Metal Core PCB

You must be among the people who are curious to know about advancements in the field of printed circuit boards.

The metal core printed circuit board might be your biggest source of curiosity and you are anxious to know more.

In this guide, you’re going to learn about everything concerning metal core PCB – from basic definition, classification, designs, application, manufacturing process, etc.

By the end of this guide, you’ll be an expert in metal core PCB industry.

Let’s get right in the subject of this guide.

Metal core PCB

What is a Metal Core PCB?

Metalcore printed circuit board (MCPCB) or thermal printed circuit board is a type of PCB with a metal base.

In other words, it is a printed circuit board with a metal as the primary material for the base or plate. The metal material at the base is responsible for spreading the heat that builds up during the process of operation.

Base metals are very good conductors of heat and dissipate the heat that builds up when the PCB is operating.

They are new advancements in replacement of the FR4 and CEM3 material manufacturers were using in the previous boards. It dissipates more heat from the more vulnerable device components to less heat vulnerable areas such as the heat sink.

Metal core PCB

In the recent past, the development of the LED has been on the rise but it has been experiencing issues.

The main issue of concern was too much heat build in the system leading to malfunctions and a shorter lifespan.

The main areas experiencing these issues were in the field of lighting especially with the high power light emitting diodes.

The application of the metal material to the base comes to a relief to the problem in the LED applications.

It is also a solution to other applications that generate a lot of heat that hinders the mode of operation. The main material in use for the MCPCB is thermal insulating layers, metal copper foil, and metal plate.

PCB layers

The basic compositions of a printed circuit board structure comprising of:

• Circuit layer
• Solder mask
• Copper layer
• Dielectric layer
• Heat Sink
• Metalcore layer

The characteristics of the thermal insulating layers, metal copper foils, and the metal plate are:

• Magnetic conductivity
• Excellent dissipation of heat
• Good mechanical strength
• Excellent processing performance

The metal core base has two main materials which are copper and aluminum for many applications.

Aluminum substrates have metal bases of copper clad plates good for the transfer and dissipation of heat from the PCB.

Copper substrates perform better than aluminum but it is costly to use in comparison to the aluminum materials.

Many clients prefer using the aluminum base because of the economic sense and use it in various applications.

The major applications for the materials are LED lighting, communication electronic equipment, and audio frequency apparatus.

Metal core PCB design

Other characteristics of the aluminum printed circuit board are:

• It uses SMT technology
• It makes an effective treatment for the diffusion of heat in the circuit design
• It reduces the temperature of the device and improves the density of relying on power.
• It prolongs the life of the device
• It has higher mechanical endurance
• Reduces the size of the device leading to low cost of assembly and hardware

Types of Metal Core PCBs?

The classification of the metal core printed circuit board is according to the trace layers and location of the PCB.

This type of classification gives us the three main types of the metal core printed circuit boards which are:

• Single Sided Metal Core PCB
• Double Sided Metal Core PCB
• Multilayer Metal Core PCB

Single Sided Metal Core PCB

Single sided metal core PCB

It is a metal core printed circuit board which has prints of traces on one side of the layer. It consists of:

• A metal base which is usually copper alloy or aluminum
• A non-conducting dielectric layer
• Copper Circuit layer
• IC components
• Solder Mask

It has a thin layer of insulating dielectric between a metal base and a copper foil. You will find the copper foil in different patterns according to the manufacturer.

Aluminum is cheap to use in comparison to copper making it the metal of choice.

It has a prepreg dielectric that offers excellent transfer of heat from the components and foil to the base plate. It performs this function while maintaining perfect electrical isolation.

The aluminum or copper base provides the device mechanical integrity, transferring and distributing the heat to a heat sink.

Apart from the heat sink, it can also transfer the heat to the mounting surface or the ambient air.

You can use it with chip & wire and surface components as it provides low thermal resistance than FR4. The metal core is less costly and allows more area in comparison to the ceramic substrates.

Advantages of Using the Single Metal Core Printed Circuit Board

• Heat dissipation and thermal transfer are better than that of the FR4 materials. The heat transfer characteristics are better than all the other materials in use before. Copper has better heat dissipation characteristics in comparison to aluminum.
• Copper has better dissipation characteristics in the air in comparison to that of aluminum. Aluminum, on the other hand, has less density and cools faster after removing it from the fire. It, therefore, means that aluminum has better heat dissipation characteristics than copper.
• It is less prone to damages and distortion especially when they are under high temperatures. You can use it in applications that require high switching of power.
• You can easily implement it in higher density designs because of their thermal ability in comparison to fiberglass.
• The surface finish of these devices is often in fine gold, HASL, and OSP which improves its heat transfer abilities.

Double Sided Metal Core PCB

The double-sided and double layer metal core PCB are available in circuits of high advancements.

