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What are the reasons for the failure of electronic components?

Electronic components mainly include components and devices. Electronic components are finished products whose molecular components are not changed during production and processing, such as capacitors, resistors, and inductors. Electronic devices are finished products whose molecular structure changes during the production process, such as electron tubes, integrated circuits, etc.

1. Resistive components

The failure of resistance components accounts for a large proportion of electronic equipment. Resistance can be divided into functions such as shunting, step-down, load, and impedance matching. According to different structures, resistance components can be divided into wire-wound resistors and non-wire-wound resistors.

The main ways of failure of resistance components are contact damage, open circuit and mechanical damage to the lead.

The influence of temperature change on the resistance is mainly that when the temperature rises, the thermal noise of the resistance increases, the resistance value deviates from the nominal value, and the allowable dissipation probability decreases. But we can also take advantage of this characteristic of resistors. For example, there are specially designed resistors: PTC (Positive Temperature Coefficient Thermistor) and NTC (Negative Temperature Coefficient Thermistor). Their resistance is affected by temperature. Very big.

Mechanical vibration will loosen solder joints and crimping points, resulting in mechanical damage such as poor contact.

2. Capacitor components

The main failure modes of capacitor components include breakdown, mechanical damage, and electrolyte leakage.

The main reasons for capacitor breakdown are:

1) The medium has defects, impurities and conductive ions;

2) The medium is aging;

3) The dielectric material has electrical and air gap breakdown;

4) The medium is mechanically damaged during manufacturing and processing;

5) The molecular structure of the medium changes;

6) The migration of metal ions forms a conductive channel or edge flashover discharge.

Capacitor failure may also be caused by an open circuit. Oxidation of the lead wire and the capacitor contact point leads to a low-level open circuit, poor contact between the lead wire and the electrode, and the metal foil of the electrolytic capacitor anode leads to an open circuit failure due to mechanical breaking. For this reason, the capacitor may also fail due to electrical parameter degradation failures, such as: the migration of metal ions in the electrode material, the self-healing effect of the metalized electrode of the material, the electrolytic and chemical corrosion of the electrode, humidity, surface pollution, etc., may all cause the capacitor. Degradation of electrical parameters.

3. Inductance components

Inductance components involve transformers, inductors, filter coils, oscillating coils, etc. Most of the failures of inductance components are caused by external factors, such as: the temperature rise of the transformer, the short-circuit of the load, the excessive current passing through the coil, etc., will cause the coil to short-circuit, short-circuit, and breakdown.

In an integrated circuit, no matter which part has a problem, the whole cannot operate normally, such as: electrode short circuit, open circuit, mechanical wear, poor solderability, etc., will all fail. Failures are mainly divided into complete damage and poor thermal stability. Thermal stability failures mainly occur at high temperatures or low temperatures, and fail if they exceed the operating temperature range of the device.

How to effectively find the failed electronic components and replace or repair the problem?

During debugging, when there is a problem that the circuit cannot work or does not work properly. First, through the dynamic observation method, that is, when the line equipment is energized, the faults of the electronic components are judged by listening, watching, touching, and smelling. For example: listen to whether there is any abnormal sound from the equipment. Look carefully for smoke and sparks in the circuit; touch the components and circuits for hotness; smell for burns and other odors.

It can also be judged by measuring the on-off conditions in the circuit with a multimeter, and by measuring various values in normal and abnormal circuits.

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Cleaning method of pcba circuit board

After PCBA processing is completed, it is often seen that there will be many residues on the surface of PCBA. These residues not only affect the appearance, but also affect the quality of PCBA. Therefore, the cleaning of PCBA is very important. Next, FASTPCBA will introduce manual cleaning. And automatic cleaning method.

1. Manual cleaning

Generally, small and medium-sized PCBA processing plants will use manual cleaning methods, which are relatively cost-effective and cost-effective. Manual cleaning tools mainly include: cleaning tank, spray can, brush, IPA or Vigon EFM, gloves, deionized water, wipe paper, air gun, sealed bag.

Manual cleaning steps:

1) Clean the circuit board in IPA or Vigon EFM, or spray IPA and EFM on the surface of the circuit board, using about 10ml per 4 square inches.

2) Use a moist soft short-bristle brush to wipe the circuit board continuously for about 10 seconds.

3) Use deionized water for rinsing, about 10 ml per 4 square inches. Effectively remove potential pollutant residues.

4) Hold the edge of the circuit board and wipe off excess deionized water with a clean lint-free wipe.

5) Visually inspect the cleanliness of the circuit board.

6) If necessary, use an air gun to dry the circuit board.

7) If the circuit board or components need to be stored for a period of time before coating, please put the circuit board or components in a sealed bag containing a desiccant.

2. Automated cleaning

The automatic cleaning process is divided into three methods: water cleaning, semi-aqueous cleaning and solvent cleaning.

The tools and materials for automatic cleaning mainly include: water washing machine, deionized water system, conductivity tester, beaker, and deionized water.

Automatic cleaning operation steps:

1) Preparation of deionized water: use electrodialysis device and ion exchange resin tank to prepare deionized water.

2) Conductivity test: Use a conductivity tester to test the conductivity of the water after electrodialysis and ion exchange resin tanks. If both meet the index requirements, it can be used for water cleaning.

3) Introduce the water washing machine: introduce the deionized water in the water storage tank to the water washing machine.

4) Set the parameters of the washing machine: the washing room and rinsing room are set to 60±10℃; the drying room is set to 60℃～90℃.

5) Setting the chain speed: generally control the chain speed at 50～150cm/min.

6) After the PCBA is cleaned, take it out from the washing machine and store it in an anti-static turnover container. The anti-static turnover container is required to be clean and dust-free to avoid secondary pollution of the PCBA after cleaning.

