A Complete Guide on PCB Soldering Process!

By Mer-Mar Electronics | Date posted: | Last updated: November 25, 2022
PCB Soldering Process

Soldering is an essential process that helps fasten components onto a PCB. The right soldering can make a huge impact on the quality as well as the performance of the custom printed circuit boards. In this article, we have explained what the PCB soldering process is, the types of soldering process; and how it can be done.

There are different types of soldering techniques as well as solders, the choice of which is critical to the success of your project. Here is a detailed overview:

Types of PCB Soldering Process

Reflow Soldering

This involves using a solder paste to temporarily attach components to their respective contact pads. Post this, the assembly is subject to controlled heat. The process of reflow soldering involves the following steps:

  • Application of the solder paste.
  • Preheating the board to bring it to the required temperature.
  • Thermal Soak so that areas that weren’t adequately heated come to the required temperature.
  • Reflow process to create the necessary solder joints and remove volatiles.
  • Cooling to prevent thermal shock and excessive intermetallic formation on the board.

Wave soldering

This is a large-scale soldering process wherein electronic components are soldered to create an electronic assembly. This process involves passing the PCB over a pan that contains molten solder. It is important to maintain the right temperature during wave soldering. There also needs to be adequate pre-heating as otherwise, the board is susceptible to stress.

The steps involved in wave soldering include:

  • Melting the solder
  • Cleaning of Components
  • Placement of components
  • Application of solder
  • Cleaning of the board

The ideal temperature during wave soldering ranges between 240-250°C.

Wave Soldering Vs. Reflow Soldering

The type of soldering you go with depends on a wide variety of factors including but not limited to:

  • Shape of the pads
  • The available time
  • Component orientations
  • Type of PCB, and more.

In some ways, wave soldering is more complex as its success depends upon creating the right environment. Board temperature and the time the board spends in the solder wave need to be monitored. However, wave soldering is also faster and more cost-effective as opposed to reflow soldering. Reflow soldering is however more suited to be used in small-scale manufacturing while wave soldering is suited for large scale production.

Explore the reflow soldering v/s wave soldering in detail.

Types of solder

Other than the soldering process, what is also critical is the choice of solder. Some of the solder types that are increasingly used include:

Lead alloy solder – It is a mixture of 60 percent tin and 40 percent lead.

Lead-free solder – Given the impact of lead on the environment, the use of lead-free solder has been growing. In fact, the EU has restricted the use of lead in consumer goods.

Silver alloy solder – These emerged as alternatives to lead solder and contain between 3-5 percent of silver.

Some Common Problems in PCB soldering process

Some common problems that one needs to watch out for in the soldering process, include:

Interfered joints

These joints result on account of movement during solder solidification. As a result, the joint appears crystalline and rough.

Cold joint/overheated joints

These result if the optimal temperature isn’t maintained or if the duration of heating isn’t long enough.

Excessive solder

If there is application of too much solder it results in bubble-like solder balls. In turn, they impact the functionality of the board.

Insufficient wetting

A badly wet joint results in poor connections and impairs the overall performance of the circuit.

Solder hunger

This refers to a situation where insufficient solder is used. In turn, it leads to poor electrical contact between the parts of the circuit

Untrimmed leads

If the leads aren’t trimmed to the required lengths, there can be the risk of short circuit as the leads can come in contact with the rest of the charges.

Points to be kept in mind during PCB soldering process

#1. Heat dissipation during assembly

It is important to effectively monitor heat dissipation during assembly and to ensure that the circuit’s components remain below the required temperature limits.

#2. Keep the soldering iron tip clean

If the soldering iron tip isn’t kept clean, you can run into a number of issues including low heat transfer leading to soldering issues.

#3. The sequence of welding parts

It is important for designers to understand the right sequence of affixing the various components.

#4. Removal of residue

Once the soldering process is complete, you are left with the flux. This needs to be thoroughly cleaned as otherwise it can lead to low voltage insulation short.

#5. Soldering SMT resistors and capacitors

Soldering resistors and capacitors is a challenging task. Experienced PCB designers can make a great deal of difference in this process.

#6. Continuity and Sensor Output

It is imperative to undertake testing for continuity and sensor output to ensure that there are no malfunctions.

