Tag Archives: SMT assembly

PC Board

Legend Printing- PC Board Fabrication Process

If you’re looking for the most advanced and efficient PCB manufacturing process on the market, look no further than the legend printing-multilayer PCB manufacturing process. This new process is revolutionizing how printed circuit boards are manufactured, offering superior performance and reliability over traditional methods. In this article, we will discuss the benefits of this new process, how it works, and why it’s the best choice for your PCB manufacturing needs.

The legend printing of multilayer PCB is revolutionizing the way printed circuit boards are made. This cutting-edge manufacturing process is making it possible to create circuit boards that are more reliable, cost-effective, and easier to use than ever before. With this process, legend printing can provide customers with superior circuit boards for a wide range of applications.

What Is Legend Printing?

Legend printing is a specialized multilayer PCB manufacturing process that combines the benefits of advanced technologies such as laser direct imaging (LDI) and inkjet printing to produce high-quality printed circuit boards. The process creates layers of fine traces on the Printed Circuit Board, allowing for a high level of detail and accuracy, along with excellent signal integrity.

The key benefits of legend printing include increased resolution, trace widths down to 5 mils or less, a wide variety of solder mask and surface finish options, and minimal time required for prototyping and production. This makes it an ideal choice for high-density designs where reliability and performance are important.

The process starts with laser direct imaging (LDI), which involves a laser beam used to create the desired pattern on the PCB’s surface. Next, an inkjet-printed layer is applied to the board before it is processed through the reflow oven. Finally, a solder mask is applied and cured, providing a protective coating to the finished product.

Legend printing ensures a superior level of quality for multilayer PCBs, giving designers the confidence to push the boundaries in their design requirements. With its combination of advanced technologies, it’s a reliable and cost-effective solution for producing complex electronic components. It also offers quick turnaround times with many fabrication capabilities, including small batch sizes and quick turnarounds. It’s no wonder why many leading companies rely on this cutting-edge technology to get them from concept to market quickly and efficiently. Moreover, if you’re looking for top-notch prototype PCBs, you can’t go wrong with legend printing.

Inkjet printing has many benefits that other processes cannot match. It provides a quick turnaround, allowing projects to go into production quickly, and allows designers to produce from a single-layer board or up to 10-layer boards. It helps make use of acid-free and water-based inks that deliver rich blacks, sharp text, high gloss finishes, and precise graphics. However, these advantages can increase the printing price. Like, an inkjet printer starts at about $10,000 and requires a costly startup investment. When these costs are factored in with maintenance fees, servicing needs, and running costs like ink replacement, this solution could prove to be too pricey for many companies.

The Multilayer PCB Manufacturing Process

Legend printing involves an advanced automated production system to ensure consistent and reliable results for customers. Generally, the process starts with a substrate, which consists of several layers of epoxy resin-bonded copper foil. Manufacturers then use imaging equipment to print the design onto the substrate and etch away the excess copper.

Then, they apply a layer of insulation material over the etched copper layer, followed by the insertion of conductive vias which electrically connect the layers. Finally, a solder mask is applied to protect the board from any accidental damage.

Through a multilayer PCB manufacturing process, you can produce intricate designs with high levels of accuracy and repeatability. This helps to ensure that your product will perform as expected when it reaches its final destination. The versatility of a multilayer PC BOARD manufacturing process also means that you can work on a wide range of different products.

Some industries that use legend printing include automotive, telecommunications, and aerospace applications. Each of these markets demands unique requirements and specifications, but they all require reliability and dependability. To keep up with the demands of each industry, we have developed innovative solutions through our experience in research and development. For example, aircraft are very sensitive structures, so some companies offer low-volume and pre-production testing services using the RISC or a rapid prototyping service. With such a service, you can reduce the lead times for tooling; maintain quality control during assembly, and reduce the risk exposure during the production ramp-up time.

The Benefits Of Legend Printing

The Legend printing-multilayer PCB manufacturing process offers several benefits for businesses looking to create complex circuit boards. By using this process, industries can ensure very high quality and accurate production.

The first benefit of using this process is that it allows for smaller board components. By using a multilayer system, more complex circuits are easy to create on smaller boards. This makes the boards easier to package and transport, saving the companies time and money.

Moreover, by using the legend printing-multilayer PCB manufacturing process, businesses can produce boards with superior electrical performance. This process can achieve high levels of precision and accuracy, leading to fewer errors and better overall performance.

Finally, this process allows for faster turnaround times. By utilizing multiple layers of production, businesses can quickly assemble complex circuits and get their products to market faster. This ensures that companies remain competitive in their industries and are able to capitalize on market trends quickly.

