日志

What is pcb flying probe testing?

05/08/2024 在： /通过：

Printed circuit board testing is a critical aspect of PCB assembly, allowing us to identify major circuit issues and address them promptly. There are various methods for PCBA testing, including flying probe testing, AOI testing, fixture testing, etc. This article will delve into the details of flying probe testing for PCBs.

What is Flying Probe Testing?

Flying probe testing is an electronic circuit testing method primarily used for testing printed circuit boards (PCBs). It employs a movable probe system that essentially “flies” over the PCB, making electrical contact with specific test points on the PCB. Ultimately, it identifies defects and verifies the electrical performance of the circuit. The flying probe testing system consists of several key components, including the probes themselves, test fixtures used to secure the PCB in place, and control software to manage the testing process.

Structural Features of PCB Flying Probe Testing

The flying probe tester is an improvement over traditional bed-of-nails testers, utilizing probes instead of a bed of nails. It features four heads with a total of eight testing probes that can move independently at high speeds on an X-Y mechanism, with a minimum testing gap of 0.2mm. During operation, the unit under test (UUT) is conveyed into the testing machine via belts or other UUT transfer systems, where the probes are then fixed to make contact with test pads and vias on the PCB, thereby testing individual components on the UUT. The testing probes are connected to drivers (signal generators, power supplies, etc.) and sensors (digital multimeters, frequency counters, etc.) via a multiplexing system to test components on the UUT. While one component is being tested, other components on the UUT are electrically shielded by the probes to prevent reading interference. The flying probe tester can detect short circuits, open circuits, and component values. Additionally, a camera is used during flying probe testing to aid in locating missing components and inspecting components with clear directional shapes, such as polarized capacitors.

Flying Probe Testing Capabilities

While flying probe testing can easily detect short circuits and open circuits, equipping them with special drivers enables them to test more complex parameters as well. Advanced probes can simultaneously probe and test both sides of multilayer boards, reducing the time needed for separate single-sided testing. Different architectures of flying probes can be used for various solutions, such as:

Signal Integrity Testing: Utilizing Time Domain Reflectometry (TDR) or Time Domain Reflectometer probes along with specialized instruments, various characteristics of PCB traces used for carrying high-speed and high-frequency signals can be tested. This setup typically captures and measures signals in both time and frequency domains to characterize defects in signal paths.

Phase Difference Measurement: Using specially designed probes to send high-frequency signals between reference traces and signal traces, the phase difference between them can be measured. This test eliminates the need for separate isolation testing to measure crosstalk between traces on the PCB.

High Voltage Stress Testing: PCBs may have insulation defects that conventional electrical tests may not detect. The insulation resistance between two traces on a PCB may be high enough to pass conventional resistance testing but still lower than the requirements in specifications. To detect this, high voltage stress testing is required, using a high voltage generator, appropriate probes, and high resistance meters.

Micro Short Circuit Detection: The presence of tiny whiskers can lead to micro short circuits on the PCB. Sometimes, they may burn off during high voltage stress testing, leaving behind carbonized residues on the PCB surface, forming high-resistance conductive paths. Micro short circuit detection probes apply low voltage to check the resistance between two traces on the PCB, gradually increasing the voltage to a level suitable for testing.

Kelvin DC Measurement: This is a highly precise DC measurement technique required for testing BGA and similar densely packed PCB patterns. It involves a force and sense pin in the flying probe. Kelvin connections compensate for losses in the testing probe.

Flying probe testing systems come in different sizes, with the main variable being the number of connectors the system uses. For example, a tester can have up to 16 connector heads, with 8 on the top and 8 on the bottom of the PCB. Of course, the cost of the system increases proportionally with the number of connectors it utilizes.

Advantages of Flying Probe Testing

Compared to traditional bed-of-nails or ICT fixtures, flying probe testing offers several advantages:

No Fixtures Required:Unlike bed-of-nails fixtures, flying probe testing doesn’t necessitate fixture setup. This saves the cost and time typically required for setting up ICT fixtures. In fact, manufacturers can set up flying probes immediately after the PCBs come off the production line, as they have access to Gerber data. On the other hand, designing and installing ICT fixtures can take weeks.

Short and Fast Program Development: Since netlists and CAD data form the basis for generating flying probe test programs, and there are multiple open-source programs to translate this information, program development time is short and requires minimal setup time. This also means that design changes can be easily integrated.

Process Flexibility: Unlike ICT’s bed-of-nails fixtures, flying probe setups are applicable to any PCB, whereas ICT’s bed-of-nails fixtures are specific to individual PCBs and useless for another. Simple modifications to internal programs are all that’s needed to adapt them to another board.

No Need for Test Points: Since flying probe testing is conducted on bare boards, probes can utilize component pads without the need for additional test points.

Controlled Probe Contact: Flying probes can achieve precise connections at closer intervals compared to bed-of-nails. For instance, high-precision flying probes can achieve testing gaps as small as 5 micrometers, while ICT’s minimum gap is 0.5 millimeters. This makes them highly useful for densely populated circuit boards or for achieving broader coverage on small PCBs.

Variable Testing Solutions and Methods: Flying probe systems can offer more testing solutions than ICT or bed-of-nails. This is possible because with programmable integrated test systems, various types of flying test probes can be utilized.

High Measurement Accuracy: Specific flying probes are employed for different tests, with precise probe positioning and complementary test instruments, ensuring high measurement accuracy.

Quick Feedback: Since flying probe test results can be obtained on-site, transmitting information to the production line can help them quickly make appropriate process adjustments. Similarly, PCB designers can receive rapid feedback during prototype design, enabling them to make necessary changes before production.

How Flying Probe Testing Works

Flying probe testing (FPT) is typically the preferred method for small batch and prototype circuit board testing as well as PCB assembly due to its cost-effectiveness and convenience for these smaller quantities.