There has been a confusion between the two types due to the similarity in the names.

The main difference between the two devices is in the layout seen in the positioning of the metal core.

Double sided PCB

A double-sided metal core PCB, you will find the metal core between the two conductor layers of the device.

You will also find a dielectric layer between a copper layer and the metal core. The metal core connects to the conductors through vias and SMD is either at the bottom or on top.

A double layer metal core PCB has the conductor layers on top of the metal core at the bottom. You will see the conductor layers on the same side as the metal core.

The type of metal cores you will find in this set up are copper, iron alloys and aluminum.

It also has a dielectric layer between the metal core at the bottom and a copper layer. You will only see the population of the SMD at the top of the device.

https://youtu.be/McOu1DAu9TA

Advantages of the Double layer and double sided MCPCB

The variants offer similar benefits as other types of the metal core printed circuit boards. The main advantages of the variants include:

• Increased reliability of performance at high temperatures. Many of the CEM3 and FR4 double sided PCBs with high density and power have heat dissipation difficulties. This is because of the weak thermal conductivity characteristics that destroy electric components when operating under high temperatures.
• The double-sided metal core PCB has a metal core with perfect inter-layer thermal conductivity and insulation. These attributes contribute to better performance of the device at higher temperatures.
• They have very good thermal expansibility. Thermal contraction and expansion is a great feature that every device has. The ability to expand under heat and contract under cold is the coefficient of thermal expansion (CTE).
• Most of the FR4 printed circuit boards have very low coefficients of thermal expansion. It means they cannot cope well with the issues of expansion and contraction. It is the factor that makes the Double sided and double layer more dependable in many devices.

Applications of the Double-sided and Double Layer PCBs

The main applications of the double layer and double sides printed circuit boards are:

• Light Emitting Diodes (LED) lights such as flashlights,
• General and street lighting
• Industrial controls
• Devices for monitoring power
• Automotive lighting such as the headlights
• Amplifiers such as sound amplify
• Testing equipment

You can choose any of the devices depending on the requirements of your application.

Multilayer Metal Core PCB

It is possible to come up with the metal core printed circuit board that has more than two layers. The structure is similar to that of the FR4 multi-layers but is more complex in designing and making.

Multi layer PCB

It can take a lot more components, put ground and signal layers in a separate layer for better performances.

In comparison to the FR4, the MCPCB requires more work, experience, and technology in laminating multiple layers.

The cost of laminating the layers with metalcore is higher but the performance is better than the other PCBs. It is capable of a wide range of activities and it has the following features:

• The base materials vary according to the application and they include copper, aluminum or iron alloys.
• The thermal conductivity also varies depending on the dielectric layer
• The board thickness also varies accordingly and ranges between 0.8mm to 3 mm
• Copper thickness ranges between 0.5 OZ, and 3.0 OZ.
• It has a great outline, from routing, V-cuts and punching processes
• The solder masks vary in color from white, black, green, blue or red oil
• It has a white or black legend or silkscreen color
• It has gold, OSP, HASL surface finishing
• The maximum panel size you can find is 600 by 500 mm

Advantages of Using the Metal Core PCB

The issue of heat buildup on the printed circuit boards has been a headache to many manufacturers worldwide.

The invention of the metal core printed circuit board was a relief to the industry due to many reasons.

The main advantages of using the metal core printed circuit board are as follows.

It has special substrate material to improve design reliability for the devices operating at very high temperatures.

Instead of being a mounting area for the material it also draws excess heat from the device making it cooler.

The heat goes to the other side of the layer where it can move out efficiently without damage to the device.

Metal core PCB

It is the solution to the devices that use LED printed circuit boards for different functions such as lighting.

The issue of excess heat is present on devices that use many LED components to light up an area for long.

It would not have been useful for the devices that have very few LED components and operate for shorter periods.

It has the ability to integrate dielectric polymer layers with higher thermal conductivity for low thermal resistivity.

Metalcore printed circuit boards transfer heat 9 times faster than the FR4 printed circuit boards. The dissipation of heat from the system maintains better performance and increases the life of the device.

It also has perfect dimensional stability in comparison to other PCBs with other materials as FR4 and CEM3.

PCB dimensions

Aluminum PCBs are better as they can withstand the heat of up to levels of 140 – 150 degrees centigrade. The dimensions will expand at a minimum between 2.5 to 3%.

The MCPCBs have higher thermal expansibility as its coefficient of thermal expansion is top notch.

Copper and aluminum have better CTE in comparison to FR4 and the thermal conductivity ranges between 0.8 to 3.0 W/c.K.

It has smaller footprints that lower the number of hardware and subsequently the cost of assembly.

It also has better mechanical durability and you can use it for an extended period before it expires.