Overall, the Legend printing-multilayer PCB manufacturing process is an excellent option for businesses looking to maximize efficiency and quality when creating complex circuit boards. By utilizing this process, you are confident that your products are of the highest quality and are produced as quickly as possible.

Why Choose Legend Printing For Your Multilayer PCBs?

When it comes to designing and manufacturing multilayer PCBs, choosing the right manufacturing process is essential. Legend printing is a leading provider of multilayer PCBs, offering a comprehensive range of services that can help you get the most out of your multilayer PCBs.

The best legend printing companies use state-of-the-art equipment and processes to ensure quality, reliability, and performance. Our advanced Circuit board fabrication process starts with a detailed design and layout phase, allowing us to create high-quality multilayer boards with accurate dimensions.

Expert engineers use advanced manufacturing techniques and equipment to fabricate the boards. After production, they subject each board to a rigorous quality assurance process to guarantee that it meets all of your specifications.

The result is a multilayer PCB that is reliable and performs as expected in any application. Engineers also use advanced testing and inspection techniques to ensure that every product is up to high standards of quality and performance. By hiring a good printing company, you can trust that your multilayer PCB will be delivered on time and meet all of your requirements.

What To Consider While Making Legend Prints

You have to consider a few things during legend printing, be it new or some modifications, such as:

  • Texts should have the same orientation in the entire board, like reference designator, part numbers, brand details, etc. You should arrange the text from top to bottom.
  • Manufacturers often have to deal with overlapping texts that need editing. You can avoid it by moving the reference designator to the right side.
  • Though you can add legend printing on both sides of the board, it becomes expensive. So, you can reduce the cost by using only one side.
  • Markings should have standard shapes and colors to have readable and low-cost printing.
  • You can reduce printing faults through measurements. Keeping the space a few mils can reduce the errors.
  • Avoid placing text in four directions as it can make repair complex.
  • The text should not overlap the holes or vias, or it will lose its significance.
  • Try not to write the text on the fast signal paths, as it can cause dielectric loss, affecting the impedance level.

Legend printing involves different text styles, depending on the circuit board manufacturer and customers. Designers should check the styles before sending the Gerber files to fabricators.

Final Thoughts

Legend printing is a specialized multilayer PCB manufacturing process that combines the benefits of advanced technologies such as laser direct imaging and inkjet printing to produce high-quality printed circuit boards. The process creates layers of fine traces on the PCB, allowing for a high level of detail and accuracy, along with excellent signal integrity. You have to consider certain things during legend printing.

The legend printing-multilayer PCB manufacturing process is an excellent option for businesses looking to maximize efficiency and quality when creating complex circuit boards. By utilizing this process, you are confident that your products are of the highest quality and are produced as quickly as possible. If you’re looking for a reliable and cost-effective solution for your multilayer PCB needs, then look no further than legend printing.

Would like to know more about legend printing or PC Board assembly? Email us at sales@pnconline.com.

Printed Circuit Board

Printed Circuit Board Heat Sink Features/Functions

Heat management is essential for living on this earth as weather and devices affect buildings, vehicles, and equipment. Thermal management is also necessary for printed circuit boards, as they will get damaged if they can’t dissipate the heat their components generate. Besides, the board also gets hot due to soldering during manufacturing. Hence, heat dissipation methods become mandatory to increase the PCB speed.

Though FR4 is good at heat management, sometimes it is not enough when there is a high-speed circuit board. Likewise, the power supplies also generate heat and you have to install heat sinks and insulators. You must have experienced mechanical engineers to assess the heat flow to create a suitable heat dissipation system.

Printed circuit boards provide current to help devices function, but electronic devices get hot and heat sinks dissipate unnecessary heat. A PCB Manufacturer will use different heat sinks to prevent the overheating of PCB components and their damage, increasing the performance of the board.

Fourier’s law is an important law of heat that determines the heat sink function. When an element gets hot, heat travels from high-temperature areas to a low- temperature surface. The heat transfer occurs in three ways, such as:

  • Conduction
  • Radiation
  • Convention

When two components having different temperatures connect, it results in thermal conduction. In other words, fast molecules collide with slow molecules, resulting in heat transfer from hot components to cool components. PCB has high-temperature components like transistors, so you need to dissipate heat to cooling mediums, like water, air, or it can be oil, or some other element. This heat transfer occurs through conduction and convention.

Types of Heat Sinks

Heat sinks come up in different types as below:

Active Heat Sinks: There is a fan in an active heat sink to provide cooling. Such a heat sink provides great cooling, however, it needs regular maintenance as it is mostly running which affects its condition.

Passive Heat Sink: Passive heat sink is without a fan, so it remains still and needs less maintenance. You can consider it reliable and more effective than an active heat sink.