The main advantage lies in the ability to complete testing at speeds ranging from a few days to a few hours, depending on the complexity of the circuit board, even for larger quantities, and with high coverage of testing.

Let’s break down its operation into steps:

  1. Creating an FPT Test Program

The design aims to test the entire circuit board and is usually completed using an offline computer with an FTP test program generator application. This typically requires Gerbers, BOMs, and ECAD files. On a machine with a motherboard, define the values of the components to be tested, test points, component formats, offsets, debugging, etc., and ultimately finalize the design of the test program.

  1. Uploading the Program to the FTP Tester

The components of the circuit board to be tested are placed on a conveyor belt within the FTP tester and transported to the area where the probes are operated.

  1. Application of Electrical and Power Test Signals

These tests are conducted at probe points and then readings are taken. This process determines whether specific sections of the PCB meet the expected results (components). Any failures or deviations from the established plan and expectations indicate defects within the unit, resulting in a test failure.

Flying probe testing is a crucial technology in the electronics industry, ensuring the quality and functionality of electronic components and systems. These tests utilize specialized equipment to perform various contact and non-contact electrical tests on printed circuit boards (PCBs), printed wiring boards (PWBs), PCB assemblies (PCBAs), individual components, and entire systems. By providing a flexible and efficient method to identify defects and validate performance, flying probe testing has become an essential tool for manufacturers and engineers.

What are the colors of PCB?

05/06/2024 在： /通过：

The color of a PCB typically refers to the hue of the solder mask on the board’s surface. PCB board staining pigments are a type of hardened resin, with the primary resin being colorless or nearly transparent. Green, as with other colors, is achieved through the addition of pigments.

We employ silk-screen printing to apply colors onto the PCB. PCBs come in various colors such as green, black, blue, yellow, purple, red, and brown. Some manufacturers have ingeniously developed PCBs in multiple colors like white and pink.

Physical Properties of PCB Colors

When selecting a PCB color, one must consider the physical properties of the PCB material. Typically composed of fiberglass and epoxy resin, PCB materials have densities, thermal conductivity coefficients, coefficients of thermal expansion, tensile strengths, and other physical attributes that directly impact performance and reliability. Different-colored PCBs may utilize varied production processes and materials, thereby exhibiting differing physical properties.

Chemical Properties of PCB Colors

In addition to physical properties, the color of a PCB also influences its chemical characteristics. PCB boards undergo heating and chemical treatments during production, and PCBs of different colors may require distinct chemical processes. This affects properties such as annealing temperature, acid and alkali resistance, and corrosion resistance. Some colored PCBs may employ more complex production processes and materials, resulting in enhanced chemical corrosion resistance.

Yellow PCB

Characteristics of Different Colored PCBs

  1. Green PCB

Green PCBs are the most popular color choice, enhancing clarity by providing a sharp contrast with white text, thus improving readability. Additionally, the surface treatment of green PCBs reflects less light, aiding in reducing glare.

  1. White PCB

White PCBs present a clean and neat appearance in various settings, gaining popularity. However, due to their tendency to obscure traces, white PCBs are not the top choice. Yet, the contrast with black silk-screen printing is notably distinct on white PCBs.

  1. Yellow PCB

Yellow PCBs cater swiftly to diverse requirements such as style, cleanliness, and visibility. However, a significant drawback of yellow PCBs is their poor contrast with traces and silk-screen printing.

  1. Blue PCB

Blue PCBs are considered thick boards suitable for labeling due to their significant contrast in silk-screen printing. While not as attention-grabbing as green, black, or white PCBs, blue PCBs are preferred for their excellent aesthetic appeal. Installing blue PCBs on LCDs is preferable as they avoid sharp contrast edges and bright background colors.

  1. Red PCB

Due to its advantages, many PCB manufacturers are keen on adopting red PCBs. Red PCBs offer excellent visibility and clearly define the contrast of traces, planes, and blank areas. Silk-screen printing appears particularly elegant against the backdrop of red PCBs.

  1. Black PCB

Black PCBs are as popular as white PCBs. Both colors produce low contrast, facilitating easy labeling of critical components. However, the primary drawbacks of black and white PCBs are the potential focal points and minor shadows, making tracing difficult. Therefore, black PCBs are unsuitable for various high-temperature applications as they may cause silk-screen printing to discolor. Moreover, black PCBs are a blend of cobalt and carbon, potentially resulting in poor conductivity.

Black PCB

How pcb colors are made

The color of a PCB (Printed Circuit Board) is primarily achieved by applying a layer of special solder mask during the manufacturing process. Here are the general steps involved in producing PCB colors:

  1. During the manufacturing process of a PCB, a thin layer of copper foil is first laid on the substrate, forming the conductive layer of the PCB. If producing a double-sided or multilayer board, both sides or multiple layers of the PCB substrate will be covered with copper foil.

  2. Next, the designed PCB circuit pattern is “printed” onto the metal conductor using a technique called subtractive transfer. In this process, the entire surface is covered with a layer of copper foil, and excess copper foil is removed through etching techniques to form the desired circuit pattern.

  3. After forming the circuit pattern, to separate the soldering and non-soldering parts of the PCB during soldering and prevent copper oxidation (pure copper surfaces quickly undergo oxidation reactions when exposed to air, and oxidized copper becomes a poor conductor of electricity, greatly damaging the electrical performance of the entire PCB), engineers apply a layer of solder mask on the surface of the PCB. This solder mask layer blocks the contact between copper and air, protecting the copper layer from oxidation.

  4. The color of the solder mask can be adjusted as needed. Since small text needs to be printed on the PCB, engineers typically add various colors to the solder mask to create different PCB colors. For example, black, red, blue, dark green, and dark brown are common PCB colors.