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What is the IPC standard in the PCB industry?

The IPC Association Connected Electronics Industry Association is a global trade association that sets certain standards for the manufacture of PCBs and other types of electronic components. In addition to manufacturing, it also provides standards for assembly, electronic equipment protection, training, market research, and public policy advocacy.

IPC has members all over the world, with more than 4,500 companies. These members come from all aspects of the electronics industry, such as designers, circuit board manufacturers, suppliers, assembly companies and equipment manufacturers.

1. The history behind IPC

IPC is a member-driven organization, established in 1957 by 6 printed circuit board manufacturers under the name of "Printed Circuit Board Research Institute". The organization was established to eliminate supply chain barriers, formulate industry standards and support industry development.

Later, the organization changed its name to the Institute of Interconnect and Packaging Electronic Circuits. Since 1999, they have adopted IPC under the slogan "Connected Electronics Industry Association". However, the complete form of IPC represents the Institute of Printed Circuits. IPC is headquartered in Bannockburn ll, and has offices in major countries such as the United States, China, India, Sweden and Russia.

2. Why are IPC standards important?

The IPC standard ensures that manufacturers manufacture safe, reliable and high-performance PCB boards by paying attention to manufacturing details and committed to maintaining quality throughout the manufacturing process.

These standards can help different companies maintain the same parameters in terms of PCB quality assurance and reliability so that they can meet customer expectations and production process improvements in many different ways.

3. The IPC standard supports PCB manufacturers in many ways, such as

* Maintain the quality and reliability of the final product: IPC standards will help manufacturers make products with higher quality and reliability. When the manufacturer maintains the standard from the first step of the manufacturing process, the final product will have better performance and a longer service life. The quality and reliability of products should be maintained to compete in the electronics industry, so manufacturers should always maintain these two factors.

* Maintain consistency: Maintaining the consistency of quality and other parameters is the most difficult task for manufacturers. By maintaining IPC certification, PCB manufacturers can maintain their consistency and ultimately improve customer satisfaction.

* Better communication: IPC standards ensure that the same language is used internally and externally to define terms related to the life cycle of electronic devices, which also reduces the risk of communication errors. With the help of IPC standards, customers, suppliers, suppliers, regulators and other personnel involved in the process will be able to communicate better with each other.

* Maintain reputation: IPC is an internationally recognized standard, so everyone in the electronics industry knows it. If you hire a new employee who knows nothing about your company, and you follow the IPC standards in the industry, then he/she can undoubtedly follow your reputation without difficulty. Therefore, this process will improve the quality of your products and increase your reputation, so that you will be able to attract more customers to buy your products.

* Reduce cost: When you follow the IPC standard in every step of the manufacturing process, the final product will have better quality and will be reliable in use, so there is no need to check the quality of each product it is manufactured, This will reduce the cost of testing. Since everyone in the process communicates using the same terminology, the possibility of delays and rework due to poor communication is also reduced, and delays and rework also cost the company.

4. PCB circuit design needs to follow the IPC standard. I have already introduced the importance of IPC in What is the IPC standard. Here are some commonly used IPC standards.

* IPC-2581: It is a standard for sending information between PCB circuit designers and manufacturers or assembly companies. It helps to provide a standardized format for exchanging design data, thereby helping to ensure consistent production results.

* IPC-2221: This is a standard for designing PCBs, which addresses topics related to PCB circuit design, such as design, layout, materials, mechanical and physical characteristics, electrical characteristics, thermal limitations, parts lists and more.

* IPC-6012B: It determines the qualifications and performance required for rigid PCB manufacturing. It meets the requirements of the product in terms of structural integrity, solderability and conductor spacing.

*IPC-A-600F: It sets acceptable standards for PCBs. It describes what the target conditions of the PCB are, and what are the acceptable and non-conforming conditions for all components of the PCB. It describes everything from gold fingers to copper plating.

* IPC-TM-650: IPC released the test method of PCB board under IPC-TM-650, which provides guidelines for evaluating all aspects of PCB. It provides a method for testing the electromagnetic migration tendency of the surface of the test board, measuring the resistance to current passing through the surface of the PCB substrate, and a method for testing the cleanliness of ions.

In addition to these standards, there are more standards for every aspect of PCB circuit design, even the smallest aspect you can't imagine. All these positions are dedicated to providing reliable and better electronic products.

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What is Ceramic PCB?

Ceramic PCB refers to a special process board in which copper foil is directly bonded to alumina (Al2O3) or aluminum nitride (AlN) ceramic substrate surface (single-sided or double-sided) at high temperature. The made ultra-thin composite substrate has excellent electrical insulation properties, high thermal conductivity, excellent solderability and high adhesion strength, and can be etched into various patterns like a PCB board, and has a large current carrying capacity. ability. Therefore, ceramic PCB has become the basic material of high-power power electronic circuit structure technology and interconnection technology.

Manufacturing method of ceramic PCB board

1. Thick film ceramic PCB

These circuit boards consist of gold and dielectric paste printed on a ceramic substrate and baked at a temperature slightly below 1000°C. Thick-film ceramic PCBs can use gold or copper, and copper is most used because of its lower cost. To prevent oxidation, the board is baked in nitrogen.

2. Low Temperature Co-fired Ceramic (LTCC) PCB

LTCC uses co-firing while burning non-glass, glass composite materials or glass crystals and other materials at the same time. The traces are usually gold to achieve high thermal conductivity, and the circuit board is baked at 900°C.

3. High temperature co-fired ceramic (HTCC) PCB

HTCC uses alumina and binders as well as plasticizers, solvents and lubricants. Circuit traces can be metals, such as tungsten and molybdenum, and the baking temperature can be as high as 1600°C to 1700°C. This method is most suitable for small circuit boards and carrier circuits.