The shape and design also determine the type of heat sink, including swaged, stamped heat sinks, machining, folded and bonded fin, single fin sink, and forged heat sink.

Factors Affecting a Heat Sink

The main purpose of the heat sink is to exchange heat, so a large part of its surface area should be in contact with the cooling component like air. The quality of the heat sink depends on different factors, including its material, finishing, and certain physical features, like:

  • Air velocity
  • Attachment technique
  • Protrusion type

    Materials That Enhance Heat Sink Function

Manufacturers use specific materials to enhance the function of the heat sink in terms of heat transfer. These materials include:

  • Compounds
  • Conductive tape
  • Thermal paste

These materials are inserted between the surface of the heat sink and the surface of the component that generates heat. Metals having high thermal conductivity are ideal for heat sinks, including aluminum, copper, etc. But, aluminum is common as it is cheaper than others.

What To Consider Regarding Heat Sinks

Many factors affecting heat sink function include length, fin spacing and density, width, airflow, heat resistance, etc.

Which Devices Need Heat Sinks?

Electronic devices with components having poor heat dissipation ability need heat sinks. The devices in this case include multiple integrated circuits, diodes, transistors, switching devices, CPU and graphic processors, and LEDs.

Key Factors of Heat Sink Design

Heat sinks dissipate heat with the help of natural and forced convection, liquid, or radiation. The requirements of thermal management vary, depending upon the applications. Apart from a heat sink design, you have to consider several other factors while designing a thermal management system for a specific device. For like, you have to consider the standards of the component level, heat sink level standards, chassis levels, and requirements for a system level.

Let’s discuss essential factors that you have to consider during heat sink PCB design.

Heat Resistance: Thermal or heat resistance is the sum of multiple resistances occurring to heat flow between a cooling liquid and the die, thermal interference resistance, as well as the resistance between a moving fluid and a heat sink. Thermal resistance is bad for thermally unstable modeling systems.

The Value of Thermal Resistance: It is not precise, instead, it is approximate. It helps evaluate the thermal conductivity of the heat sinks and semiconductors. Heat dissipation depends on heat sink parameters that need proper analysis while designing the heat sink device. Heat sinks can be meshed through a 3D thermal resistance to have a complex system of thermal factors. Different platforms help design heat sink meshes.

Heat Sink Materials:  Generally, copper and aluminum are ideal heat sink materials as described above. These materials are good at conducting heat, especially copper as it also helps absorb heat, resists rust, and resist biofouling, moreover, it is also antimicrobial resistant. Though copper is better than aluminum, it is thick and costly compared to aluminum.

Another material is diamond and its thermal conductivity is also high due to the lattice vibrations it has. Some other materials for thermal applications include copper-tungsten pseudo-alloy, and AlSiCDymalloy.

Size and Shape of Heat Sink:  The shape and the size of the fins also help enhance heat dissipation. You can evaluate various fin shapes through modeling.

Fin Placement or Location: The arrangement of fins in a heat sink affects its cooling quality. Its configuration should be optimized to minimize the resistance of fluid movement, providing maximum air in the heat sink.

Cooling Quality: The cooling quality of the heat sinks has to be high. The aspect ratio of fins should be less to perform well. If the distance of the fin from the heat sink base is more, it will reduce the heat transfer to a cooling medium.

The function of the fins in a heat sink is to absorb heat from the electrical components of a device and sends it to the cooling medium. Besides, you should choose a cooling medium matching a PCB design and device requirements.

Heat Dissipation: Certain factors reduce the heat sink performance like a rough surface and gaps. They cause high resistance to thermal contact, thus affecting heat dissipation. You can reduce such thermal resistance by using thermal interface materials because most resistance-reduction techniques have limitations. You should consider specific things while selecting a thermal interface material, such as contact pressure, the material’s resistivity to current, and the dimensions of the surface gaps.

Attachment Methods: The attachment of the heat sink with PC Board components affects its thermal efficiency. So, you should choose the attachment technique carefully, considering the requirements of a thermal management system in terms of mechanical and thermal properties. Some popular attachment techniques include,

  • Thermal tape
  • Standoff spacers
  • Flat spring clamps

However, these attachment methods don’t end here as there are many others. You would also see m rein the future as engineers continuously update these methods according to new technologies.

By considering the above factors, engineers can design an effective heat dissipation system, including a heat sink.

Frequently Asked Questions

What Is Heat Sink?

The heat sink is a device and a way to manage heat in electronic products. Electronic components like transistors release heat, and you need heat sinks to dissipate heat to cooling mediums, like water, air, or it can be oil and other elements.

Do All Electronic Devices Need Heat Sinks?

