The Process of a Printed Circuit Board Assembly

mwcms on August 30, 2021

The PCB assembly process undergoes thorough and intricate steps. PCB’s being the staple circuit board mechanism in most of the electronic appliances is undoubtedly major components that require perfect assembly otherwise they can be major causes of concern for many industries.

BluePrints and Layouts

The assembly process in factories start with a framework or blue print layout and make their way to the customers. Due to the advancements in PCB production, modern manufacturing units hardly have any workers on the production floor. This is because most of the manufacturing process is subject to automation and efficient machinery.

In the starting stage of assembly, the burr board inserts into the laser marking machine, which marks a serial number on the board so that the board can have a manufacturing label. This process is common in large scale production, but is not something common to all Printed circuit board manufacturers.

Applying Solder Mask

The process initiates with the application of solder to the circuit board. Solder mask is a material that sits on top the circuit as a layer in which you can install components of the circuit board. A specific inspection machine then inspects the circuit board and ensures that it is aligned.

Once the inspection is complete, it applies solder all the way across the surface board in an evenly fashion. After solder application, the solder goes through another inspection to ensure that it is applied evenly.  Once the inspection is complete, the board is ready to undergo the next stage.

Adding Component Placements

The next stage involves the addition of the placements. Machines rapidly add placements on the board that are coming from the reels. This machine includes heads that pick up the reels and attaches them to the circuit board. This reel placement happens for about eight times before the circuit board is ready for the next stage.

After all the components attach to the board, it is then ready for the reflow process. This process is important since the solder needs to melt so that it can adhere and be a good surface that provides mechanical and electrical connections between components and parts.

Reflow process

When it goes under the cooking process of the machine, it comes out from the other side to cool. Cooling process takes place so that all the junctions between the components can form and solidify. This results in the next step which involves testing.

Inspection and Electrical Testing

The final inspection will now ensure that all the components are situated in their correct specific placements so that the circuit board assembly is ready for use.  In this testing, advanced machines identify whether the pins are contacting the pads in the exact location. At this point, the SMT process is in completion.

Electrical testing can have implications that follow two processes. The first involves the bed of nails, which helps manufacturers test at a high volume at a shorter time, however it require expensive fixtures. The second testing method is a flying probe, which is a high mix at a small volume.

If the circuit board assembly includes large BGA components, then manufacturers need to inspect whether the pins are reaching the right layer.  These pins are usually behind each component and therefore, you cannot test those using automated machines. In this scenario, manufacturers will likely use the help of X-ray images and make sure that the soldering and components are adequate.

Parts of a PCB, or Printed Circuit Board

Whether the PCB board is inside an air conditioner, or a refrigerator, you can find numerous different parts mounted on the bare board. The main components that you are likely to find and which are critical for its functioning involve a Fuse, transformer, and a switch. The quantity and types of these components can vary according to the specific electrical appliance.

To Conclude

All of these processes and testing are then finalized by a functional test. As you can see, the process of a printed circuit board assembly is full of inspections and automated machine work. Thus, it is a true reflection of the detailed workings in a mass production factory.

 

Everything You Need to Know about Solder Mask Material

mwcms on July 16, 2021

Solder Mask material is a fine layer of polymer. In terms of application, engineers will often use this material for copper traces in a circuit board, PCB. It is an essential material in circuit building projects, protecting the PCB from oxidization. This is, however, not the only use case and benefit of solder masks when it comes to the construction of circuit boards.

PREVENTS THE BRIDGES FROM DEVELOPING

Printed Circuit Boards or PCB usually has components of copper placed extremely close to each other. The solder masking helps an engineer avoid solder bridges from manifesting due to the pads spaced closely.

Solder bridge refers to an electrical connection between two copper components on a PCB board. Therefore, the correct application of a Solder Mask can be instrumental in avoiding this issue. Their use case for PCBs is increasingly widespread and fine-tuned into the mass production of circuit boards.

Hence, you will not only find the solder mask material as a hand assembly use case but also integral to the mass production companies of PCB. Companies involved in mass production often use wave or reflow techniques to solder their circuits.

APPLICATION PROCESS

The application process of solder involves firstly, applying the solder material on the board, and then following it up with making openings into the material for the copper components. Engineers that craft circuit boards will make these openings, often by using photolithography techniques.

Traditionally, solder mask material has a green physical appearance, but you can find it in many other colors as well. You can also use solder-masking techniques to construct your very own solder mask at home.

