FR4 PCB | PCB & MCPCB - Best Technology

Archive for the ‘FR4 PCB’ Category

How to choose surface finish on Printed Circuit Board？

Saturday, December 17th, 2022

When finish the PCB design, we should choose a suitable surface finish to protect traces from corrosion. Nowadays, the most popular surface treatments for PCB manufacturer to use are HASL/LF HASL, OSP and ENIG.

Different surface treatment has its unique functionality and the cost also is different. This article we will show you the pros and cons of the three surface finishing which use while the PCB manufacturing process.

HASL Surface Finish

HASL (Hot Air Solder Level) can be known as tin-lead HASL and lead-free HASL, it was the mainstream surface treatment technology in the 1980s, but with the increased of “small and high density” demands in PCB, there are less and less circuit boards use the HASL technology because it will cause the defective products due to the solder point are easy to leave on the board surface during SMT process. In view of this situation, some PCB board manufacturers or designers prefer use OSP or immersion gold to ensure the good quality products as well as smooth production process.

Tin-lead HASL

Advantages:

1） Economical and widely available.

2） Excellent solderability.

3）Better mechanical strength & lustrousness than lead-free HSAL.

Disadvantages: it is harmful to environment and violates RoHS compliance.

Lead-free HASL

Advantages: low cost, good solder performance and environmental.

Disadvantages: mechanical strength & lustrousness are not good than lead HASL.

In additional, due to the poor surface flatness of HASL circuit boards, neither leaded nor lead-free HASL is not suitable for soldering fine-pitch components or plated through-holes, because it will cause the short circuits and poor welding during the assembly process.

OSP

OSP (Organic Solderability Preservatives) also named as pre flux, the working principle is to generate a layer of organic film chemically on the copper surface to protect the surface from oxidation or vulcanization in the room environment. Meanwhile, OSP also can increase the oxidation resistance, heat shock resistance and moisture resistance of a PCB.

OSP is equivalent to an anti-oxidation treatment, the protective thin film can be easily removed by the flux quickly under the high soldering temperature, then it makes the exposed copper surface immediately combined with the molten solder in a very short time to become a solid solder spot.

At present, the usage of OSP surface finishing process has increased significantly because it is appropriated for both low and high-end products. If your application has no surface connection functional requirements or storage life limitations, the OSP process is the most desirable surface treatment process.

Advantage:

1）With all the advantages of bare copper soldering, expired (more than 3 months) boards can also be resurfaced, but one time is better.

2）Good for fine-pitch, BGA and smaller components.

3）Low cost and easy to rework.

4）Simple process and easy to ensure quality.

Disadvantage:

1）OSP is easily affected by acid and humidity, so must be packed with vacuum.

2）Need to do surface treatment again if storage time more than 3 months.

3）It should be used within 24 hours after unpacking.

4）OSP is an insulating layer, so the test point must be printed with solder paste to remove the original OSP layer for electrical testing.

ENIG

ENIG (Electroless Nickel/Immersion Gold) is one of a chemical nickel gold deposition method, the working principle is to generate a layer of coating by chemical REDOX reaction to get a thicker gold layer. Currently, ENIG is mainly used in the surface of the circuit board with connection functional requirements and long storage life.

Advantage:

1）Can be stored long time as well as no oxidation.

2）Good flatness surface and suitable for small solder point components.

3）Good solderability.

4）Can be used as the base material for COB wire bonding.

Disadvantage:

1）High cost than other two surface treatments.

2）Easy to exist black-pad issue during production process.

As we can know from above information, each PCB surface treatment has its own merit and demerit, you can choose the one according to the effect you want to reach, as well as your cost.

If you don’t know which is best for you, you can send inquiry to us, our professional engineering team and PCB sales will choose the suitable one for you. Welcome to contact us if you have any other questions.

What is RF PCB board?

Tuesday, November 23rd, 2021

You may have ever heard of RF PCB, but do you know What it is and What are the characteristics of these kinds PCB?

Today let us make a simple introduction for it.