Technical Specifications of Metal Core PCB

Assuming you are a baker and you need to make a birthday cake for one of the loyal clients.

There are certain ingredients and equipment that you will need to make a good cake for your client.

Well, consider the specifications that you require to make a good cake and become an MCPCB designer or manufacturer.

 Metal core PCB design

Making a good, functional and durable metal core printed circuit board requires you to have certain specifications.

These are the factors that will determine the outcome and success of the metal core printed circuit board.

Continue reading and find out more about the technical specifications of a good metal core printed circuit board.

·Material types including aluminum, COB Copper PCB and Iron-based PCB

In and PCB design and layout project, you will have to collect different types of material to make a good and functional product.

The PCB materials that you will be using are of different types depending on the final application of the product.

They vary in terms of quality, quantity, durability, strength, weight, density, electrical and heat conductivity among other characteristics.

The most significant material that you will need to make a good metal core printed circuit board is the metal.

Metal core PCB

It is the main material that also gave meaningful contributions to the name of the metal core printed circuit board.

There are various types of metal that you can use in making a good metal core printed circuit board.

The metal that you will put in play when making an MCPCB should be able to determine the quality of the product.

The material or metal has to have the specific characteristic that will determine the performance of the product. The characteristics of the metal that you will have to look at are:

• Temperature resistance of the metal core
• Adhesion of the metal core
• The tensile strength of the metal core
• The flexibility of the metal core
• The dielectric strength of the metal core
• Dielectric constant of the material among other thermal, electrical and physical factors.

The types of metallic material that you will need for the MCPCB include aluminum, copper, and iron alloys among others.

The metal materials should allow using surface mount technology to place the components on the circuit board.

They should also be mechanically durable, thus extending the life of the metal core printed circuit board.

·Aluminum PCB

The aluminum printed circuit board is a PCB which has aluminum as the main material for the core of the MCPCB.

 Aluminum PCB

Aluminum printed circuit boards have three main parts which include:

• Circuit layer which is the copper foil circuit layer that is present in all the printed circuit boards.
• The dielectric layer or the insulated layer
• The metal layer or the substrate layer

In this case, the metal layer or the substrate material is aluminum which is also of different types.

In many of the metal core printed circuit boards, you will find aluminum as the main substrate material.

It is one of the materials that many manufacturers prefer to use because of the following reasons.

• It has low operating temperatures
• It reduces the size of the of the printed circuit boards
• It increases the power density of the printed circuit board
• It is durable and extends the lives of the dies
• It also has very few interconnects of the components you will need on a PCB
• It improves the mechanical and thermal performance of the printed circuit board
• It allows for a better use of the surface mounting technology
• It expedites the heat sinks and other types of mounting hardware
• It is the cheaper type of the metals and the price will vary according to the requirements of the LED.

You can make an aluminum PCB by laminating an electrically insulating and thermally conductive dielectric between the copper foil and metal base.

Etch the copper foil into the circuit pattern you desire and the metal plate will draw heat away via a thin dielectric.

Circular aluminum PCB

LEDs and power converters use the aluminum PCB more but you can also find it in other applications.

RF and automotive companies are seeking to explore the benefits of using this printed circuit board. There are many configurations of the aluminum printed circuit board which include:

• Flexible aluminum printed circuit board
• Hybrid aluminum printed circuit boards
• Multilayer aluminum printed circuit boards
• Through hole aluminum printed circuit boards

You will choose either of the types of aluminum PCBs depending on the application.

·Copper Core PCB

Copper is another type of metal that you can consider using when making a metal core printed circuit board.

It is one of the best metal materials in the industry because of the perfect nature of its characteristics.

Copper PCB

A copper core printed circuit board consists of the following:

• Substrate material which is copper in this case
• It has a high thermal conductivity or prepreg insulation layer
• Copper circuit layer

Apart from the explanation above, there is three type of copper core printed circuit boards including:

• Chip on board copper PCB where the light emitting diode chip directs the heat sink directly to the copper substrate.
• Has a direct heat path with no dielectric layer below the heat path pad.
• The other has a direct heat path with no dielectric layer and an aluminum-copper alloy PCB.

· Iron-based PCB

Iron-based printed circuit boards depend on materials such as silicon steel, special steel in place of FR4 and CEM1.

It is important in the dissipation of heat away from the components of the board that are critical.

It transfers the heat to other less critical areas of the PCB such as the metal cores or the heat sinks.

Metal core PCB design

The truth, it is a good heat conductor and hence dissipates the heat buildup away from the device.

It is relatively cheaper to use in comparison to other types of metal such as copper and aluminum.

Iron-based PCB is, however, heavier than the two metals and is strong enough thus durable.

Metal Core PCB Design Guidelines

A metal core printed circuit board is available in different designs depending on the application.