Hence, the quantity, quality, or type of the solder mask material ultimately depends on the particular PCB. Every PCB is different, not only in terms of size but also in terms of applications. PCBs for certain electronic instruments may have more components than some others.
Therefore, the physical dimensions of a particular PCB, the number of openings, and the volume and sizes of components are considerations that factor in before every soldering process.

TYPES

Typically, you can find four types of solder mask materials, each having its unique physical properties and distinct applications.

TOP-BOTTOM SIDE MASKS

The use of this type of solder mask is common amongst electronic engineers. They use this type of solder to recognize the openings in the solder layer. The layering of this solder mask often follows a film or an epoxy technique.

EPOXY LIQUID SOLDER MASKS

This is one of the cheaper solder masking options since it is a polymer that you can easily silkscreen on the PCB. Silk-screening refers to a printing method in which you have to apply woven mesh to hold the ink patterns.

LIQUID SOLDER MASK/PHOTO IMAGEABLE SOLDER MASK

This solder material is often the more superior out of the four. In terms of property, it is a mixture of two different liquid components. For this reason, it has a much higher shelf life than other solder mask liquids. Furthermore, it is also versatile in its application, meaning, that you can use multiple techniques to apply this solder mask material type.

DRY FILM PHOTO IMAGEABLE SOLDER MATERIAL

This type of solder mask material is excellent for high-density wiring boards. Since the film is dry, it is less likely to escape through the holes. Moreover, when using dry film, you should use the vacuum lamination application technique.

CONCLUSION

Solder mask materials are emphatic for the PCB industry. Without their application, all circuit boards are vulnerable to damages due to short circuits. Moreover, they also have an essential role in the functionality of the particular circuit board, and they allow aspiring circuit board creators to practice their PCB crafting skills.

What Software and other Tools PCB Engineers Use?

mwcms on May 10, 2021

Electronic engineers must understand the layout and design of the electrical circuits. It can be a strenuous exercise task for an engineer to work without printed circuit boards (PCBs). This is where the need for PCB designing software and tools comes into play. 

These software and tools help an engineer to design a blueprint of the PCB. Moreover, an engineer can use the software to pull old designs from the PCB libraries, customize design procedures, and verify circuits’ schematic designs. 

Basics of PCB Layout and Design Process

The success of PCB prototyping and manufacturing is a result of an immaculate design process. 

The printed circuit board design and the layout process are vital as they allow the engineer to create an error-free prototype and a flawless manufacturing process. However, the type of software and tool used to accomplish the layout and design is vital to the entire exercise. 

Before getting down to the software and tools, let us have a clear picture of the basic process of PCB design

  • Creation of schematic design
  • Capturing of schematic design
  • Determining PCB template, fixed components, card dimensions and heat sinks
  • Deciding PCB stack layers
  • Determining line impedance
  • Component placement
  • Signals trace routing
  • Generating Gerber file

Software and Tools Engineers Use

Engineers use several software and tools to complete the above-mentioned process efficiently and precisely. 

Electronic Design Automation (ECAD) Tool

This one is a category of design tools used for the process of schematic design capture. These tools work simultaneously in the modular design flow to produce PCB’s design description. Some of the most popular tools that fall within the ECAD category are as follows. 

  • ORCAD

The PCB design engineers use this software to create an electronic schematic and blueprint of the circuit board. 

  • EAGLE

EAGLE is an acronym for “Easily Applicable Graphical Layout Editor.” This software is a solution-driven design program for printed circuit boards. EAGLE contains a PCB layout editor, schematic capture editor, Bill of Material Tools (BOM), and auto-router. 

  • PADS

PADS is a layout tool that contains advanced analysis, schematic designs, and, most notably, the feature to collaborate from ECAD to MCAD. 

5 Popular Designing Software and Tools Used by PCB Engineers

Although there is a wide range of PCB designing software and tools available in the market, here are the top five. 

  1. Altium Designer – it is famous for its feature to simulate your printed circuit board using the Altium PCB software. 
  2. PCB Artist – this software by Advanced Circuits is famous for its best shipping record and active consumer base. If you are looking for an intuitive solution for PCB designing, look no further. 
  3. SolidWorks PCB – this one has a robust design technology with ease-of-use. You will also get an on-demand bidirectional mixing feature along with the flawless collaboration of CAD and PCB designs. 
  4. Ultiboard – this PCB designing software by National Instruments allows you to leverage modular hardware and an expansive ecosystem. You can benefit from a quick prototyping atmosphere and save hours on the development phase. 
  5. DipTrace – if you are looking for a comprehensive design solution, smart manual routing, and shape-based auto-route, DipTrace is the answer. This software has a single environment that enables you to benefit from the direct conversion circuit to board feature and revise the schematic annotations in run-time.