  5. After applying the solder mask, a series of post-processing steps such as hot air leveling, milling the outline, electrical testing, final inspection, etc., are required to ensure that the quality and performance of the PCB meet the requirements.

Why are most PCB green now?

The prevalence of green PCBs stems from several factors:

  1. Glass Epoxy Resin Material:

    • Historically, green was the standard color for the solder mask made from glass epoxy resin, which is commonly used in PCB manufacturing. While other colors have been introduced, green remains the preferred choice.

  2. Contrast with White Printed Text:

    • Green PCBs offer simplicity and time efficiency for assembly workers, as scanning them is straightforward and quick due to their familiarity with the color. Additionally, green creates less eye strain during scanning compared to other colors and provides contrast with white printed text on the circuit board.

  3. Military Applications:

    • Military standards have a significant influence on the preference for green PCBs. Many believe that green is highly effective for military purposes, leading to a demand for green PCBs from suppliers who also serve other clients. Consequently, green PCBs become surplus products for military suppliers, further reinforcing their acceptance.

  4. Exposure Rate of Solder Mask:

    • While other colors like blue, white, or brown exist, they may not offer a higher solder mask exposure rate compared to green. Darker colors tend to have higher pigment deposition, resulting in darker solder masks. White and black solder masks have high exposure rates, but green provides adequate shading for worker exposure and design tolerances.

  5. Better Machine Recognition:

    • During PCB manufacturing processes such as board fabrication and surface-mount component soldering, visual inspection is crucial. Green PCBs offer better visibility in yellow-lit environments, aiding machine recognition and calibration for tasks like solder paste application and automated optical inspection (AOI).

  6. Comfort for Workers:

    • In some manual inspection processes (although increasingly replaced by automated testing), workers may observe PCBs under strong lighting. Green PCBs are more comfortable for the eyes in such conditions.

  7. Cost Reduction:

    • Green PCBs have widespread use, enabling economies of scale in production and procurement. Standardizing on one color reduces production line costs, as bulk purchasing of the same-color solder mask lowers procurement costs. Consequently, green solder mask is advantageous in terms of manufacturing costs and lead times.

  8. Relative Environmental Friendliness:

    • Green PCBs are relatively environmentally friendly, as they do not release toxic gases during high-temperature recycling of waste boards. Other PCB colors, such as blue and black, contain cobalt and carbon, which pose risks of short circuits due to weaker conductivity.

Additionally, darker-colored PCBs, such as those in black, purple, or blue, may increase difficulty in board inspection and present challenges in manufacturing control.

The influence of PCB color on circuit boards is multifaceted. It affects not only the cost and appearance of the PCB but also directly impacts the physical and chemical properties of the PCB materials, thereby influencing the performance and reliability of the PCB. Therefore, when selecting PCB colors, it is necessary to consider a comprehensive range of factors such as the application environment, requirements, and costs of the product. Meanwhile, manufacturers need to enhance the quality and performance of PCBs through more sophisticated production processes and materials to meet the production needs of PCBs in different colors.

The status of packaging substrate in the PCB industry

04/30/2024 在： /通过：

If the PCB industry were a pyramid, undoubtedly, the substrate would be the gleaming jewel perched at its apex.

 

Firstly, it holds immense importance.

The substrate is the core material in the chip packaging process, characterized by its high density, precision, performance, miniaturization, and thinness. It, along with the die and leads, forms the chip after packaging and testing. The IC substrate not only provides support, heat dissipation, and protection for the chip but also serves as the electronic connection between the chip and the PCB, playing a pivotal “linking and enabling” role, and can even embed passive or active devices to achieve certain system functions.

 

Secondly, its barriers are exceptionally high.

According to the minutes of the investor survey by Xinsen Technology, newcomers in the substrate field require at least 2 to 3 years to establish a team, acquire land and build factories, complete decoration and debugging, pass large customer certifications, and ramp up production capacity. Looking at the recent projects of domestic manufacturers in substrate production, the construction phase alone takes up to 2 years, with several more years needed for capacity ramp-up. Moreover, projects involving high-end substrates like FC-BGA require even higher investment amounts due to the exorbitant equipment prices. Just consider, any random substrate project easily surpasses 2 billion yuan in investment, making it a “fighter jet” in the industry’s “burning money” battle.

Aside from raising the investment threshold, the high processing difficulty is also a core barrier in substrate production. From the perspectives of product layers, board thickness, line width and spacing, and minimum annular width, substrates tend to lean towards precision and miniaturization. Moreover, with a unit size smaller than 150*150 mm, they represent a higher-end category of PCBs. Among them, the line width/spacing is the core differentiation, with the minimum line width/spacing of substrates ranging from 10 to 130 micrometers, far smaller than the 50 to 1000 micrometers of ordinary multilayer rigid PCBs. Ordinary PCB factories cannot handle such high-difficulty technical tasks.

 

Thirdly, its market prospects are incredibly vast.

With the rapid advancement of technology in the electronics industry, terminal application products are trending towards miniaturization, intelligence, and customization, making the demand for high-end PCB products more prominent. Moreover, driven by a new wave of computational power, China’s substrate supply fails to meet the robust market demand, presenting the industry chain with expansive market space.

From the global demand perspective of IC substrates, these products are primarily applied in fields such as CPUs, GPUs, and high-end servers.

In recent years, with the widespread application of technologies like 5G, AI, and cloud computing, the demand for high-computational chips has been continuously increasing, thereby propelling the growth of substrate production value. This trend has stimulated a significant growth in the demand for chips and advanced packaging in the electronics industry, indirectly promoting the development of the global substrate industry.

