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All About Aluminum PCB: Types, Process, and Applications

By Mer-Mar Electronics | Date posted: | Last updated: January 27, 2023
aluminum PCB

Metal Core Printed Circuit Boards are known to find use in several applications. Aluminum PCBs are one of these which are quite popular. Such PCBs are known for their electrical insulation & thermal conducting capabilities. When it comes to applications with high power & tight tolerances, their importance cannot be overstated.

Composition of an Aluminum PCB

Aluminum PCBs comprise of the following layers:

1. Copper Foil Layer

It is a thick layer of copper which is responsible for the higher current carrying capacity of Aluminum PCBs. The copper foil ranges from 1 to 10 ounces.

2. Dielectric Layer or the Insulating Layer

A thermally conductive layer, it is known for its insulation, bonding as well as dissipation of heat.

3. Aluminum Base

Made of aluminum substrate it is known for high thermal conductivity.

4. Aluminum Base Membrane Layer

It keeps the surface protected from scraping & etching. Typically, this layer has a thickness of 1 mm.

Process of manufacturing Aluminum PCBs

The various steps involved in manufacturing of aluminum PCBs include:

  • Pretreating Aluminum PCB laminates
  • Generating circuits on the copper layers
  • Drilling holes on production panels
  • Solder mask printing
  • Silkscreen printing
  • Choosing the surface finish
  • Punching & routing the PCBs

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Types of Aluminum PCBs

Broadly there are multiple types of aluminum PCBs, the choice of which depends upon the application in which they are being used. These include:

1. Through-hole Aluminum PCBs

Largely in such PCBs the aluminum is pre-drilled and laminate material applied.

2. Flexible Aluminum PCBs

As their name suggests they offer a high level of flexibility on account of the flexible dielectrics that are used. With such flexible PCBs, the need to use connectors is highly reduced.

3. Hybrid Aluminum PCBs

These find wide use in RF applications. They use a non-thermal material as the sub-assembly, which is bonded to the Aluminum base using thermal materials.

4. Multi layered aluminum PCBs

These have multiple layers of thermally conductive dielectrics. They are extremely suitable for heat conductivity in complex products.

What makes Aluminum PCBs so popular in various applications?

On account of its wide range of advantages, Aluminum PCBs find use in several applications. Some of these include:

  • They are light in weight and hence work very well for miniaturized, light-weight applications. Despite their light weight they are known for their strength.
  • They are known for their heat dissipation quality. With aluminum PCBs, you can rest assured that on account of its superior thermal expansion performance, the various components on the board have improved shelf life. Once again in case of high temperatures, aluminum substrate retains dimensional stability.

  • Aluminum PCBs come with a number of environmental benefits as they are non-toxic and also recyclable.

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  • With widespread availability of aluminum, these PCBs are economical & therefore do not increase the cost of the PCBs.

Where do Aluminum PCBs find use?

Aluminum PCBs are particularly preferred in applications that require effective heat dissipation. Some of the applications where there is widespread use of Aluminum PCBs include:

  • Audio Equipment
  • Power supply equipment
  • High power LED Lights
  • Automotive applications
  • Office automation equipment
  • Power modules
  • Industrial power equipment
  • Interior lighting
  • High-power scanners
  • Solar cell substrates
  • Semi-conductor refrigeration devices, and more.

To Sum Up

Aluminum PCBs are game changers because they offer improved heat dissipation, and they are extremely cost-effective. It is important to use the right contract manufacturer who has the requisite experience in manufacturing Aluminum PCBs.

In the absence of rich experience, the PCB manufacturer may face issues related to areas such as solder mask printing where a thick copper foil can hinder solder mask printing.

For this, using a quality solder mask oil or filling in resin before the solder mask are an effective solution.

Similarly, it is important to know how to store aluminum PCBs as they attract moisture. When you partner with Mer-mar Electronics you can rest assured that you will get the right product. Mer-mar Electronics is ISO-9001:2015 AS9100D Certified who has 40 years of experience in PCB assembly and PCB fabrication. Fill out the form below to request a free quote now.