RF PCB, means radio frequency PCB. People also called these PCB High frequency PCB, it is for the PCB with a higher electromagnetic frequency, and it is used on the products field with high frequency. (Frequency greater than 300MHZ or wavelength less than 1 meter) and microwave (frequency greater than 3GHZ or wavelength less than 0.1 meter). It is made by microwave substrate with common PCB manufacturing process or with some special way to make.

High-frequency boards have very high requirements for various physical properties, accuracy, and technical parameters, and are often used in communication systems, automobile anti-collision systems, satellite systems, radio systems and other fields.

How can we know which PCB materials are suitable for making the RF boards?

When evaluating the high-frequency characteristics of a substrate material, the key to its investigation is the change in its DF value (Dissipation Factor).

For substrate materials with high-speed and high-frequency characteristics, in terms of changing characteristics at high frequencies, there are two distinct types of general substrate materials: one is that with the change of frequency, its (DF) value changes very little. There is another type that is similar to the general substrate material in the range of change, but its own (DF) value is lower.

The common epoxy resin-glass fiber cloth-based materials (FR4), the DK value at the frequency of 1MHz is 4.7 and the change of the DK value at the frequency of 1GHz is 4.19. Above 1GHz, the change trend of its DK value is gentle. The change trend is that as the frequency increases, it becomes smaller (but the change is not large). For example, at 10GHz, the DK value of FR-4 is generally 4.15. The substrate material with high-speed and high-frequency characteristics changes in frequency. When the DK value changes slightly, the DK value keeps changing in the range of 0.02 when the frequency changes from 1MHz to 1GHz. Its DK value tends to decrease slightly under different frequency conditions from low to high.

On the other hand, the thermal expansion coefficient of the high-frequency circuit board substrate and the copper foil must be the same. If they are inconsistent, it will cause the copper foil to separate during the cold and hot changes. Secondly, in a humid environment, the water absorption rate must be low, and high water absorption rate will cause dielectric constant and dielectric loss when wet. In general, the heat resistance, chemical resistance, impact resistance, and peel resistance of the high-frequency sheet must be good.

The following are several commonly used high-frequency and high-speed PCB boards we have summarized:

Rogers: RO4003, RO3003, RO4350, RO5880, etc.

TUC: Tuc862, 872SLK, 883, 933, etc.

Panasonic: Megtron4, Megtron6, etc.

Isola: FR408HR, IS620, IS680, etc.

Nelco: N4000-13, N4000-13EPSI, etc.

Other materials like Arlon, Teflon, Taconic are also good for the manufacturing of RF PCB boards.

If you have any question for RF pcb, welcome to send your request and question to discuss more.

A Brief introduction for different layers on Multilayer PCB

Friday, October 29th, 2021

When it comes to multilayer PCB, we know the multilayer PCB are consisted by many different layers. Do you know what’s the purpose for these layers?

Here I would like to give you a brief introduction for the functions of each layer on a Multilayer PCB design.

Mechanical layer: There may be one or several mechanical layers in a PCB depending on the design. There should be at least one mechanical layer as it shows the physical dimensions of the board. Generally, it used GM1, GM2 to name the file on the Gerber.

Solder paste layer: This is a material applied onto the PCB layers where components are mounted, mostly through soldering. It helps with the bonding of the solder with the component pin and improves the solder flow. PCB Assembly supplier will make stencil according to the solder paste layer on the Gerber.

Generally, it used GPS, GBS to name the file on the Gerber.

Solder mask layer: This layer is a mask or a protective coating applied onto the board to prevent damage and contamination. It is typically green in color; however, you can also choose other colors such as blue, black, white depending upon your requirements. Generally, it used GBS, GTS to name the file on the Gerber.

Ground planes and power planes: These are layers for copper, the ground and the power planes are connected to an onboard voltage point. Generally, it used GND, PWR to name the file on the Gerber.

Split planes: This is a modified version of power and ground planes; they are split in a manner that they can be connected to multiple voltage points or potentials.

