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Electrostatic’ s Power─Trivia Series 1

March 23rd, 2022

The Introduction to Electrostatic

Static, the excess charge on an object, is a phenomenon caused by the unbalanced distribution of charge in the material system. When an object is charged, the charge will remain on the object unless it is removed by other objects, so it is called “static electricity”.

As is known, we cannot touch PCB directly with our hands because of the electrostatic. But most of people have thought lowly of electrostatic’ s power, deeming that it is not strong enough to be harmful to some devices, especially electronic components.

On the contrary, electrostatic can be in some way devastating. According to the statistics, electrostatic discharge (ESD) account for the highest proportion in the ranking of causes leading to the failure of high electrostatic sensitive devices, which is 59%.

Pie Chart

The Generation of Electrostatic

There are various ways resulting in the generation of electrostatic. But, triboelectrification, namely indicating that electrostatic is generated by friction, is the most common one.

Where there is friction, there will be electrostatic. When walking, the shoes will rub with the floor, leading to the triboelectrification. Also, the frictions between our hair and clothes are so easier to generate the static that every movement in the PCB workshop will unintentionally cause the generation of static.

Then the static generated will have a great impact on the PCB and electronic components. But, how great the electrostatic’ s power is, or in other words, what kind of damage can it cause to the printed circuit boards or electronic components? And what can we do to eliminate the electrostatic?

We will talk about it next time, hence if you would like to know more, you are welcome to contact us, or you can continuously follow our blog site, on which we will keep sharing more information about PCB.

What Should be Prepared Before Starting the SMT Process?

February 15th, 2022

SMT, whose full name is Surface Mounted Technology, is the most popular technology in electronic assembly industry. It refers to process on PCB (Printed Circuit Board), putting various electronic components on PCB, such as resistors, capacitors, inductors, and so forth. Also, there are some dos and don’ts in the whole process of PCBA.

As noted previously, there are all sorts of electronic components that will be used in the assembly process of Printed Circuit Board. Therefore, it is extremely important to take some measures to keep a check on static. Here are three steps before entering the SMT workshop.

First, put on anti-static clothes and hats. It is to prevent static existing in clothes and hair from influencing the board, for static has a potential and tremendous destructive power.

Anti-static Clothes and Hats

Second, what we have to do is to put just one hand on static elimination instrument, and do not leave our hand from it until the red light turns to green, which aims to eliminate the static existing in our body.

Static Elimination Instrument

Third, across the air shower door. In this way, dust that is invisible on our body can be blown off in about 5 seconds.

Air Shower Door

Only finishing the three steps above can we enter the PCB assembly workshop. And after entering the workshop, there are also something needed to be prepared.

  • Solder paste. The storage temperature of solder paste is 2-10 degrees Celcius, hence it has a period of regaining temperature, which conducts in the rewarming machine for 4 hours. Then the solder paste should be rabbled in a blender for 5 mins in order to help three ingredients in it to be fully integrated, which can help to achieve a better printing and back-flow soldering effect.
Solder Paste
  • Oven. This machine is used to get rid of the moisture from materials or boards, ensuring that PCB will not be defective due to moisture during the subsequent assembly process. Moreover, different boards have different requirements. But generally, the baking parameter is 105 degrees Celcius, lasting 1.5 hours.
Oven
  • Dryer. It is used to maintain a set temperature and humility of materials and boards that needs to be processed that day, which is also to avoid that moisture does harm to materials and boards after removing the moisture by oven.
Dryer
  • Tension test of stencils. Before manufacturing, the stencils’ uniformity should be tested by tensiometer, which mainly tests the four corners and the center part of the stencil, guaranteeing the solder paste printing quality. And the parameter should be between 30 and 45.
Stencils

To sum up, although there are lots of preparations should be done before starting the formal assembly process, each of them is significant, for they will probably influence the quality of boards directly. Besides, only a good preparation can make a certain that the follow-up process can keep going. Thus, it is a must to prepare well in advance.

And EBest Circuit (Best Technology) is an experienced electronic company. It not only can provide PCBA service, but can provide other services, such as FPC, FR4 PCB, Rigid-flex PCB and so on. And if you have any questions about SMT, or any other questions about assembly, you are welcome to contact us.