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PCB Assembly

PCB Shield: Types of Shielding, Material Used, and Importance!

By Mer-Mar Electronics | Date posted: | Last updated: January 25, 2023
pcb shield

The one thing you need to protect an electronic circuit against is electromagnetic interference. Failure to do so will result in performance issues and could also lead to PCB failure.

It is the Electromagnetic Compatibility or EMC that determines that a device is compatible with its environment.

In order to design PCBs with EMC, some simple design guidelines can come in handy. Some of these include:

PCB Guidelines for EMC

  • Referencing high-speed signals to a solid plane.
  • Ensuring that the current flow in any trace on a PCB completes the entire circuit loop and comes back to the source through the reference plane.
  • Ensuring that the return current follows the path of least impedance.

An important way that takes care of EMI is PCB Shielding.

What is PCB Shield?

PCB Shielding is essentially an effective way of protecting the board against electromagnetic signals. Additionally, they make sure that stronger signals do not escape. In the absence of this, there can be crosstalk, power supply noises, electromagnetic interference and more. Electromagnetic Interference can particularly lead to issues such as disrupted communication, interference with wireless devices, component failure as well as software errors.

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How to implement EMI shielding in your PCB layout?

There are several ways to implement EMI shielding in the PCB layout. Some of these include:

  • Metal shielding cans involve the use of a metal box that restricts electromagnetic radiation.
  • Elastomer electromagnetic shielding materials.
  • Ferrite beads, rods, and plates.
  • High conductivity mesh materials.
  • Separated ground replacements.

It is important to remember that irrespective of which method you choose you need to follow the best practices when it comes to installing the chosen shielding.

Types of PCB Shielding

There are broadly two types of PCB Shielding:

1. PCB RF Shielding

These work by lowering the coupling of electromagnetic fields & hence blocking electromagnetic radiation & radio frequencies. These shields also include a Faraday Cage.

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2. Arduino Shielding

This shield can be mounted on top of the Arduino board. Particularly Arduino has a wide range of shields for prototyping. These are preferred as they are easy to use and are known to be extremely cost-efficient. Importantly there is a library available with editable codes, that renders the process simple. Additionally, the added advantage they offer is that Arduino shields can be stacked on top of each other. They, therefore, combine different functionalities. An important aspect to be remembered here is that the shields must use the pins of the Arduino board itself as there needs to be a common GND. Arduino Shields placed on Arduino Boards help in wireless communication, motor control, LCD control, connecting to internet frameworks, to mention a few use cases.

Arduino Shields, in turn, are of various types. These include:

  • Wireless Shields
  • Ethernet Shields
  • GSM Shield
  • Proto Shield

Attributes of PCB Shield

With a PCB level shield, the following features can be incorporated:

  • You can ensure a small footprint.
  • Through-hole or surface mount.
  • There are ventilation holes.
  • Removable covers ensure easy access to components.
  • Shock & vibration can be countered with locking mechanisms.
  • There is insulation padding.
  • low-profile configurations.
  • Multi-cavity patterns.

Material used in PCB Shielding

Normally the following material is widely used in PCB shielding:

  • Tin plated cold rolled steel
  • Tin plated copper
  • Nickel silver
  • Stainless steel
  • Tin plated phosphorous bronze

As a thumb rule, tin-plated steel is preferred if the shielding is below 100 MHz & tin-plated copper is used if it is above 200MHz.

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A Word of Caution

While tin plating is extensively used as it renders soldering easy, the use of aluminum isn’t preferred as it is known to have heat-sinking properties.

To sum up

PCB shielding is the much-needed protection that your circuit requires. Depending on your frequency range, you need to choose the best-suited material. With RF PCB shields you can also block out radio frequency.

To get high-quality PCB hiring an experienced PCB manufacturer is the best option. If you are looking for an experienced PCB manufacturer, then you are at the right place. Mermar Electronics has 40 years of experience in delivering high-quality PCB. Mermar Electronics is an ISO-9001:2015 AS9100D Certified who provides PCB assembly, PCB fabrication, and PCB design services under one roof. Fill out the form below to request a free quote now.

