Electronic circuit board or Printed circuit board manufacturing (PCB) employs a diverse range of techniques. Prototype electronic circuits manufacturing techniques are often significantly different from those used in high volume production. Large-scale electronic manufacturing generally involves fully automated assembly techniques using equipment that can produce low cost complex circuits quickly and accurately with minimal human intervention. Alternatively, if only one circuit is to be built (for evaluation or testing purposes) then a hand-built prototype is much more appropriate. Computer aided design (CAD) and computer aided manufacture (CAM) are now widely used in the production of electronic circuits. When an electronic circuit is developed for a commercial application, it is usually tested and proved using computer simulation prior to manufacture.
National Diploma in Engineering
A printed circuit board (PCB), a self-contained module of interconnected electronic components is found in various devices such as beepers, pagers, radios, sophisticated radar and computer systems. There are three major types of printed circuit board construction namely single-sided, double-sided, and multi-layered.
Analysis Of PCB Using CAD
Computer aided design (CAD) software is a simulation program with integrated circuit emphasis (SPICE) software direct current (DC) analysis, alternating current (AC) small-signal analysis and more complex analysis methods e.g. transient analysis, pole-zero analysis, sensitivity analysis, noise analysis.
Software simulation allows identifying and troubleshooting potential design flaws before production preventing capital and resource loss. Furthermore, computer simulation gives a designer the flexibility to experiment and fine tune the initial design to achieve an optimum, reliable and functional design
Safety certification (ISO 90012000)
All the manufacturing processes are under the guidelines of ISO 90012000 covering the safety requirements for printed wiring boards for use as components in devices or appliances. Testing analyzes characteristics such as flammability, maximum operating temperature, electrical tracking, heat deflection, and direct support of live electrical parts. The suitability of the pattern parameters, temperature and maximum solder limits are determined in accordance with the applicable end-product construction and requirements
Use Of Surface Mounted Technology
Surface-mount technology (SMT) is the current method for constructing electronic circuits .The components are mounted directly onto the surface of printed circuit board (PCBs) through soldering. Electronic devices so made are called surface-mount devices .
SMT drastically reduces the size of components and replaces the use of leads to hold components in place by soldering.
Surface mount components dont require drilling lots of small holes in PCBs
A number of handy ICs are only available in surface mount packages (e.g. single- and double-inverter ICs, and single- and double-gate logic ICs).
Surface mount components allow for much smaller circuits enabling the use of a wide variety of BEAM bots.
Manufacturing Process
The processes used in the manufacturing of PCBs are
Etching Printed circuit boards are manufactured by applying a layer of copper over the entire surface of the circuit board on either one side or both sides. This creates a surface with copper everywhere .The unwanted areas are removed and the process is called a subtractive method, the most common subtractive method is known as photoengraving.
Photoengraving The photoengraving process uses a mask combined with chemical etching to subtract the copper areas from the circuit board. The mask is created with a photo plotter, which takes the design from a CAD (Computer aided design )PCB software program.
Lamination Many printed circuit boards are made up of multiple layers, these are referred to as multi-layer printed circuit boards. They consist of several thin etched boards or trace layers and are bonded together through the process of lamination.
Drilling Each layer of the printed circuit board is connected to another. This is achieved through drilling small holes called VIASthrough an automated drilling machine. The walls of each hole (for multi-layer boards) are copper plated to form l thole plated-through holes that connect the conductive layers of the printed circuit board.
Solder Plating Solder Resist Pads and lands, which will require components to be mounted on, are plated to allow solderability of the components. Bare copper is not readily solderable and requires the surface to be plated with a material that facilitates soldering. Nowadays nickel and gold both are being used offer solderability and comply with RoHS standards.
Silk Screen When visible information needs to be applied to the board such as company logos, part numbers or instructions, silk screening is used to apply the text to the outer surface of the circuit board. Where spacing allows, screened text can indicate component designators, switch setting requirements and additional features to assist in the assembly process.
Testing Bare board testing verifies each circuit connection as correct on the finished circuit board. Electrical testing involves computer unit to send a small current through each contact point and verify that such current can be detected on the appropriate contact points.
Quality Assurance
Visual and electrical inspections are made throughout the manufacturing process to detect flaws. Some of these flaws are generated by the automated machines. For example, components are sometimes misplaced on the board or shifted before final soldering. Other flaws are caused by the application of too much solder paste, which can cause excess solder to flow across two adjacent printed circuit paths. Heating the solder too quickly in the final reflow process can cause a tombstone effect where one end of a component lifts up off the board and does not make contact.