Keep out layer: This layer is crucial as it defines the working boundary and keeps it separate from the outer mechanical layer. Generally, it used GKO to name the file on the Gerber.

Silkscreen layer: This is typically the text displayed on the boards through which you can identify components with their names. It is typically white in color when solder mask color is green, black, blue and red. But you can also choose other colors such depending upon your requirements. Generally it used GTO, GBO to name the file on the Gerber.

Routing layer: These layers help to interconnect the components. They can also be present on the top and bottom layers of the board.

Drilling Layer: This is the layer to show the drilling information of the PCB. Usually, it names DRL on the Gerber.

Once we understand the purpose of each layer for PCB, then understanding the construction of PCB becomes easy, no matter how complicated the board structure.

With over 15 years of PCB manufacturing experience, BEST Technology can meet different requests from customers no matter it is prototype or high-volume PCB.

Send us your request, let us to make the high-quality printed circuit boards for you.

Why most of PCB boards are green?

Tuesday, August 24th, 2021

You may have found such a situation, most of the PCB boards are with green colors, while other colors are relatively rare to see, do you know why?

As we know that the Printed Circuits Board consists of Solder Mask Layer, Silk screen layer, solder PAD, Copper traces, surface finishing and other parts, etc.

Among them, the solder mask refers to the part of the PCB that is covered by oil. Since most PCB boards use green oil, the part of the green oil that can be seen on the board surface is the solder mask, which play an important role during the reflow soldering process.

Then why are most of the PCB boards green? The main reasons are as follows:

Green is less irritating to the eyes. We all know that green is good for the eyes and can resists fatigue. So when the PCB board with green solder mask, relative production and maintenance personnel are not prone to eye fatigue when staring at the PCB board for a long time, and it is less harmful to the eyes.

2. Cost for Green oil is lower. Since green is the mainstream in the production process, the purchase of natural green oil will be larger, and the purchase cost of green solder mask will be lower than other colors. At the same time, using the same color oil in mass production can also reduce the replacement cost.

When the board works on the SMT soldering process, it needs to go through the process from Tinning, post soldering and final AOI inspection. These processes all need to be optically positioned and calibrated. The green background color is better for the recognition of the instrument.

Okay, now, do you understand why most of PCB boards are with green colors?

Though we know green is the most common one, but other colors such as red, yellow, blue, purple, black or some other colors are okay for us to make.

If you have PCB board with a special color want to make, please contact us and we will try best effort to meet your request.

What kind of test for Coil Printed Circuit Board?

Wednesday, August 11th, 2021

In year 2019, one of our US customers asked us, Marina can Best Technology make a Coil PCB (Printed Circuit Board) with FR4 material? Yes, of course, we can make different kinds of PCB for our customer, included for the Coils PCB, which currently is widely used for wireless charging and antenna products. Please see the following Coils board from Best Technology.

The manufacturing process is same as other PCB manufacturing process, and just make sure the etching process and pay attention for the etching tolerance of the coils trace. And when coils PCB board finished, do you know what kind of test need to do to check the functional of Coils boards?

Today I would like to share how Best Technology test Coil PCB board. Everyone knows that we check the quality of PCB board with Flying probe tester,Â as the production efficiency is extremely low and the inductance and capacitance cannot be accurately measured. In this way, we need to use LCR meter to make verify the inductance and capacitance. See the LCT meter as following.

Best Technology chooses the digital meter LCR Meter to test the impedance characteristics of the coil. From the LCR tester you know see two numbers, one for inductance and another for resistance.

After test each coils printed circuit board, we will make record at our paper to make sure every measurement data will meet for customer requirement.

Currently, LCR Meter only provides a single-channel test function, and can only test the impedance characteristics of a set of coils at a time. But this is the effective test method for Coil printed Circuit Board. But we believe we will buy more LCR meters to let the test coil board become quicker.

