Archive for the ‘PCB Technology’ Category

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

in test

To test the PCB boards, we require the NETLIST file. Normally we create a reference netlist file from the customer’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

tester2

Here are Best Tech E-tester Capabilities

Minimum Continuity Resistance0.1 Ohms
Maximum Test Voltage1000 Volts
Max Isolated Resistance25 M Ohm – 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

tester1

During the 3 years’ 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

customer highly comments on our service

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

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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?

multilayer pcb

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

  1. 1. IPC-6011: General Performance Specification for Printed Boards
  2. 2. IPC-6012: Appraisal performance and specifications for Rigid printed boards
  3. 3. IPC-6013: Appraisal performance and specifications for Flexible printed boards
  4. 4. IPC-6016: Fixed performance and specification of HDI or printed circuit board of high density interconnection layer
  5. 5. IPC-SM-840: Appraisal and performance of permanent performance
  6. 6. IPC-HM-860: Multilayer Hybrid Circuit Specification
  7. 7. J-STD-003: Solderable test for printed boards
  8. 8. IPC-A-600F: Acceptance conditions for printed boards
  9. 9. IPC-A-61: Acceptability of electronic components
  10. 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-610—Acceptability of Electronic Assemblies. … 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.

resin filled production bpm20599

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.

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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 SMT(Surface Mount Technology). 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.

shorts circuit

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

probe flying test

Probe test is no need fixture, so it is very popular in the printed circuit boards manufacturing. 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.

AOI test

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

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Aluminum vs Copper Core PCB

Wednesday, May 19th, 2021

In Best Technology, currently the most common metal used for Metal Core PCB manufacturer are Aluminum, Copper. Today let’s talk about the main differences between aluminum substrate and copper substrate, hoping to help you choose the right substrate in future design projects.

Although they both share similar properties and functions, there are still a few variations between the two kinds of metals. Some of the key differences between aluminium and copper core PCBs are explained in the points below.

1. Thermal Conductivity

The thermal conductivity of copper substrate is up to about 400(W/mK) and the thermal conductivity of aluminum substrate is generally about 200W(W/mK). The thermal conductivity is higher, the transfer efficiency will be better, and the heat dissipation will be better, then the working life will be longer.

 Thermal Conductivity

2. Electrical Conductivity

Both aluminum and copper, being metals, are electrical conductors of electricity, although the exact degree of this varies between the two metals. When it comes to electrical conductivity, copper has a clear advantage over aluminum. In other words, in applications where there is a need for efficient electrical conductivity, copper makes for an ideal pick.

 Electrical Conductivity

3. Electrical Resistance

Resistance is very important when it comes to PCB design, as it can have an effect on the overall function and stability of the component. Given that copper has a higher density than aluminum, it tends to have a lower resistance than aluminum, so copper is an better choice where there’s a requirement for thinner circuits and faster electricity transfer.

Electrical Resistance

4. Weight

Since copper has the higher density for per unit area, the weight of copper PCB is much heavier than aluminum PCB for the same design.

In applications where light-weight construction is required more than anything else, aluminum is the preferred material of choice. On the other hand, applications where weight is not much of an issue, tends to be the ones where copper is widely used.

Weight

5. Application

Copper core PCB is the best heat dissipation among all MCPCB, so it’s mostly used in automobile headlights, taillights and some high-tech electronic products (unmanned aircraft, mining machine) high-power lighting equipment. The aluminum core PCB is mostly used in indoor lighting, energy saving lighting, street lighting and other energy-saving lighting electronic products.

Application
Application

In conclusion, due to the above different parameters and performance, the cost of copper is generally more expensive than aluminum. If you have other questions about MCPCB, welcome to contact us .

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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 that’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.

visual inspection

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 doesn’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 the printed circuit board. The multimeter approach gets mixed reviews in most electronics forums, but tracing your test points can help you figure out what isn’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.

probe flying test
probe flying test-1

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.

E-tester

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.

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What’s fiducial marks on the PCB?

Saturday, April 24th, 2021

You may ever be recommended by some PCB manufacturers to add the fiducial holes on the board edge. Do you know what is fiducial marks and what’s the purpose for this kind of holes in a PCB?

Now, let me to show you something for what is the fiducial holes.

Fiducial holes, we also call it fiducials mark, while we assemble a PCB, it will need to locate the positions for each component, and it is positioned based on the fiducial mark as the reference point.

There are 3 types fiducial marks, first type is fiducial marks on a single board, second type is the fiducial marks on a PCB panel, third one is the fiducial marks for some single component on the board.

