Making electronic devices functional without PCB is impossible, so PCBs are highly demanded in the technical world. You need to learn about its various forms to make the most appropriate selection of PCB. PCB assembly comes in two forms:
- Single-sided assembly
- Double-sided SMT assembly
Each form of PCB has a different pricing point and different applications. Electronics and applications like computers, mobile phones, industrial (and even radio equipment) commonly incorporate them.
PCBs having just one layer of conducting material on one side are known as “single-layer PCBs.” In contrast, the opposite side of the board is utilized to integrate various electronic components. In addition, a variety of materials, such as paper reinforced phenolic resin and glass fibre reinforced epoxy resin, and copper foil, have been used to make single-layer PCBs.
For the most part, double-sided PCBs are identical to single sided PCB, except they include two trace layers. It is possible to cross over the traces of a printed circuit board using double-sided PCBs, which place copper and components on both sides. In this way, there is no need for point-to-point soldering, resulting in a more significant density of circuit boards. Now we will see each type of assembly in detail with all the pros and cons.
What are Single Sided PCBs?
Printed circuit boards or PCBs are used to connect electronic components, and these boards are in use in a wide variety of electronic devices. Single-sided printed circuit boards are circuit boards with the conductive copper and components mounted on one side of the board and the conductive wiring connected on the other side.
These PCBs are one of the most commonly produced boards as they are straightforward and essential to make.
Application of Single sided PCB
Single sided PCB is quite straightforward than their dual-sided equivalents yet capable of powering many everyday electrical devices. You may find them in mass production gadgets since they’re so cheap to create. Single-sided printed circuit boards are used in various electronics and applications, including the following:
- Camera technology
- Amplified instruments
- Sources of energy
- A kind of hard disc that uses solid-state technology
Benefits of Single Sided PCBs
Single-sided circuit boards are considered one of the best choices for wide applications due to their advantages. Here are a few benefits of single-sided printed circuit boards:
- Simple and basic designs make single-sided circuit boards incredibly cost-effective and economical to manufacture and produce.
- Single sided PCB is the most excellent option for primary and low-density circuit designs since they are commonly known by diverse manufacturers.
- There will be fewer manufacturing issues with single-sided boards since they are less complicated, allowing manufacturers to build these boards at more significant numbers and quicker rates.
- In a wide range of applications and electrical components, they are often employed.
- Single-sided printed circuit boards (PCBs) may be more reasonably priced and readily accessible with larger purchases.
How to design a single-sided PCB?
Suppose you are designing a single-sided PCB and do not know where to start. In that case, fortunately, we will take the design of a positive and negative power supply circuit as a reference case to introduce the design steps and techniques in detail. Single PCB design mainly involves the following knowledge.
- Design method of simple schematic diagram
- Generating a single-sided PCB with the schematic diagram
- Schematic editing method
- The setting of routing rules
- Single-sided PCB design method
Single-sided PCB design steps and tips:
Design tips for single-sided PCB schematic diagram
1#use the wizard to generate PCB files
Open the files panel and click the generation Wizard dialogue box.
2# from schematic to PCB
There are two methods to import the connection relationship of the schematic diagram into PCB:
Execute the menu command [design] in the schematic, editing environment and update the PCB document…
Execute the menu command [design] in the PCB editing environment and import changes from…
Before executing the menu command, you must first ensure that the schematic file and PCB file are in the same project file and that both the schematic file and PCB file have been saved; otherwise, you cannot execute the update command.
3 #replacement component package
Replace package in PCB
Replacing the package in the schematic
The following items cause common errors in updating PCB:
- Package library of component is not loaded
- Missing or incorrect package name for the component
- The number of pins of the element does not correspond to the number of pads of the package
- The elements are inconsistent with the real objects
Single-sided PCB design tips
1# component layout
For this project, you should follow the below principles:
1)The layout is based on the signal flow direction, from left to right or from top to bottom, followed by input (AC signal), rectification à filtering, voltage stabilization;
2)For convenient operation, connectors P1 and P2 are close to the board edge;
3)Adjust the components so that the flying lines cross as little as possible and the connecting lines are as short as possible;
4)The orientation of components shall be consistent as far as possible, neat and beautiful.
Adjust the position and direction of components according to the above principles. The PCB, after manual layout adjustment, is like the below:
2 #PCB environment parameter setting
Execute the menu command [design] [PCB selection]
3# understanding the working layer in PCB
Execute the menu command [design] [PCB layer color]
- signal layers:
It is used to place copper film conductors, copper-clad areas, pads, vias, etc., and supports up to 32 signal layers. The signal layer includes a top layer, bottom layer and 30 intermediate signal layers (mid-layers 1 ~ 30).
The single panel can only use the bottom layer to lay the copper film conductor, the double-sided board uses the top layer and the bottom layer to lay the copper film conductor, and the middle signal layer and the internal power/ground layer can be used for boards with more than four layers.