If you have any comments on the testing for Coil printed circuit board, you are welcome to send us query and we are happy to discuss with you. You can visit www.bestpcbs.com to know more about us. Thank you

The way to add the mouse bite on the PCB Panel #Bestpcb

Saturday, July 31st, 2021

#Bestpcb #Best PCB

Maybe youâ€™ve ever been recommended by your PCB manufacturer to add a mouse bite on the PCB edgeï¼Ÿ

But, whatâ€™s mouse bites? Is it something about the Rat?

Of course not, it is kind of connection way for PCB Panel.

As you know, usually the Printed Circuits Boards are manufactured on a standard sized panel, and sometime, the panel will with sharp edges, and those sharp edges are often referred to as “mouse bites” and they are left over after depanelization.

mouse bite PCB depanelization Best Technology

Mouse Bites usually presented as row of tiny holes on the board edge, just like the half holes around a stamp, which to connect and allow those small boards in an array.

Here is the picture for you to see how the mouse bites presented on the Gerber drawing and what it is when it is finished.

Partial Effect drawing after Penalization: (the way of connecting bridge is used in the middle, this way can reduce the residue of burr in minimize)

Some People also called mouse bites as perforated breakaway tabs, it is designed for a better the purpose of the mouse bites is for a better grasp when mounted.

Here is the design rules if you need to add the mouse bites on your PCB panel.

The distance between each single board need to arranged as 1.2mm and 1.6mm.

The distance between each holes need to be 0.2mm, the distance between holes center should be 0.75mm.

Need to add two rows, the mouse bites extend to 1/3 of the board, if there is a some circuits on the board edge, you will need to avoid it.

After adding mouse bites, the shapes of the two sides of the hole are connected, which is convenient for the production of gongs after work.

Here are some of our PCB with mouse bites for your reference.

If you want to add mouse bites on your PCB board, you are welcome to send us your request and we will help you make it on your PCB Panel.

What is E-Tester for Printed Circuit Board?

Sunday, July 11th, 2021

When the bare Printed Circuit Board qty become volume fabrication, the PCB manufacture will not use the Probe flying tester to test the PCB circuit board. Best Tech will make new PCB test fixture to test the bare PCB, The electrical Test (E-test), which is the final electrical test to verify net continuity and the absence of shorts on the bare printed circuit boards (PCBs). In Best Tech PCB factory, we perform 100% electrical testing on all bare PCBs its facilities as per IPC-6012 class 2 standard. And from the following photo in computer, you can see it will show PASS for PCB.

in test

To test the PCB boards, we require the NETLIST file. Normally we create a reference netlist file from the customerâ€™s original Gerber files during PCB fabrication.

We always prefer to receive the CAD file based on the netlist for comparison. Since a CAD based netlist is generated before PCB routing, it provides another layer of checking (against the Gerber files). This allows us to catch any PCB faults introducing in the event of an error in the Gerber files. For full turnkey PCB assembly (PCBA service) projects, this helps to ensure that the PCB boards are 100% correct before any components are populated.

tester 2

Here are Best Tech E-tester Capabilities

Minimum Continuity Resistance	0.1 Ohms
Maximum Test Voltage	1000 Volts
Max Isolated Resistance	25 M Ohm â€“ 2 G Ohm
Electrical Test Pitch (Fixture)	20mil(0.5mm)
Electrical Test Pitch (Flying Probe)	4mil
Debug /check for missing pins: (Test fixture)	10 minutes
Test time per board:	40 seconds
Setup time:	30 minutes

All points are tested simultaneously. However, this process involves set-up to create the fixture itself and additional costs associated with the cost of materials.

The electrical test fixture has a limited shelf life and repeat using times. For every PCB it will need a fixture and its custom-made for a customer only. Many other factories only store 2 years shelf life for electrical test fixtures, but Best Tech will store at least 3 years for customer.

In order to ensure the quality of fixtures and spare enough space to store fixtures, Best Tech leaves one floor to keep the fixture. See attached fixture photo.

tester 1

During the 3 yearsâ€™ time, customer no need to pay the fixture charge again if the update is no update. The flexible test fixture shelf-life policy, it will help customer save the cost.

At the end of the PCB production process, we use electrical test to check the interconnectivity of the PCB is correct against the original board data.