You will also find different designs of the MCPCB depending on the requirements of the customer.

You should make sure that the design you intend to use will work well without interruptions.

Designing a metal core PCB follows the same procedure you use in making other types of printed circuit boards.

In this case, the only factor that will change is the substrate material which you will change to a metal.

To make the design cost-effective and manufactural, there are secondary considerations to pay attention to.

You will look at the considerations for mechanical operations, legend, solder mask, and mechanical fabrication.

To make a cost-effective design, there are many considerations that you will have to look at including:

• The type of material you will use which may be aluminum, copper or iron for the substrate. It will be the main factor in considering the number of components to place on your design, it will also affect the size of the design that you are working on.
• The thickness of the base material is also a meaningful consideration when coming up with a good design. Using the standard thickness many manufacturers use will help in controlling the cost.
• The flatness of the design is another factor to pay attention to. The amount of copper that you will need on the design will affect the flatness of the design. In this case, you will have to consider the coefficient of thermal expansion (CTE) rules.

Following the rules will allow you to include the heavy components of the copper circuits to thicker bases. It will also eliminate the possibility of bowing when the equipment is put up for operation. The additional thickness of the dielectric is important for routing, scoring, drilling, and punching.

• You should also make considerations on the dielectric and know that it is costly to use higher dielectrics. The standard TG for a dielectric is 140 degrees but you can 170 degrees of the dielectric TG.
• The copper circuit foil is another consideration to look at and the thinner the foil, the more expensive. The metal base material will improve the electrical conductivity of the device in comparison to the FR4.
• Prepreg or isolation is another important factor in designing a metal core printed circuit board.

 Metal core PCB

There are many types of software that you can use in making a metal core printed circuit board.

The software that you have been using to make the FR4 printed circuit boards are the same for the MCPCB.

In this case, you will make various considerations on the type of material among other things.

The considerations on the design will depend on the type of PCB you will be making.

When making the design make sure you have the schematics that match the type of PCB you intend to make.

·Size of the Metal Core PCB

The size of the metal core printed circuit board will vary according to the components of the PCB.

The type of material you will use will also determine the size of the metal core printed circuit board. You will have different applications requiring different sizes of the printed circuit boards.

The size of the metal core printed circuit board will determine the overall weight of the device. The bigger the size of the metal core printed circuit board, the heavier it will be.

Bigger sizes of the MCPCBs offer wider surface areas for faster dissipation of heat from the PCB.

 PCB dimensions

When fabricating a metal core printed circuit board, you should look at the following considerations:

• The panel size of the metal core printed circuit board
• Look at the standard panel sizes of the metal core printed circuit board and compare them to your specifications.
• The PCB panel standard size
• The fabrication size of the PCB panel

·The thickness of the material e.g. Aluminum e.t.c

The circuit board has the properties of single and additional cores with connections of epoxy sometimes the prepreg.

The thickness of the metal core printed circuit board will vary according to the type of material in use.

The final application of the board will also influence the thickness of the circuit board.

Different manufacturers offer different board thickness but there are standard thickness sizes that are available.

You have the choice of deciding how thick your metal core printed circuit will be. Make sure that the board works well and does not have malfunctions whenever you are using it.

 PCB Thickness

The laminate thickness is another factor that you will need to consider when talking about the thickness of the material.

The thickness of the laminate will also vary depending on the type of material you use for lamination.

You have to consider the thickness of the material for trace impedance.

Whenever you are calculating impedance, look at the consequences of conformal coating because of the solder mask covering of the circuit board.

You will realize that the solder mask will reduce the impedance of the traces that are very thin. Increasing the thickness of the traces will reduce the impedance of the solder mask.

The thickness of the material will affect different factors ranging from conductivity, functionality and heat resistivity.

It will determine how and where you will apply the metal core printed circuit board. The type of material will also affect the thickness depending on the properties of the material.

The thickness of aluminum on a board will vary from the thickness of copper for the same mode of performance.

This is because the physical properties of aluminum and copper differ accordingly so does the thickness.

·Insulation Thickness

Insulation thickness is another factor that you will need to consider when making a metal core printed circuit board.

The thickness of the insulation will affect certain factors such as that of the impedance of the copper traces.

The thicker the insulation the greater the impedance and the impedance reduces as you make the insulation thinner.

Insulation material

When making a metal core printed circuit board strives to make the insulation thickness smaller to reduce impedance.

In many cases, the cool clad is in use for the many applications in metal core printed circuit boards. The benefits of the cool clad insulation are:

• It reduces the thermal or heat impedance by half lowering the chip temperatures and increase the performance of devices.
• It extends the life of the light emitting diodes even more than using the normal insulating substrates.
• It is stress-free since it has proven reliability and robustness against thermal cycling and high temperatures improving durability.

