Top 6 PCB assembly myths you must know to meet high-quality standards!

By Mer-Mar Electronics | Date posted: | Last updated: September 26, 2022
PCB Assembly myths

Knowledge, as they say, is power. However, this knowledge must be well-founded. There are several myths that also do the rounds, and which are followed without attention can lead to devastating consequences. When these myths have to do with PCB Assembly, one must be quite careful. A well-assembled PCB can make or break your product. Let us look at the top 6 PCB Assembly myths as also debunk them!

PCB Assembly Myths

If these myths are not debunked there is a big chance of costly PCB fabrication errors, production of defective boards & more. So here goes:

#1 Myth: It is all right to place components anywhere on the board

The fact, however, is that components such as resistors, LEDs, transistors, diodes, inductors, capacitors need to be placed at specific locations as per the requisite specifications. Failure to follow these specifications can lead to a whole lot of issues on the board, compromising its functionality.

#2 Myth: Via in pad can damage assembly

Many manufacturers believe in this myth & do not use via in pads on their boards. In doing this they miss several advantages that via in pads offer, namely that they reduce inductance, increase density, and employ finer pitch array packages. It is however important that via in pads are assembled correctly. For example, you need to ensure that plating chemicals do not get trapped while making via in pads. An experienced contract manufacturer will be able to ensure that he is able to reap the advantages offered by via in pads.

#3 Myth: Both prototypes & actual production runs follow the same layout

The fact is that typically for a prototype a through-hole manufacturing process is preferred as quantities are limited and the soldering process easy. When it comes to the actual production, often surface-mount technology is used since it offers a wide range of advantages including but not limited to:

  • Improved flexibility, reliability & performance.
  • Improved component density that works well with miniaturization.
  • It lends itself to the creation of smaller & lighter boards.
  • Takes away the need of drilling of holes.
  • It lends itself to automation.
  • Offers ease of assembly.

#4. Myth: Trace widths cannot be less than 3 mils

While this may have been a fact in the early days of PCB manufacturing, it is not true anymore. With advancements in PCB Assembly, it is entirely possible to go with trace widths smaller than 3 mils.

#5. Myth: The right current delivery is not crucial

The fact however is that to ensure the performance of the board, right current delivery is extremely crucial. Some parts require more power than others & this aspect needs to be considered during the early assembly stages.

#6. Myth: A beautiful design is everything

A beautiful design can have PCB designers quite excited. After all, if you can have any track width, spacing and more, it does offer you a certain freedom. The fact, however, remains that the design needs to consider a host of real-world limitations, especially those to do with PCB Assembly. The design must lend itself to ease of assembly as otherwise it can lead to real world issues that can have an implication for functionality as well as for the cost.

To sum up

While it is important to be aware of the facts to do with PCB assembly so that proper quality standards can be maintained, it is equally important to go with a PCB assembly partner who is equipped with industry best practices and who does not need to waste a lot of time for no reason.

It is best to go with a partner who can not only help you with your prototype but who is also well-equipped to handle high-volume runs. Mer-Mar Electronics also provides high-volume PCB assembly and other PCB services like PCB fabrication, PCB designing, and prototyping services. Just fill out the form to get a quick PCB quote now.

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Top things you should consider while preparing wire harness assembly design!

By Mer-Mar Electronics | Date posted: | Last updated: August 6, 2022
Wire harness design

Wire harnesses refer to wires that are bundled together to suit specific applications. They come in a wide range of complexities from individual wires to a complex harness that comprises of hundreds of individual wires. The good thing about wire harnesses is that they can be highly customized to transmit power as well as data. Additionally in terms of location they can conform to a wide variety of space constraints. Some of the aspects that need to be considered when it comes to wire harness design so that it functions safely and as per specifications include:

  • Environmental considerations
  • Power Demand
  • Lengths

Taking these details into account at the design stage means that costly errors can be avoided later & that the results are more effective. Let us look at some of the aspects that you need to consider while manufacturing a wire harness.

Wire harness design: Things to keep in mind

Environmental considerations

It is imperative to consider the demands of the environment in which the harness must function. Some of the environmental hazards that cable harness assembly must face include:

  • Extremes of temperature
  • Exposure to water
  • Exposure to chemicals
  • Exposure to vibration leading to abrasion

It is important, therefore, to choose the right wire depending on the environmental factors. The wrong choice of wire can lead to issues including but not limited to breakdown of insulation, safety issues, compliance failures, costly accidents, and more.

Parts Considerations

It is extremely important that when you share the list of parts with a contract manufacturer, you make sure that the partner can cross reference these parts to a manufacturer. In case your requirements do not pertain to a specific manufacturer or brand, a mention of “or equivalent” can go a long way for the contract manufacturer to be able to substitute the parts in a way it optimizes quality as well as costs.