Most devices need heat sinks to dissipate heat to cooling components. However, some electronic components have a built-in ability to dissipate heat. Generally, lasers or power transistors can’t transfer heat and need a solution to manage heat. MOSFETs and IGBTs are good examples in this case. So, here you need a heat sink device. 

Can PCB Survive Without Heat Sinks?

PCB components release heat which can damage them, making the electronic device slow. However, it also depends on the PCB materials as some have their heat dissipation property. Mostly you need a cooling system to enhance PCB performance. 

What Are The Types Of Heat Sinks?

The basic types in this case include the active heat sink system and the passive heat sink system. Some other types are also popular, like swaged heat sinks, stamped heat sinks, machining, folded and bonded fin, single-fin sinks, and forged heat sinks. 

Which Factors Influence The Heat Sink Design?

Many factors affect heat sink design, including its material, fin shape, and performance, fin size and location fin configuration, attachment technique of heat sink, and finally the thermal interface.

Final Thoughts

Devices having PCB also have heat sinks because they get hot due to high temperatures caused by different components. Heat sinks are either active or passive. You have to consider a few factors while designing the heat sinks, like its material, fin shape, and performance, fin size and location fin configuration, attachment technique of the heat sink, and finally the thermal interface. Various models help determine the heat sink parameters and geometry to provide a high-level heat transfer.

Would like to know more about the Heat Sink Features and Functions or pcb assembly services? Just Email us at sales@pnconline.com

Metal Core and Metal Black Printed Circuit Board

Printed Circuit Boards are a crucial component of any electronic device, but the materials used to manufacture them can significantly affect the performance and durability of the device. Metal core and metal black PCBs are two types of PCBs that offer numerous benefits over standard FR-4 PCBs. Here, we will explore the advantages of using metal core and metal black PCBs in electronic projects. We will discuss how they can improve their performance and reliability,   as well as their suitability for a variety of applications.

When it comes to a circuit board design, the metal core and metal black printed circuit boards offer a number of advantages over traditional PCBs. These benefits include improved heat dissipation, increased strength, electrical isolation, and reduced electromagnetic interference (EMI).

The use of the metal core and metal black printed circuit boards is a great way to improve the performance of your electronic devices. This type of PC Board provides excellent electrical and thermal conductivity, making them ideal for applications that require more power, speed, and accuracy. Metal core and metal black PCBs are also more resistant to environmental factors, such as temperature changes and corrosion, making them a better option than traditional PCBs.

What Are The Benefits Of Metal Core PCB?

Metal core PCBs are gaining popularity in the electronics industry due to their many advantages over traditional FR-4 and other standard PCBs. Metal core PCBs feature a dielectric layer, which is made from metal instead of a traditional fiberglass-epoxy material used in other PCBs. Such a metal core serves as a heat spreader and helps have better heat dissipation and improved thermal performance. This makes them ideal for applications that require high-level dissipation, and large temperature ranges.

The metal core also allows for a much thinner board than can be achieved with standard PCBs, reducing the overall weight of the assembly and making it easier to integrate into the design. As the metal core increases the rigidity of the board, it reduces the possibility of warping or cracking due to vibration and mechanical shock.

The copper layer used on the MCPCBs is often thicker than on standard boards, providing increased electrical performance as well. The additional copper layer also adds greater protection against EMI (electromagnetic interference), making them ideal for high-frequency and wireless applications.

Another benefit of metal-core PCBs is that they are more reliable than standard PCBs. As the metal core has better thermal conductivity than traditional fiberglass epoxy, it reduces the risk of solder joint failure due to overheating. This means that components are less likely to fail due to excessive heat, resulting in greater reliability.

Overall, the metal core PCBs offer many advantages over traditional PCBs, making them ideal for applications that require high power dissipation, thin boards, or robust performance in harsh environments. While they may cost more upfront than other types of PCBs, the benefits that come with using the MCPCBs often outweigh the costs in terms of improved performance and reliability.

For anyone looking to upgrade an existing project, or build one from scratch, there is never been a better time to consider switching to the metal core. If you’re looking to improve your product’s efficiency and reduce downtime, switching to a metal core PCB, maybe the right move for your next project.

Metal core PCBs are a special type of printed circuit board that uses metal instead of the traditional epoxy resin-based substrate. Metal core PCBs provide many advantages over their traditional counterparts, such as increased heat dissipation and better performance in higher-power applications. However, metal black PCBs offer a slightly different approach.

Metal black PCBs are constructed using metal cores that are plated with a black finish. This black finish helps reduce the emission of electromagnetic interference or EMI that can interfere with sensitive electronic components and impair their performance. Besides, the black finish helps absorb heat, which is beneficial in high-power applications.

