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Questions and Answers
Who first developed the printed circuit board?
Who first developed the printed circuit board?
Surface Mount Technology involves using wire leads that pass through holes on the PCB.
Surface Mount Technology involves using wire leads that pass through holes on the PCB.
False
What is the common base material used in PCBs?
What is the common base material used in PCBs?
fiberglass
The main types of PCBs are single-sided, double-sided, and __________ PCB.
The main types of PCBs are single-sided, double-sided, and __________ PCB.
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Which material is commonly used for flame resistance in PCBs?
Which material is commonly used for flame resistance in PCBs?
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Match the following PCB types with their characteristics:
Match the following PCB types with their characteristics:
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Traditional PCB designs were created electronically using advanced software.
Traditional PCB designs were created electronically using advanced software.
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What does FR stand for in FR-4 material?
What does FR stand for in FR-4 material?
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Which of the following functions is NOT performed by CAM systems?
Which of the following functions is NOT performed by CAM systems?
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Panelization involves grouping multiple designs onto a larger panel for manufacturing.
Panelization involves grouping multiple designs onto a larger panel for manufacturing.
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What is the process of separating individual PCBs from a panel called?
What is the process of separating individual PCBs from a panel called?
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The first step in copper patterning is to replicate the pattern on a protective mask on the _______ foil PCB layers.
The first step in copper patterning is to replicate the pattern on a protective mask on the _______ foil PCB layers.
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Match the following terms with their descriptions:
Match the following terms with their descriptions:
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Which method is commonly used for fast and efficient depaneling of PCBs?
Which method is commonly used for fast and efficient depaneling of PCBs?
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Silk screen printing is used to remove unwanted copper during the copper patterning process.
Silk screen printing is used to remove unwanted copper during the copper patterning process.
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During panelization, it is efficient for assemblers to mount components on ________ instead of single PCBs.
During panelization, it is efficient for assemblers to mount components on ________ instead of single PCBs.
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Which method involves milling away the copper foil from a substrate?
Which method involves milling away the copper foil from a substrate?
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In subtractive methods, copper is added to the board to form the desired pattern.
In subtractive methods, copper is added to the board to form the desired pattern.
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What chemical is commonly used for chemical etching of PCBs?
What chemical is commonly used for chemical etching of PCBs?
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The process where a reverse mask is applied to an unpatterned board is called the ______ process.
The process where a reverse mask is applied to an unpatterned board is called the ______ process.
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Match the following PCB manufacturing processes with their descriptions:
Match the following PCB manufacturing processes with their descriptions:
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Which of the following describes laser resist ablation?
Which of the following describes laser resist ablation?
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Drilling holes in a PCB typically uses drill bits made of metal alloys.
Drilling holes in a PCB typically uses drill bits made of metal alloys.
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What is the primary purpose of using the semi-additive process?
What is the primary purpose of using the semi-additive process?
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What material is recommended for drill bits due to its effectiveness against abrasive board materials?
What material is recommended for drill bits due to its effectiveness against abrasive board materials?
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High-speed steel drill bits are ideal for drilling PCBs due to their durability.
High-speed steel drill bits are ideal for drilling PCBs due to their durability.
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What are the small holes called that are used to connect board layers in PCBs?
What are the small holes called that are used to connect board layers in PCBs?
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The files that describe the locations and sizes of drilled holes in PCBs are known as ______ files.
The files that describe the locations and sizes of drilled holes in PCBs are known as ______ files.
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Match the following types of vias with their definitions:
Match the following types of vias with their definitions:
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What is typically applied to exposed copper after a PCB is etched?
What is typically applied to exposed copper after a PCB is etched?
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Laser-drilled vias provide a superior surface finish inside the hole compared to mechanical drilling.
Laser-drilled vias provide a superior surface finish inside the hole compared to mechanical drilling.
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What treatment is used to prevent oxidation of bare copper on PCBs?
What treatment is used to prevent oxidation of bare copper on PCBs?
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Study Notes
PCB Designing - Introduction
- Printed Circuit Boards (PCBs) are non-conductive substrates that mechanically support and electrically connect electronic components.
- Components are connected using etched tracks, pads, and other features on a laminated copper sheet.
- PCBs populated with electronic components are called Printed Circuit Board Assemblies (PCBA).
PCB Designing - History
- First developed by Australian engineer Paul Eisler.
- Earlier technologies included point-to-point wiring and wire wrapping.
- PCBs provide a structured way to connect various points together.
PCB Designing - Types
- Primarily three types: single-sided, double-sided, and multilayer PCBs.
PCB Designing - Components
- Basic PCBs consist of copper foil, copper plating, solder flow, solder mask, traces, and slots/cut-outs.
- The copper-clad fiberglass material or thin copper sheets are attached to each side of the board.
PCB Designing - Through-Hole Technology
- Initial PCBs used this technology.
- Components' leads passed through holes in the board and soldered to traces on the other side.
- Variations include single-sided (one side plated), and double-sided (both sides plated) boards.