In terms of market size, the Chinese substrate market reached 20.1 billion yuan in 2022, a year-on-year increase of 1.5%. According to forecasts from the China Industry Research Institute, by 2023, this market size will reach 20.7 billion yuan, with a growth rate of 3%. Simultaneously, the production volume of Chinese substrates has been increasing year by year. In 2022, the production reached 1.381 million square meters, an 11.73% increase year-on-year. It is expected to reach 1.515 million square meters by 2023, with a growth rate of 9.7%.

Looking at the medium to long term, the IC substrate market is expected to maintain rapid growth. According to Prismark’s forecast, by 2027, the market size of IC substrates will reach 22.286 billion US dollars, with a compound annual growth rate (CAGR) of 5.10% between 2022 and 2027. It is estimated that by 2027, the overall size of China’s IC substrate industry will reach 4.387 billion US dollars, with a CAGR of 4.60% between 2022 and 2027.

The recent surge in Chiplet packaging technology has injected new vitality into the growth of IC substrates. The rapid growth in the market size of Chiplet processor chips will drive the demand for ABF substrates. Advanced packaging technologies will increase the consumption of ABF substrates, and the introduction of 2.5/3D IC high-end technologies into products may enter mass production in the future, inevitably bringing greater growth momentum.

 

Fourthly, its players are industry giants.

Currently, IC substrate companies from Japan, South Korea, and the Taiwanese region hold absolute leading positions. According to statistics from the Taiwan Printed Circuit Association, the top ten global substrate suppliers and their market shares in 2022 were as follows: Unimicron (17.7%), Nan Ya Printed Circuit Board (10.3%), Ibiden (9.7%), Samsung Electro-Mechanics (9.1%), Shinko Electric Industries (8.5%), JCET Group (7.3%), LG Innotek (6.5%), AT&S (6.1%), Daeduck Electronics (4.9%), and Compeq Manufacturing (4.7%).

The top five global BT substrate manufacturers were LG Innotek (14.2%), Samsung Electro-Mechanics (11.9%), Compeq Manufacturing (10.3%), JCET Group (9.5%), and Unimicron (7.7%). The top five global ABF substrate manufacturers were Unimicron (26.6%), Ibiden (14.6%), Nan Ya Printed Circuit Board (13.5%), Shinko Electric Industries (12.8%), and AT&S (8.0%).

Although China’s IC substrate industry started relatively late, strong players have emerged continuously. Major suppliers include Shennan Circuit, Xinsen Technology, and Zhuhai Youya, which primarily possess mass production capabilities for BT substrates. Furthermore, since 2019, some manufacturers primarily engaged in PCB products have also begun investing in IC substrate projects, indicating a quietly evolving industrial landscape.

In conclusion, factors such as technological difficulty, industry players, investment barriers, market prospects, and critical roles have firmly established substrates at the forefront of the industry, rightfully earning them the title of the gleaming jewel atop the PCB pyramid.

Wave soldering operation guide for pcb assembly

04/28/2024 在： /通过：

What is wave soldering?

Wave soldering refers to the process of forming a solder wave of melted solder alloy, typically using an electric pump or an electromagnetic pump, to achieve the desired solder wave height. Alternatively, nitrogen gas can be injected into the solder pot to create the wave. During wave soldering, a printed circuit board (PCB) with pre-mounted components passes through the solder wave, forming a specific shape of solder fillet on the liquid solder surface. This process, in which the PCB with components is passed through the solder wave at a specific angle and with a certain immersion depth to achieve solder joint connections, is called wave soldering.

Historical Development of Wave Soldering

  1. Origin of Manual Wave Soldering Wave soldering, as an electronic soldering technology, originated in the early 1960s. At that time, manually operated wave soldering equipment was widely used. Due to its simple structure, complex operation, and low efficiency, the application of manual wave soldering equipment was somewhat limited.

  2. Automation Control of Wave Soldering Equipment In the early 1970s, wave soldering equipment began to transition towards automation control. With the continuous development of electronic technology, the equipment gradually achieved automation control, greatly improving production efficiency. During this period, various automatic control systems for wave soldering equipment, including PLCs and microcontrollers, began to appear.

  3. Digitization of Wave Soldering Equipment Since the 21st century, wave soldering equipment has been advancing towards digitization. The application of digital technology has enabled wave soldering equipment to achieve higher precision, more stable quality, increased production efficiency, and reduced production costs. In particular, the application of CAD technology in wave soldering equipment has resulted in more stable and consistent soldering effects.

The working principle of wave soldering

The fundamental principle of wave soldering is to utilize molten solder to form a wave on the soldering surface. The soldering material is heated and melted as it passes through the wave, then contacts the soldering surface to create a solder joint. The key to wave soldering lies in controlling the temperature and flowability of the solder to ensure joint quality.

  1. Formation of molten solder: Initially, molten solder is formed in the solder pot through pump pressure, creating a specific shape of solder wave on its surface.

  2. Transport of circuit board: The circuit board is conveyed through the wave soldering machine on a chain conveyor, passing through the preheating zone to ensure temperature control during soldering.

  3. Soldering process: As the circuit board passes through the solder wave at a certain angle, its pins pick up solder from the liquid solder, which solidifies during cooling to form solder joints. The solder wave wets the soldering area and extends to fill, facilitating the soldering process.

  4. Soldering quality: Wave soldering technology is suitable for soldering a variety of metals and non-metals, including aluminum, copper, steel, as well as plastics, ceramics, and other non-metallic materials. It is widely used in electronics, machinery, automotive manufacturing, and other fields, providing efficient, fast, and precise soldering to meet high-precision, high-reliability, and high-quality soldering requirements.

The Process of Wave Soldering

The wave soldering process involves the following steps:

  1. Preparation: Ensure the quality of the PCB and electronic components to be soldered, and perform necessary surface treatments such as cleaning and oxide removal.

