Commercial PCB

Every single day, designers face the challenges of coming up with more synchronised electrical devices using commercial PCB.

Besides, consumers are continually shifting to high tech and better-performing gadgets. At the heart of this innovation is the commercial PCB.

Are you a prospective investor in the field of commercial PCB?

Or are you seeking relevant information?

Whatever, your needs are, we’ve got everything you ask in this single guide.

These are just a few concepts you will learn: commercial PCB design, prototyping, assembly, sourcing and more.

You’ll only have to read till the end.

• What is a Commercial PCB?
• Types of Commercial PCB
• Classification of Commercial PCBs
• Applications of Commercial PCB
• Commercial PCB Design and Layout
• Step by Step PCB Design
• Prototyping Commercial PCB Step by Step Process
• Commercial PCB Assembly
• Sourcing for Commercial PCB

What is a Commercial PCB?

A commercially printed circuit board is essentially the kind of advanced PCBs that designers specially manufacture for commercial purposes or applications.

So it generally means that apart from commercial reasons the PCBs can as well be for general industrial uses.

Before we proceed further, what’s a PCB?

Commercial PCB

A Printed circuit board is a base for most of the primary connections in an electrical appliance. Naturally, it’s on this board that severally little electrical wiring connections get intertwined to connect mechanical components of the device.

Looking at the inner section of an electronic, you will notice plate-like chips usually coloured. Besides they have several small components firmly embedded on them. Now that’s the PCB. The PCBs serve a range of simple to complex vital functions in an electronic.

A glance at the PCB you notice different configurations they have, some tiny, thin, flexible, rigid, while others large.

Whatever, it is like, their purpose remains the same.

So which exactly are the types of the PCBs?

Types of Commercial PCB

The PCBs are available in several configurations such as:

• Rigid PCBs
• Flexible PCBs
• Rigid-Flex PCB

Importantly, the PCBs exist in the above distinct forms to be capable of providing particular special abilities to serve their purposes. However, the functions remain the same amongst the types of PCBs that is the interconnection of various electrical components.

Let’s focus on each now.

i.Rigid PCBs

Rigid PCB is a form of the PCB with a material majorly made of solid substrates. Now, this material is responsible for making the board firm, inflexible and untwistable.

Rigid PCB

It’s this property that gives the name ‘rigid.’

Rigid PCB is most common in electronics. A computer motherboard is a perfect example.

ii.Flexible PCBs

Unlike the rigid ones, a flex PCB is thin, flexible hence most of them are light in weight and small in size as well.

Flexible PCB

These excellent properties make flex PCBs increasingly adorable by most designers. Highly sophisticated devices constitute a significant source of the flex circuits. They include GPS trackers, satellites, etc.

iii.Rigid – Flex PCB

The Flex PCB and Rigid PCB can be both integrated into one board and serve a similar function. The combination of these two brings an excellent blend of the two separate properties of the two circuitry.  The result is the Rigid-Flex PCB.

Rigid flex PCB

Therefore, Rigid-Flex is both flexible and rigid evident from its structure.

Classification of Commercial PCBs

Aside from the types, we have discussed earlier on. It’s possible to yet classify the commercial PCBs into different designs and structures. Such forms are as follows.

1. Single sides commercial printed circuit boards
2. Double-sided commercially printed circuit boards
3. Multi-layer commercial printed circuits

Note that in this section and the following segments, we shall be discussing the PCBs as a single unit and not having a bias of any PCB.

We shall analyze each.

Single sided vs double sided PCB – Photo courtesy: Engineering Project

a)Single sided commercial PCB

This form of single sided PCB comprises one layer of conductive material on the dielectric film. Consequently, these individual units are adaptable for modest designs.

Having a single conduction side only means that you can only execute any function from one side.

By drilling or laser technique, non-plated holes exist on the film base.

b)Double sides commercial PCBs

This type has got dual conductive layers. Besides, for separation, the conductor materials have got an insulator in between them.

Because of the two sides, they have got plated through holes. The holes connect the two conducting sides.

This circuitry is beneficial since it makes designing interconnection easy.

c)Multi-layer commercial PCBs

This PCB type has more than three layers of conductor materials. Insulating materials occupy the spacing between each layer. Optionally, you will find PCBs which have got outer protective covering layers.

Multi layer PCB – Photo courtesy: The Engineering Project

The multilayer assembly involves merging both the single and double PCBs into a unit. Plated through holes fits onto the attached through holes.

As we earlier noted, every electronic component is crucial, and we can’t neglect any. Each part has a unique applicable area. The commercial PCBs aren’t an exception.