Advantages of ceramic pcb board

1. High resistance.

2. Outstanding high frequency characteristics.

3. High thermal conductivity: It is related to the material itself, ceramics are compared to metals. Both resins have advantages.

4. Good chemical stability, anti-vibration, heat resistance, pressure resistance, internal circuits, MARK points, etc. are better than general circuit substrates.

5. It is more accurate in printing, patching and welding.

Disadvantages of ceramic pcb board

1. Fragile

This is one of the main shortcomings. At present, only small-area circuit boards can be produced.

2. The price is expensive

There are more and more requirements for electronic products. Ceramic circuit boards only meet the requirements of some relatively high-end products, and low-end products will not be used at all.

Application of ceramic PCB

Ceramic PCB enjoys its greatest realization in high-speed, high-power circuit applications. Compared with traditional circuit board materials, these circuit boards can reduce parasitic capacitance by up to 90%, and provide the greatest hope for future use in aerospace, medical equipment, industry, and automotive industries.

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What are the requirements for PCBA shipping packaging?

Since PCBA carries more electronic components, it has extremely high requirements for ESD static electricity and anti-collision. Therefore, the safe packaging of PCBA boards is particularly important. Many factories use the simplest bubble bag to package products, but this is only suitable for short-distance transportation, which is often the delivery method.

For long-distance transportation, international express delivery, etc., the industry's more peer-to-peer packaging method at this time is electrostatic bag + PE pearl cotton + carton for packaging. This has the advantage of effectively avoiding static electricity damage and buffering impact during transportation.

After the PCBA processing is completed, we need to transport the PCB board to the customer in various ways. During the transportation and packaging process, we need to pay attention to the following requirements.

1. Packaging materials PCB boards are relatively fragile and easily damaged products, so they must be carefully packaged in bubble bags, pearl cotton, electrostatic bags, and vacuum bags before transportation.

2. Anti-static packaging Static electricity will penetrate the chips in the PCB board. Because static electricity is invisible, intangible, and easy to generate, it is necessary to use anti-static packaging during the packaging and transportation.

3. Moisture-proof packaging Before packaging, clean and dry the surface of the PCB board, and spray the three-proof paint.

4. Anti-vibration packaging Put the packaged PCB board in an anti-static packaging box. When it is placed vertically, it should not be stacked up to more than two layers, and a spacer should be placed in the middle to keep it stable and prevent shaking.

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Why use a PCB prototype?

Before starting a complete production run, you must ensure that your printed circuit board (PCB) is functioning properly. Since PCB is an indispensable part of many electronic devices, if a product performs poorly or fails after full production, you may pay a high price. Prototyping the PCB in advance can help avoid this situation.

No matter how careful your designer is on the project, invisible problems and small errors will always threaten the functionality of the final product. Generally, when testing the functionality of PCB-based solutions, your engineers will use PCB prototypes early in the design process.

Before moving to more complex designs, they usually order multiple PCB prototype runs to test a single function or redesign. Prototyping enables them to find any elements that need correction in the early stages of the process, thereby reducing project risks and costs.

What is PCB prototype?

PCB prototypes are early samples of products whose sole purpose is to test design concepts to see if they are effective. Although most prototypes are usually used to test basic user functions, engineers need some (if not all) functional PCB prototypes to check the complete functionality of the design.

Engineers and designers use different types of PCB prototypes to test different design aspects. Throughout the project, your design team may use multiple PCBs at different stages of their design process. Examples of these prototypes include:

Visual models: They illustrate the physical aspects of the PCB design and show the overall component structure and shape. As the initial prototype in the design process, engineers use visual models to review and communicate the design easily and economically.

Proof-of-concept prototypes: These prototypes focus on duplicating the main functions of the PCB board, and do not have all the functions of the final product. They show feasibility.

Working prototype: These functional boards contain all planned functions and features of the final product. They help identify problems and weaknesses in the design, but rarely represent the appearance or appearance of the final product after it is finished.

Functional prototypes: The designer makes these similar to the final product. They provide the most accurate idea of ​​the final design.

What are the advantages of PCB prototype?

PCB design engineers use prototypes to repeatedly test the functionality of their solutions throughout the design process, and do it every time a new change or addition is made. However, you may ask, why use PCB prototype before standard production runs.

Although prototypes seem to add some cost and steps to the process, they play an important role in the design process. They allow your designers and their teams to test at multiple design stages and make adjustments if necessary to customize solutions before full production runs.

This creates several advantages for your designers and clients:

1-Reduce time

Whenever engineers develop a PCB design, they usually go through multiple iterations during testing before creating the final product. Although this can be a time-consuming process, the PCB prototype helps speed up the process by:

Visual aid: Showing the prototype of the final product to the customer as a visual aid helps to easily communicate the design, thereby minimizing the time spent on interpretation or redesign requested by the customer.

Complete testing: Prototype design eliminates guesswork in the equation, allowing your design team to quickly and accurately identify problems.

Minimize rework: Prototyping allows your design team to view and test the circuit board before full production, saving time and money.

2-Accurate and reliable prototype

A reliable PCB prototype can more easily solve the problems in the entire development process. A high-quality PCB prototype accurately represents the functions of your final product, and allows designers to view and test the following: PCB design, functional testing, condition testing, and final product design.

3-Manufacturing review and assistance

When you use PCB prototype production services, you will benefit from a new perspective from a third party. Some problems may arise during the design process, including excessive input, design blind spots, and design rule checking (DRC) restrictions. These issues can lead to design flaws, inefficiencies, and many other issues that designers missed during the review process.

4-Ability to test components individually

For complex projects, the ability to test and verify each component individually enables your team to pinpoint where the problem is. Without individual component testing, it is difficult to find the problematic area.