  2. Application of solder paste: Apply solder paste to the appropriate soldering areas on the PCB, typically covering the contact surfaces of component pins and PCB pads.

  3. Component placement: Precisely mount electronic components onto the PCB at predetermined locations. This can be done using automated pick-and-place machines or manual methods.

  4. Wave soldering machine setup: Configure the wave soldering machine according to the soldering requirements and specifications, including soldering temperature, wave height, preheating zone, and soldering speed.

  5. Soldering process: Move the assembled PCB through the conveyor system to the solder wave area. The molten solder in the wave area makes contact with the PCB pads and component pins, forming solder joints.

  6. Cooling and solidification: Once the PCB exits the solder wave area, the solder joints are rapidly cooled and solidified through a cooling process, establishing stable solder connections.

  7. Inspection and quality control: Inspect and perform quality control checks on the soldered PCB, including visual inspection, X-ray testing, and solder joint reliability testing, to ensure that the soldering quality meets the requirements.

Operation Guide for Wave Soldering Equipment

  1. Preparing for Wave Soldering

(1) Turn on the main power switch according to the equipment’s operating schedule and control the solder pot switch time via the time electromagnetic valve.

(2) Check if the solder pot temperature indicator is functioning properly: Measure the temperature around 15mm below and above the solder pot’s liquid level with a thermometer, and ensure that the actual set temperature remains within a range of ±5°C.

(3) Check the operation of the lead cutter: Adjust the height of the cutter head based on the thickness of the PCBA, aiming for component pin lengths between 1.4 to 2.0mm.

(4) Verify the normal supply of flux: Pour flux into the fluxer, adjust the air inlet valve, and activate the fluxer to check for foaming or spraying of flux. Adjust the flux ratio to meet the requirements.

(5) Check the solder level height; if it is below 12-15mm from the solder pot, add solder promptly. Add solder in batches, not exceeding 10 kilograms each time.

(6) Clean the solder dross from the solder surface, and add anti-oxidant after cleaning.

(7) Adjust the angle of the transport rail: Adjust the total width of the rail according to the total width of the PCBAs to be soldered, ensuring moderate clamping force. Adjust the rail slope based on the pin density of the soldered components.

 

  1. Startup Process for Wave Soldering

(1) Turn on the flux switch, adjusting the foam adjusting plate thickness to half of “l” during foaming. For spraying, ensure the board is symmetrical, with moderate spray volume, preferably avoiding spraying on component surfaces.

(2) Adjust the air knife airflow to allow excess flux on the board to drip back into the foam groove, preventing drips on the preheater that could cause a fire.

(3) Turn on the transport switch and adjust the transport speed to the desired value.

(4) Turn on the cooling fans.

 

  1. Post-Wave Soldering Procedure

(1) Turn off the switches for the preheater, solder pot wave, fluxer, transport, cooling fans, and lead cutter.

(2) During operation, replace the flux in the foam groove every two weeks and measure it regularly.

(3) After shutdown, clean the wave soldering machine and claws thoroughly, soaking the nozzles in a cleaning solvent.

Wave soldering

Advantages and Disadvantages of Wave Soldering

Advantages:

High Efficiency: Wave soldering can simultaneously solder a large number of through-hole components, increasing production efficiency and output.

Welding Quality: Through strict control of welding parameters such as temperature, soldering time, and solder flux flow, wave soldering ensures stable welding quality.

Low Cost: Wave soldering can use standardized components and equipment, reducing production costs.

Disadvantages:

Component Limitations: Wave soldering can only solder through-hole components and cannot solder surface mount components.

Large Size Limitations: Wave soldering requires the PCB to be tilted on the soldering pallet, so there are certain limitations on the size and shape of the PCB.

Maintenance Difficulty: Wave soldering machines require regular maintenance and cleaning, which can be challenging.

Applications of Wave Soldering

Wave soldering technology has been widely applied in various electronic products, including consumer electronics, communication equipment, computers, and more. Here are the main application areas of wave soldering:

● Household Appliances: Wave soldering has become the primary welding technology in the manufacturing of household appliances, including TVs, DVDs, stereos, and more.

● Automotive Electronics: Wave soldering technology has been applied in automotive electronic products, including in-vehicle entertainment systems, safety control systems, etc., enhancing the reliability and safety of automotive electronic products.

● Communication Equipment: Wave soldering technology has been widely used in communication equipment such as base stations, routers, etc., enabling high-density and high-speed circuit designs.

● Industrial Control: Wave soldering technology has been applied in the field of industrial control, including PLCs, industrial computers, etc., improving the reliability and stability of equipment.

Future Development of Wave Soldering

With the trend of miniaturization and high-density electronic products, wave soldering technology is continuously innovating and developing. Here are the future development directions of wave soldering:

● Increased Automation: The automation level of wave soldering machines will continue to increase, including automation of component feeding and solder liquid supply.

● Improved Welding Quality: The welding quality of wave soldering machines will continue to improve, including more precise control of welding parameters such as temperature, welding time, solder flux flow, etc.

● Innovation in Welding Materials: With the growing environmental awareness, the welding materials used in wave soldering machines will continue to innovate and improve, including the adoption of lead-free solder and other environmentally friendly materials.

● Expansion of Application Areas: Wave soldering technology will be applied in more electronic products, including smart homes, the Internet of Things (IoT), etc.

In summary, as an important electronic component welding technology, wave soldering has been widely applied in various electronic products. With continuous technological innovation and development, it will play an increasingly important role in the future.