Next, we focus on the applications.

Applications of Commercial PCB

The rigid PCBs require little maintenance. Above all, they are suitable for use in industries that deals with mobility stress.

Meanwhile, the robust nature of the flex PCBs makes it accessible in sophisticated devices that require high flexibility.

However, these commercial PCBs serve in various similar sectors with the difference only evident on the use in the individual gadgets.

We shall look into that.

Some of these areas of application are:

Industrial automation

·Mechanical industry

PCBs do serve in some of the highly demanding power industries. The electronics in this sector do sustain the extreme working condition here.

The development of thicker copper PCBs has even simplified the work. These unique PCBs are found in the industrial machinery, measuring equipment and power machinery generating machinery.

·Health sector

The PCBs are vital when it comes to medical devices. Such PCBs aren’t like the others; in fact, they are High -Density Interconnect PCBs (HDI PCB) with exclusive structural designs such as a flexible base.

Some of the PCB applications are medical monitors, scanning tools, control systems, internal devices, and scientific instruments.

·Regular electronics

PCBs are also available in ordinary consumer electronics like smartphones, computers and even smartwatches. The PCBs in these electronics are of high volume but little cost.

So generally the consumer devices which make use of the PCBs are handset phones, computers,  recorders, home appliances, and entertainment gadgets.

·Automotive industry

Cars and other automobiles make use of various electronics. The electronic circuitry in these devices utilises PCBs. The difference is that such circuit boards are of high-frequency signals, especially for the relevant sensor and radar electronics components.

Some of the parts which incorporate PCBs include control systems, navigation tools, entertainment systems, and safety devices.

·Aerospace industry

The aerospace industry suffers from extreme pressure and stress due to vibrations. It’s because of this stress that most of the aerospace machinery such as the jets and rockets use flexible PCBs.

Besides, these PCBs have to be light and small in size. Above all, they’re of extreme accuracy.

Monitoring and testing equipment are the classes of electronics that benefits from PCBs.

·Lighting devices

The ever-preferred LED lighting owe their functions to the PCBs especially in the high-end output LED applications. With such integration, it’s easy to enhance the displays and indicators of the LED.

Some of the typical applications of the PCB LEDs in this sector are evident in the telecommunications lighting, automotive indicators, computer displays, and indicators.

Several methods and conditions preceeds the general PCB manufacturing process. All this care is necessary for ensuring that the final manufacturing step is free from errors and faults.

A vital pre-procedure is the PCB designing and layout.

So what do you need to consider when designing the commercial PCBs?

Keep reading for details about that.

Commercial PCB Design and Layout

The PCB design is one of the very critical concepts in designing an electronic and thus need to be carefully done.

Now basically the design always begins from the schematic designing. A schematic diagram is a complete framework that majorly comprises of the electrical components such as the integrated circuits (IC), footprints and wiring connections.

A schematic design is essentially a circuit diagram and thus must incorporate all the necessary footprints.

Once the schematic is completed and ready, then a PCB layout follows. To do this, specialists prefer to use CAD software.

The layout process is technical. It involves a careful analysis of the requirements of each component and placing them on the board.

PCB design and layout

The layout would then consist of the component footprints and the ratlines. The ratlines provide a guide for the creation of the traces, copper pours and the vias.

When the PCB layout is ready, one more procedure needs to follow before the actual manufacturing; that is the verification process.

The verification process is necessary for spotting issues and mistakes that require attention in the PCB layout.

The three common types of verification include;

• Connectivity – connectivity test verifies whether all the components have got a connection of the conducting material.
• Conduct a Consistency test between the schematic and layout. With the help of CAD software, it’s easier to identify any impending inconsistency.
• Design rule check. You have to ensure that your layout coincides with the intended minimum trace width, trace spacing, and drill diameter.

It’s thus evident that the PCB design and layout requires a host of knowledge, standards and techniques.

To make the designing work more straightforward, you need to follow a guideline.

Step by Step PCB Design

This procedure is one of the numerous ones available and covers some of the critical areas. We shall divide it into sections. Have a look.

I.The initial board constraints design

This section focusses on the overall checks on the boards including factors such as size, shape etc. the elements you need to consider here are:

• Choosing reference holes and points that match the manufacturing process. Note that these hole/ points should be without components and very open.
• Allocate enough board size for the circuitry that’s suitable for accommodating all the necessary components and tracks.
• Figure out the number of layers you require. However, proceed with caution, more layers increase costs. For intricate designs, you will surely use several tracks and sheets.
• Consider and determine the board mounting technique. Depending on the method, you should regulate the consumption of the board spacing.