The insulation thickness of the new material is also under the compliance of the RoHS, and Fire rating. It also has lead free solder compatibility.

· Thermal Conductivity and Thermal Management for PCB’s

Heat management is very important in a printed circuit board when it is in operation.

Whenever a printed circuit board is operating, there is a buildup of heat that it generates in the process.

The heat buildup may cause a lot of harm to the device slowing it down or destroying the components.

It is, therefore, important to have a good material that will help in thermal conductivity and management for the PCB’s.

 Aluminum PCB for high power applications

It is the reason why many manufacturers prefer using metal core printed circuit boards to help in thermal management.

The metal materials are good conductors of heat and help in eliminating heat from the most critical areas to the less critical areas.

You can use the C-Therm TCi thermal conductivity analyzer to obtain precise, accurate and rapid measurements.

It will help in determining the thermal conductivity of the printed circuit board components.

Knowing the thermal conductivity of the components on a printed circuit board will help you in the thermal management of the MCPCB.

The thermal management of the printed circuit board involves placing the right material at the right places to dissipate heat.

It starts with knowing the thermal conductivity of every component and then determining better materials to use in heat dissipation.

You will then choose the right metalcore that will help in conducting the heat from the highly critical areas.

· Surface Finishing

The surface finishing of the metal core printed circuit boards also varies depending on the material in use.

Many manufacturers prefer dipping the material in gold, HASL among other things depending on the application requirements.

The customer also has the right of deciding on the type of surface finishing he will want for the setup.

PCB surface finish

The metal core circuit surface finishing will differ in different factors such as rates, serviceable life, availability, assembly processing, and consistency.

It is because every type of finish differs in terms of its advantages, procedures, products, and setting suitable for different applications.

It is important for the designer and customer to be in touch with the manufacturer to have serious discussions on this factor.

It will also give the metal core printed circuit board a complete and attractive look

·Solder Stop

Solder stop or solder mask or solder stop mask a layer of polymer that you will apply on the copper traces.

It will help the copper traces protecting it from oxidation and prevent the solder bridges from forming between the pads.

There are certain pads that may be close to other pads and may form solder bridges.

Solder masking

A solder bridge is an electrical connection that you did not intend to have on the printed circuit board.

PCBs have solders masks in place that will help in the prevention of the formation of solder bridges.

It is a technique that requires mass production of boards using the reflow technique or solder baths.

After application, it is important to have openings when you are placing the PCB components on the board.

Photolithography is the process by which you will make holes when placing the components of the circuit board.

Green was the main color in the past but you can find a variety of colors at the moment.

Solder masks are available in different media in accordance with the application and customer demands.

The most common solder mask id the epoxy green as it is cheap and you will silkscreen it on a PCB.

Other types of solder masks that you can use include the liquid photoimagable ink (LPI) or the liquid photoimagable solder mask (LPSM).

Legend Print

You can have a legend print on one or both sides of the metal core printed circuit board.

It depends on the number of layers that the MCPCB will have and also the type of MCPCB.

The components of the legend print include switch settings, component designators, test points among other things.

The components of the legend will assist you in the assembly of PCB components, servicing, testing and using the circuit board.

There are three main methods that you can use to make the legend prints on the metal core printed circuit board. The three methods include:

• Silkscreen printing using epoxy ink thus the name screen or silk.
• Liquid photo imaging which is more accurate in comparison to screen printing.
• Inkjet printing which is a new method that prints variable data that is unique to one other print.

When making your metal core printed circuit board, you can use the process of legend print to complete it. You can choose either of the three methods for printing the key concepts available on the legend. You will have to make an outline of the kind of legend you need before commissioning the drawing process.

· Milling

It is the process of removing areas of copper from the sheet of the PCB material.

It is the process that makes way for the recreation of signal traces, pads, and structure according to the layout file.

PCB milling

It is a process of removing material instead of adding material to make the final piece of the MCPCB.

There is basically two process of milling which involves physical milling and chemical etching.

Physical milling does not involve the use of chemicals thus making it a safe process that you can do comfortably. The quality of a material that goes through the process of milling will depend on:

• The true nature of the systems true milling accuracy and accuracy
• The condition of the milling materials and the rotational speed of the feeding bits
• The quality of the board that has gone through the process of chemical milling depends on:
• The accuracy of the photomasking
• Quality of the photomasking
• State of the milling chemicals
• Some of the benefits of using physical milling are:
• You don’t have to use chemicals thus making it a safe process
• You will end up with high-resolution boards in comparison to the process of chemical etching
• It saves on time as you can turn around a complete board in less time in comparison to chemical etching
• It is cheaper in comparison to chemical etching as it does not require additional material and expertise.

·V-scoring

It is the process of making a groove in the shape of the letter Vee on top and at the bottom of the board.