The black finish also helps to prevent corrosion in the PCB itself, which can cause premature failure of the PCB over time. Moreover, the black finish increases the electrical resistance of the PCB, which can help protect against the short circuits caused by sudden changes in the voltage.

Finally, the metal black PCB offers an aesthetically pleasing look and a more rugged construction than a traditional printed circuit board. This makes the board ideal for a variety of applications that require superior durability, such as outdoor or industrial environments.

Overall, both metal core and metal black PCBs offer distinct advantages when compared to traditional printed circuit boards. While metal core PCBs provide greater heat dissipation and performance in higher-power applications, metal black PCBs offer superior protection against EMI and corrosion, as well as a more robust design for difficult environments. Ultimately, the choice of which type of PCB to use will depend on the specific requirements of the application.

For instance, if the application requires a higher level of heat dissipation and power output, then metal core PCBs may be preferable. On the other hand, if low levels of EMI emissions and protection against corrosion are desired, then metal black PCBs may be more appropriate. The final decision will ultimately depend on the specific needs of your project.
Which Type Of PCB Is Right For My Project?

When it comes to selecting the right type of PCB for your project, there are a number of factors to consider. One important factor is the type of material used for the PCB. Metal core and metal black PCBs are two popular options for many projects. Each one offers its own unique benefits, so let’s take a closer look at what each has to offer.

Metal core PCBs are constructed with an insulated metal substrate layer sandwiched between two layers of copper. This metal substrate layer helps conduct heat away from the board more efficiently than other PCB types, making it ideal for applications that generate high levels of heat. MCPCBs are also more resistant to temperature fluctuations, which makes them well-suited for automotive and avionics systems that need to perform reliably in changing environments.

Metal black PCBs are a specialized type of MCPCB that offer additional protection against an electrostatic discharge. Such boards contain an integrated layer of insulating polymer that is laminated over the metal core and then coated with a black solder mask. This makes metal core PCBs well-suited for electronic equipment where electromagnetic interference or electrostatic discharge (ESD) could damage the components.

When it comes to choosing the right type of PCB for your project, both MCPCBs and MBPCBs have their advantages and disadvantages. If you need a PCB that can handle high temperatures, then an MCPCB is the right choice. If you need a PCB that provides additional protection against EMI/ESD, then an MBPCB is the better option. Ultimately, it’s important to carefully evaluate your project’s requirements before deciding on which type of PCB is best for your needs.
FAQs
Why DO Manufacturers Us Metal Core And Metal Black PCBs?
When it comes to the design and manufacture of printed circuit boards, there are several advantages to choosing a metal core or metal black PCB. From improved thermal dissipation and electrical conductivity to better environmental protection and durability, these types of boards offer an array of benefits that cannot be achieved with conventional FR4 boards. Not only can metal core and metal black PCBs help reduce costs in the long run, but they can also enable more efficient product designs.

Overall, it’s clear that the benefits of using a metal core or metal black PCB greatly outweigh the costs.

What Is A Metal Core PCB?

Metal core PCB is a special type of printed circuit board that uses metal instead of the traditional epoxy resin-based substrate. Metal core PCBs provide many advantages over their traditional counterparts, such as increased heat dissipation and better performance in higher-power applications. However, metal black PCBs offer a slightly different approach.

What Includes In A Metal Core PCB?

The structure of a metal core PCB has multiple layers, including the circuit, copper, metallic, and dielectric layer, as well as the solder mask.

Wrap Up

In conclusion, metal core and metal black PCBs offer a range of advantages for designers and manufacturers. They provide superior heat dissipation, improved mechanical strength, longer product lifecycles, and improved EMI shielding properties. These advantages can help reduce costs and increase the longevity of the products, leading to improved customer satisfaction and increased profits.

Whether you are looking for increased performance, durability, or functionality, the metal core and metal black PCBs offer an ideal solution. The exceptional benefits these materials provide make them an ideal choice for engineers designing high-end applications.

With their ability to improve product performance while reducing production costs, the metal core and metal black PCBs should be seriously considered when designing a printed circuit board. With so many different varieties available, the sky’s the limit.

Would like to know more about the metal core and metal black PCB or printed circuit board assembly? Email us at sales@pnconline.com

Drill, Lamination, and Plating of PCB Design

Understanding Drilling

PC Board drilling involves different drilling machines which can make more than 30,000 holes in an hour. The machines have built-in systems for making precise holes and consist of spindles that can drill at a high speed of up to 110,000 RPM. An automated system and laser help manage drill bits to provide high-quality vias.

Drilling Of Through-Hole Vias

Standard PCBs have a through-hole where all PCB layers are drilled together under an NC machine. Then comes the plating of the holes’ inner and outer sides, and manufacturers use the same technique for all through holes, including the mounting holes.