Advantages of LED PCB Compared with Common Standard PCB

December 22nd, 2021

With the development of electronic products, the requirements of circuit boards applied in electronic products are becoming higher and higher. The volume of printed circuit boards is also shrinking exponentially, the assembly density is increasing, and the internal wiring of the line layer is becoming more and more intensive. Compared with PCB, LED PCB with metal core can achieve better heat dissipation effect.

LED PCB material:

First of all, LED PCB space utilization is higher, it takes up relatively small space, but can withstand relatively high-power output.

It is well known that when the power of the circuit board is high, high heat will be generated. If the heat cannot be dispersed in time, it may lead to the shortening of the working life of LED products, and the more serious consequence is the safety problem of the circuit board due to overheating.

Therefore, in order to make the LED lighting system longer life, it is generally used to print the circuit board with metal core, and the characteristics of the metal core is relatively large density, strong thermal conductivity, conducive to heat dissipation effect.

LED PCB board design:

The LED PCB is also unique in that its components are located on the surface, rather than through holes, because the metal core at the bottom dissipates heat more quickly.

LED PCB surface mounting

Some LED printed circuit boards have through-holes, especially multilayer metal core printed circuit PCB. Because the number of layers of the circuit board increases, the circuit layout is more complex, heat is more difficult to emit, and the existence of the through hole is to achieve faster heat dissipation. The drilling holes on the LED board are mounting holes, which are usually larger than the standard PCB through holes.

LED PCB solder mask color:

In addition, LED printed circuit board solder resistance layer color is also its characteristics.

The color of solder resistance layer on the LED printed circuit board is usually white, while the PCB board has a series of colors such as black, green and red and so on. This is also determined by the characteristics of LED boards in practical applications. Since LEDPCB board is usually used as backlight board, photosensitive solar ink is usually coated on the surface of the circuit board. White Taiyo Solder mask can achieve high temperature resistance, not easy to change color, high reflectivity, so as to achieve the reflection effect of lighting and better lighting effect.

LED PCB

Via Tented, Via Filled & Via Plugged

December 20th, 2021

Via Tented, Via Filled (filled with solder mask) & Via Plugged (Via In Pad – Conductive material or Non-Conductive material)

One of the most confused idea during our PCB design is the difference between Via Tenting, Via Filling and Via Plugging. Designers often get mixed up between them and fail to take full advantage of the process.

Today, let us discuss them, so that you can be confident in specifying your design requirements clearly when submitting PCB files to EBest Circuit (Best Technology) before final manufacturing.

Via Tented

What is via?

A plated through hole (PTH) in a Printed Circuit Board that is used to provide electrical connection between a trace on one layer of the Printed Circuit Board to a trace on another layer. Since it is not used to mount component leads, it is generally a small hole and pad diameter.

A. Three methods and definitions of via processing

There are three methods for via processing: via hole opening & via hole cover oil & via hole plug oil

1. Through hole opening window: it is the tin on the solder ring of the via (the tin is exposed like a plug-in pad). The window is usually used to debug the measurement signal. The disadvantage is that it is easy to cause a short circuit.

2. Through hole cover oil: it is the welding ring of the through hole (via) covered with solder mask ink

3. Through hole plugging oil: refers to plugging the hole with ink.

Secondly, the inspection standards for a processing method

1. Through-hole opening window is like a plug-in pad, and the window is sprayed with tin. Inspection standard: tin can be tinned, and tin can be easily tinned.

2. The inspection standard of the via hole cover oil: it is not easy to tin in the patch.

3. Inspection criteria for via plug oil: First, it must be opaque, and it must be covered and blocked by ink.

Finally, we are talk for comparison and distinction between via hole cover oil and via hole plug oil:

1. Via plug oil This process is an important supplement to via plug oil, so generally high-quality boards will require via plug oil. And often many engineers who are just entering the industry are stupid and unclear. So how do you distinguish between the two?

2. The requirement of via hole cover oil is that the ring of the via hole must be covered with ink. The emphasis is to ensure the thickness and coverage of the ink on the edge of the hole. The key control is that the ring does not accept false copper exposure and orifice oil. Thin

3. Through hole plugging oil is the production of plug holes with ink inside the holes of the through holes. The emphasis is on the quality and density of the plug holes. After the holes are plugged, no light can be transmitted.