Here are the pictures for you to understand the types of the fiducials.

Fiducial holes types
Fiducial holes

Fiducial mark on a single board is designed for positioned all circuits features on a single board. It is necessary to have a fiducial mark on a single board.

And fiducial marks on a PCB panel is used to assist positioning the circuits. 

For the fiducial mark of a single component, it is designed to position the fiducial mark of a single component, which can improve the placement progress (For QFP, CSP, BGA and other important components must have the fiducial marks).

So, it is important to add the fiducial holes on a PCB board.

Also, while we make the panel for the PCB board, on the diagonal of the four corners, it is required to have 2 fiducial points at least on 2 diagonal corners.  you can also place 4 marks on the four corners, but generally, assembly plant will only need 2 marks for recognize.

See below a PCB panel for reference:

PCB panel drawing Best Technology
Fiducial holes on a panel

In the other hand, while you design the PCB, please try not to put the silk screens, pads, traces etc. within 2mm of the optical fiducial marks. Otherwise, the SMT machine will not be able to recognize the optical fiducial on the PCB boards.

And if you add the fiducial holes on the area which without any circuits, to avoid the holes being etching while the process, so generally we suggest to add a metal circles around the fiducial holes, to make it more obviously on the boards.

If you have any new PCB design which you also want to add the fiducial marks.

You are welcome to contact Best Technology for a help and we will show our best help for you.  

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What’s the differences between thick film ceramic PCB and DPC ceramic PCB

Wednesday, April 21st, 2021

Ceramic PCB including Alumina PCB (Al2O3 PCB), Aluminum Nitride PCB (AlN), Bryllium Oxide PCB(BeO PCB) etc.

There are other differences except the substrate material is different.

  1. The method of making conductor is different.

The conductor for thick film ceramic is made by printing, but DPC is made by vacuum sputtering and plating.

  • The conductor is different.

The conductor for thick film ceramic PCB is Au or AgPd, but for DPC ceramic PCB, it is copper.

  • The thickness of conductor is different.

Normally, it is 10-20um for thick film ceramic PCB, copper thickness can be 10um-300um for DPC ceramic PCB.

  • The solder mask is different.

It is glass glaze for thick film ceramic PCB, the most popular color is greenish and blue. Glass glaze can withstand very high temperature, up to 850C

It is normal solder mask oil for DPC ceramic PCB, the most popular color is white.

The above is only simple introduction for the difference, if you want to know more differences between thick film ceramic PCB and DPC ceramic PCB or other details about ceramic PCB, please contact us

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What is Blind Via and Buried Via for Printed Circuit Board?

Thursday, April 15th, 2021

In the Printed Circuit Board industry, believe that you are familiar with blind via and buried via. What is blind via and buried via for PCB? And do you know is the Blind via or Buried Via have special application in your Printed Circuit Board?

In order to know more, we would like to share more information with you today.

Best Technology is an experienced FR4 PCB manufacturer in China since year 2006, with more than 15 years design and fabricate experience for PCB, Best Technology accumulated more than 1000 customers from all over the world.

Before start, we need to know what kinds of hole for FR4 Circuit Board, Via, Blind Via and Buried Via.

What is a Via?

Vias are the copper-plated holes in the PCB that allows the layers to layer connection. The standard via is called a through-hole via, but there are several disadvantages to using through-hole vias in Surface Mount Technology (SMT). For this reason, we often use a blind via or buried via instead. A blind or buried via can be processed in a wide range of different measures, including plugged copper mask via, a plugged solder mask via, plated via or staggered via.

Via
staggered via

What is Blind Via?

The via connects the external layer to one or more inner layers of the PCB and is responsible for the interconnection between that top layer and the inner layers.

Blind Via

What is Buried Via?

For a buried via, is the inner HOLE, between both sides in the board up and down inside the layer after pressing is cannot see. So, it doesn’t have to take up the outer area.

Buried Via

Blind and buried vias are particularly advantageous in HDI board because they optimize the density of the boards without increasing board size or the number of board layers you require. They are most commonly used in high-density PCB designs like, or in FPGA and custom chip packaging.Here is the photo which Best Technology took from our production line to make HDI Printed Circuit Board for our USA customer.

HDI board under production
HDI process

Best Technology is a very professional manufacturer in printed circuit board and HDI Board. If you are interesting to know more information of us, come to contact us and we are looking forward to discuss with you more for Printed Circuit Board.