V scoring PCB

You should make sure that you live some material at the center so that the board remains intact. Many people refer to the process as either V-scoring or V-groove scoring.

You will use the process of V-scoring to group a set of circuits boards together to make the process of assembly simpler.

It provides a solid structure for the process of assembly allowing for the application of less pressure.

The end result will be the separation of the boards that you have put together.

You can base the V-score specifications on the cross-sectional view, depth of the score, indicating distance among the Vees.

The area that remains between the two vees is the web. Make equal measurements before scoring to have standard specifications of the V score.

·Z-axis milling

You can handle the core of the Z-axis milling in several ways. The first and simplest form of milling is the solenoid which pushes against a spring.

When the solenoid has enough power, it will push against a spring stop that will limit downward travel.

The second process uses the pneumatic cylinder and a gate valve under the control of a software.

The amount of air pressure and small size of the cylinder reduces control between the down and up stops. It is useful for the up and down milling tasks.

The third type uses a stepper mortar allowing the movement of the milling head in small but accurate steps.

You can adjust the speed of the steps to allow the drill beats inside the metal material rather than hammering in. depth and speed will be under your control using the software.

Metal Core PCB Manufacturing Process

The process of manufacturing metal core printed circuit boards is the same for all types of metals you will use.

It involves every step that you will follow in manufacturing a normal printed circuit board but you will replace the substrate.

The most common substrate for standard PCBs was the FR4 but you will replace it with a metal.

The first step in manufacturing a metal core printed circuit board is by making the design and output.

You will create the design of the MCPCB using design software as the final output should look the same.

The software you can use in designing includes OrCAD, Altium designer, KiCAD, pads, eagle among other types available.

The designer should be able to inform the manufacturer of the type of software he is using to make the schematic.

It will help in reducing the issues that may arise as a result of discrepancies. The designer will then export the design to the manufacturer for approval and support.

Many designers forward the schematic using a software known as the Gerber which maintains the beauty of the design.

The second step is printing the designer’s copy of the schematic onto a film after conducting a DFM check.

Many manufacturers use plotters to transfer the schematic on to a film which they will use to image the PCB.

Plotters use precise technology of printing to give the precise image of the printed circuit board design.

The final product is a plastic with the photo negative of the printed circuit board in black ink. The area in black ink represents the conductive parts of the MCPCB while the clear areas are non-conductive. On the opposite side, the black area is for etching while the clear part will represent the copper.

Every layer of the printed circuit board and the solder mask will have its own black and clear sheet.

For perfect alignment punch registration holes through every film. Adjust the table the film sits until you get the perfect match to get the exact punching of the hole.

 Metal core PCB

The third step involves printing the image on the film back on to a copper foil as you make the MCPCB.

At this point, you will have to check on the basic forms of the PCB as you collect the materials.

The main substrate board, in this case, will be the metal core such as aluminum or copper.

Remember to maintain a clean environment when going through these process to eliminate any errors.

Go through every detail in this process making sure that the specks of dust do not settle on the board.

Any speck of dust settling on the board may lead to short circuits on the board after manufacturing is complete.

The final product, in this case, is a board having resists that cover cooper areas properly which remains on the final form.

A technician can assist in the examination of the board to eliminate any chances of errors in this case. The resist that is present in this case will denote the copper that emerges in the final printed circuit board.

The fourth step involves the removal of the copper that you will not need on the final board. You can remove the excess copper by using a chemical that will eat away the excess copper.

The copper that you will need will remain under the protection of the photoresist.

You should note that different sizes of the copper boards will require different amounts of chemical concentrations.

Heavier copper material will need extended periods of exposure to assist in track spacing.

Complete the process by washing off the protective layer of the copper and remain with the copper that you need.

The fifth step involves punching the alignments making sure that they are all in a line.

The registration holes will align the outer layers with the inner layers.

You will use the optical punch machine that will permit exact correspondence for accurate punching of registration holes.

After the layers have been put together, you will not have the chance to make any adjustments in the inner layers.

There is another machine that you will employ to assist in the inspection of the layers ensuring no defects.

You can use the original Gerber to help in the inspection using laser and compares the digital image with original Gerber files.

After inspection, the design will go through to the final stage where the circuit board will take shape.

Every layer at this point will wait for union with other layers after all the inspection and confirmation is complete.

The outer layer will join up with the metal substrate through layer-up and bonding processes.

The bonding will happen on a heavy steel table with the help of metal clamps and pins for holding the layers.

Make sure that everything fits well to avoid any problems with the shifting of the alignments.

After placing every layer on top of the other, the process of bonding begins with the assistance of bonding press computers.

The computer will control the heating process of the stack up to temperatures that will allow bonding.