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PCB Shield

Important PCB Design Files for PCB Assembly & Fabrication

By Mer-Mar Electronics | Date posted: | Last updated: February 28, 2023
pcb design files

While a PCB ensures the success of an electronic device, it is possible for the PCB to do so if it is fabricated correctly. To do that it is important that the PCB design files to describe the board specifications correctly. Detailed documentation ensures that there is no guesswork when it comes to fabricating & assembling the boards.

Some of the important PCB design files include Gerber Files, IPC-2581, Netlist, Drill Files, BOM, Fab Drawings, Pick & Place Files & ODB++ Files. Let us look at some of these design output files in detail:

Files Needed for PCB Assembly

1. PCB Gerber Files

These files are generated once the layout design is complete. In fact, Gerber files are generated for every layer of the PCB. Some of the Gerber Files for manufacturing therefore include:

  • Aperture definitions
  • TOP
  • Solder Mask Top
  • Solder Paste Top
  • BOT or bottom layer
  • Solder Paste Bottom
  • Silkscreen Top
  • Silkscreen Bottom
  • Assembly Top
  • Assembly Bottom, and more

It is the complexity of the board that determines the number of files created.

Files Needed for PCB Fabrication

1. ODB++ Files

Simply put, these files help designers combine all information as also run the necessary manufacturability tests. An intelligent file, it consists of material stack-up, bill of materials, component placement and more, in a single file. Unlike a Gerber file, the ODB++ Files include a large amount of data and also take away the possibility of human errors.

2. Bill of Materials (BOM)

An extremely important file, it contains a list of all the components required in the PCB. Some of the other crucial information mentioned in the PCB BOM includes:

  • Description of parts
  • The quantity required
  • Manufacturer Part Number
  • Footprint of the component
  • Any notes or comments

3. FAB Drawings

These offer manufacturing details of the PCB. Some of the information includes:

  • Board Dimensions including the length, width & thickness
  • Board Outline- It is imperative that for denser boards that have buried vias, additional outlines be added.
  • Drill Details- It needs to include the different drills used such as laser holes, micro via, via on pad, plugged via, blind via & buried via.
  • Stack-up details including
    • Finished PCB thickness- Typically the finished PCB thickness is 62 mils
    • Prepeg thickness- This is dependent on adjacent layers
    • Copper thickness- Typically the thickness of the plating ranges from 20 to 100 microinches
    • Copper cladding thickness- This largely is contingent upon the strength of the current
  • Copper trace & etching tolerance
  • Class of fabrication
  • Color of solder mask
  • Color of silkscreen
  • Impedance Traces, and more

4. Drill Files

With drilling being an expensive as well as an irreversible process, a drill file has a lot of importance. It indicates the position, the size as well as the number of holes in the PCB. The drill holes can be plated or non-plated. Non-plated holes are used as mounting holes. These are also used when the PCB has to be electrically isolated. There are separate files created for plated as well as non-plated holes.

5. IPC-2581

This is a PCB assembly & manufacturing standard. IPC-2581 has a large number of files within a single file. It contains the following information:

  • Layer stack information
  • Material information
  • PCB Test Points
  • Notes for Assembly
  • BOM
  • Netlist in-circuit testing, and more

6. PCB Netlist

It is a list of networks that determine the board’s connectivity interconnection. A PCB netlist performs several functions. Firstly, it is possible to map the designer’s netlist with the manufacturer’s netlist. Customer netlist is also used for electrical validation of the PCB.

7. Pick & Place Files

With most PCB assembly processes being automated & using pick & place machines, Pick & Place files have a special importance. It offers information about the position as well as the orientation of components. Some of the information mentioned in Pick & place files include:

  • Location of components
  • Reference Designators
  • Orientation of components
  • Placement on top or bottom of the board, and more

To Sum Up

Detailed data received from designers can go a long way in ensuring that the PCBs are fabricated & assembled to perfection.  In the absence of this detailed data, there are chances of costly errors at a later stage.