Blind and Buried Via Drilling

The drilling of blind and buried vias occurs before lamination. The two-layered PCB goes through lamination after drilling. Whereas a multi-layer PCB is stacked and laminated after which it needs drilling and plating.

You can also make blind vias by drilling with a controlled depth where the drill machine works through the entire laminated board. Such a technique of making blind vias is cheaper than a sequential method, however, the hole size has some limitations. Besides, the routing of circuitry needs a specific technique.

Micro-vias Drilling

The drilling of micro-vias involves a laser machine because their size has to be small which is not easy to create through mechanical drilling. Micro-vias are ideal for thick PCBs, and you can connect them vertically by stacking them in layer pairs. Such as, in a traditional buried via, you can sequentially fabricate micro-vias whereas the buried vias need copper plating to connect the stacked vias.

When it comes to component holes, the through-hole technology works well. Such components are switches or standard connectors or mechanical components that need strong mounting that’s why the through hole suits them. Some common examples of devices having such holes include power regulators, resistors, op-amps, and capacitors, as they conduct heat and current.

How To Select A Drill

Though drilling is a basic function for a PCB Manufacturer, engineers use certain techniques to have precise drilling.

  • Sometimes a board needs lots of drills of the same size, which can cause changes in the bit during drilling. Such a change creates errors in terms of tolerance between hole diameters. So, engineers use drills of different sizes to avoid the quantity of the same-size drills.
  • Drilling diameter should be minimum, like in mechanical drilling, a six to eight mils drill is ideal for a 62-mils thick board. Whereas it is hard to use the small drill sizes in mechanical drilling, and its aspect ratio also makes plating difficult. So, engineers have to use laser drilling which is more expensive than normal drilling techniques. You have to use large drills for thick PCBs which are more than 62mils thick.
  • Use blind and buried vias when they are necessary otherwise avoid them. As their fabrication involves a sequential buildup method that increases the manufacturing cost of a raw board.

Different aspects affect the drilling methods and manufacturing cost of the PCB. Even the drill size affects the quality and cost of manufacturing. Too small holes highly increase a board’s cost, whereas too large holes can make assembly harder, increasing its cost. Engineers can avoid such issues by carefully designing a PCB, and having economical manufacturing.

PCB Plating or Metallization and Soldering

You need metal pads or lands to help components in mounting or soldering. You can’t solder the bare copper and have to plate it with an easy-to-solder material. In the past, lead-based tin was a common plating material. But, these days the environmental changes call for advanced materials like gold and nickel.

Unsoldered parts of the board need materials to resist soldering, such as polymer coating that prevents the bridging of traces. Moreover, it creates short circuits in the adjacent part leads.

Fabricating the External Layers

The above etching is ideal for circuits of external layers and the process includes drilling, metallization, and photoengraving. The final finishing happens after the external layers’ metallization. In general, the process includes soldering, silk screen application, testing, as well as packaging.

PCB Lamination

PCB lamination is crucial in terms of accuracy and creating a well-finished board. The process involves lots of stress, as you have to take care of the properties of PCB materials in terms of performance and production. PCB engineers and manufacturers have to work together to develop a functional product without sacrificing production.

Understanding the Lamination Process

The lamination of individual layers involves two main steps, such as:

Laying up:  It involves the stack-up of multiple layers. The manufacturer starts it from the bottom of the base substrate. Then comes the prepreg and internal etched layers. Then all layers are pinned together to make a final board without any disturbance. Laying up prepares the PCB before pressing.

Pressing of layers: Pressing involves heat and pressure that melts prepreg to finish the etched copper layer, making the insulation layers essential for electronic layers which can work closely. Prepreg bonds the layers, getting hard after curing, and makes a PCB mold.

You need to consider different factors during pressing. Like, many PCBs can be pressed together to save time and production costs. However, manufacturers have to place a separator between the individual layers to bear high pressure and heat without changing the PCB shape.

The laminating press also needs a vacuum to prevent the PCB voids to hinder the dielectric property, affecting its structural strength. The environment after pressing also needs consideration to prevent the STP quenching due to weather conditions. Manufacturers should store the pressed circuit boards in a press to cool them down. Cooling of the boards prevents the thermal contraction of the board.

Lamination Styles

Two styles are common in this case, such as:

  • Foil lamination
  • Cap lamination

PCB Lamination with A Foil: the foil lamination is simple and involves less hassle, as you have to foil the base and top layer. After lamination, the layers go through etching just like internal layers.  Foil lamination is more advanced than cap lamination, but you have to select the foil layer with care to remove them easily later on. The technician should work in alliance with the designer and material manufacturers to ensure precise production.