To Sum Up

The right soldering is a matter of precision and having enough experience and access to soldering best practices. It is important, therefore, to go with the right partner who can make a difference to the project.

Mer-Mar Electronics is one of the leading PCB manufacturing companies, providing all in one PCB assembly and fabrication solutions. Our consistent quality & quick turnaround endear itself to our customers, who look on us as a one-stop shop for all their PCB manufacturing requirements. In case you have any questions or require more information about our PCB manufacturing services, contact us via email at or call us on (760) 244-6149.

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The Essential Guide to Wire Harness Manufacturing Process

By Mer-Mar Electronics | Date posted: | Last updated: February 22, 2022
Wire Harness Manufacturing Process

Wire Harness Manufacturing process is an extremely specialized process that involves several measured steps. Before we get into them, let us look at the difference between a cable assembly and a wire harness.

Simply put a cable assembly is an external connection to devices and needs to take into account factors such as:

  • Thickness
  • Flexibility
  • Type of insulation

A wire harness, on the other hand, offers connectivity between systems in an electromechanical assembly. Wire harnesses are built on panels that has pegs. The harness, therefore, is laid out to bespoke dimensions. It is important to remember that the more detailed and precise the specifications, there will be fewer issues on the assembly floor. Some of the information that the contract manufacturer will require in order to build the wire harness, includes:

  • Connector images with pin locations
  • Wire lists
  • Detailed BOM with part numbers
  • Assembly drawing
  • Test specifications

Best Practices in Wire Harness Design

The benefits of good wire harness design includes the fact that it improves the service life of wires, optimizing the space required for wires, organizing all wires in one place for easy access. It is imperative therefore that best practices be followed when it comes to wire harness design.

Some of the best practices in wire harness design include:

  • Identifying problems that could be posed by the physical environment such as moisture, temperature, electrical interference and more.
  • Choosing the correct routing option.
  • Ensuring that exact measurements are adhered to when it comes to cutting wires and calculating the bend radius.
  • The harness must fit correctly in the space it is intended for. It is important, therefore, to take the size of the outer protective casing into account.
  • The type of terminals and how they fit into the wire radius is also an important design decision.

Important Steps in the Manufacturing Process to Build Your Wire Harness

The broad steps followed by contract manufacturers to build a wire harness include:

  • Robust design review – Basis your design, the contract manufacturer will examine the entire documentation and Bill of Materials to see that everything is in place.
  • Preparing the material – Post finalization of the Bill of Materials, the components and materials required for production and test of the harness are purchased.
  • Assembly documentation – The Contract manufacturer will also create a detailed Assembly Documentation including:
    • Assembly steps
    • Images
    • Test procedures.
  • Prototype – Typically before producing the wire harness, the contract manufacturer creates a prototype. This helps to perfect the assembly and to ensure that the quality expectations are met.
  • Production of Wire Harness – The building of the wire harness involves cutting the wire to length and laying it on the assembly panel. The next steps involve adding connectors, tying bundles of wires and attaching labels.
  • Testing – A detailed testing protocol is finally undertaken. The harness is checked for a number of issues including:
    • Construction
    • Labeling
    • Checked for usage on-site

Dos and Don’ts to be followed in building the Wire Harness:

Below are some of the tips to be followed when it comes to building the wire harness assembly:

  • The termination recommendations for attaching the wires need to be followed. The recommendations could be in the form of stripped and bare or stripped and tinned.
  • Similarly, the recommendations for torque values on fasteners need to be followed.
  • Generic specifications for wires such as 300V or 600V need to be adhered to. It is best not to give the contract manufacturer a specific UL code. That way the contract manufacturer can use wires that fit the requirement, are available and that are cost-effective.

As a thumb rule it is imperative that you work with the contract manufacturer from the early stages of development so that the electronic contract manufacturer can help with the selection of best performing parts. Additionally, it is advisable to go with a contract manufacturer that has experienced engineers with the necessary expertise who are equipped with industry best practices so that you do not land up making any costly mistakes in the wire harness manufacturing process.