In case there are internal specifications for production, you need to make sure that the same is shared with the partner so that the harness meets your bespoke specifications.

1. Lengths and Tolerances

You need to know the exact dimensions as well as the acceptable tolerances for the lengths.

2. Covering

Some of the covers available include:

  • Braided Loom
  • Split Sleeve
  • Conduit
  • Tape

Each of them has their own distinct set of advantages. Understanding them in detail will ensure that you are able to determine which one will work best for your bespoke application. In choosing the covering (or not), ensure that you keep the following aspects in mind:

  • Flexibility
  • Serviceability
  • Troubleshooting, and more.

3. Splicing and splice locations

Do remember to review the kind of splicing you need before you reach out to the wire harness manufacturer.

4. Wire color and labeling

To help identify circuit names, wire colors as well as any text that you want printed is to be determined early.

5. Type

Ensure that you choose the type of wire with care. Wire that is used for automotives, for example, is quite different from those used in electrical control panels. Some of the aspects to keep in mind include:

  • Voltage Ratings
  • Insulation Material
  • Bare or plated copper, and more.

6. Terminals, seals, and connectors

There are a wide variety of terminals in wire harness, seals as well as connectors. In fact, connectors cater to several types of terminals and seals. Additionally, some connectors require additional accessories. It is important therefore to identify such accessories in advance.

7. Labeling

In case you need certain connectors to be labeled, it is imperative that a note be placed on your drawing that informs the contract manufacturer of your requirements.

8. Testing

Depending on your bespoke requirements & where the harness needs to be used, you may have specific testing requirements. In some cases, a continuity test may be in order while in others a high voltage test may be imperative.

Work closely with the PCB contract manufacturer

It is important to recognize that a drawing can seldom be perfect. There could be occasions where in your bid to offer too many details on the drawings you have rendered it extremely cluttered. On the other hand, in a bid to avoid clutter, you could end up giving information that is too unsure for the contract manufacturer. It is therefore advisable to work closely with the contract manufacturer to ensure that you give the right level of details as well as choose a convenient way to handle any deviations and/or revisions.

Choice of the right PCB contract manufacturer can go a long way in ensuring that the process is streamlined & your wire harness is created to meet your exact specifications.

When it comes to the right PCB manufacturer you can consider Mer-Mar Electronics which provides cable harnessing assembly service without any hassle. We specialize in assembling simple wire cable harness assemblies through to complex custom-build cable and wire harnesses using combinations of single-core or multicore cables.

Get a quote to know more details.

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The PCB Components Assembly Process – A Complete Guide!

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

When it comes to the assembly process of PCB components, there are both automated as well as manual steps involved depending on the complexity of the board. Of course, the assembly process also has a lot to do with the fact whether the assembly is being done for through-hole components, surface mount components or whether they are mixed PCB components.


Typically, these are components with long leads and are a generation behind surface mount components. These components involve that leads be inserted into holes and then soldering them. Typically such components are only mounted on the top end of the board.


While designing PCBs with through-hole components, it is important to place the holes at distances that are specified by the component manufacturer. When dealing with multi layered printed circuit boards What is also important are plated through-holes. These holes also act as vias for connecting circuits on the outer layers.

For such boards since drilling of holes is a key requirement, the area that is available for routing of traces is limited. That typically means that you have to use a board with a large area that may not be conducive to the trend of miniaturization that is prevalent. Alternately, you can use a board with multiple layers.


Whether you choose to use manual or automated component mounting, it is important that the component leads are pre-processed so that insertion becomes seamless.


Largely, through hole components are soldered by a process of wave soldering. The machine throws up molten solder through a nozzle. As the components assembly passes over this wave, the components are soldered in place.


For such components, the exercise of drilling need not be undertaken. In fact these are smaller components that can be packed together and they work particularly well in dense assemblies. Also surface mount components can be mounted on both sides of the board.


Since space does not need to be allocated for the holes, a high component density is a given. High density is also achieved by using small vias or tented vias in pads when it comes to fine pitch components such as BGAs (Ball Grid Array packages).


The use of a stencil to deposit solder pads at the right areas is important. Solder paste deposition may be manual or automated.


Typically pick-and-place machines are used to mount small components. This ensures that each component is mounted in the right location with solder paste on the pads.


Since solder paste is already present all that is required is to melt the solder so that the component is held in place. For this purpose, a reflow soldering machine comes in handy. It has infrared heaters that generate heat that melts the solder paste & fixes the components.


Some applications make use of a mixed technology & hence use both surface mount as well as through-hole components.


In such cases the surface mount components are typically placed on the underside of the board. This is advantageous as the wave soldering process ensures that they are soldered along with the through-hole components.


For the surface mount components it is important to use a glue deposition process. Essentially a dispenser places glue between the pads. The pick-and-place machine next mounts the surface mount components. Pro tip – It is important for the board to go through a curing process so that the glues is sufficiently hardened & the component is held in place.