4. The method of plugging the via hole is to first fill the via hole with ink to block the via hole, so that the ink on the solder mask will not flow into the via hole, so as to achieve the situation that the via hole does not appear yellow. (If you have strict requirements and place an order for via hole cover oil, the cover oil is usually not full or yellowish, you can change it to via hole plug oil later). In addition, the smaller the vias are, the easier it is to plug them. The vias of the fortress oil are not easy to be too large (the circuit board proofing plugging oil is directly plugged with ink, and the printing tape is plugged. It is recommended that the vias that need to be plugged are designed to be <0.5mm. This is also free; no additional money is required).

If you have more question Via Tented, Via Filled& Via Plugged, warmly welcomed to contact Best Tech for more FR4 design service.

What is PI heating film?

December 20th, 2021

With people’s pursuit of high-quality life, now many electronics products are designed including heating film. It is kind of emerging material in the current industrial development.

The heating film is divided into different temperature resistance grades due to the different materials, and it can be divided into different names due to the different internal heating mechanisms.

Today let us mainly to introduce the Flex heating film, which conductor is made of Polyimide film (PI), people also called it PI heating film, Kapton Polyimide Heater, Kapton heating film or Polyimide Heating Plate.

Flexible PI Heating Film is designed with various resistance circuits according to the customer‘s request, which use Polyimide film (PI film) as the outer insulator, and use metal foil as the inner conductive heating element, to laminate both materials together by high temperature and high pressure.

You can know more details about the Flex heating film when you check below stack up and photos.

As Polyimide Heater is kind of surface heating material, which forms the maximum heat conduction surface with the heated body, so such heating method has very good conductivity, and with the characteristic of fast heating and low thermal inertia

It can withstand 300 ℃ high temperature in the short term, and work below 160 ℃ in the long term.

In other hand, the thickness of the flex heating film is between 0.13-0.3mm, which makes such product very flexible and light, and occupies very small space on the entire product design. So Flex heater is very good for using on the situations where space and weight are limited, or where the heater is exposed to vacuum, radiation, oil or certain chemical substances.

Here the list for where the Flex heater mainly used in:

1. Heating of household appliances

2. Under cold environmental conditions, make the instrument reach the designed working temperature, such as camera defogging heating.

3. Vacuum heating and baking field

4. Car rearview mirror defrosting, radar snow removal, defrosting, etc.

5. Medical care and beauty equipment industry

The following are some products which includes the flexible Polyimide Heater inside.

Believe it will supply a good reference for you to know this product.

So, as you can see that the product with Flex heating improve highly for our life quality.  Our company has more than 15 years experiencing on manufacturing Flex PCB and Flexible heating film, if you are interesting to know more manufacturing details about PI heating film, you are welcome to contact us.

What is LED Thermal Management?

December 20th, 2021

LED lighting (Light Emitting Diodes) can provide more lumens per watt than incandescent bulbs, and the amount of light emitted does not depend on the size or shape of the bulb. It has significantly smaller footprint, higher efficiencies and lasts a long time.

One of the big challenges of LED lighting is LED Thermal Management, since around 70% of the electricity used by an LED becomes heat, and LEDs work best around room temperature, if the heat is not managed with some sort of thermal management solution, it can result in reduced efficiency in the LED, shorten the life of the bulb itself, and possibly causing damage to other components near it. In this context one of the best places to start with would be thermal management within the Metal Core PCB.

Thermal Management in MCPCB

If you are using LED power, there are chances that you would encounter problem at or above 80 watts. For example if you are considering application like the street lighting which might require up to 150 watts per lamp, led thermal resistance at such high power point would be a cardinal concern.

MCPCB can be created using a wide range of heat-dissipating materials without changing the LED component. From copper which offers better thermal conductivity to aluminum which is cheaper to specialized MCPCB using coated steel, ceramics or many other options. To address the LED thermal resistance issues and achieve optimum thermal management using LED, external heat sinks can also be used. This facilitates dissipation of exceptionally large amount of heat.

In fact on an average MCPCBs have several different shapes and degrees of heat dissipation profile. However the most challenging ones are no doubt the types in which the LED applications have to be stored in airtight enclosure to protect from the environment around. Thermal management in this case could be anything from air-to-air heat exchangers to using internal fans to even heat transfer via a series of conduction and convection alternatives.