- internal plane layers:
It is mainly used to lay power lines and ground wires. It supports up to 16 internal power/ground wire layers (plane1 ~ 16). The internal power supply/ground wire layer is not used for the single and double panels, and it is possible to use the multi-layer panels.
- mechanical layer
It is mainly used to place the physical frame size, dimension, assembly instructions, etc., of the PCB. It supports up to 16 mechanical layers (mechanical L ~ mechanical L6).
- The alignment hole, printed board frame, etc., are placed in mechanical L; The mechanical structural parts on the board are placed in mechanical layer 3;
- The marked size, annotation text, etc., are placed in mechanical.
- mask layers:
There are four layers, including two paste layers:
- The top paste layer
- The bottom paste layer.
Setting the solder paste layer is to facilitate the installation of chip-mounted components. The layer without surface-mounted components must not be set with a solder paste layer.
There are two solder layers:
- Top solder
- Bottom solder.
Setting the solder resist layer is to set a protective zone around the pad and prevent soldering tin from being stuck to the wiring, filling area, copper coating area and other places that do not need to be welded during wave soldering.
On the circuit board, except for the places that need to be welded (mainly component pin pads and wiring pads), a layer of solder resist paint is applied (the solder resist paint is generally green or yellow). A single panel only needs the bottom layer of the solder mask, and other panels generally need two solder masks.
- silkscreen layers
It is mainly used to place the outline, label, annotation and other information of components. There are two layers, including a top overlay and a bottom overlay.
In general, components are placed on the top layer as much as possible, so only the top-level silkscreen layer is set. However, if components are placed on the bottom layer under special circumstances, the bottom-level silkscreen layer is required.
- Other layers:
The layers used to place pads, vias and wiring areas
7)The default display color of some auxiliary designs is set in the [system color] area:
Work level settings
Execute the menu command [design] [layer stack manager]
Click the command menu at the bottom left layer stack example
Select a signal layer, such as the top layer, and then click the [add layer] button on the right of the figure to add an intermediate signal layer. If you click, the [add internal power layer], the internal power/ground layer will be added.
4# wiring rule settings
Execute the menu command [design] [rules]
Click routing to expand routing rules. It can be seen that there are seven rules:
- Width (wiring width)
- Routing topology
- Routing priority
- Routing layers
- Routing corners
- Routing via style
- Fan out of control
Execute the menu command [automatic wiring] [all objects]
If any abnormality is found during the automatic wiring, execute the menu command [automatic wiring] and [stop] to terminate the wiring.
In addition to automatically routing all objects, you can locally route specified areas, networks, and components.
6#manual wiring modification
#7adjust the component text position
Execute the menu command edit [arrange] [locate] component text position.
8#adjust the size of the mechanical border
Use the “place line” tool in the utility toolbar to draw a closed mechanical border line on the mechanical layer 1
Execute the menu command [view] [display 3D PCB]
How to Manufacture Single PCB Structure?
The single-sided board is the most straightforward kind of printed circuit board since it has all of the components on one side and all of the wirings on the other. This PCB is referred to as single-sided because the wires are only visible on one side.
Pads, vias, mounting holes, cables, components, connections, fillers, and electrical boundaries comprise the majority of a single PCB. Each member serves the following primary functions:
• A pad is a metal hole used to solder components’ pins.
• The term “via” refers to a metal hole linking component pins between layers. It is used to secure the circuit board.
• The electrical network’s copper film is utilized to link the component pins.
• Connectors: They are used to join components on separate circuit boards.
• Filling: It covers the ground wire network with copper, which efficiently reduces impedance.
• Electrical border: This defines the size of the circuit board; no component on the board may extend beyond the boundary.
What are Double-Sided PCBs?
Double sided SMT assembly is one of the most popular PCBs as it enables manufacturers to produce more complex circuits, which can benefit uses in higher technology low volume PCBA applications and electronics. There are many applications and electronics in which double-sided PCBs can be used, including lighting systems, vending machines, amplifiers, car dashboards, and many more.
Double-sided PCBs are similar to single sided PCB versions, except they have two-sided traces with a top and bottom layer. These boards can mount conductive copper and components on both sides of the circuit board, allowing the paths to cross. This results in a higher density of circuits without the need for point-to-point soldering. These circuit boards are more complex than single sided circuit boards, so they can be more challenging to produce. However, the benefits of using double-sided PCBs are more significant than the cons of using them.
Uses of Double-Sided Assembly
Because of their complexity, double-sided PCBs are more difficult to manufacture than single sided options. Double-sided PCBs, on the other hand, are preferable over single sided PCBs. Double-sided PCBs may be utilized in a wide range of electronic applications, including the following:
- Lighting systems using LEDs
- Dispensing devices
- In-car displays
- Controls for the industrial environment
- Telecommunications PCB
Benefits of Double Sided PCBs
Double-sided PCBs are a frequently utilized component for numerous applications since it offers greater freedom in the design and more sophisticated circuitry. Here are a few benefits of double-sided boards:
- The fundamental advantage of double-sided boards is that you have an additional layer to add more components, which essentially improves the density of the circuit.