 

Top 8 PCB manufacturers in Thailand

04/24/2024 在： /通过：

As an important economy in Southeast Asia, Thailand is actively attracting the investment of global PCB manufacturing companies. At present, many PCB manufacturers from China, South Korea, Japan, and the United States have established factories in Thailand. From 2022 to 2027, the compound growth rate of the global PCB output value was about 3.8%. It is expected that by 2027, the global PCB output value will reach about 98.388 billion US dollars. This global growth trend provides a good external environment for the development of the Thai PCB industry. Today we will count Top 8 PCB manufacturers in Thailand.

1.Shennan Circuits Co., Ltd.

Shennan Circuits Co., Ltd. (hereinafter referred to as “SCC”), founded in 1984 , is headquartered in Shenzhen, Guangdong, China. Its main manufacture facilities are located in Shenzhen, Wuxi and Nantong, Jiangsu, China. Its business is all over the world, and there are subsidiaries in North America and R&D sites in Europe.

Manufacturing capacity

Items Mass Sample
Layers 2~68L 120L
Max. Board Thickness 10mm（394mil） 14mm（551mil）
Min. Width Inner   Layer  2.2mil/2.2mil 2.0mil/2.0mil
Outer Layer 2.5/2.5mil 2.2/2.2mil
Registration Same   Core ±25um ±20um
Layer to Layer ±5mil ±4mil
Max. Copper Thickness 6Oz 30Oz
Min. Drill Hole Dlameter Mechanical ≥0.15mm(6mil) ≥0.1mm(4mil)
Laser 0.1mm（4mil） 0.050mm（2mil）
Max. Size (Finish Size) Line-card 850mmX570mm 1000mmX600mm
Backplane 1250mmX570mm 1320mmX600mm
Aspect Ratio (Finish Hole) Line-card 20:1 28:1
Backplane 25:1 35:1
Material FR4 EM827, 370HR, S1000-2, IT180A, EM825, IT158,   S1000 / S1155, R1566W, EM285, TU862HF
High Speed Megtron6, Megtron4, Megtron7,TU872SLK,   FR408HR,N4000-13 Series,MW4000,MW2000,TU933
High Frequency Ro3003, Ro3006, Ro4350B, Ro4360G2, Ro4835,   CLTE, Genclad, RF35, FastRise27
Others Polyimide, Tk, LCP, BT, C-ply, Fradflex, Omega   , ZBC2000,
Surface Finish HASK, ENIG, Immersion Tin, OSP, Immersion   Silve, Gold Finger, Electroplating Hard Gold/Soft Gold, Selective OSP，ENEPIG

2.Kinwong Electronics

Kinwong Electronics

Established in 1993, Jingwang Electronics is a world’s leading high -tech enterprise developing, producing and selling high -tech research and development, production and sales of high -end electronic materials. Establish 11 offices worldwide to provide FAE localized instant service.

Kinwong’s products cover conventional PCB, Flex PCB, Metal Base PCB, Rigid-Flex PCB, HDI PCB, High Layer Count PCB, Substrate Like PCB，RF PCB, Copper Inlay, etc. We are one of the few domestic manufacturers that covers rigid circuit boards, flexible circuit boards and metal base circuit boards. Kinwong provides customers with competitive, reliable products, solutions and services in the fields of Automotive, Telecom, Computing, Smart Terminal, Industrial & Medical, Power Supply and Consumer.

Conventional circuit board manufacturing ability

Layer Count: 2L/4L/6L/8L/10L
Max. Delivery Panel Size: 699mm×594mm
Max. Copper Weight (Inner/Outer Layer): 12oz
Max.Board Thickness: 5.0mm
Max. Aspect Ratio: 15:1
Surface Finish: LF-HASL, ENIG, Imm-Ag, Imm-Sn, OSP, ENEPIG, Gold Finger

3.Shengyi Electronics Co., Ltd.

Shengyi Electronics Co., Ltd. was established in 1985. It is headquartered in Dongguan City, Guangdong Province. It is a national high -tech enterprise specializing in high -precision, high density, and high -quality printing circuit board. Shengyi Electronics provides customers with a one -stop printing circuit board solution, which is widely used in the fields of communication equipment, cars, aerospace and other fields.

Technology capability

Shengyi Electronics

4.APCB Electronics (Thailand)

APCB Inc. Founded in August 1981, it is a multi -layer PCB factory located in Taipei, Taiwan. The main PCB projects are mainly produced by consumer electronics.
After years of hard work through the APCB team, whether it is developing new technology or investment in advanced production equipment, we have successfully expanded production capacity and improved quality. By doing this, we can expand our product line to various applications, including electronic products, computer -related accessories, communication products, etc.

Technology capability

5.Circuit Industries

Circuit Industries was founded in 1990. It is the leading manufacturer of printed circuit board (PCB) or printed circuit board (PWB) in Thailand engaged in PCB manufacturing; aluminum PCB and so on. The company has obtained the following certification: UL File E-115789 safe printed circuit board (PCB); ISO 9001:2015 quality management system; ISO 14001:2015 environmental management system; ISO 45001:2018 occupational health and safety management system; automotive parts manufacturer quality management system IATF 16949:2016; and TLS 8001:2010.