Best Tech did the E-Tester to test the PCB 100% before delivery to customer, this makes Best Tech get highly comments from our customer on the world with good printed circuit board quality and best service. See the customer highly comments of Best Tech.

customer highly comments on our service

You are warm welcomed to contact Best Tech to discuss about the Printed Circuit Board (PCB).

What is IPC standard for PCB?

Monday, June 28th, 2021

Do you know what is IPC standard for PCB?

IPC, it is a trade association whose goal is to standardize the assembly and production requirements of electronic devices and components. It was established in 1957 as the Institute of Printed Circuits. IPC has developed thousands of standards and specifications to regulate the electronics manufacturing industry

IPC standards are related to PCB design, production technology, electronic assembly, etc., in order to achieve high reliability, high quality, high performance, and meet user specifications.

For PCB manufacturing, do you know which IPC standards are commonly used?

Here I would like to share you some standards which we mainly use:

1. IPC-6011: General Performance Specification for Printed Boards
2. IPC-6012: Appraisal performance and specifications for Rigid printed boards
3. IPC-6013: Appraisal performance and specifications for Flexible printed boards
4. IPC-6016: Fixed performance and specification of HDI or printed circuit board of high density interconnection layer
5. IPC-SM-840: Appraisal and performance of permanent performance
6. IPC-HM-860: Multilayer Hybrid Circuit Specification
7. J-STD-003: Solderable test for printed boards
8. IPC-A-600F: Acceptance conditions for printed boards
9. IPC-A-61: Acceptability of electronic components
IPC-4761: Design Guide for Protection of Printed Board Via Structures

One of the most widely used industry standards in the manufacturing of printed circuit boards is IPC-A-610C Acceptability of Electronic Assemblies and IPC-A-600 Acceptability of Printed Boards. This standard is used primarily for the incoming inspection of bare boards from a PCB fabricator.

In the IPC-A-610C document, electronic products are divided into level 1, level 2, and level 3. The higher the level, the stricter the quality inspection conditions. Here are how 3 levels divided:

Level 1 products: called general-purpose electronic products. Including consumer electronic products, certain computers and their peripherals, and products whose main purpose is to use functions.

Level 2 products: called dedicated service electronic products. Including communication equipment, complex industrial and commercial equipment and high-performance, long-life measuring instruments. Under normal use environment, this kind of product should not malfunction.

Level 3 products: called high-performance electronic products. Including high-reliability, long-life military and civilian equipment that can continue to operate. This kind of product must not allow any interruption failure during use, and at the same time, it is necessary to ensure the reliable startup and operation of the equipment in a harsh environment. Such as medical life-saving equipment and all military equipment systems.

It is no problem for us to manufacture the PCB following the standard in IPC 6012 /6013 Class 2 and Class 3, as well as following to the standard listed above/

These acceptance conditions are the basis for the inspection of our company’s products, as well as the working standards of the employees at the production site, and also become an important part of the training of the employees for PCB production and assembly in our company.

Send us your PCB drawing, let’s help to make your PCB design into a real board.

What is flying probe test printed circuit boards?

Wednesday, June 16th, 2021

Before leaving PCB manufacturing line, bare PCBs (Printed Circuit Boards) have to pass electrical tests so that it guarantee that boards go for high performance and high reliability after finish the SMTï¼ˆSurface Mount Technologyï¼‰. Electrical tests are implemented to find out electrical and circuitry issues such as shorts, opens, resistance, capacitance etc. all of which indicate whether bare boards or assembled board are correctly fabricated.

When test probes work, it moves quickly from test points to other test points as per instructions instructed by the computer set up program. Â

Probe test is no need fixture, so it is very popularÂ in the printed circuit boards manufacturing.Â The most significant reason is their cost. it is highly cost-effective for prototypes and low to mid-volume production. And the most important factor, the test reports can be provided for each board after finish tested and it is very easy to export from the computer, you can send to your customer very quickly for the test results of PCB.

