity, such as fiber and glass. Circuits are performed on the PCB with copper tracks instead of electrical wires, for communication with components.

In order to do the development of a printed circuit board with your own hands, you must first purchase the following tools and materials:

• mini drill (Dremel);
• household iron;
• laser printer / photocopy machine;
• latex gloves;
• safety glasses for the eyes;
• etching solution (iron chloride);
• fine tip marker;
• ruler;
• matte / glossy paper;
• plastic tweezers;
• plastic straws;
• rags;
• sanding paper.

Design creation

If the radio amateur already has a mock-up for making a printed circuit board with his own hands, he can simply skip this step and go to the next or draw a diagram directly on the board, if he has no plans to execute the PCB by printing. Before you create a board, you first develop a circuit. It is best to do this using reliable design software such as Eagle Layout Editor. For people who are looking for less sophisticated software, Microsoft Powerpoint can be advised. When printing the layout using a laser printer or photocopy machine. Inkjet printers will not work because their ink is soluble in water and cannot be transferred to PP. Use any glossy paper, even magazine articles are suitable.

Next, use a regular household iron, ironing the printed circuit on the board. When ironing a printed layout, ink is transferred from paper to the board. You need to set the maximum temperature of the iron, if the paper is thick, but if not, then average. Next, soak the board in a vessel with tap water for 2-5 minutes or put it under running water from the sink. Then gently wipe the surface so that ink is not removed. Saw off the excess PP board and grind it with thin sandpaper. If during cleaning some areas with ink were unintentionally deleted, you need to restore the circuit with a marker and a ruler.

Board etching and recovery

There are various options for the etching solution, but the most common is ferric chloride, which is used in the manufacture of printed circuit boards with their own hands. Use the reagent in a plastic container and never in a metal container. Pour the reagent into the container, leave the board for 30-45 minutes, then remove it from the container. The ink-protected area is etched and removed at the end.

PCB manufacturing technology:

1. Rinse the circuit board with tap water after etching in the solution, be sure to wear gloves and glasses when cleaning. It is also recommended that you use plastic tweezers and do not use metal tools.
2. They clean the remaining ink with washing soap after etching to expose the copper part of the board, you can clean it with a small piece of fine sanding paper, giving it a shine.
3. Then drill holes with a mini-drill according to the scheme and rinse again with water. Drilling is performed on the copper side, since the scheme is placed there, which will serve as a guide.

Effectively placing traces on a printed circuit board is a difficult skill and requires a lot of patience. This task has been greatly simplified thanks to the advent of readily available free Diptrace software in Russian (version 2.0.1.7) for designing layouts, which can be downloaded from the official website.

Verify Design Requirements

It is recommended that you perform circuit check functions before it is built into the circuit board. By studying the types of components using software, you can ensure that the circuit interval is within tolerances, there are no problems with size restrictions, and other placement requirements that are mandatory for this type of object are met to ensure reliability and safety of operation. Board quality and ease of placement increase the efficiency of the finished product.

A program for developing printed circuit boards can identify complex designs that can lead to conflicts between components or electrical circuits during production, cause problems with track widths, the size of the physical component of the board, and even electromagnetic interference from other elements.

Therefore, the layout of the software should be optimized using software that best suits the needs of the designer. Some functions are present in many proposals, but few have improved tools for designing printed circuit boards, in connection with which the designer is better to use the advice of specialists before choosing a program.

Software selection

The most important element in electronic circuits and equipment is the printed circuit board. It is possible to build an electronic circuit with breadboard and zero boards, but this method is low-level and less efficient, since the design scheme will be susceptible to damage, and the result can be disastrous, since the design involves a complex process of placing components of the circuit. Today, the Internet offers many programs for the production of printed circuit boards.

Software selection requirements:

1. Functionality should correspond to the style of work of the designer. Many developers start with a diagram and transfer the results to the design of the PP layout. If the software in question does not support this direction, it is probably better to choose another program.
2. Flexibility. Creating a great layout is one thing, but if it is executed by a low-functional program, it will not bring much value to the product. Layout software should be suitable for both rigid and flexible boards according to the designer's choice.
3. Software support - the supplier must provide effective support, especially for designers who are new to CAD tools.
4. Updates - the minimum frequency of program updates by the supplier once every six months. The layout and design of software are constantly evolving along with technology. Software that does not change over time will be useless in a relatively short period.

The introduction of breadboard software in the design process of the printed circuit board will increase the efficiency of component placement and reduce the number of problems that occur when the boards go to the stages of prototype creation and final manufacturing. The sooner problems are discovered in the process, the cheaper they are. This becomes even more important, as engineers are faced with the task of developing more complex, multi-layer and thin PPs for modern electronics and miniature devices. Smartphones and smart flat-screen TVs are just some examples of applications for increasingly complex PP layouts.

Many developers recommend using Sprint-Layout for printed circuit boards - this is a software tool used to make single-sided, double-sided, and even multi-layer PCB models. With it, you can quickly and easily design a circuit board, since the tool has no restrictions on how to design your circuit board.

Eagle and Multisim Design Process

Making a printed circuit board that supports physical electronic components and wiring them through copper surface mount tracks is truly remarkable. In order for the home software to be up-to-date, functional and reliable, the best software design process is performed with CAD software, for example Eagle. This type of PCB design software contains a library of components that you can use to build circuitry. It is also possible to change the position of the circuit design, and then change in accordance with the requirements of the standard and convenience.