Technology capability

Subject
Small Volume
Mass Volume
Remarks
Max. Layer Count 10 Layers 10 Layers Through hole type only. For HDI sequential lamination Max. 6 Layer
PTH Aspect Ratio 10 : 1 8 : 1 Material Thickness : Drill diameter
Min. Drill Size 0.15 mm 0.2 mm –
Min. Board Thickness (Final) 0.8 mm 0.8 mm –
Max. Board Thickness (Final) 3.0 mm 3.0 mm FR-4 Multilayer only
Min. Prepreg Thickness 0.075 mm 0.075 mm –
Min. Finished Copper Thickness 1 OZ (35 μm.) 1 OZ (35 μm.) –
Inner Layer Max. Finished Copper Thickness 2 OZ (70 μm.) 2 OZ (70 μm.) –
Outer Layer Max. Finished Copper Thickness 3 OZ (105 μm.) 3 OZ (105 μm.) –
Min. Line Spacing (Inner Layer) 0.1 mm (4 mil.) 0.125 mm (5 mil.) Higher Copper Thickness Requires Wider Line and Spaceing
Min. Line Spacing (Outer Layer) 0.1 mm (4 mil.) 0.125 mm (5 mil.) –
Min. Annular Ring 0.125 mm (5 mil.) 0.125 mm (5 mil.) –
Drill Accuracy (+/-) 35 μm. 35 μm. –
Multilayer Layer Registration (+/-) 35 μm. 35 μm. –
Solder Mark Registration (+/-) 75 μm. 75 μm. –
Rout / Score Tolerances (+/-) 0.2 mm 0.2 mm –
Blind Via YES YES Mechanical Blind Via
Blind Via Aspect Ratio 1:1 1:1 Via Plug / Filled and Capped NOT AVAILABLE
Buried Via YES YES

6.Team Precision Public

Team Precision is Thailand EMS and has more than 20 years of experience in the industry. The range of manufacturing services includes global procurement and various types of production assembly via the Internet, such as Tongkou assembly, SMT assembly, thin spacing BGA, FLIP Chip, COB (Chip-on-Board) dust-free room environment assembly, DI (DE- Ionized) Water-Cleaning, Chemical Compound EncapSuration, Box Build and Retail Packing Ready to Sell.

Technology capability

●11 SMT lines in 2 factories
●Through whole auto insertion machines.
●FLIP CHIP Technology
●Chip-On-Board (COB)
●Flexible Printed Circuit Assembly (FPCA)
●In line solder past inspection
●In line Automatic Optical Inspection (AOI)
●X-Ray Inspection
●DI water cleaning
●In house laser engraving
●Conformal coating eg. Spray, Dip etc.
●Potting process eg. poly urethane or epoxy etc.
●In circuit and functional test
●Static walk-in burn in chamber
●Dynamic burn in chamber
●Complete Product Assembly : Box-Build to retail packing assembly
●Failure analysis equipment
●Various logistics from order fulfillment service to warehousing services eg.

●Direct shipment to end customers, Milk run delivery in overseas market, hub for the region etc. with on line monitoring.
●Kanban and certified Lean-Sigma and IPC team
●ROHS/REACH compliance

7.Besttech Manufacturing

BestTech Manufacturn Co., LTD was originally established in 2003 and is a small electronic subcontracting manufacturer service plant. The demand for high quality and fast turning PCB assembly services in Pathumthani (Thailand) has been recognized. It is a subcontractor manufacturer serving the electronics industry. It uses conventional or hybrid technology to produce surface mount modules free of charge.

Technology capability

Material Type SS PCB DS PTH MULTILAYER PCB
Laminate Used FR-1, FR-2, CEM-1, CEM-3, FR-4 CEM-3, FR-4 FR-4
Doosan, Hitachi,Isola Doosan,Shenyi, Kingboard Doosan,Shenyi,Kingboard
High CTI Laminate Available High CTI Laminate Available High CTI Laminate Available
Halogen Free Laminate High TG Performance Laminate High TG Performance Laminate
Upon Request Upon Request Upon Request
Overall Thickness 0.80mm to 2.00mm 0.40mm to 2.00mm , Max. 2 Layers 0.40mm to 2.00mm , Max. 4-16 Layers
Copper Foil Thickness 35um, 70um 35um, 70um, 105um 35um, 70um ,105 um
Pattern Image Line / Spacing 0.20mm Line / Spacing 0.10mm Line / Spacing 0.10mm
Solder Mask UV, PISR Upon Request PISR PISR
Tamura/Union/Taiyo/Coates Min. opening 0.10mm Min. opening 0.10mm
  Coates, Taiyo, Peters, Vantico Coates, Taiyo, Peters, Vantico
  Green, Yellow, Blue, Black Green, Yellow, Blue, Black
Legend UV UV UV
Min. Feature Width 0.18mm Min. Feature Width 0.18mm Min. Feature Width 0.20mm
Product dentification Week Code Printed On Legend Week Code Printed On Legend Week Code Printed On Legend
Peelablemask Maximum Tenting hole size 2.80mm Maximum Tenting hole size 2.80mm Maximum Tenting hole size 2.80mm
Fabrication Minimum Hole Size For NC Drill 0.30mm, for Punch 0.65mm Minimum Hole Size For NC Drill 0.25mm, for Punch 0.30mm Minimum Hole Size For NC Drill 0.25mm, for Punch 0.30mm
Minimum Punch Soft Tool Shelf Life 200k Minimum Punch Harden Tool Shelf Life 150k Minimum Punch Harden Tool Shelf Life 150k
Minimum Punch Harden Tool Shelf Life 150k FR-4 Not Recommended to Punch Hole FR-4 Not Recommended to Punch Hole
FR-4 Not Recommended to Punch Hole V-Cut is available V-Cut is available
V-Cut is available Chamfering is Available Chamfering is Available
Chamfering is Available    
Surface Finishing Electrolytic Ni/Au Plating for SS PCB ENIG ENIG
Rosin Flux Coating OSP Coating OSP Coating
OSP Coating HAL or HASL HAL or HASL
Roller Tin on SS PCB, HAL on CEM-3, FR-4 Products    
Products Acceptance Criteria Follow IPC-A-600 Acceptance Criteria Follow IPC-A-600 Acceptance Criteria Follow IPC-A-600 Acceptance Criteria
 

8.Leadsin Technology Co.Ltd

LST is a one-stop EMS solution service provider who integrates PCBLayout, PCB manufacturing, PCBA solution and product design,component procurement, SMT, DIP finished product assembly and testing.