Mer-Mar Electronics has been in the business for over 40 years and has a skilled & experienced engineering team who works on different design systems. Our manufacturing experts build your PCBs, cable assemblies, wire harnesses, and more. In case if you have any questions or require more information about cable and wire assemblies services, get in touch with us via or call us on (760) 244-6149.

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The NPI in PCB Assembly Process: A Guide for Electronics Manufacturers

By Mer-Mar Electronics | Date posted: | Last updated: January 12, 2022
New Product Introduction

Introducing new products is both an exciting process, as well as one that is fraught with risk. For one, it requires collecting authentic data and having a well-organized process. It is only this kind of discipline that can ensure the introduction of repeatable, high-quality products in the market.

What really is New Product Introduction (NPI)?

New Production introduction results from a process that ensures serial production of a product. It enables the transformation of a prototype into a fully finished end product. There is continuous iteration until the end result is achieved.

PCB Assembly & New Product Introduction (NPI)

For companies dealing in PCB assembly, it is extremely important to implement the NPI process. It guarantees repeatability of the production process and helps prevent errors besides ensuring that you do not have to deal with any unexpected costs. PCB Assembly companies that use New Product Introduction as a process are therefore able to offer high-quality products to customers.

Key Benefits of New Product Introduction Assembly

Some of the advantages of New Product Introduction, include:

  • Detects potential errors at the design stage and leads to improved production efficiencies.
  • The many tests performed before a new product is introduced such as SPI/X-Ray inspection, RLCD examination, and verification of documentation ensures that the final product meets customer requirements.
  • Since NPI involves development of a production process that follows best practices, it also ensures that any steps that aren’t of value are eliminated. That this results in time saving is a given.
  • Additionally, it gives the PCB Assembly supplier full control over each phase of the process. It also offers quick time-to-market capabilities that is a priceless advantage given the competitive times.
  • Streamlined processes ensure that there aren’t any last-minute revisions or changes. In turn, this results in a reduction in PCB manufacturing costs.

Steps in New Product Introduction (NPI)

The NPI process can be broken into the following steps:

  1. Define: This is a crucial step since it scopes the product’s functional performance. Some of the areas to be defined in this phase include:
    • Primary Objectives
    • Scope of the project
    • Key Deliverables
    • Converting product functional requirements into designs through the process of Quality Function Development.
  2. Feasibility Analysis: This stage involves reviewing product design concepts and ascertaining the feasibility of success.

  3. Development: At the development phase DFM principles are taken into account. Some of the activities undertaken in this phase include:
    • 3D Models
    • Concept level Drawings
    • Bill of Materials
    • DFM & DFA reviews, and more.
  4. Testing: Robust testing right from conceptualization to design and manufacturing phases is undertaken, so as to ascertain the strengths and weaknesses of the product.

  5. Implementation: This stage involves creating documentation related to the product including:
    • Manuals
    • Catalogues, and more.
  6. Evaluation: In this phase product review is undertaken that includes analyzing customer feedback.

  7. Full-scale Production: The product is finally ready for full-scale production.

New Product Introduction (NPI) Best Practices

While NPI is a complex process, some of the best practices involved in the New Product Introduction Assembly include:

  1. Consistency – One of the aspects that ensures consistency is to assign a NPI number to the product. Automating this process ensures that there isn’t the risk of any errors that accrue on account of any manual data collection.
  2. Data authentication – This, of course, is a very crucial aspect of New Product Development. Ensuring availability of verified data and the right equipment eases the New Product Introduction Process.
  3. First batch size – It is important to determine the optimal size of the first batch of products. It doesn’t work very well to produce the entire batch in the first round.
  4. NPI Assembly supervision – It is extremely important for an NPI engineer to consistently supervise assembly. It is useful to document all observations during the process to be able to ensure constant improvement.
  5. Change of status and reporting – Detailed reports that explain the product building process including a description of all the issues that arose during the assembly phase are a must-have. The use of specialized analytical tools can ensure elimination of errors during production as well as assembly.

NPI (New Product Introduction) in PCB Assembly

In the PCB assembly field, it is extremely important to continuously monitor the NPI PCB assembly process as well as document all conclusions. This ensures that every subsequent batch’s quality keeps going up.