5-Reduce costs

So why add PCB prototype in your design process? Because it reduces the overall cost of the project. By helping your design team find problems faster, you can fix them before investing in standard production runs. It is cheaper to rework defective components than to produce the entire project.

6 – Complete the project efficiently

Using PCB prototype production enables your design team to find problems early and quickly determine the components that need to be adjusted. Without it, discovering the causes of insufficient performance and other defects would be a time-consuming process that may greatly extend the time frame of the project.

Why produce a PCB prototype?

Because this is a powerful tool for designers to provide time and cost savings while ensuring high-quality final products. It has many benefits, such as shortening project time and cost, being able to test components individually, completing projects efficiently, and accurate prototypes. Therefore, industry professionals recommend using prototyping to test new designs and revisions.

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Preparation work before PCBA soldering

PCBA welding involves many PCBA processing links, and the quality of PCBA welding is closely related to these links. PCBA electronics manufacturers must ensure that every link is done well in order to provide customers with high-quality PCBA services. Today, FASTPCBA will analyze with you what preparations the factory has to do before wave soldering?

1. Use a density meter to measure the density of the flux. If the density is too high, dilute it with a thinner.

2. Check the PCB to be soldered (the PCB has been coated with SMD glue, SMC/SMD SMD glue and solidified and completed the THC insertion process). The soldering surface of the socket and the gold finger and other parts of the attached component socket are coated with solder resist. Or stick it with high temperature resistant tape to prevent the socket from being blocked by solder after wave soldering. If there are large-size slots and holes, they should also be attached with high-temperature tape to prevent the solder from flowing to the upper surface of the PCB during wave soldering. (The water-soluble flux should be a liquid solder resist. After coating, place it for 30 minutes or bake under a light for 15 minutes before inserting the components. After soldering, it can be washed directly with water.)

3. If using traditional foaming flux, pour the flux into the flux tank.

These three steps are actually the work that must be done before the entire wave soldering process, and as an smt chip processing plant, the process file should be written first in the process control.

Choose FASTPCBA for high-quality pcba circuit boards, quality assurance, no MOQ requirements, welcome to make samples.

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Happy Mid-Autumn Festival

As one of the most important traditional Chinese festivals, the Mid-Autumn Festival falls on the 15th day of the eighth lunar month, September 21 in 2021.

It takes its name from the fact that it is always celebrated in the middle of the autumn season. The day is also known as the Moon Festival, as at that time of the year the moon is at its roundest and brightest.

This day is also considered a harvest festival since fruit, vegetables and grain have been harvested by this time.

It is an evening celebration where families gather together to light lanterns, eat moon cakes and appreciate the round moon. The full moon is a symbol for family reunion, which is why that day is also known as the Festival of Reunion.

The Mid-Autumn Festival celebrations date back more than 2,000 years. The word "Mid-Autumn" first appeared in the famous ancient book Zhou Li (The Zhou Rituals, a book telling the rituals in the Zhou Dynasty). However, it was not until the early Tang Dynasty (618-907) that the day was officially celebrated as a traditional festival. It became an established festival during the Song Dynasty (960-1279), and has become as popular as the Spring Festival since the Ming and Qing dynasties (1368-1911). Celebrations have continued ever since and more customs for marking this occasion have been formed.

In feudal times, Chinese emperors prayed to Heaven for a prosperous year. They chose the morning of the 15th day of the second lunar month to worship the sun and the night of the 15th day of the eighth lunar month to hold a ceremony in praise of the moon. In the Xicheng district of Beijing is the Yuetan Park, which originally was the Temple of Moon, and every year the emperor would go there to offer a sacrifice to the moon.

The Chinese government listed the festival as intangible cultural heritage in 2006. It was made a public holiday in 2008.

The Mid Autumn Festival is approaching, FASTPCBA will be off for 3 days (19th- 21st Sept). PCB, SMT Factory & Component Warehouse & Shipment Our factory and the express delivery service will be off from 19th Sept to 21s t Sept, 2021. So, the lead-time and shipment of orders during the festival will be delayed for three days, work on the 22nd.

Happy Mid-Autumn Festival

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What are the reasons for the failure of solder joints in PCB assembly?

With the development of electronic products to miniaturization and precision, the PCBA processing and assembly density adopted by the chip processing plant is getting higher and higher, and the solder joints in the circuit board are getting smaller and smaller, and the mechanics and electricity it carries And the thermodynamic load is getting heavier and heavier, and the requirements for stability are increasing. However, PCBA solder joint failure may also be encountered in the actual processing process, and it is necessary to analyze and find the reason to avoid solder joint failure again.

Reasons for the failure of solder joints in PCB assembly: 1. Bad component leads: plating, pollution, oxidation, coplanarity. 2. Bad PCB pads: plating, pollution, oxidation, warpage. 3. Solder quality defects: composition, impurity, and oxidation are not up to standard. 4. Flux quality defects: low solderability, high corrosion, low SIR. 5. Defects in process parameter control: design, control, and equipment. 6. Defects of other auxiliary materials: adhesives, cleaning agents.

How to increase the stability of PCBA solder joints: For the stability experiment of PCBA solder joints, including stability experiment and analysis, its purpose is to evaluate and appraise the stability level of PCBA integrated circuit devices on the one hand, and to provide parameters for the stability design of the whole machine.

On the other hand, it is necessary to increase the stability of the solder joints during PCBA processing. This requires the analysis of failed products to find out the failure modes and analyze the causes of failure. The purpose is to correct and improve the design process, structural parameters, welding process and increase the yield of PCBA processing. The failure mode of PCBA solder joints has an impact on the cycle life. The prediction of is very important and is the basis for establishing its mathematical model.

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What is included in the one-stop PCBA service?