Copper Clad or Cap Lamination: It is an original method that PCB manufacturers have been using for years. There is a layer clad with copper between the base layer, top layer, and first and last inner layer. Such lamination is suitable for blind vias, however, you need a special laminate between the external and nearby layers to enhance a PCB function.

Purpose Of Sequential Lamination

You can use sequential lamination for advanced vias where drilling and plating come after lamination. However, vias other than through holes should be made before lamination, leading to sequential lamination. Such a technique involves many precautions in terms of materials and design to have a successful lamination. For like, you have to consider the z-axis CTE, Tg or glass transition temperature, and copper retention. A copper filling helps reduce copper accumulation to have a well-managed uniform CTE expansion.

The selection of the materials for PCB lamination involves great care. Besides, you should use the latest design software.

Testing a Final Product

Remember that PCB testing is very important to check damaged connectors and short circuits. Optical testing consists of layer scanning to find defects, whereas electrical tests involve a flying probe to verify different connections. It is easier to detect short circuits or breaks through electrical testing.  Whereas the optical inspection can better detect poor clearances between the conductors.

Final Thoughts

Drilling, plating, and lamination are important processes of PCB construction.  PCB drilling involves machines that can make more than 30,000 holes in an hour. The machines have built-in systems for making precise holes and consist of spindles that can drill at a high speed of up to 110,000 RPM.

An automated system and laser help manage drill bits to provide high-quality vias.  The two-layered PCB goes through lamination after drilling. Whereas a multi-layer PCB is stacked and laminated after which it needs drilling and plating.

The drilling of micro-vias involves a laser machine because their size has to be small which is not easy to create through mechanical drilling. Micro-vias are ideal for thick PCBs. Plating of the holes is also essential to provide electrical connections.

PCB laminating press needs a vacuum to prevent PCB voids to hinder the dielectric property, affecting its structural strength. The environment after pressing also needs to be considered to prevent any damage due to weather conditions.

Would like to know more about the Drilling, Lamination, & Plating or smt assembly? Email us at sales@pnconline.com

PC Board Electrical Schematic and Its Functionality?

Whatever we create, including a PC Board,is a picture or an idea that we convert to paper in the form of a diagram. You can’t proceed with manufacturing without a proper PCB layout or schematic.

An electrical schematic is a conceptual plan or drawing that helps understand the physical aspect of a PCB in terms of assembly.
The basic purpose of electrical schematicsis to have design communication.It should help manufacturers clearly understand it.Besides, the schematic directs you to makea PCB layout.

Schematics involve specific elements which are essential to understand, such as:

  • REFDES or reference designates
  • Symbols representing the components
  • Outputs
  • Nets

To know schematics in detail, you have to understand the above elements.

REFDES or Reference Designators-Identifying Labels

Identifying labels or reference designators help understand components because they describeso much about them. If REFDS is precise, it helps a reader to identify the types of the components and symbols,depicting every component.
So, each electrical component or part has a standard symbol.However, onlyspecific schematics follow such standards.
In some cases, reference designators can fully describe the component type, like when there is a generic box with pins itrepresents a passive component.

At the same time, reference designators also connect to theBOM, and bill of materials. Every Printed Circuit Board component needs a part number that BOM shows. Besides, it also helps find the area or location where components should be installed.
The format of the reference designators consists of a code in the form of a letter that describes the component, and its type having a specific number.

Symbols Representing Components

The electrical schematic has specific symbols of the physical components of PCB assembly in terms of soldering. They also describe the circuit boards’ structures, such as test points and vias.

The symbols are specific shapes or they are diagrams to indicate the type of PCB components. There are symbols for all electrical components like capacitors, diodes, resistors, and transistors.

The symbol of each component consists of pins that help in creating the electrical connections. The pins of all schematic symbols have specific numbers,depicting the physical components.

Designers can assign either a single symbol or multiple symbols to represent a single component of a PCB. Whereas the components having several pins are assigned many symbols to create a readable electrical schematic.

When a component is having multiple symbols, each symbol representing the same component has a similar designator.

Electrical Components-Resistors

PCB has many electrical components, including resistors. The U.S designers use a zigzag line to describe a resistor. Whereas its symbol is a rectangle according tointernational standards.On the other hand, the letter R in schematics isa representation of the resistor.

CapacitorSymbols and Letter

Capacitors have two types, includingpolarized capacitors and non-polarized, and both have different symbols. The curved line is a symbol of a negative terminal of a polarized capacitor. Whereas the plus sign denotes a positive terminal of a polarized capacitor.Whereas the letter C defines a capacitor in schematics with REFDES.