As a leading PCB manufacturer in the USA, Mer-Mar Electronics delivers PCB manufacturing services with specialized support, reliable testing, and multi-functional features. Our consistent quality and quick turnaround time captivate us to our customers, who look on us as a one-stop shop for all their PCB requirements. To know more contact us at or call us on (760) 244-6149.

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SMD vs SMT – What is the difference?

By Mer-Mar Electronics | Date posted: | Last updated: September 14, 2022
difference between smd and smt

With both SMD and SMT growing in popularity, they are often used interchangeably. It is perhaps also because both work hand in hand to offer reliable PCBs. It is, however, important to differentiate between them.

Simply put, SMT refers to Surface Mount Technology, which is an PCB assembly technique that helps arrange components on the circuit board. SMD, on the other hand, refers to Surface Mount Devices. These are components fitted onto the circuit boards. They are designed to be mounted directly on the PCB.

Difference between SMD and SMT

The primary difference between the two is that one refers to the mounting process while the other refers to the actual components. However, they are clearly dependent on each other. It is the proper selection and arrangement of SMDs that is the primary process behind SMT. Automated SMT machines can mount several SMDs onto the board in a short period of time. While SMDs determine the capacity of the board, SMT involves the installation of these components on the board.

Let us look at both in some more detail:

What is SMT in electronics?

Surface Mount Technology is a relatively newer way of arranging components on the printed circuit board. Prior to this, components were arranged using through holes where component leads are placed into drilled holes on a bare PCB. Surface Mount Technology, on the other hand, involves soldering the components directly onto the boards. Since there is no need to pass leads through the PCB, the process is far quicker as well as cost-efficient. The big advantage of SMT PCB assembly is that it saves space. What it means is that more components can be housed on a smaller board. In times of miniaturization of devices, its advantage cannot be overstated.

Process involved in SMT (surface mount technology) includes

1. Printing

This involves applying a coat of solder paste onto the pads of the PCB.

2. Mounting

This refers to placing the surface mount components accurately onto the pads.

3. Reflow Soldering

This process involves melting the solder paste by passing the board and components through a hot oven.

4. Testing

The final process involves testing the boards through processes such as AOI which runs a number of quality checks on the boards such as component alignment and checking for solder bridges.

As is evident from the above processes, SMT is an intricate process that involves applying the right amount of solder paste to mount each component. SMT also lends itself to automation as machines can be programmed to mount components on the PCB in a short time frame. This ensures accuracy while also speeding up the production process and making go-to-market that much quicker.

Some of the other advantages of SMT

  • Significant savings in weight and real estate.
  • Reduced cost of the board as also a reduction in material handling costs.
  • Stability and better mechanical performance.
  • Components can be placed on both sides of the board and in higher density.
  • PCBs created with the surface mount technology process offer higher circuit speed. Also, because SMD components have no leads or have short leads, RF interference is reduced.
  • It offers more resistance to vibration and there is less noise.

The drawbacks of SMT however include the fact that it requires a high capital investment that can increase costs, particularly when you are dealing with low volume runs. SMT inspection equipment can also turn out to be very costly.  Additionally, SMD components are prone to damage if dropped. Also, the power of such components is generally less.

What is SMD (surface mount device) in electronics?

Surface Mounted Devices are the components fitted onto PCBs. Evolved SMDs use pins that can be soldered directly onto the PCBs as opposed to using leads and wiring them through the circuit board. It enables many more components to be fitted on the board and improves its functionality. With no holes to be drilled, they also make the process quicker and cost-effective.

What is important is to choose the right SMDs and then mount them correctly on the board. SMDs can now be automatically mounted onto the electronic board as opposed to manually soldering them.

Types of SMD

Some of the various types of SMD include:

  • Chip Resistors
  • Network Resistors
  • Capacitors
  • Diode
  • LEDs
  • Transistors
  • Integrated Circuits

Mer-Mar Electronics offer high-quality SMT PCB assembly services in quick turnaround time. Our SMT PCB assemblies are known for their high mechanical strength & a reliable choice for many industries. If you require SMT assembly, surface mount PCB fabrication, or any kind of services, contact us at or call us on (760) 244-6149.

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