Completed boards are also tested for functional performance to ensure their output is within the desired limits. Some boards are subjected to environmental tests to determine their performance under extremes of heat, humidity, vibration, and impact.
National Diploma in Engineering
A printed circuit board (PCB), a self-contained module of interconnected electronic components is found in various devices such as beepers, pagers, radios, sophisticated radar and computer systems. There are three major types of printed circuit board construction namely single-sided, double-sided, and multi-layered.
Analysis Of PCB Using CAD
Computer aided design (CAD) software is a simulation program with integrated circuit emphasis (SPICE) software direct current (DC) analysis, alternating current (AC) small-signal analysis and more complex analysis methods e.g. transient analysis, pole-zero analysis, sensitivity analysis, noise analysis.
Software simulation allows identifying and troubleshooting potential design flaws before production preventing capital and resource loss. Furthermore, computer simulation gives a designer the flexibility to experiment and fine tune the initial design to achieve an optimum, reliable and functional design
Safety certification (ISO 90012000)
All the manufacturing processes are under the guidelines of ISO 90012000 covering the safety requirements for printed wiring boards for use as components in devices or appliances. Testing analyzes characteristics such as flammability, maximum operating temperature, electrical tracking, heat deflection, and direct support of live electrical parts. The suitability of the pattern parameters, temperature and maximum solder limits are determined in accordance with the applicable end-product construction and requirements
Use Of Surface Mounted Technology
Surface-mount technology (SMT) is the current method for constructing electronic circuits .The components are mounted directly onto the surface of printed circuit board (PCBs) through soldering. Electronic devices so made are called surface-mount devices .
SMT drastically reduces the size of components and replaces the use of leads to hold components in place by soldering.
Surface mount components dont require drilling lots of small holes in PCBs
A number of handy ICs are only available in surface mount packages (e.g. single- and double-inverter ICs, and single- and double-gate logic ICs).
Surface mount components allow for much smaller circuits enabling the use of a wide variety of BEAM bots.
Manufacturing Process
The processes used in the manufacturing of PCBs are
Etching Printed circuit boards are manufactured by applying a layer of copper over the entire surface of the circuit board on either one side or both sides. This creates a surface with copper everywhere .The unwanted areas are removed and the process is called a subtractive method, the most common subtractive method is known as photoengraving.
Photoengraving The photoengraving process uses a mask combined with chemical etching to subtract the copper areas from the circuit board. The mask is created with a photo plotter, which takes the design from a CAD (Computer aided design )PCB software program.
Lamination Many printed circuit boards are made up of multiple layers, these are referred to as multi-layer printed circuit boards. They consist of several thin etched boards or trace layers and are bonded together through the process of lamination.
Drilling Each layer of the printed circuit board is connected to another. This is achieved through drilling small holes called VIASthrough an automated drilling machine. The walls of each hole (for multi-layer boards) are copper plated to form l thole plated-through holes that connect the conductive layers of the printed circuit board.
Solder Plating Solder Resist Pads and lands, which will require components to be mounted on, are plated to allow solderability of the components. Bare copper is not readily solderable and requires the surface to be plated with a material that facilitates soldering. Nowadays nickel and gold both are being used offer solderability and comply with RoHS standards.
Silk Screen When visible information needs to be applied to the board such as company logos, part numbers or instructions, silk screening is used to apply the text to the outer surface of the circuit board. Where spacing allows, screened text can indicate component designators, switch setting requirements and additional features to assist in the assembly process.
Testing Bare board testing verifies each circuit connection as correct on the finished circuit board. Electrical testing involves computer unit to send a small current through each contact point and verify that such current can be detected on the appropriate contact points.
Quality Assurance
Visual and electrical inspections are made throughout the manufacturing process to detect flaws. Some of these flaws are generated by the automated machines. For example, components are sometimes misplaced on the board or shifted before final soldering. Other flaws are caused by the application of too much solder paste, which can cause excess solder to flow across two adjacent printed circuit paths. Heating the solder too quickly in the final reflow process can cause a tombstone effect where one end of a component lifts up off the board and does not make contact.
Completed boards are also tested for functional performance to ensure their output is within the desired limits. Some boards are subjected to environmental tests to determine their performance under extremes of heat, humidity, vibration, and impact.
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