Inductor Symbol and REFDES Reference

Inductors are also important passive components of a PCB, and their construction involves a series of curves.Manufacturers use a coil of wire to make inductors. Whereas the letter L defines a capacitor in schematics with REFDES.

Diode Symbol and REFDES Reference

Some other PCB electrical components within the PCB design include diodes that permit the current to travel in just one direction. The diode has different types, including

  • Zener diodes
  • LEDs or light-emitting diodes
  • Schottky diodes

Zener diodesprevent the reverse flow of a current. However, the reverse flow can happen at a certain electrical power level.
There are also LEDs or light-emitting diodes which emit light when having a forward flow of a current.
The Schottky diode has simple features,but it switches quickly and the voltage drops in a lower forward direction.
Other than LED, the letter D or L defines a capacitor in schematics with REFDES.

Transistors Symbol and REFDES Reference

Transistors involve the flow of current at the primary terminal and they function like switches. The basic types of transistors include:
Bipolar Junction Transistors-BJTs: It is a current managing device that helps a current flow either into one base pin or out of it, changing to high currents passing through emitters and collectors.

Field-Effect Transistors-FETs: The FE transistor is another current-managing device that helps voltage turn on the current on the pin, via source pins and adrain. Various drawings indicate transistors and the letter Q and M define a resistor in schematics with REFDES and also represent the MOSFET. However, some designers use the letter T in the wrong way.
Variable Resistors’ Symbol andREFDES Reference

Variable resistors have two categories:

  • Potentiometers-three terminals
  • rheostats-two terminals

The function of the variable resistors is to customize resistance according to users. An arrow across the resistor represents the rheostats, whereas an arrow on the side of the resistor shows potentiometers.

There are also varistors or voltage-dependent resistors which resemble the variable resistors, but they are denoted by a line across them.The symbols of the resistors include R, VR, and RV, depending on the type of the resistor.

IntegratedCircuits, Symbol, and REFDES Reference

A single-package circuit developed with a semiconductor is an integrated circuit. You can also consider such circuits asamplifiers, processors, power regulators, and memory of a device. The shape of the integrated circuit is like a rectangle or a square that you can install on a PCB. It is a box with power inputs and outputs or pins and sometimes a board has many boxes.

The symbolof the integrated circuit in a schematic is the IC or the U.

Resonator, Crystals, and Oscillators, Symbol and REFDES Reference

PCB also has resonators, crystals, and oscillators, which give a consistent frequency output. These elements are different in terms of circuitry and characteristics but they have a commonfunction.

Some Other Symbols

There are also several other symbols to show interconnections on a schematic having labels to find their electrical nets.
Mostly there is no reference designator for non-component symbols, however, some have symbols like TP or test points, and X, and MH on REFDES.

Understanding Nets in Schematics

The wired connections on the printed circuit boards are what designers call nets. They are lines that connect symbol pins to the nets. You have to properly label the nets while making schematics to help manufacturers identify them. Specific symbols depict thenets to the same or different pages when you don’t draw them as connections, such as interpage and intrapage symbols.

Try not to overlap the nets to have good readability, however, you can’t ensure it every time. A dot or a circle on a schematic diagram shows two nets’ connection. If there is no DOT in a schematic, it means there is no connection between the nets. Whereas advanced drawings have wire hops to show that the nets don’t connect.

Outputs of Schematics-Netlists & BOM

The schematic diagram has two important outputs, including BOM, and netlists. The netlist is a file that designers use to understand routing and parts’ placement on a PCB. The format of thenetlists can vary in symbols. The name of the nets is presented in the netlist, showing thelocation of connectionsbetween the PCB parts. Netlist also has an output tool to give names to the nets which were without names.
Generally, there are several tables in a netlist, listing the PCB components and their names, net names, and some other essentials. Sometimes the netlists include additional information to help you understand the SPICE.

Bill of Materials-BOM

Bill of materials shows data in the form of a spreadsheet,matching the REFDES in schematicshaving a number and a physical component. Designers use different formats for BOM outputs, depending on the nature of schematics and your requirements in terms of output.
There can be many reference designators with independent partnumbers to help with manufacturing. Some detailed BOMs consist of specific part numbers of a company, quantities of components at different locations on a PCB, and the part numbers for different vendors. In other words, BOM has essential information to understand schematics and develop it through different steps, including SMT assembly.

Final Thoughts

You must know that the electrical schematic is a drawing that helps understand the physical aspect of a PCB in terms of assembly. The main aim of electrical schematics is to have design communication and help manufacturers construct the PCB. It should help you clearly understand parts and assembly. All electrical components have standard symbols. But, only specific schematics follow such standards. Different software help make electrical schematics that you can explore online.
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