It will also control the cooling rates of the stack up ensuring perfect bonding of the stack-ups.

The final step in this process will involve unpacking of the layers accordingly.

After that, you will take the layer through the process of drilling the linking via holes requiring exact precision.

You will use an X-ray locater to determine the drill points as the computer controls the micro-movements of the drill.

The computer will use the drilling file to find the exact locations of the board you will need to drill.

The next step is plating and copper deposition on the board where thin copper films will also go through the vias.

Make sure you clean up the board well as it goes through the process of chemical baths assisting in a deposition.

A computer will assist in controlling the entire process of dipping, removing and processing.

The next step is electroplating the whole layer using a very thin layer of copper on the areas of exposure.

Tin plating will assist you in the removal of the excess copper that you will have after copper deposition.

The tin will protect the copper traces area from destruction during the etching process.

The design goes through the process of etching once again as it removes the excess copper from the design.

After this process, you will see a proper establishment of the connections and conducting areas. You will clean it up before using epoxy ink before applying the solder mask on the device.

The portions that are under a cover will be safe from hardening as you will have to remove them.

The boards will receive blasts of UV light that will be passing through a solder photo film mask.

Pass the device through the oven for curing of the solder mask on the device.

The device is now ready for the next process of surface finishing to increase the solder-ability of the device.

Then take it through the process of inkjet writing indicating all the vital information of the MCPCB.

You will take it through coating stage before finally curing the device.

The complete board will undergo an electrical test making sure that the circuit is working properly to conduct power.

It is the process that will confirm if the final product conforms with the original design.

You can use the flying probe test to assist you through the process of electrical testing.

The last and final step of manufacturing is taking it through the process of V-scoring and profiling.

Different boards will be cut away from the original panel using a V-groove or a router. It will help in the popping out of the board away from the original channel.

Metal core PCB

Metal Core PCB Prototyping Steps

The process of the metal core printed circuit board prototyping is basically the same as that of the standard PCB prototyping.

It is important to note the fundamentals of the MCPCB before starting the process of prototyping.

The information will guide you through every step of prototyping as it will be a representation of the final figure.

The first step in the process of prototyping is coming up with the right design using the designing software suits.

Make sure the manufacturer knows about the type of software you will employ in the designing.

The second step involves coming up with the right schematic design of the metal core printed circuit board.

The schematic will have the right information that engineers and manufacturers will need during the process of production.

It has information about components, materials, hardware you will need for the process as it determines the functionality.

It will also determine the characteristics, placement of the components, involving the right selection of the size and grid of the panel.

It is an initial phase of the final design and you have to run a test of the schematic to identify flows.

The third step is having the bill of materials to get all the materials that you will need for the whole process.

Make sure that you get the manufacturer to look at the bill of material so that he can help you. The bill of material will have the information as follows:

• The quantity of the components that you will need
• It will have the reference designators of the codes you will use in identification of individual parts
• The value specifications of every unit in the right units
• The footprint of the design knowing the location of every component on the board
• Have the manufacturer part numbers to identify the part manufacturer?

PCB prototyping

The next step is the designing of the routes by indicating the traces and indicating the point of placing components.

There are various factors that play roles in the planning of routing. Such factors include noise sensitivity, power levels and generation of the signal noise.

You will have to do checks at every interval of the prototyping process. There are points that you will need to do thorough checks before allowing it to move to the next step.

The common problems that you will have to evaluate and eliminate any problems are:

• Thermal issues including the heat spots
• The presence of a thermal path
• The different dimensions of the copper materials such as thickness
• Design rule check where you will compare the layout and the design.
• Electrical checks
• Antenna checks
• Quality assurance assessments
• The next steps that will come after checking will be for the process of fabricating the prototype. The main processes you will have to go through include:
• Creation of the photo film
• Printing of the inner layers
• Aligning of the layers
• Fusing all the layers together
• Drilling of the holes on the prototype
• Copper plating of the prototype
• Imaging of the outer layer
• Plating of the prototype using copper and tin
• The final process of etching
• Application of the solder mask
• Application of the surface finish
• Application of the silk screen before cutting and sourcing.
• Assembly followed by stenciling of the solder paste, picking and placing of the components.
• It also includes the process of reflow soldering before taking it through inspection and water quality control
• The final step is the insertion of the through hole components before conducting functionality tests.

The processes of the metal core printed circuit board prototyping is similar to the other processes of standard prototyping.

The difference will come in the bill of materials where you will have to include the metal materials for the substrate.

Metal Core PCB Components Mounting Guidelines

The guidelines that you will have to follow when mounting your MCPCB components will help generate the perfect MCPCB.

The first step in the whole process will involve understanding the mechanical constraints of the model. It is important as it is the factor that will affect the shape and size of the board.

