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PCB Blog

PCB Basic Knowledge: PCB Core Materials and Prepreg Materials

We often refer to the PCB (printed circuit board) plays an important role in the electronics industry. PCBs build a bridge to the world of electronics, so to speak, and the core material and prepreg of PCBs assist in the construction of printed circuit boards.

In this article will take you to understand what is PCB core and Prepreg material, and the differences between them and the application.

What is Prepreg material?

Simply put, Prepreg is a glass fiber with a resin binder impregnation. It is a dielectric material used to provide proper insulation between copper and PCB Core.

Prepreg is also commonly refers to as a bonding material that either combines two cores or a core and a copper foil. This plays a crucial role in PCB design and manufacturing.

The different types of prepreg depend on their thickness and the amount of resin they hold, the higher the resin they contain, the higher the price.

  • Standard resin (SR)
  • Medium resin (MR)
  • High resin (HR)

The process of manufacturing Prepreg

Why is Prepreg so important in the PCB manufacturing process?

  • Easy to apply
  • Facilitates waste management in the manufacturing process
  • Multiple Prepreg options available to meet different needs
  • Helps reduce the weight of equipment

What is a PCB core material?

A PCB core consists of a FR4 (flame retardant) rated glass fiber epoxy laminate with copper laminated on both sides. It is a rigid base material with copper laminated to the instrumentation used to manufacture single-sided, double-sided and multilayer circuit boards.

The difference between PCB core material and Prepreg material

Simply put, core material is the product of prepreg and lamination. As such, it is much more rigid compared to prepreg. Prepreg is partially dry without lamination and is not as rigid as core. The core consists of a glass fiber epoxy laminate which is flame retardant and has copper on both sides.

Another important difference between PCB prepreg and core is its dielectric constant. While the dielectric constant of the core does not change, the dielectric constant of the prepreg changes before and after lamination. The different dielectric constants are also a function of the following factors.

  • Resin content
  • Resin type
  • Glass braid

Explore KingPCB’s services

PCB cores and Prepreg are both important components of PCBs, and understanding these basics is critical to PCB manufacturing.

With over 10 years of combined experience in PCB manufacturing and assembly services, KingPCB offers advanced assembly technology and advanced PCB solutions. More than just high quality, we also offer the most competitive prices.

Don’t hesitate to contact us now to learn more about our PCB services

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PCB Blog

How Solder Paste Helps PCB SMT Assembly

What is Solder Paste?

Solder paste is a kind of gray paste, a new soldering material applied to PCB SMT assembly, which helps to fix electronic components on PCB boards, making electrical connections and mechanical bonds between PCB pads and surface mount devices.

Solder paste is mainly composed of flux and solder powder (Flux & Solder Powder)

The role of flux

  • Removes oxides from metal surfaces
  • Protects the components to be soldered
  • Holds the device in the proper position

What are the factors that affect the function of the solder paste?

  • Uniformity of solder paste particles
  • Percentage of solder powder in the flux
  • Viscosity of the solder paste
  • Thixotropic index and metal content of the solder paste
  • Reflow process

What are the types of solder paste?

According to the flux type, solder can be divided into rosin-based solder paste, no-clean solder paste, water-soluble flux solder paste.

Solder paste in PCB SMT assembly

Reflow Soldering

For reflow soldering in PCB SMT assembly

Create solder joints

Solder paste as a homogeneous mixture of solder alloy and flux, solder paste helps to create reliable solder joints.

Leaded Components

Solder paste helps increase component density and reduce PCB manufacturing costs when assembled with leaded components

Stencil Printing

It helps in adding components to PCBs in established patterns

Jet Printing

Jet printing solder pastes are made from different formulations and therefore the solder paste has a higher fluidity.

Points to note when using solder paste

Make sure the stencil is accurate

Poorly printed stencils can hinder the application of solder paste.

Make sure the screen printer is programmed correctly

Accurate measurement and calibration of the solder paste screen printing equipment is key.

The right amount of solder paste

Excessive amounts and small amounts can lead to errors.

Correct process

You can choose between metal screen printing and mesh screen printing.

Safe handling

Solder paste contains organic solvents. When handling, try to avoid inhaling the fumes released by the solvents during operation, and avoid contact with skin and mucous membrane tissues for too long.

Explore our PCB assembly services

KingPCB has over 10 years of experience in PCB SMT assembly, and we are fully capable of meeting your PCB manufacturing and assembly needs.

You can send your PCB quotation request by email, and your inquiry will be answered within two hours.

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PCB Blog

5 Tips Fast Track to be A PCB Assembly Expert

PCB assembly is the process of assembling all the electronic components together. People sometimes confuse PCB assembly and PCB manufacturing. There are two completely different concepts, PCB manufacturing covers PCB design, and PCB prototyping.

This article will describe the different PCB assembly techniques and processes to help you better understand the principles of PCB assembly.

 

Contents

  1. What is PCB?
  2. PCB Assembly Technology
  3. PCB Assembly Process
  4. How to Improve the Quality of PCB Assembly
  5. PCB Assembly -KingPCB’s Service

 

What is PCB?