PCBA is a series of processing processes such as PCB circuit board manufacturing, component procurement and inspection, SMT assembly, DIP assembly, program firing, testing, and aging. There are many links involved in the PCBA processing process, and the quality of each link must be controlled to produce a good PCBA circuit board.

1. PCB Circuit Board Manufacturing

After receiving the PCBA order, analyze the Gerber file, pay attention to the relationship between the PCB hole spacing and the board's bearing capacity, do not cause bending or breakage, and whether the wiring considers key factors such as high-frequency signal interference and impedance.

2. Procurement And Inspection of Components

The procurement of components requires strict control of channels, and must be picked up from large traders and original factories, and 100% avoid second-hand materials and fake materials. In addition, a special inspection post for incoming materials is set up, and the following items are strictly inspected to ensure that the components are free of faults.

PCB: Reflow soldering furnace temperature test, no flying leads, whether the vias are blocked or leaking ink, whether the board surface is bent, etc.;

IC: Check whether the silk screen is completely consistent with the BOM, and keep it at constant temperature and humidity;

Other common materials: check the silk screen, appearance, power-on measurement, etc. The inspection items are carried out according to the random inspection method, and the ratio is generally 1-3%.

3. SMT Assembly

Solder paste printing and reflow oven temperature control are key points, and it is very important to use laser stencils of good quality and meeting process requirements. According to the requirements of PCB, some steel mesh holes need to be enlarged or reduced, or U-shaped holes are used to make steel mesh according to process requirements. The furnace temperature and speed control of the reflow soldering is very critical to the solder paste infiltration and soldering reliability. It can be controlled in accordance with the normal SOP operation guidelines. In addition, AOI testing needs to be strictly implemented to minimize defects caused by human factors.

4. DIP Assembly

In the DIP assembly process, the mold design for wave soldering is a key point. How to use molds to maximize the probability of good products after the furnace is a process that PE engineers must continue to practice and summarize experience.

5. Program Firing

In the previous DFM report, you can suggest to customers to set up some test points on the PCB, the purpose is to test the PCB and PCBA circuit continuity after soldering all components. If you have conditions, you can ask the customer to provide a program, burn the program into the main control IC through the burner, and test the function changes brought about by various touch actions more intuitively, so as to test the function of the entire PCBA Completeness.

6. PCBA Board Test

For orders with PCBA test requirements, the main test content includes ICT, FCT, aging test, temperature and humidity test, drop test, etc., according to the customer's test plan operation and summary report data.

FASTPCBA is a 20 Years PCBA Manufacturer, Providing One-Stop PCBA Solution: PCB Manufacturing + Components Sourcing + PCB Assembly + Testing. Welcome to pay attention to us! !

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HDI PCBs for Medical Electronic Equipment

In the past few decades, the size of PCBs has become smaller and smaller, and few industries have used this advantage more than the medical industry, but the electronic design of medical equipment is not limited to reduction in size. Nowadays, electronic engineers have more reasons to use HDI PCB than ever before, the ever-changing needs of the medical industry!

What are HDI Printed Circuit Boards?

First of all, the first thing is: HDI PCB can integrate a large number of internal wiring by using advanced technology to make it more compact. The new technology helps reduce size without sacrificing performance and provides engineers with multiple construction options based on the application.

HDI PCB Board requires other manufacturing technologies, such as:

* Sequential stacking * Stacked microvia * Staggered micropores * Buried hole * Plated through holes * Laser drilling

Why is high density pcb board important to medical technology?

Medical equipment must meet the highest standards, which means you need the best technology currently available. The quality of life is also problematic-the less invasive and invasive the device, the earlier the patient will use it.

The most obvious demand for cutting-edge technology in the design of medical electronic equipment. For example, pacemakers need to be small, light and reliable. The high-speed transmission in HDI PCB is ideal for medical equipment, where the equipment response time may mean life or death.

The demand for smaller circuit boards and better performance has resulted in hdi circuit boards allowing more components to be placed on each side of the original circuit board. Designers can use the increased I/O in a smaller space. The signal transmission speed is faster and the signal loss is less.

HDI PCB is more challenging and expensive in design and manufacturing, but usually the benefits are worth it. Medical PCB assembly usually requires HDI technology, even if the cost per board increases.

Limitations of HDI Printed Circuit Boards

Each technology has its limitations, and HDI Printed Circuit Boards technology is no exception.

For most medical device manufacturers, the biggest limitation of HDI Printed Circuit Boards technology is its cost.

Manufacturing hdi circuit boards requires expensive equipment and expertise, which not every board manufacturer has. Since each board requires more time to build, the yield is lower. The correct materials need to be used to construct the multiple layers of the circuit board to achieve the desired results.

This technology is relatively new and evolving rapidly, so what happened last year may not be the case this year. You must also find out which of the six variants is best for your device-without the help of an expert inside, this is a difficult task.

HDI PCB: Is it necessary or necessary?

Compared with standard PCB boards, what we can do with hdi circuit boards now seems to sound like magic, especially for generations. However, magic requires careful engineering and manufacturing, so your products are not only smoke and mirrors.

If you and your manufacturing partner can combine the right hdi circuit boards with the right applications, you will end up with smaller and more efficient circuit boards. It will be worthwhile to bring the patient's peace of mind.

Keywords: HDI PCB | HDI Printed Circuit Boards | HDI PCB Board | HDI Circuit Boards | HDI PCB Manufacturer | FASTPCBA

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The Process from Bare PCB Board to PCBA Board

What is the process from bare PCB board to PCBA board? The following FASTPCBA will give you a detailed explanation:

SMT placement process

SMT ( Surface Mounted Technology ) is one of the most popular technologies and processes in the electronics assembly industry.

Simply put, it is a method of mounting leadless or short lead surface mount components ( SMC/SMD ) on the surface of a PCB ( Printed Circuit Board ) or other substrates by reflow soldering or dip soldering. Circuit assembly technology to be welded and assembled.