 II.The layout of the PCB Design

This process includes the issues you need to consider before undertaking the actual design of the circuit.

It involves sketching an approximate plan of the actual location of the various components of the PCB.

III.Designing of the planes and layers of the PCB

You do the designing by taking into account the earth or the power rails.

• Determine if you would use an entire plane for power or earth or any other purpose.
• Eliminate any potential partial planes or significant gaps on the board. Such things may generate stress on the board thereby creating warping.

IV.Designing of the Tracks

• Establish an ideal width of the track you want to use in this way you will get to know the correct size for your tracks. However, they need not be too narrow or too broad.
• Deliberate on the track size especially for the current carrying ones. For a suitable size consult a manufacturer.
• Design the PCB pad according to the hole ratio and size. You can get this information with a PCB manufacturer.
• Ascertain the necessary pad shapes and sizes

V. Thermal properties

When dealing with high output modern  PCBs, thermal issues play a significant role in their functioning, unlike the small PCBs.

So, therefore, you need to leave adequate cooling space for heat generating components.

VI.Signal, RF and EMC factors.

Avoiding problems associated with the signals, RF and EMC require solving the routing issues of the tracks. To do this, you will have to.

• Avoid creating parallel running tracks. Such trucks often lead to a high degree of crosstalks which in turn leads to several electrical faults in the circuit.
• If the tracks have to cross then, it should be at perpendicular points. Crossing at the right angles reduces the crosstalks, capacitance and mutual inductance.

I am optimistic you have what it takes for PCB designing.

Next, we describe the prototyping procedure.

Prototyping Commercial PCB Step by Step Process

Before indulging in the prototyping process. Allow me to take you through the following.

A PCB prototype is a small copy of the intended PCB design used for testing the functionality of the board before advancing into the real manufacturing stage.

Commercial PCB prototype

Indeed, the prototype board brings several benefits among them:

• It enables you to test multiple designs before proceeding to use them.
• Prototypes allow you to detect and correct errors earlier enough before manufacturing. It thus saves you both financial and time resources.
• The prototypes simplify your upcoming production process
• Besides, you achieve an accurate portrait of your intended board.

Do you know the actual PCB prototyping process?

We dive into that.

We shall summarise the process to eliminate complexity.

1.Designing the prototype

Designing is the initial stage. To help with this process, you can use design softwares such as OrCAD, Altium Designer, KiCad, etc. remember to specify the software vividly.

2.Schematic designing

Work with a designer to come up with a schematic diagram. Afterwards, to ascertain its accuracy, it’s advisable you run it through a series of tests and verifications.

Once, you correct the defects; then you can proceed to transform it into a netlist.

3.Develop a bill of materials

A BOM is a comprehensive document which describes all the necessary information about the components, assemblies, and materials that you will require for manufacturing. The manufacturers require this list too.

BOM

Some of the information in the BOM you require when sourcing for components include the quantity of the elements, identification codes of the parts, and technical specifications of each unit among others.

4.Designing the routing

Routing is critical since it gives a path for the connection of every PCB element. You could do routing easily by using traces.

Importantly, with good software, use the netlist you earlier on created to plan for the routing.

5.Performing checks

Throughout the process, check for irregularities and correct them before the production stage.

Some checks to do are thermal related checks, design rule check (DRC), layout versus schematic (LVS) check, electrical rule check (ERC) and antenna check.

When certified, you move into fabrication.

6.Developing a photo film

With the ready designs, the manufacturers can now make a photo film of the PCB. The Plotter printer is useful for creating such a picture.

7.Printing the interior layers

Now for this procedure, you need to apply copper material to the substrate material of the PCB.

8.Align the layers of multi-layer PCBs

Precisely align the several layers and punch a registration hole onto them. Punch a hole before combining them.

9.Fuse the multilayers

At this particular stage, we now fuse the outer layers otherwise called prepreg and the first substrate layer covered by copper foil.

You can fuse them by applying a two tied procedure, i.e. Layer-up followed by bonding.

10.Drill the holes

Now drill holes into the stack. You could use an X-ray locater together with a computer control drill.

11.Copper plating the PCB panel

This process involves introducing a thin layer of copper to cover the board. Don’t spare the inner walls of the holes.

12.Imaging the outer layer

Using a similar process to the earlier one but with a photoresist layer, image the outer layers. The result is a transposition of the inner layers.

13.Copper and tin plating

Perform copper plating followed by tin plating on the board.