PCB Designing - Surface Mount Technology
- Emerged in the 1960s.
- Components were redesigned with small metal tabs or end caps for direct soldering onto the PCB surface, instead of passing through holes.
PCB Designing - PCB Base
- The base material of the substrate is fiberglass.
- FR-4 is commonly used due to its high-temperature characteristics.
- A solid core gives PCBs rigidity and thickness.
- Flexible PCBs use high-temperature plastics like Kapton.
PCB Designing - FR-4
- A composite material combining woven fiberglass cloth and an epoxy resin binder.
- It is flame-resistant, thus "Flame retardant".
- Created from epoxy, glass fabric reinforcement, brominated flame retardant, etc. in 1968.
- Uses bromine to enhance flame resistance.
PCB Designing - PCB Design Equipment
- Early PCBs were manually designed using tape on translucent film.
- These designs were typically larger and reduced photo-graphically to 1:1 scale.
- Modern PCB design relies on computerized PCB CAM systems and software for more efficient layout and design.
PCB Designing - PCB CAM
- PCB Computer-Aided Manufacturing (CAM) performs key functions:
- Input of fabrication data.
- Data verification, potentially including Design for Manufacturing (DFM) checks.
- Compensation for manufacturing process variations (e.g., scaling).
- Generatting output files for copper patterns, solder resist, layout, drill files.
PCB Designing - Panelization
- A procedure grouping multiple PCBs for efficient manufacturing onto a larger panel board.
- Typically a panelized board has one primary design, though multiple designs can be combined.
- Two primary panel types: assembly (often called Arrays) and bare-board panels.
- Manufacturing panels are often preferred due to production efficiency and plating process requirements.
PCB Designing - Depaneling
- Once manufacturing is complete, the panel is separated into individual PCBs.
- Techniques often include drilling/routing perforations along the board's boundaries.
- V-shaped grooves are also used as a line of weakness for breaking apart PCBs.
PCB Designing - Copper Patterning
- Replicating the PCB design on a protective mask placed on the copper foil layers is the initial step in PCB production.
- Unwanted copper is removed through various etching processes.
- Techniques include silk screen printing, Photoengraving (using UV-sensitive photoresist masks) and direct imaging techniques, along with thermal resistant procedures.
PCB Designing - PCB Milling
- Uses a mechanical milling system to remove copper foil from the substrate in non-plated sections.
- Laser-based techniques also exist for removing excess copper or material where no resist is needed.
PCB Designing - Subtractive, Additive, and Semi-Additive Processes
- Subtractive: Removes copper from completely copper-coated PCBs, leaving desired patterns.
- Additive: Electroplates the pattern onto a bare substrate through a more complex process. This approach often has lower material waste.
- Semi-Additive: Starts with a thin copper layer on the board. A reverse mask pattern is then applied. Copper is plated only on the exposed areas. This is often used in multilayer boards.
PCB Designing - Chemical Etching
- Uses ammonium persulfate or ferric chloride to dissolve unwanted copper.
- Frequently used for creating Plated-Through Holes (PTHs), a critical manufacturing process to create connectivity between opposite sides, which often involve electroless copper plating.
PCB Designing - Drilling
- Holes are drilled with small diameter drill bits, often solid tungsten carbide-based, which are more durable and efficient than steel or other less durable solutions.
- Drill requirements often involve factors such as high RPM, and high feed-rate.
PCB Designing - Holes (Conductive)
- Holes may be made conductive through electroplating or inserting metal eyelets (hollow), for electrical and thermal connectivity.
- Specialized holes called 'vias' connect different layers within the board.
- 'Blind vias' connect an internal layer to an outer layer.
- 'Buried vias' interconnect two or more internal layers without reaching any external layer.
PCB Designing - Plating and Coating
- PCBs have solder, tin, or gold plating over nickel as a resist for etching away the unnecessary underlying copper.
- After etching, a solder mask is applied, then the exposed copper is coated with compounds to prevent corrosion.
- The coating might include various materials like nickel/gold, or other anti-corrosion substance. A matte solder is frequently used for better bonding surfaces or for stripping to bare copper.
PCB Designing - Legend Printing
- Silk screen printing, liquid photo images and ink jet printing are techniques employed to print identification information on PCBs.
PCB Designing - Final Steps
- Testing (ensuring proper functionality.)
- Soldering.
- Packaging (encasing the board for protection.)
- Protection
PCB Designing - Advantages
- Fixed components, reduced short circuit and wrong wiring risk, economical mass production, high reproducibility.
PCB Designing - Disadvantages
- Difficult repair after damage, harmful effects on environment from etching process, difficulties with updating existing designs, unsuitable for some non-specific circuit applications.
PCB Designing - Component Library
- Component information is stored in a library in the design software for retrieval and placement. This includes design information that is needed for component identification and positioning information.
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Description
Explore the fundamentals of PCB designing in this quiz, covering the history, types, components, and technologies involved in printed circuit boards. Understand the evolution and significance of PCBs in electronic design and manufacturing.