What preparations need to be made before SMT placement?

1. There must be a MARK point on the PCB, also called a reference point, which is convenient for the placement of the placement machine and is equivalent to a reference object;

2. To make a stencil to help the deposition of solder paste, transfer the exact amount of solder paste to the exact position on the empty PCB;

3. SMD programming, according to the provided BOM list, the components are accurately positioned and placed in the corresponding position of the PCB through programming.

After all the above preparations are completed, SMT patch can be carried out.

First of all, the placement machine determines whether the board's feeding direction is correct according to the MARK point on the incoming board, and then brushes the solder paste on the stencil, and deposits the solder paste on the PCB pads through the stencil.

Next, the placement machine places the components on the corresponding positions of the PCB board according to the placement programming, and then undergoes reflow soldering to effectively contact the components, solder paste and the circuit board.

Finally, automatic optical inspection is carried out to check the components on the PCB board, including: virtual soldering, solder connection, device orientation, etc., but the functional inspection cannot be done because the board has plug-in components that have not been soldered.

It should be noted that some devices have positive and negative poles or pin order, so it is necessary to check the incoming materials to prevent patch errors, especially for BGA packaged devices. If the direction is wrong, subsequent disassembly and repair soldering are compared Time-consuming and laborious.

DIP plug-in process

DIP ( Dual In-Iine Package ) is the English abbreviation for dual in-line package. In fact, it is a device that can be perforated and welded on the PCB board, commonly known as plug-in components.

What preparations need to be done before DIP plug-in?

1. Prepare the furnace fixture and fix the PCB board to facilitate the transmission on the conveyor belt;

2. Need to correct the pins of plug-in devices with too long pins to a proper length;

3. Manpower is required to insert the plug-in device into the via hole of the corresponding PCB.

Next, briefly describe the DIP plug-in process: The DIP plug-in process is much simpler than the SMT patch process, but it requires human assistance to insert the plug-in component into the corresponding hole, and then pass through the wave soldering machine, the plug-in device is perfectly welded On the PCB board.

Some people may worry, isn't the solder in the solder pool splashed all over the board?

The answer is no. The solder in the solder pool will only stick to the place where it is in contact with the metal and will not stick to the green solder mask. This is the role of the solder mask.

After the plug-in device is soldered, is the PCBA completed? Of course not, because the board after the patch and plug-in is also checked and functionally verified.

The functional test of the produced PCBA can be divided into two steps:

The first step: human visual inspection of PCBA, preliminary screening of defective boards, such as: tin connection, false soldering, missing soldering and other visible errors with the naked eye, and then send the defective board for repair, the board with no problem will enter the second step.

Step 2: Check the PCBA with the test fixture, which is actually the power-on test function of the PCBA. Use the test on the test fixture to do the corresponding test for the corresponding test point of the PCBA, such as: power on and off, relay pull-in, communication, etc., judge Whether each small module on the board can work normally.

After the above two steps of screening, not only the problem board can be screened out, but also the problem of the problem board can be determined during the screening process, which reduces a certain amount of work for subsequent repairs of the problem board.

Therefore, it can be seen that in the process from PCB bare board to PCBA, technicians conduct strict and comprehensive tests on every step, just to ensure that every step in the product production process is normal. Only in this way can we continue. step.

Waterproof, dustproof and anti-corrosion treatment for PCBA

Water-proof, dust-proof and anti-corrosion treatment is to spray or dip wax on PCBA. Each company may have its own way of processing, some manually apply the three-proof paint, some machines spray the three-proof paint, some dip wax, and of course some do not do the treatment.

At this point, the entire process from bare PCB to PCBA is introduced.

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Please attach your Gerber Files / Bom List By email: [email protected], to get a free quote on PCB and Assembly Services, one of our helpful staff will contact you shortly.

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What is the main process of PCBA testing and what tests are there?

PCBA testing refers to the testing of the PCBA board for IC programming, circuit continuity, current, voltage, and pressure. PCBA has many uncontrollable factors in the production process, and it is difficult to ensure that PCBA is a good product. PCBA testing is a necessary link to strictly control the quality of shipments. Next, I will introduce the main process of PCBA testing.

1. What tests are mainly included in the PCBA test? According to different products and different customer requirements, PCBA testing will be different. In general, PCBA testing mainly includes ICT online testing, FCT functional testing, and aging testing.

2. PCBA test process PCBA testing generally develops a specific test process based on the customer's test plan. The basic PCBA test process is as follows:

Program burning After the PCBA board completes the welding process of the front end, the engineer begins to program the microcontroller in the PCBA board to enable the microcontroller to achieve specific functions.

ICT test The ICT test mainly uses the test probe to contact the test point of the PCBA to realize the test of the PCBA circuit open circuit, short circuit and the welding condition of the electronic components. The accuracy of the ICT test is relatively high, the instructions are clear, and the scope of use is relatively wide.

FCT test FCT test can test the environment, current, voltage, pressure and other parameters of PCBA. The content of the test is relatively comprehensive, which can ensure that the various parameters of the PCBA board meet the design requirements of the designer.

Aging test The aging test can ensure the stability of the product by continuously energizing the PCBA board, simulating the user's use scene, detecting some hard-to-find defects, and inspecting the service life of the product.

After PCBA passes a series of PCBA tests, the PCBA board with no problem can be affixed with a qualified label, and finally it can be packaged and shipped.

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In the process of PCBA processing, how to do solder paste printing is the key point

In the process of PCBA processing, how to do solder paste printing is the key point

Solder paste printing is very important for PCBA. It directly affects the overall soldering effect of PCBA. In the process of PCBA processing, how to do solder paste printing has become a problem that must be considered by production managers. The effect of solder paste printing consists of four parts: stencil, solder paste, printing process, and detection method. Below, FASTPCBA will give you a specific analysis.