14.Etching

Use a chemical solution to remove excess copper on the surface. The tin, however, would make the conductive copper intact. The result is a conductive connection.

15.Solder masking

Clean the board and apply solder mask preferably epoxy. Then do the post-masking process.

16.Surface finishing

Here apply extra plating, followed by gold and silver. To get homogenous pads to use a hot air pad. Consequently, you have a surface finish.

Of course, you can also attach silkscreen on the surface of the PCB.

17.Cutting

After guaranteeing the functioning of the board, cut distinct boards from the large panel. Use either a v-groove or a router.

After this, you can:

• Avail all the components you need for the preparation of the PCBA prototype stage.
• Solder paste stenciling – Stencilling ensures that the solder applicator applies the paste to the specified locations of the components in the final PCB.
• At this point use a pick and place machine, for putting SMDs on the PCB.
• Perform another reflow soldering to cool down the solder paste which in turn attaches the SMDs to the board.
• Conduct an inspection and quality check, e.g., physical Checks, optical monitoring and x-ray monitoring
• Introduce through-hole components.
• Undertake a functionality test – this test is the final step for the prototype, and it involves simulations of the PCB aims at simulations.

There you have it. A complete functional PCB prototype ready for implementation in the fabrication of your PCB.

With the commercial PCB Prototype, we can now move to the commercial PCB assembly.

Commercial PCB Assembly

Before kickstarting the PCB assembly, several pre-assembly measures play an essential role. Such kind of actions includes a DFM check.

Figure 11 Commercial PCB assembly

The check takes a close look at the details of the design together with a close analysis of the design precision.

So the test is vital in the identification of potential errors and irregularities.

If you’re confident of the precision of the board, then you can proceed into the fabrication stage.

Step 1: Prepare the circuit board

This initial procedure involves several practices that you do to make the board for the actual assembly.

These measures are: selecting both appropriate board and panel size. Finally, drying the sheet of any moisture.

Step 2: Solder paste stencilling

At this point, you apply solder paste using a printing machine onto the board. After that, with the help of a stencil, now apply the paste onto distinct locations on the board.

Step 3. Placing parts on the board

You will require a pick and place machine (PNP) to help with fixing the components onto pre-programmed locations the board.

However, there’re two methods of doing the placing i.e. Surface mount technology and Through Hole Technology.

Through hole technology

Surface mount technology (SMT) – this technique involves the use of an automated machine. The device through its rotating component reels picks the parts such as ICs and mounts them on the pads of the board surface.

Then the solder paste attaches them firmly.

Through-Hole Technology (THT) – This method is for use with through-hole parts such as protruding wires or leads. These parts would get mounted on the boards by plugging through holes on the circuits. THT is suitable for capacitors and coils.

Step 4: Reflow soldering

This stage is suitable for use with surface mount technology.

At this stage, you pass the boards through a reflow oven. In the oven, the high heat melts the solder.

After that, the board passes through a system of coolers where the solder solidifies and firmly attaching the components.

Step 5: Cleaning

Use a fiber brush to remove any unwanted materials on the board surface.

Step 6: Inspection and testing

Since PCBA is a technical process, it’s, therefore, error-prone. To eliminate potential mistakes, you have use inspection methods. Some of them include:

• Automated optical inspection – Automated Optical Inspection machine is suitable for this method; it uses a system of cameras that scan the board for any potential errors.
• X-Ray inspection
• Visual Inspection

Apart from the inspection methods, you could use testing mechanisms. These tests help in assessing the functionality of the board. Such tests are:

Electrical tests to determine the rate of the functionality of the PCBs

Testing is the final step in PCBA. Just like in the prototype process, it’s vital to regularly do inspections and checks throughout assembly.

Apart from the above assembly technology, you could also opt for using some other two assembling techniques, i.e.

• Surface Mount Assembly (SMT)
• Mixed PCB Assembly

Let’s have a look at both.

·SMT Assembly

Surface mount process is very efficient. Besides, its procedures are entirely automatic from the initial stage to the last.

Briefly, these are the steps involved:

• Solder paste printing

With the use of a solder, paster printer applies solder paste on the board surface. The stencil is a plus for accuracy.

• Components mounting

Here, the conveyor sends the board to the PNP machine which in turn picks the elements and places them accurately on the board.

• Reflow soldering

Just after mounting, pass the board through an oven. The high temperature melts the solder paste. Later on, the board passes through a cooling chamber where it solidifies making the surface mount devices become firmly attached on the board.

·Mixed technology PCB Assembly

So far we have discussed the SMT and THT technology for mounting devices.