PCB manufacturing technology with Eagle:

1. Open the Eagle board design program.
2. A window with a menu bar will appear.
3. Click on the file menu.
4. Choose a “new design” from the drop-down menu.
5. Click on the library menu.
6. Select “devices / symbol” from the drop down menu.
7. Select the appropriate comment by double-clicking on it so that the component appears in the window.
8. Add all components and draw a diagram with the correct connections.
9. Enter the rating of each component in accordance with the requirement.
10. Go to the command toolbar and click on "Text Editors", "Options" and close the window.
11. Then a black screen appears with a layout or diagram, it is saved in the image format.
12. The layout is generated from the final circuit board software for its layout, which is sent to the production unit, where a negative image or mask is printed on a plastic sheet.
13. Choose raw materials.
14. The base of the PCB is made of safety glass or fiberglass with a copper coating on one or both sides of the board.
15. PCBs that are made from unbreakable phenolic paper are less expensive and are often used in household appliances. It is possible to use a thin industrial laminate coated with copper on one or two sides.
16. Next, go through the standard PP manufacturing procedure described above.

Various manufacturing methods

It is easy for a ham radio to make circuit boards at home. This will save a lot of time on debugging processes and double-checking connections on the layout. You can make your own Arduino.

There are three main manufacturing methods:

1. Iron on glossy paper by heating.
2. The scheme by hand on the PP.
3. Laser etching. Since the laser method is an industrial method of manufacturing circuit boards, home craftsmen use the first two.

PCB Design:

1. Software design is usually done by converting a circuit diagram into a layout using software.
2. There are many cool open source software packages for creating and designing software layouts.

Many electronic home appliance developers recommend those that offer the greatest advantage:

• Cadsoft Eagle;
• PCBWizard.

Circuit Diagram in Cadsoft Eagle

Using layout software to work in the design process of printed circuit boards will improve quality, allow you to create projects that are ready for production, accelerate market entry and reduce costs. Cadsoft Eagle - one of the highest quality software for creating boards. For example, consider the creation of a PP - touch switch using the IC555.

Execution algorithm:

1. Enter Eagle: File> Export> Image and execute the layout.
2. They print the PP layout using a laser printer and A4 photo paper or glossy paper and make sure that the printout is made on the glossy side of the paper.
3. Cut the copper board according to the size of the layout using a hacksaw or cutter.
4. Process the copper side of the circuit board using sandpaper or abrasive sponge scrubs. This removes the upper oxide layer of copper as well as the photoresist layer. Polished surfaces also allow better sticking of paper images.
5. Transfer PP to a copper plate. Be sure to flip the top layer horizontally. Lay the copper surface of the board on the printed layout, make sure that the board is correctly aligned with the borders of the print layout, and use the tape to hold the board and printed paper in the correct position.
6. After printing on glossy paper, iron the iron with its image side down to the copper side, then heat the electric iron to maximum temperature.
7. They put the board and photo paper on a clean wooden table, covered with a tablecloth, the back of the photo paper to themselves, iron the photo paper, applying slight pressure, for about 5-15 minutes.
8. After ironing, place the printed plate in warm water for about 10 minutes. The paper will dissolve, then you can carefully remove it. In some cases, when removing paper, individual tracks lose color, so you can use a black marker to darken them.
9. Before etching, wear rubber gloves first.
10. Place the newspaper on the floor so that the pickling solution does not spoil it.
11. Fill a plastic box with water.
12. Dissolve 2-3 teaspoons of ferric chloride in water.
13. The circuit board is released into the etching solution (iron chloride solution, FeCl3) for about 30 minutes, the reagent reacts with unmasked copper and removes unwanted copper from the board.
14. Use pliers to remove the PP and check whether the entire unmasked area is etched or not, you can leave it in the solution for a while.

Care must be taken when disposing of the pickling solution; it is toxic to fish and other organisms in the aquatic environment. It is strictly forbidden to pour it into the sink; instead, it is diluted many times and poured into a safe place.

Practical design with DesignSpark PCB

DesignSpark PCB is an RS Components PCB design tool. It is part of a suite of applications designed to support rapid prototyping through mechanical and electronic design and was launched on the market in 2010.

RS Components has developed an online community that is actively developing the project, which is not surprising, since RS is a world-famous and respected organization that publishes its solutions for electronic design. The tool is free, but there is an option for commercial use.

Despite its free, this is a complete and professional program that allows you to create several pages of schematic models, has no restrictions on the size of the circuit board and produces standard files in the final format.

Craftsman tips

A simple scheme can be developed after several hours of training. More complex projects that use sophisticated software require more dedication and patience, so it’s better to use the advice of professionals.

Tips for beginners:

1. Download and install optional PCB software.
2. Start the PP schema constructor. In Eagle, you can do this by going to File, New, and Schema.
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9. Resize panels by moving borders as needed. It’s good practice to leave approximately 1/2 inch of space on each side of the rectangular board.
10. If Sprint Layout 6 is used and you need to create grounding, use the “polygon gnd” command, press “Enter” and use the mouse to create the selected area. Select "Auto" in the left menu to automatically adjust the polygon for transes, pads and transitions. In principle, everything, after that, the PP layout is ready.

Thus, we can conclude that the design of the printed circuit board does not require special skills and great patience. For this, it is not necessary to undergo special training, since most markup programs come with tutorials and step-by-step examples that are successfully used to learn the basics.