PCB is an abbreviation for printed circuit board. PCB’s primary function is to house electronic components and make electrical connections in the electronic components. PCB can be single-layer, double-layer or multi-layer. In 2014, the global bare PCB market exceeded $60.2 billion and expectingto reach $79 billion by 2024.

 

PCB Types


Main PCB Components

Diode: it allows current to flow in one direction

Lead: light-emitting diode that glows when current flows through it

Resistors: color-coded components that allow current to flow through

Capacitors: design to retain charge for device operation

Switches: allow or prevent the movement of current

Inductors: passive components that resist sudden changes in current

Battery: links voltage to the circuit

 

PCB Manufacturing Process

Single-sided process flow

Board cutting → dry film (line) → etching → CCD drilling → solder resist → character → molding → surface finish → electrical testing → final inspection → packaging and shipping

Double-sided process flow

Board cutting→ drilling → sinking copper → board electricity → dry film (line) → lamination → etching → two drilling (some ranked in the solder resist and surface treatment after) → solder resist → character → surface finish (sinking gold some ranked in the character before) → molding → electrical testing → final inspection → packaging shipments

Multi-layer process flow

Board cutting → inner line → browning → pressing → drilling → dross removal → copper sinking → board electricity → dry film (line) → graphic plating → etching → two drilling (some are ranked after anti-soldering and surface treatment) → anti-soldering → character → surface finish (some are ranked before gold sinking) → molding → electrical testing → final inspection → packaging and shipping

PCB Assembly Technology

SMT assembly technology

What is SMT assembly technology? SMT is a method for assembling electronic circuits boards in which components are mounted or placed directly on the top layer of a PCB. Compared to THT, components become smaller and placement of components on both sides of the board. It allowing smaller PCB components with higher circuit density. SMT is ideal for high automation, reducing labor costs, and greatly increasing productivity, and components can be mounted on carrier strips.

THT assembly technology

What is THT technology? THT is the insertion of components with tails or leads into drilled holes in the PCB, also known as feedthrough board assemblies. The leads are then soldered to pads on the bottom of the board, usually using a wave soldering process. THT mounting is very reliable because it creates a strong mechanical bond and the process is relatively mature. Compared to the SMT process, there are fewer variables that may cause solderable problems. The process can make bare boards more expensive due to additional drilling and the potential need to print on both sides of the PCB.

Hybrid PCB assembly

What is hybrid PCB assembly? As electronics tend to be smaller and more functional designs, this places higher demands on PCB assembly. It is challenging to assemble highly complex circuits in a limited space using only SMT or THT, combining SMT and THT technologies with appropriate adaptations to simplify soldering and assembly.

 

PCB assembly process

Solder paste printing: The first step is to apply solder paste to the board. The printed circuit board and solder stencil are held in place by a mechanical fixture, and the machine applies the paste to the stencil until it covers each opening area evenly.

Pick and Place: Using a mounter that automatically places surface mount components on the PCB. The machine picks up the PCBs with vacuum clamps and moves them to a pick and place station where the PCBs are. Then placed on the workstation and the SMD components are placed on top of the solder paste in the specified location.

Reflow: The circuit boards are transferred via conveyor to a large reflow oven. It heats the solder in the paste at high temperatures to melt the solder. When heating is complete, the board will pass through a series of ovens consisting of cooler heaters, which will help cool and cure the melted solder.

Check: The assembled board should tested functionally to check for bad connections. Common inspection methods include manual inspection, x-ray inspection, and automated optical inspection.

Through-hole component insertion: When the board assembling with other types of components, such as SMT or PTH, you need to use manual welding or wave soldering welding methods to insert PTH components.

Functional test: Functional test is the last step of PCB assembly to test the functionality of the PCBA. The test will simulate PCB operation and monitor the electrical characteristics of the PCB with power and analog signals passing through the PCB.

 

How to improve the quality of PCB assembly?

Choose proper component size: It is important to choose the correct package size for each component. It is advisable to choose a larger package. That is relatively easier to assemble the entire board again when disassembling and soldering the components.

Design reasonable component footprint: Component footprint is another key consideration for PCB assembly. Furthermore each package is created exactly according to the pad pattern specified in the data sheet for each integrated component.

Design suitable component spacing: Insufficient spacing between components caused by overheating, is one of the main causes of PCB failure. This situation is more obvious in some complex circuits. Redesign and manufacturing will be time-consuming and costly.

Ensure accuracy of the BOM: An error can lead to huge trouble, and manufacturers need to spend a lot of time identifying the problem. When there are new components or replacement, the client should  update the BOM sheet in time to ensure its accuracy and validity.

Use of marker points: For use as a point of Mark points are very important for PCB assembly, especially when it comes to close spacing of components.

 

PCB assembly – KingPCB’s services

KingPCB Limited provides complete PCB assembly services. Including PCB manufacturing, component procurement, and assembly. KingPCB’s uses the most advanced equipment, with years of experience and stable relationships with electronic component suppliers. We provide the most reliable and highest quality one-stop PCB assembly services to meet the different needs of our customers.