However, some components aren’t available through SMT technique, e.g., special connectors and capacitors.

Consequently, some assemblies combine the two techniques on the same PCB.

Through hole assembly process

Below is a brief overview of the necessary steps involved.

1. Solder the sides that would receive the SMDs.
2. Pass the preceding sides through a PNP machine, then subsequently pass it via reflow solder.
3. Glue the solder side SMDs in place on the non-soldered sides of the PCB.
4. Insert the other Through Hole devices into the holes of the PCB using a machine.
5. Also, install hand devices on the PCB
6. Now solder all the sets of the installed components.
7. Install other parts that need hand soldering.
8. Finally, test the PCB.

Now, I am very sure you have all the information about the commercial PCB assembly.

Having known that, one ultimate question remains unanswered.

How do you find the commercial PCBs.?

For a detailed guide on sourcing for commercial PCBs, keep on reading.

Sourcing for Commercial PCB

Getting to develop reliable supply for your PCBs is a noble task that plays a significant role in your company or business.

Several aspects would determine your success rate in acquiring your much desired proper commercial PCB sourcing.

But what does it take?

Commercial PCB assembly

Below we discuss issues you should consider when sourcing for commercial PCBs.

a)Consider your budget

Finance is quite sensitive in all organizations; yours not excluded. Various PCB manufacturers would serve you with different quotations.

You, therefore, need to pick on the reasonable one according to your costs. However, you need not shy away from high prices because they could be for high quality purposes.

b)Determine the type of your products, i.e. Common types or high-tech brand

Without doubt, the kind of PCBs you venture into would lead you to a corresponding suitable fabricator.

In case you’re dealing with the conventional type, then go ahead and partner with the highly productive manufacturer in terms of volume and short lead time.

For high tech products, consider the manufacturer capabilities and product quality.

c)Lead time

Before anything, set your priorities right. Decide on your level of flexibility and deadlines.

Why?

Lead time would influence your ability to deliver your products promptly to the market thereby serving your consumers.

Therefore, you have to partner with a PCB manufacturer that serves you in time within your limits.

Your returns depend on it.

d)Verify the scope and capabilities of your prospective manufacturer partner

Focus on a range of issues such as the physical aspects of the PCBs, e.g. width etc.

Besides, you could certify the credentials of the manufacturer.

Ask for quality certifications and standards including ISO9001, RoHS, IPC quality grade, UL. Etc. These standards confirm the ability of the manufacturer to undertake any PCB related process.

e)The manufacturer’s volume output

In terms of volume, we can generally classify the manufacturers into three groups, i.e. Low capacity, mid-capacity, and mass capacity.

Each fabricator is capable of producing on a different scale compared to others. Get to know what the type of your manufacturer on that scale.

Then select the one that best suits your volume requirements.

f)Consider the location of the manufacturer

One major factor that most people assume is the location. Try and see how close you are to intended partner. Distance contributes a lot.

Even if you’re far away from each other, is the manufacturer capable of serving you in time with the products?

Thus you need to consider a fabricator who is easily accessible.

g)Assess the credibility of the manufacturer

Reliability is a decisive factor in partnership. You don’t want to partner with a company that doesn’t honor the contract but continually breaches it.

To ascertain credibility try reaching out to friends and get their opinions about the fabricator. Furthermore, look for any testimonials or ratings of the manufacturer before engaging them.

h)Does the manufacturer provide after sale service?

Looking at after sale service, it seems pretty negligible yet very critical.

How do you want your components and commercial PCBs packed? Is the company able to do that? What about the shipping costs and discounts? Tax clearance? Product warranty?

Pick on one with suitable services because that could enable you to cut down on unnecessary expenses.

i)Does the manufacturer have got a competitive support team

More often, emergencies do occur.

In case of such situations are you able to get support team on time?

What about the communication between you and the partner?

Do they have a competitive communication system and customer care agents?

When it comes to communications, you don’t take risks. Consistent and timely contacts save a lot.

Hopefully, those concerns cover all that it takes for sourcing commercial PCBs.

Conclusion

I trust that you do have all the information you seek about the commercial PCBs. From the design, layout, prototype assembly to sourcing of the PCBs you have read a lot but very essential information.

Please note that the designing and assembling of the PCB requires equally both knowledge and experience.

Furthermore, sourcing of the PCBs could be tiresome, but when you engage internationally recognised experts, then you’re better off. Many counterfeits exist in the global market.

Above all, I am optimistic you have all the information to deal with commercial PCBs.

Good luck!