- With perfect space available on the circuit board, this enhances the PCB flexibility of the design, allowing you to insert more components and have room for more connections if required.
- Double-sided circuit boards prefer to employ more complicated circuitry since there is more area. This implies that these boards are excellent for complex electronics or demanding applications.
- Being able to utilize both sides of the circuit board considerably minimizes the size of the panel required. This may be a considerable cost-saving which makes double-sided PCBs less costly.
Manufacturing process of PCB double sided board
Customer requirements → engineering design data → manufacturing work order mi → material cutting/plate baking → drilling → copper deposition/plate surface plating → grinding and brushing → circuit → copper-tin plating → film removal/etching → tin removal →Resistance welding → nickel deposit → forming/stamping → completion test → high temperature levelling → finished product inspection → finished product warehouse
1) Blanking: cut out the size convenient for processing from the whole copper-clad laminate with a certain plate thickness and copper foil thickness
2) Drilling: drill conductive holes or plug-in holes on the board according to the computer drilling program
3) Copper deposition: deposit a thin layer of chemical copper in the drilled hole to deposit a layer of copper on the non-conductive epoxy glass cloth substrate (or other substrates) by chemical method so as to facilitate the subsequent electroplating to form a circuit;
4) Copper plating on the whole plate: it is mainly used to thicken and protect the thin layer of chemical copper to prevent it from being oxidized in the air and form no copper or holes in the holes;
5) Circuit (graphic transfer): paste a dry film on the board or screen print a graphic anti electroplating ink, and make a circuit graphic after exposure and development
6) Graphic plating: thicken the circuit on the board that has finished the graphic circuit so that the copper thickness in the hole and the circuit reaches a certain thickness, which can load a certain current
7) Etching: remove the graphic ink or dry film and etch the excess copper foil to obtain the conductive line pattern
8) Tin removal: remove the tin layer on the formed figure to expose the required circuit
9) Screen printing solder resist ink or sticking solder resist dry film: print a layer of solder resist ink or stick a layer of solder resist dry film on the board, and make solder resist graphics after exposure and development. The primary purpose is to prevent a short circuit between lines during welding
10) Metallization/tin spraying: deposit gold or spray a layer of tin on the plate where welding is required to facilitate welding and prevent oxidation of the copper surface
11) Characters: some symbolic characters are printed on the board, which is mainly convenient for customers to install components
12) Stamping/forming: process the shape of the plate according to the customer’s requirements
13) Electrical test: detect whether there is an open or short circuit in PCB by closing the circuit
How are Double-Sided SMD Boards Assembled?
Double sided SMT assembly is a little trickier. On both sides, electrical components and cables are installed. It’s labour-intensive to make, but the benefits far exceed the drawbacks.
Assembling and fabricating PCBs involves a number of steps. The components will be put on the board, then soldered, examined, and tested once the solder paste has been applied. Each and every one of these procedures is meticulously carried out to provide the finest possible quality in the final product.
Double-sided boards are made by first assembling and soldering one side, then flipping the board over to finish the other. A lower melting temperature must be used when applying solder paste on the opposite side. As a result, it has no effect on the other side. Pick-n-place soldering and vapour phase soldering are the next steps.
Distinguishing Factors Between Single-Sided and Double-Sided Printed Circuit Boards
Various types of printed circuit boards are used in electronics and applications, making PCBs a precious technology. From computers and mobile phones to radio equipment and industry, circuit boards are all employed in various applications.
Single-sided printed circuit boards are widely used in many electronics, whereas double sided SMT assembly is used in higher technology electronics.
These printed circuit boards are very similar, making it difficult to choose between the two for manufacturing. These PCBs may be used for a wide range of purposes, but it all depends on what you require.
Frequent Asking Questions
- How are double-sided PCBs made?
It is constructed from a substrate material, often fibreglass, onto which copper foil is bonded to create a conductive channel that runs the length of the board. Double-Sided PCBs, also known as two-layer PCBs, are printed circuit boards with conductive copper layers on both sides.
- What is a solder mask on a printed circuit board?
Soldermask is a protective layer of liquid photo imageable lacquer applied to both the top and bottom surfaces of a Printed Circuit Board. The Soldermask’s purpose is to shield the copper from oxidation other than the solder pads. During this, I’m creating shorts. Welding (bridges)
- How does a double-sided printed circuit board work?
While single-sided printed circuit boards contain just one conducting layer, double-sided printed circuit boards feature a conductive layer on each side. Manufacturers may use vias to construct traces on both sides that travel around and link layers.
Choosing the right sort of printed circuit board (PCB) for your project means knowing the distinctions between the many types of PCBs available.
Printed circuit boards with a single layer of copper are often employed in a broad range of electronic applications because they are inexpensive. Moreover, single sided PCBs are one of the most prevalent printed circuit boards.
However, double sided SMT assembly is the standard board because it allows circuit designers and manufacturers to create more complicated circuits, which may be helpful in electronics and high-tech applications.