Due emphasis paid at the design stage & effective communication with the manufacturer can go a long way in ensuring that the PCBs are efficient. You can contact Mermar Electronics who communicate with you regarding all files details before starting PCB process so you can avoid costly errors. Contact Mermar Electronics at sales@mermarinc.com or fill out form below to request a free quote.

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SMT Line Guide: Overview, Process, and Equipment Used!

By Mer-Mar Electronics | Date posted: | Last updated: December 27, 2022
smt line

SMT Line or Surface Mount Technology Production Lines imply the manufacturing facilities that enable PCB assembly and their subsequent testing. The SMT production process can in turn be broken down into smaller processes, each of which requires different machines, all of which, in turn, comprise the SMT Line.

Types of SMT Lines

In turn, SMT Production lines can be of two kinds:

1. Automatic SMT Line

Essentially where the pick and place machine are fully automatic.

2. Semi-Automatic SMT Line

Where there is the need to manually load/unload PCB boards.

SMT Line Process

The broad process in assembly involves:

  • Applying solder paste to the PCB
  • Placing components
  • Using the reflow process to solder the boards
  • Testing

Let us look at each of these processes in some detail:

1. Applying Soldering Paste

This involves printing the paste on the board with the help of a silk screen. A custom stencil ensures that the solder paste is applied only in the requisite areas. Once it is ascertained that the paste is evenly applied, it is time for component placement and assembly.

2. Component Placement and Assembly

In this process, the electronic components are loaded. The assembly machine then removes each component, and places it in the exact position on the board where it needs to be affixed. The next process involves the boards to be put in a reflow oven for soldering.

3. Component Soldering

The reflow soldering process involves the boards being warmed with heated air. In turn, this results in the melting of the soldering paste. This ensures that the components are fused to the PCB. The boards are subsequently cooled ensuring that the components are well fused to the board.

4. Testing

It is important that a thorough inspection be undertaken to ensure that the quality of the boards is robust. For this Automated Optical Inspection is made use of. Through this method, the system automatically checks each board, and any deviations are highlighted. Not only does this ensure accuracy, but it also makes sure that costly mistakes are avoided later.

Equipment used in SMT Lines

Below is an overview of the main equipment that is used for SMT lines.

1. Pick and Place Machine

This is the most important equipment for SMT lines. As its name suggests, this machine picks up the surface mount components & places them accurately on the PCB pads.

2. Solder Paste Mixer

This equipment is responsible for accurately mixing the solder powder & paste. It goes a long way in standardizing the operation & besides of course saving labor.

3. Oven

An oven is required to bake PCB boards & to remove any moisture from them.

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4. SMT Loader

It is responsible for placing the PCBs into the solder printing machine.

5. Solder Paste Printing Machine

As its name suggests, it is used to print solder paste on to the boards.

6. Solder Paste Inspection Machine

This is instrumental in checking that the solder paste is printed properly on the PCB.

7. Reflow Machine

Reflow soldering ensures that the solder melts & the components therefore fuse with the board. Reflows can be of several types, the main ones being:

  • Hot Air Reflow
  • Infrared Reflow
  • Hot gas Reflow, and more.

8. AOI (Automated Optical Inspection)

This performs a crucial role in checking for any placement failures both pre- and post-solder. With any errors highlighted at this stage, it saves a lot of time, effort and money that could be otherwise spent correcting any errors.

9. Docking Station

Simply put, this is a connection station for the different equipment that make up a SMT line.

10. SMT Unloader

After reflow soldering an unloader both receives and stores the final circuit boards.

Needless to mention that the automation of the above processes goes a long way in:

  • Standardizing the process and ensuring that each board adheres to the exact specifications.
  • Weeding out any errors, timely.
  • Resulting in savings in terms of labor costs and effort.

The role of automation particularly cannot be over-emphasized when it comes to PCBs that are used in mission-critical operations where the smallest of errors can have fatal consequences.

To avoid such errors and to make error-free PCB end products contact Mermar Electronics. We are an ISO 9001:2015 certified PCB assembly manufacturer who provides custom PCB fabrication. Contact us at sales@mermarinc.com or fill out the form below to request a free quote.

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