Thermal Management of MCPCB

Thermal management is important for the electronic systems to encompass the processes along with the technologies.The main objective of thermal management is to ensure the temperature remains consistent for the functional and absolute maximum limits. The temperature exceeding the limit may cause destruction physically or may lead to a system failure. Therefore, MCPCB is essential because efficient thermal management increases the feasibility, enhances durability, and reduces the failure rates.

It also enables the high circuit density design for the users. Basically, thermal conductivity is a specific material from a property with the ability to conduct proper heat management as soon as it enters into the system. The conventional PCB share less thermal conductivity and also not capable enough to meet the increased demand for the thermal constraint required for high power dissipation PCB. The best alternative to solve this problem is the Metal Core Printed Circuit Board.

If you have any questions about MCPCB, welcome to contact EBest Circuit (Best Technology).

What is RF PCB board?

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.

The SMT production progressing

November 18th, 2021

SMT (Surface Mounted Technology) is the most popular Technology and process in electronic assembly industry. SMT refers to a series of process processes based on PCB. Due to the better outcome and higher efficiency, SMT has become the primary approach used in the process of PCB assembly. In some extent, the turn-key service is a way to reduce the cost.

There are the SMT progressing in the following.

1. Solder paste printing: The function is to print the solder paste to the PCB pad to prepare for the welding of components. The screen-printing machine is located at the front end of SMT production line.

(Automatic solder paste printer)

2. Part mounting: The function is to accurately install surface assembly components into fixed positions on the PCB. The equipment is the SMT machine, located behind the screen-printing machine in the SMT production line.

3. Furnace curing: its function is to melt the patch adhesive, so that the surface assembly components and PCB board firmly stick together. The equipment used is the curing furnace, located behind the SMT machine in the SMT line.

4. Reflow welding: The function is to melt the solder paste, so that the surface assembly components and PCB board firmly stick together. The reflow furnace is located behind the SMT machine in the SMT line.

(Reflow soldering)

5. AOI optical detection: its function is to detect the welding quality and assembly quality of assembled PCB board. The equipment used is automatic optical detection (AOI)

(AOI machine)

6. Maintenance: its function is to detect the failure of the PCB board for repair. The tools used are soldering iron, repair workstation and so on. Configured after AOI optical detection.

7.Dividing board: its function is to cut PCBA of multiple connecting boards, so that they are separated to form a single individual, generally using V-cut and machine cutting.

8. Grinding plate: its role is to scrub the burr parts to make them smooth and flat.

9. Washing plate: its function is to remove welding residues such as flux and other harmful to human body on assembled PCB board and manually clean it.

Turnkey service reduces customers’ time in contacting with multiple suppliers for separate steps in PCB assembly manufacturing. And the scientific order arrangement system allows customers to get PCB assembly products with higher quality and less cost in a shorter time than the traditional way of PCB assembly.

(SMT production line)

What kind of MCPCB is suitable for your electronic project?

November 13th, 2021

If you need a Metal Core PCB for your project, there are some different types can be selected, the selection of the MCPCB type depends upon the type of application and project you are performing. This blog will provide you information about the metal based PCB, which will also illustrate the construction, uses and distinguishing features of the MCPCB boards, hope it can help you to choose the most appropriate MCPCB for your subsequent projects. 

Types of Metal Clad PCB 

There are many different types of the MCPCB depending upon the type of base material, currently the most common metal used for MCPCB manufacturers are Aluminum, Copper and steel alloy. The selection of the base material depends upon the type and nature of the electronic project.

1) Aluminium core PCB

Aluminium is a better material that we can use for the core of a board. The reason is that it has high heat transfer capability. Moreover, it also shows the heat dissipation capacity to the maximum extent. Aluminium is also relavitively cheaper as compared to the copper material. Therefore, it represents the cheaper and better manufacturing of the printed circuit boards.

2) Copper metal core PCB

Copper is the best material for the core of MCPCB, since this material shows the best heat transfer capability. Moreover, this material is also fit for the excellent heat dissipation during the process. These features save the PCBs from the thermal issues.

The copper core PCB shows the best thermal conductivity as compared to other PCBs. The normal value of the thermal conductivity for these PCBs is 2.0W/mk. However, we can get this value of thermal conductivity up to 12W/mk in the case of insulating layer. Therefore, these types of the PCBs have the tremendous use in the high-power LED lights.