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Interesting color matching – Silkscreen and Solder mask

Tuesday, March 23rd, 2021

In Best Technology, solder mask and silkscreen are available in a variety of colors. For example, common colors of solder mask are black, white, blue, green, red. Common silkscreen colors are black, white, yellow, red, blue. Generally according to the different needs of customers to use collocation, but sometimes if the color collocation is not appropriate will produce color difference.

The following is a list of common collocations that we recommend based on our experience for your future project design.

Solder maskRecommended Silkscreen
BlackWhite
WhiteBlack/Blue/Green/Red/Yellow
BlueWhite
GreenWhite
RedWhite

For the most part,the color of solder mask doesn’t have any effect on PCB’s

functionality.But if the color of the silk screen does not match properly,which may

Cause chromatic aberration(for example,a yellow silkscreen on a black solder mask,

The silkscreen visual may look green)or make reading the silk screen more difficult

To read(for example, a black silkscreen on a light black solder mask).The solder mask will also affect your ability to visually inspect the PCBs. Below are the solder mask comparison from the highest contrast to the lowest for your reference.

Green

Most customers will choose to use Green solder mask for their project since Green is easy on the eyes and allows for high contrast between traces, planes, and empty space on the PCB. Green solder mask has become an industry standard. High contrast allows technicians to most easily review for manufacturing defects.

green

Red

A Red solder mask will provide a bold and clean looking PCB, however the contrast between traces, planes, and empty space significantly lower than it is with a green solder mask. Magnification may be needed when inspecting fine traces on the board for defects with a Red mask. White silkscreen will be better than black silkscreen on a board with red solder mask.

red

 Blue

Blue solder masks have even lower contrast, and magnification becomes required when inspecting for manufacturing defects. These PCBs look visually pleasing and professional and are a good choice for fully-developed products that will not require trace visibility.

blue

Black

Black masks have almost no contrast between traces, planes and empty space. A Black mask will absorb heat, increasing the danger of overheating for sensitive components. Pay attention that in order to avoid the appearance of color difference as far as possible do not choose the silkscreen like yellow, green, red, or blue. White will be the better choice.

black

White

A white mask will be the hardest to clean, and also has the lowest contrast. If possible, we suggest that you avoid choosing white, especially in the prototyping stage. It’s the best choice to use white solder mask for LED board, following pictures for your reference.

whtite

If you have other questions about solder mask, welcome to contact us. (Email:sales@bestpcbs.com), we will prove you professional suggestions and solutions.

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The Advantages of Surface Mount Technology of a printed circuit board

Friday, March 19th, 2021

Surface-Mount Technology has been the industry standard for assembling printed circuit board. It has maintained its popular due its wide array of advantages and relatively few drawbacks. For more than 15 years’ experience, Best Technology has been offering surface-mount service for worldwide customers, and SMT service become a great part of our business.

See some photo which we are do assembly for our customer this month.

SMT 1

Top Advantages of Surface-Mount Technology

Smaller size and reduced weight are the two main advantages to SMT. Components can be aligned closer together and end products will be more compact and light weight.

SMT 2

Here are additional benefits of SMT:

1.Component placement auto correctly â€“ there is no alignment between the PCB solder pads and components pads to avoid placement errors.

2.Low cost:

The advantage of small size up to 0201. One set, SMT typically requires lower production costs than through-hole placement. The size of the board is reduced, the number of drilled holes is reduced, and routing of traces is reduced. So bring down the cost of the whole project.

3.Design flexibility â€“ You can combine through-hole technology and SMT manufacturing on the same board for greater functionality.

4. Printed circuit boards created with the SMT process are more compact, providing higher circuit speeds. (This is the main reasons most manufacturers choose for this method.)

5.Higher circuit speeds â€“ Most manufacturers rate this the number-one benefit.

Lower resistance/induction â€“ High-frequency performance reduces unwanted consequences of RF signals.

6. Quick Turn Around

Using Surface-Mount Technology, it can save lots of time, SMT is a much more streamlined manufacturing process compared to through-hole. Time is saved because components are applied using a solder paste instead of drilling holes in the PCB

7. Quantity â€“ More components can be positioned using both sides of the circuit board, creating more connections for each component. Fewer circuit boards are needed for devices.

8. Stability â€“ Better performance delivery is realized with vibration mechanical conditions. SMT connections are more reliable, it can reduce the dis connection risks during the final test.

SMT 3

Best Technology offers expert surface-mount technology services in China, along with manufacturing bare printed circuit board, flexible circuits, and MCPCB fabrication. With more than 15 years rigid PCB board experience, Best Technology has the resources, equipment, and know-how to produce your PCBs quickly and reliably.

different assembled board photo

Call Best Technology now and let us become your partner of PCB assembly service.

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