PCB assembly

The second step involves having knowledge of the constraints you might face during the assembly process.

It will also help in determining the space you need to have when placing the components on the board.

This determines the points where you will place the components of the printed circuit board.

The third step involves giving enough room or allowance for the integrated circuits to breath.

It will give the components enough space between one another thus enhancing the mode of operation.

It will save you a lot of time when it comes to the process of placing components if you plan well.

When placing the components, keep the similar ones facing the same direction.

It will also assist the manufacturer in the installation, inspection, and testing of the parts in place.

It is a critical process when dealing with the surface mounting of the component using the process of wave soldering.

The next step involves grouping the parts that will assist in minimizing the connection paths. It will make the job of connecting the components very easy without a lot of stress.

Make sure that when you are placing the components, start with the components at the edge first.

It will assist in preventing any movements of the components during mechanical enclosures.

Also, it makes it easy for the placement of the switches, connectors, USB ports and jacks among other components.

Do not overlap the parts by cutting corners when using the boards of small sizes on the part outline or the pads.

Maintain a good space between the paths of about 40 mils for a smooth electrical connection.

This will help maintain a better flow of current without crossing paths that may cause short circuits.

When working on a simple board, place the components on a single layer. Placing them on one part of the layer will reduce the cost and time of placement.

Remember to place the integrated circuit pins and the polarized components in a similar direction.

Make sure that the components you are placing are the same as the placements on the schematic. The schematic should act as a guideline in the placing of the components on the board.

FR4 PCB Vs. MCPCB – Ultimate Comparison

The metal core printed circuit board is a replacement for the standard printed circuit board.

It means that the metal substrate of the MCPCB replaces the FR4 substrate on the standard printed circuit board.

The FR4 has the problem of heat buildup so the metal core will come as a replacement for the FR4 substrate.

FR4 PCB

 There is a difference between the FR4 PCB and the MCPCB in terms of different factors as follows:

· Conductivity

The metal core printed circuit boards are better conductors in comparison to the FR4 printed circuit boards.

This is because of the material that they use in making the MCPCBs which are better conductors than the FR4.

The copper, aluminum, and iron are better conductors of heat thus than the FR4 substrate.

This function of conductivity makes MCPCBs better in the heat dissipation in comparison to FR4 printed circuit boards.

It will also enable the metal core printed circuit boards to work better and last longer than FR4 PCBs.

· Plated through holes

FR4 printed circuit board uses through holes and the through hole components if possible.

In the metal core printed circuit board, you will not find through holes in one layer MCPCBs. All the components of the device are surface mounted.

·Thermal Relief

MCPCBs are better in comparison to the FR4 printed circuit boards in terms of heat relief.

This because of the type of material you will find in the metal core printed circuit boards.

The metal substrate you will find in a metal core printed circuit board is better-heated conductors.

The fact that it conducts heat better than the FR4 substrate males it better in terms of thermal relief.

It helps in dissipating heat from the device faster than the FR4 devices. It is the factor that makes it a better device for thermal relief.

FR4 depends on Vias for thermal relief thus making it slower in heat dissipation.

·Solder Mask

In the FR4, the solder masks are of dark colors such as red or blue on both sides of the board.

In metal core printed circuits you will find exclusively whiteboards in many of the cases.

This is especially in the light emitting diodes applications.

·Thickness

The FR4 has many varieties of thickness due to the fact that you have to stack up different layers.

In the MCPCB the thickness is under limit depending on the thickness of the metal material you will use.

·Machining process

The machining processes in both FR4 and MCPCB are the same except in the V-scoring process. In the V-score process of the MCPCB, you will use the diamond coating for the drills to drill the metal.

Main Applications of Metal Core PCB

Metalcore printed circuit boards are important in certain applications that often generates a lot of heat in its operation.

The metal core will help in the dissipation of the heat that builds up during the operation process. manufacturers use it to maintain the good performance of the device and for longer operating periods.

High power LED on metal core PCB

The main application of the metal core printed circuit board is:

• Audio equipment such as the amplifiers (Input and output), audio amplifiers, balanced amplifiers, preamplifiers, power amplifiers among others.
• Equipment for a power supply such as the switch regulators, SW adjusters, DC/AC converters among others.
• Equipment for electronic communication such as filter circuits, frequency amplifiers and electrical telegraphy.
• Automation equipment in the office such as motor drives
• Computers and other computing devices such as the power supply devices and the CPU motherboards
• Power modules such as solid relays, converters, rectifier bridges and so on
• Lanterns and lamps promoting energy saving lamps, LED lamps among other applications.

Conclusion

Metalcore printed circuit boards are the next big thing and might come as replacements for the other boards available.

It is time for you to change from the other boards and embrace the metal core printed circuit board.

It will save you money and also improve the life of your devices.