It is now safe to turn over the board & insert the through-hole components. After this follows the wave soldering process.

To sum up

While PCB assembly of through-hole components seems simpler, the fact remains that there could be opportunities for failure. For example, if component leads are close there are chances of shorts. Also, a big disadvantage with through-hole components is that they do not lend themselves to high density assembly.

Surface mount components on the other hand can take care of many of these issues. The components can be packed densely. Also, with the reflow soldering process the quality of soldering is far higher.

Mer-Mar Electronics is one of the leading PCB manufacturing companies, providing all-in-one PCB assembly solutions. Our consistent quality & quick turnaround endear itself to our customers, who look on us as a one-stop shop for all PCB manufacturing requirements.

If you have any queries regarding our surface mount assembly or through-hole PCB assembly services, or need urgent assistance, then please do not hesitate to contact our team of skilled personnel. Send us an email with your queries at or call us at (760) 244-6149.

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What makes flex circuit assembly stand out from the competition?

By Mer-Mar Electronics | Date posted: | Last updated: October 17, 2022
Flex Circuit Assembly

While for the most part we are used to circuit boards in their traditional formats, the growth of ergonomic product designs, as well as the evolution of wearable tech, necessitates a different kind of circuit board. You sure need boards to fit in miniature spaces as also for them to be resistant to vibration, mechanical wear and tear, and more.

All of these objectives can be achieved with a flexible circuit board. While earlier assembling flex circuits was prohibitively expensive both in terms of material and man-hours, flex assembly costs have been dropping, making it convenient to use them in everyday products.

Some of the many benefits that flex circuit board offer, include:

Ability to take different shapes

This of course is the most obvious advantage, as such boards can be bent and folded. It also allows components to be placed in optimal positions within the product. Essentially it lends itself to miniaturization of products, which is a growing trend.

Weight Reduction

Space, Weight and Packaging remain important issues when it comes to PCB design. With flexible circuits bulky wire and solder connections can be avoided. In turn, this leads to a significant reduction in weight and space and also in packaging size.

Reduced assembly costs

With bulky wire and cables being significantly reduced in flex circuits what is also reduced is the cost of wire as also the labor cost.

Helps with dynamic flexing

Flexible circuits can withstand flexing. Examples of this include disk drives, laptop hinges and more

Thermal management

Flexible circuits are frequently seen in high power, high frequency designs as polyimide materials can withstand high heat applications. Laos thin polyimide dissipates heat quickly.

Great for aesthetics

Flexible circuits work well in terms of product aesthetics, which is major draw for consumers. It lends itself to sleekness and rates high on consumer confidence.


Polyimide materials are known for their bio-compatibility and hence find high application in medical as well as wearable applications.

High on Reliability

As opposed to a rigid board, a flex board can simplify the system design by reducing the number of interconnections required. This also takes away the possibility of human error and increases reliability.

Aspects to be kept in mind when it comes to flex circuit assembly, some of these include:


As opposed to rigid PCBs that can work with standardized dimensions and conveyor belt-style processes, flex circuits may need to be assessed individually. Some of the areas to pay importance to, include:

  • The pallet needs to fit its unique shape
  • The pallet needs to accommodate both the top and bottom circuit configuration
  • The flexible circuit assembly needs to lay flat on the pallet otherwise an air cushion beneath the circuit can cause mechanical resistance during solder paste screening as well as pick-and place. The air cushion also can cause components to bounce off the PCB assembly.
  • It requires special tooling and backup fixtures for unique designs
  • The pallet geometry needs to be customized so that the circuit remains flat.
  • Also with pick-and-place machines working at high speed and small margin of error, there can be issues if there is any difference between circuit dimensions and actual flex circuit geometry.

Heat Sensitivity

The other issue that needs due importance is that of heat sensitivity. Essentially, flex circuits are far thinner than rigid boards. On account of this, the heat that is applied in soldering cannot be dissipated. What is important is also that there should be precise soldering tools as well as extremely experienced technicians. It is only with the investment in the state-of-the-art tools as well as trained technicians that productivity can be improved.


Flex circuits require appropriate backing during the testing process. For example, in case of Flying Probe testing, there needs to be a special custom fixture to offer support to the PCBA. In case of in-circuit testing, a rigid backing is designed into the clamshell fixture.

With flex circuits increasingly solving the constraints, their use is likely to become even more ubiquitous.

Mer-Mar Electronics is one of the leading PCB assembly manufacturers, providing all in one PCB assembly and fabrication solutions. Whether you are looking for flexible PCBs, flexible PCBs fabrication or flexible circuit board assembly, we have you covered. Send us an email with your queries at or call us at (760) 244-6149 related to our flexible PCB manufacturing and assembly.

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