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PCB Blog

How to Choose the Right PCB Assembly Vendor

PCB Assembly Vendor

How to Choose the Right PCB Assembly Vendor?

One of us may be aware of the fact that almost each electronic device or gadget in our daily lives. Perhaps has one integral and basic component that is common. It could range from laptops, smartphones, desktops, dishwashers, televisions, air conditioning machines, etc. All these machines certainly cannot function without a PCB assembly. Hence, there is clearly an integral role to play as far as these Prototype PCB Assembly technologies and units go. A few years back, PCB assembly was an integral part of the manufacturers of various end user products.

Slowly, the concept of OEM or Original Equipment Manufacturers became the norm and also the necessity. This led to many third party manufacturers becoming vendors for different types of PCB assembly machines. In fact, it makes much better sense for most manufacturers to have third party service providers when it comes to meeting their specific needs and requirements of PCB assembly technologies, machines, and kits.

In this article, we will try and learn about the basics of PCB assembly. Additionally, we also will have a look at the various points to keep in mind. Whenever as manufacturers or other small scale units you are planning to hire the right PCB ASSEMBLY VENDOR.

WHAT EXACTLY IS PCB ASSEMBLY ABOUT?

Put in simple words, PCB assembly is a process of assembling, soldering and attaching various electrical and electronic components. This is done on manufactured and pre-formatted printed circuit boards or PCBs. PCB assembly is an integral and critical part of any specialist production machinery. It is extremely useful whenever there is a need for mass production and the entire unit is often referred to as PCBA. There is a subtle difference between PCB and PCBA and it would be a good idea to have a basic understanding about the same.

To put it simply, PCB refers to the empty circuit board and in most cases the board is deep green in color.

It may resemble a green slate with some divided spaces and lines. The PCB unit by itself cannot be of too much use unless the entire assembly is complete. This is where the role of a professional and experienced. PCB assembly vendor becomes quite critical and for many manufacturers and even for OEMs (original equipment manufacturers). Their role is indispensable.

When we refer to PCBA, we are talking about the entire process of soldering as well as assembling the various electronic components onto a circuit board.

This is referred to as assembling or finishing the circuit board. Hence, it is quite obvious that PCBA are in use in different types of electronic devices rather than the PCB.

We hope the above may have given our readers a reasonably good insight and information about the most important aspects of PCB. Let us now try to list down a few important points that may be helpful in identifying and then employing the right PCB ASSEMBLY VENDOR.

As mentioned above, there is an ever-growing demand for third party PCB assembly vendors.

At the same time, there are dozens of such assembly vendors. As customers and end users of the PCBA products, we must be sure that we hire the right service providers. This is not an easy job simply because many small scale and medium entrepreneurs and manufacturers of various end products do not have the right idea about the whole thing.

Hence, we are sharing below a few of the most important points to note in mind when it comes to hiring these professionals.

* Quality of pcb.

This is the key differentiator from one pcb manufacturer to the other. Quality when it comes to assembling pcbs means many things. There are many attributes that go in defining quality and here are a few of the most important ones. To begin with, the board should be of the right dimensions. Further, the holes must have been accurately positioned and drilling perfectly. There is something known as a bare board test and all pcb units must pass this test. The board material should be of good quality and should be free from board warping and other such issues.

* Ability to cater to specific requirements:

There is no point hiring a pcb manufacturer who cannot promise that he will work exactly for the required specifications. They should be ready to receive files containing the designs and layout in file formats that the customers are happy with. They should be able to produce the right that they choose the right type of pcb materials with the right number of layers, tolerance capabilities and other specific requests from the clients.

* Cost is a factor.

There is no doubt that cost is a factor of major importance and significance. As end products become extremely cost-sensitive, the pcb assembly vendors should be ready to offer their final products at a competitive price without compromising on quality under any circumstances.

* Being able to meet timelines.

Turnaround times are also extremely important considerations. This is because most pcb assembly companies that make use of the kits and other end products would like the products delivered to them within the given deadlines. This may look easy to begin with, but as volumes move up, maintaining uniformity, quality, integrity and also adhering to tough and demanding timelines is not an easy job. It requires a complete understanding of the entire process of pcb making from start to end. Meeting demanding timelines and turnaround times often read to

* Best of manufacturing facilities.

We must always bear in mind that your pcb assembly end product is as good as the manufacturing facilities and the skills of your personnel. Therefore, before you choose a pcb assembly vendor make sure that you inspect their manufacturing facilities. They should be state of the art. And these facilities should also have the support of suitable technical staff at all levels. In fact, many oems and even manufacturers of various end products take the responsibility of supporting the right manufacturing facilities on behalf of the vendors. the quality and processes are also often monitored by them on a continuous basis.

CONCLUSION

The above are just a few of the most important tips that one should keep in mind while choosing a suitable assembly vendor for your PCB. There are other attributes like being able to scale up numbers in case of increased demand. Being able to make design changes in line with changing product needs and requirements amongst other things.

To conclude, hiring a good PCB assembly vendor does take quite a bit of time, effort, understanding and patience.

Contact us today to know more about KingPCB PCB assembly services.