1. Steel mesh The opening of the stencil must be appropriately enlarged or reduced according to the layout of the electronic components on the PCBA board to determine the amount of tin on the pad, so as to achieve the best soldering effect, avoid the occurrence of tin connection, less tin, etc., which requires craftsmanship The engineer conducts a rigorous evaluation. In addition, the material of the steel mesh is also critical, which affects the tension of the steel mesh and the life of repeated use.

In addition, the cleaning and storage environment before feeding the steel mesh is particularly critical. Strict cleaning must be carried out every time before going online, and check whether the vias are blocked or there is tin dross. Some PCBA manufacturers recommend purchasing a stencil tension meter, and perform a tension test of the stencil before each feeding.

2. Solder Paste Solder pastes need to be selected from mid-to-high-end brands, such as Senju, Vitero, etc., and it is better to contain active ingredients such as gold or silver. The solder paste must be stored strictly in a refrigerator at 2 to 10 degrees Celsius, and relevant statistics must be made for each storage and delivery. The recovery of solder paste must be strictly controlled within the scope of the IPC standard, and the tin paste must be strictly implemented before going online. Paste mixing program.

3. Solder paste printing At present, manufacturers are using fully automatic solder paste printers, whose equipment can well control the printing strength and speed and other parameters, and has a certain automatic cleaning function. The operator only needs to set the parameters in strict accordance with the regulations.

In the mass production process, it is particularly important to detect the phenomenon of blocked holes and deviations of the stencil, especially when some defects detected by SPI after printing show an upward trend, it is necessary to stop the machine to check the operating conditions of the stencil itself.

4. SPI printing effect detection After the solder paste printing machine, it is particularly important to configure the SPI solder paste detector, which can effectively detect many defects such as small tin, continuous tin, gap, wire drawing, offset and so on in the solder paste printing process. So as to maximize the overall welding PPM value.

It is not a secret to manage the effect of solder paste printing. It requires managers to carefully implement every management method in the PCBA processing process. And design a set of closed-loop mechanism that can find and detect defects.

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The Difference Between Medical PCB Circuit Board And Ordinary PCB Circuit Board

The development of society is fast. People are paying more and more attention to health, and the equipment in the medical industry puts forward higher requirements on the performance of pcb materials. What are the technical requirements for reliability, high frequency, high speed, and high conductivity of pcb in medical treatment?

Medical PCB circuit boards have become one of the most complex and challenging in the industry. Many people in the industry have said that medical PCB and ordinary PCB are the same board. Is there any difference?

To sum up, the medical PCB circuit board has the following aspects:

1) "Safety" and "Reliability": These are the core issues of PCB boards in the medical industry. Life support products or high-end products refer to IPC-3 level standards, and non-life support or low-end products refer to IPC-2. The large-scale medical terminal establishes its independent standard enterprise standard, strictly controls the reliability of the product. So this point is very important.

2) Long service life: General product warranty time is more than 5 years, large medical equipment requires at least 10 years, and the product lasts for a long time. The difference between medical PCB and ordinary PCB is still there.

3) Large hierarchical span: from consumer medical products that meet conventional requirements, to mid- and high-end medical products that meet high reliability and high stability requirements, to small portable products that meet high-density, high-integration, and smart Versatile and multifunctional wearable medical products.

4) Product conservative: The application of new medical technologies and new products to the market is slow, and the verification and testing of new products is repeated, which often requires comprehensive evaluation.

5) Traceability: Products require strict process records and product traceability. Some large-scale medical terminals require the traceability of PCB processing records for 10 years.

6) The process and fire protection requirements of medical pcb boards are different. The ordinary pcb process has different methods for spraying tin and cleaning the board. On the premise of taking process measures and ensuring quality and safety, it can be used for repairs as appropriate.

7) The general medical PCB demand is small, the process requirements are many, back drilling, multiple pressing, mixed pressure, high precision, special impedance, thick copper, thick gold, embedded copper block, etc. The price focus will be very low, which is also different from ordinary pcb boards.

Among all medical PCB board materials, FR-4 is the most widely used. For medical PCB design, there will be differences in the choice of FR-4 board based on the positioning of its own products and the control of the price of raw materials. For circuit boards used in medical equipment, reliable medical pcb circuit board manufacturers should be selected.

FASTPCBA is a manufacturer of medical pcb manufacturing and pcb assembly Manufacturer in China for 20 years.

We Through ISO9001, ISO14001, ISO13485 Certification, it not only proves that under the quality assurance system, FASTPCBA can continuously provide high-quality products that meet the needs of medical device customers, and further demonstrates our company's higher requirements for product quality standards. We have a professional engineering team available to assist you with Medical PCB Manufacturing & PCB Assembly Services.

Turn your medical project to PCB or PCBA, contact us.

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How are solder beads formed on the PCBA circuit board? How to eliminate it?

The phenomenon of solder beading is one of the main defects in surface mount production. Its diameter is about 0.2-0.4mm. It mainly appears on one side of the chip resistive component, which not only affects the appearance of board-level products, but also more serious Because of the dense components on the printed board, it will cause a short circuit during use, which will affect the quality of electronic products. Therefore, it is very important to understand the reasons for its occurrence and strive to control it most effectively.

The causes of solder beads are caused by many factors. The temperature and time in reflow soldering, the printing thickness of solder paste, the composition of solder paste, the production of templates, the mounting pressure, and the external environment will all be affected in all aspects of the production process. The formation of solder beads has an impact.