3) Stainless steel PCB

Another important material that has an excessive use in the metal core PCBs is the Stainless steel PCB, which also can provide better capability of connectivity and high performance, and it’s more rigid than both aluminum and copper, but thermal conductivity is lower than them too. 

copper core & aluminum core pcb

Stack up of Metal core PCB

The stack up and construction of the MCPCB depends on the number of layers in the PCB. The PCB with the single layer, two layers and multiple layers have the different methods of stack and construction.

1) Single Layer Metal Core PCB

A single layer MCPCB consists of a metal base, Dielectric Layer, Copper Circuit Layer. The advantage is that it provides a better connection between components of the PCB, and it’s efficient at the heat dissipation in the high-power generator systems. These PCBs have the holes on the board for the mounting process of the electronic components. It can also have the screws around the chassis of the board for the arrangement of the components.

Single Layer Metal Core PCB
  • Two (Double) Layers MCPCB / Double Sided More Core PCB

In some cases, there’s not enough space on the single layer PCB for the mounting of enough electronic components. So we need to use the two layers conducting material to resolve this issue.

Regarding the MCPCBs with two layers of copper conductor, there are two basic types, one is Two (Double) layers MCPCB, the other one is Double Sided More Core PCB, which depends on your demand of the mounting of the electronic components, the components can be soldered on both sides on Double Sided More Core PCB.

If you would like to know more details of the differences between Double Sided MCPCB and Double/Two Layers MCPCB, welcome to click following link.

Double Sided More Core PCB

3) Multi Layers metal core PCB

The Multi Layers MCPCB have the more complex and integrated circuit/construction, which can be populated more components on the boards, put signal and ground layer into seperated layers, to achieve better performance in electrical performance. It’s best for heat transferring from electrical components to the chassis of the board. The use of these boards is tremendous in the digital and analogue devices.

Multi Layers metal core PCB

If you have any questions about MCPCB, welcome to contact EBest Circuit (Best Technology).

Ceramic PCB antennas for Bluetooth sports headset

November 11th, 2021

What is the function of the built-in ceramic antenna for the s Bluetooth sports headset?

Ceramic antenna is another miniaturized antenna suitable for Bluetooth devices. The types of ceramic antennas are divided into block-shaped ceramic antennas and multilayer ceramic antennas. The block-shaped antenna is to use high temperature to sinter the whole ceramic body at one time, and then print the metal part of the antenna on the surface of the ceramic PCB.

Ceramic PCB for Bluetooth sports headset

The firing of multilayer antennas by low-temperature co-firing. The multilayer ceramic PCB are laminated and aligned and then sintered at high temperature. Therefore, the metal conductor of the antenna can be printed on each ceramic dielectric layer according to the design needed, which can reduce the size of the antenna size and then can achieve the purpose of hiding the antenna. Since the dielectric constant of the ceramic is higher than other PCB, so using ceramic antennas can effectively reduce the size of the antenna, it is very good for Bluetooth sports headset application. 

Ceramic PCB for Bluetooth sports headset
Ceramic PCB for Bluetooth sports headset

The material of the ceramic antenna is ceramic, and the weight is only 200g. Its frequency range is between 902MHz and 928MHz. In terms of dielectric loss, the ceramic medium has a smaller dielectric loss than the PCB, so it is in the low power consumption rate. The Bluetooth module is very suitable for it. The effect of the ceramic antenna is stronger than that of the on-board antenna. Generally, there are ANT access feet and ground feet, which are also very convenient to use.

Ceramic PCB for Bluetooth sports headset

The principle of ceramic antennas is divided into two parts: one is the transmitting antenna and the other is the receiving antenna.

  • Porcelain antenna transmitting antenna uses an electrode called “antenna” to turn the high-frequency electric field formed between the antenna and the ground into electromagnetic waves, which can be emitted and propagated to a distance.

Ceramic antenna Receiving antenna uses an electrode called an “antenna” to induce electromagnetic waves from the air into an electric field, generate high-frequency signal voltage, and send it to the receiver for signal processing.

Please feel free to contact sales@bestpcbs.com if you want to know more about ceramic PCB