Advantages of Flying Probe Test:

Low test cost (Eliminates fixturing costs and time)

Short test development time

Fast computer program development, easy integration of design changes

Rapid feedback provided to PCB design engineers at prototyping period

Process flexibility

Circuit access, even in the absence of test points

Controlled probe contact, programmable for any type of board

Different test solutions and approaches integrated in a single test system

Intrinsic positioning and measurement precision

Disadvantages of Flying Probe Test

Everything has two sides. Apart from obvious advantages, flying probe test have some disadvantages.

Since flying probes have direct physical contact with vias and test pads and small pits are easily caused on board surface, when flying probe tester is working on components without test pad, it’s possible that probes have contact with component leads so that loose leads or leads with badly-performed soldering may be missed.

In spite of the disadvantages mentioned, flying probe test is still regarded as a significant test method for PCB fabrication. Flying Probes have enhanced the competitive variable as lost time due to retooling has been removed. Prototype and Quick Turn product is the perfect match for Flying Probes as they carry out in low quantity orders and are quick to change jobs, unlike the long setup times with fixture testers.

By the way, to test circuit shorts, opens, Best Technology also do AOI checking to make sure there is no issue for PCB manufacturing.

Contact Best Technology right now, to discuss more for printed circuit boards.

How to Test for an Open Short Circuit on a PCB?

Tuesday, May 18th, 2021

Every printed circuit board need to do full test before ship to our customer. but you may have doubt, the PCB was made according to the original Gerber file, why finish the PCB production process, why the short Circuit will occur on a FR4 circuit board?

A short circuit may also occur during reflow soldering. the solder paste may accidentally connect two pins that are very close to each other. In some cases, errors can occur during the PCB design process because the wiring between different networks accidentally connects.

We believe every PCB manufacture have their own test method to do short circuit, but today I would like share how Best Technology to Check for Short Circuits in a Printed circuit board.

Here are some important steps:

Step 1 Visual inspection

The first step for locating short circuits on PCB is to carefully look at the entire surface of the PCB. Best Technology QC guys use a magnifying glass or low magnification microscope during the circuit board examination. We check the whole board surface to see if there are some traces break off. Any cracks or blobs of solder should get careful attention. Check all your vias. If you specified unplated vias, make sure thatâ€™s the case on the board. Poorly plated vias can create a short circuit between layers and leave you with everything tied to ground, VCC, or both.

All the testing work will carry out according to IPC 6012 class 2.

Step 2 Use a Digital Multimeter to find out where is the problem

To test a circuit board for a short circuit, you need to check the resistance between different points in the circuit. If visual inspection doesnâ€™t reveal any clues as to the location or cause of the short circuit, grab a multimeter and try to track down the physical location on theÂ printed circuit board. The multimeter approach gets mixed reviews in most electronics forums, but tracing your test points can help you figure out what isnâ€™t the problem.

Step 3 use Probe flying Tester &E-tester

As long as you are in Printed Circuit board field, you are definitely known Probe flying test and E-Teter.

Flying probe test systems require no test fixture, it can serve both prototype and small production, providing maximum flexibility for PCB manufacturers and this job can complete in a short time.

But when your circuit board become to volume, you will need to open a test tooling/test fixture to test the Printed Circuit board to test the open short circuit.

In my next blog in June, I will introduce Probe flying test to you in more detail.

If you have any question about printed circuit board, you are welcome to contact Best Technology.

It is our great pleasure to communicate with you for any issue for printed circuit boards.

PCB & MCPCB – Best Technology

Archive for the ‘FR4 PCB’ Category

How to choose surface finish on Printed Circuit Board？

HASL Surface Finish

OSP

ENIG

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What is RF PCB board?

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A Brief introduction for different layers on Multilayer PCB

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Why most of PCB boards are green?

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What kind of test for Coil Printed Circuit Board?

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The way to add the mouse bite on the PCB Panel #Bestpcb

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What is E-Tester for Printed Circuit Board?

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What is IPC standard for PCB?

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What is flying probe test printed circuit boards?

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How to Test for an Open Short Circuit on a PCB?

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