Solder beads are produced when the board is passed through the reflow soldering furnace. The reflow curve can be divided into four stages: preheating, heat preservation, reflow and cooling. The main purpose of the preheating stage is to heat the printed board and the surface mount components above to between 120-150 degrees, so that the volatile solvent in the solder paste can be removed and the thermal vibration of the components can be reduced. Therefore, vaporization will occur inside the solder paste during this process. At this time, if the bonding force between the metal powders in the solder paste is less than the force generated by vaporization, a small amount of solder paste will flow away from the pad. When the temperature is close to the peak of the curve during the reflow soldering stage, this part of the solder paste will also melt, and then squeeze out from under the chip resistive components to form solder beads. It can be seen from the process that the higher the preheating temperature, the faster the preheating speed, which will cause splashing in the atmospheric phenomenon, and the easier it is to form tin beads. Therefore, we can adopt a moderate preheating temperature and preheating speed to control the formation of solder beads.

The selection of solder paste also affects the quality of soldering. The metal content in the solder paste, the oxide content of the solder paste, the particle size of the metal powder in the solder paste, and the printing thickness of the solder paste on the printed circuit board all affect the solder bead to varying degrees. The formation.

1: The metal content in the solder paste: the mass ratio of the metal content in the solder paste is about 90-91%, and the volume ratio is about 50%. When the metal content increases, the viscosity of the solder paste increases, which can more effectively resist the force generated by vaporization during the preheating process. In addition, the increase in metal content makes the metal powders tightly arranged, so that they have more opportunities to combine and are not easy to be blown away during gasification. The increase of the metal content can also reduce the tendency of the solder paste to collapse after printing, so it is not easy to form solder beads.

2: The oxide content in the solder paste: The oxide content in the solder paste also affects the welding effect. The higher the oxide content, the greater the resistance during the bonding process after the metal powder is melted. During the reflow soldering stage, the surface of the metal powder The content of oxides will increase, which is disadvantageous? "Wetting" leads to the formation of tin beads.

3: The particle size of the metal powder in the solder paste. The metal powder in the solder paste is very small and spherical, with a diameter of about 20-75um. When mounting fine-pitch and ultra-fine-pitch components, it is advisable to use metal powder with a smaller particle size The solder paste is about 20-45um. The overall surface area of ​​the solder particles is greatly increased due to the shrinkage of the metal powder. The finer powder has a higher oxide content, which will alleviate the tin bead phenomenon.

4: The printing thickness of the solder paste on the printed circuit board: the printing thickness of the solder paste is a main parameter in the production, and the printing thickness of the solder paste is usually between 0.15-0.20mm. If it is too thick, it will cause "collapse" to promote tin beading. Formed. When making the template, the size of the pad determines the size of the printed hole on the template. Usually, in order to avoid excessive solder paste printing, the size of the printed hole is made to be less than 10% of the contact area of ​​the corresponding pad. We have done such a practice, and the results show that this will reduce the tin bead phenomenon to a considerable extent.

If the mounting pressure is too high during the placement process, when the component is pressed on the solder paste, a part of the solder paste may be squeezed under the component. During the reflow soldering stage, this part of the solder paste melts to form tin beads. Appropriate placement pressure should be selected during placement.

Solder paste usually needs to be refrigerated, but before use, it must be returned to room temperature before it can be opened for use. Sometimes the solder paste is opened when the temperature is too low, which will cause moisture on the surface, and the moisture in the solder paste will also cause Sikkim beads are formed.

In addition, the external environment also affects the formation of tin beads. We have encountered such a situation. When the printed boards are stored in a damp warehouse for a long time, small water droplets are found in the vacuum bag containing the printed boards. Moisture will affect the welding effect. Therefore, if conditions permit, high-temperature drying of printed boards and components before mounting will effectively inhibit the formation of tin beads.

The shorter the time the solder paste is in contact with air, the better. This is the basic principle of using solder paste.

After taking out a part of the solder paste, close the lid immediately, especially the inner lid must be pressed down tightly to squeeze all the air between the lid and the solder paste, otherwise it may be scrapped within a few days.

Summer is the season most likely to produce solder balls. In summer, the air temperature is high. When taking out the solder paste from the refrigerated place, be sure to leave it at room temperature for 4-5 hours before opening the lid. If the solder paste can be used up in a short period of one month, refrigeration is not recommended.

It can be seen that there are many factors that affect the formation of tin beads, and it is far from enough to adjust a certain parameter. We need to study how to control various factors in the production process, so as to achieve the best welding results.

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Why does PCBA have bubbles during soldering?

The pores produced by the welding of PCBA boards are also known as bubbles. Generally, reflow soldering and wave soldering during PCBA processing will produce pores, so how to improve the problem of PCBA board soldering pores? PCBA manufacturer FASTPCBA will explain it in detail for you.

1. Bake Bake PCBs and components that have been exposed to the air for a long time to prevent moisture.

2. Control of solder paste The solder paste contains moisture and is prone to pores and tin beads. First select a good quality solder paste. The temperature recovery and stirring of the solder paste are strictly performed according to the operation. The time that the solder paste is exposed to the air is as short as possible. After the solder paste is printed, reflow soldering needs to be carried out in time.

3. Workshop humidity control Monitor the humidity in the workshop in a planned way, and control it between 40-60%.

4. Set a reasonable furnace temperature curve Test the furnace temperature twice a day, optimize the furnace temperature curve, and the heating rate should not be too fast.

5. Flux spraying During wave soldering, the spraying amount of flux should not be too much, and the spraying should be reasonable.

6. Optimize furnace temperature curve The temperature of the preheating zone needs to meet the requirements, not too low, so that the flux can be fully volatilized, and the speed of passing the furnace cannot be too fast.

There may be many factors that affect PCBA soldering bubbles, which can be analyzed from the aspects of PCB design, PCB humidity, furnace temperature, flux (spray size), chain speed, tin wave height, solder composition, etc. It needs to be debugged many times. It is possible to get a better process.