We have rich manufacturing experience and professional technical team to provide PCB service for global customers, our products cover automotive, medical, industrial control, communication, internet of things, consumer electronics, quality assurance and affordable price.

Technology capability

Number of layers 1-48 layers
Materials FR4, Tg=135150170180210, cem-3, cem-1, aluminum substrate, PTFE, Rogers, Nelco
Copper thickness 1/2oz, 1oz, 2oz, 3oz, 4oz, 5oz
Board Thickness 8-236mil (0.2-6.0mm)
Minimum line width/spacing 3/3 million (75/75um)
Minute drilling size 8 million (0.2 mm)
Min HDI laser drill size 3 million (0.067 mm)
Aperture tolerance 2 million (0.05 mm)
PTH copper thickness 1 million (25 microns)
Resistance welding color Green, Blue, Yellow, White, Black, Red
Strippable solder mask layer yes
surface treatment HASL (ROHS), ENING, OSP, sinking silver, sinking tin, shining gold, golden fingers
Gold thickness 2-30u “(0.05-0.76um)
Blind hole/buried hole yes
V-shaped cutting yes

Detailed guide for PCBA processing

04/22/2024 在： /通过：

The PCBA processing process covers the entire process from raw material procurement to finished product shipment, including SMT chip mounting, DIP plug-in processing, PCBA testing, three-proof coating, and finished product assembly. Each step strictly follows the process requirements to ensure the quality and performance of the final product. In this article, we will detail the manufacturing process of PCBA, with the specific contents as follows.

SMT Chip Mounting Process

The process of SMT chip mounting includes: solder paste mixing → solder paste printing → SPI → mounting → reflow soldering → AOI → rework.

  1. Solder Paste Mixing

After taking the solder paste out of the refrigerator and thawing it, it is mixed manually or by machine to be suitable for printing and soldering.

  1. Solder Paste Printing

Place the solder paste on the steel mesh and use a scraper to print the solder paste onto the PCB pads.

  1. SPI

SPI, namely solder paste thickness detector, can detect the printing condition of solder paste, playing a role in controlling the effect of solder paste printing.

  1. Mounting

Various components are automatically mounted on the circuit board using machine equipment.

  1. Reflow Soldering

The assembled PCB board is reflow soldered, where the solder paste is heated to become liquid through high temperature inside and then cooled and solidified to complete the soldering.

  1. AOI

AOI, namely automatic optical inspection, can scan and detect the soldering effect of the PCB board, identifying any defects.

  1. Rework

Defects identified by AOI or manual inspection are reworked.

DIP Plug-in Processing Process

The process of DIP plug-in processing includes: plug-in → wave soldering → trimming → post-solder processing → cleaning → quality inspection.

  1. Plug-in

Process the pin of the plug-in material and install it on the PCB board.

  1. Wave Soldering

Pass the assembled board through wave soldering, where liquid tin is sprayed onto the PCB board, and then cooled to complete the soldering.

  1. Trimming

The pins of the soldered board need to be trimmed if they are too long.

  1. Post-solder Processing

Manual soldering of components is performed using an electric soldering iron.

  1. Cleaning

After wave soldering, the board may be dirty and requires cleaning using cleaning solution and washing tank, or by using a cleaning machine.

  1. Quality Inspection

Inspect the PCB board, and defective products need to be reworked before qualified products can proceed to the next process.

PCBA Testing

PCBA testing includes ICT testing, FCT testing, aging testing, vibration testing, etc.

PCBA testing is a comprehensive process, and the testing methods adopted vary depending on the product and customer requirements. ICT testing checks the soldering of components and the continuity of circuits, while FCT testing examines the input and output parameters of the PCBA board to ensure compliance with requirements.

PCBA Three-proof Coating

The process of PCBA three-proof coating includes: brushing Side A → air drying → brushing Side B → room temperature curing. The spraying thickness is 0.1mm to 0.3mm. All coating operations should be carried out under conditions of not less than 16°C and relative humidity below 75%. PCBA three-proof coating is widely used, especially in harsh environments with high temperature and humidity. The coating provides excellent insulation, moisture resistance, leak resistance, shock resistance, dust resistance, corrosion resistance, anti-aging, anti-mildew, anti-loosening of components, and insulation against electric arcing. It can extend the storage time of PCBA, isolate external erosion, pollution, etc. Among them, the spraying method is the most commonly used coating method in the industry.

Final Assembly

The PCBA boards that have been tested OK after coating are assembled into the outer casing, followed by testing, and finally ready for shipment.

PCBA production is a chain of processes, and any problem in any link can have a significant impact on the overall quality. It requires strict control over each process.

 

Overall, PCBA processing requires meticulous attention to detail and adherence to industry standards to produce reliable and high-quality electronic devices.

Medical pcb manufacturing process

04/17/2024 在： /通过：

As technology rapidly advances, the medical industry’s demand for electronic products is also growing. Among the various electronic components, PCBs undoubtedly play an indispensable role in medical devices. However, the requirements and standards for PCBs in the medical industry far exceed those in other sectors. Why is this so? This article will explore the high demands and standards of the medical industry for PCBs. In this article, we will discuss the manufacturing process of medical PCBs.

Importance of PCBAs in Medical Devices

  1. Precision: Medical devices require a high level of precision to ensure accurate diagnosis and effective treatment. Any defects or errors in the circuit board could lead to equipment failure or provide incorrect information, posing serious risks to patients’ health.
  2. Reliability: Medical devices often need to operate in continuous working environments, placing high demands on the reliability of the circuit boards. Sudden equipment failures could result in surgery interruptions, data loss, or other medical accidents.
  3. Safety: Medical devices are directly related to patients’ lives and health, so the design and manufacturing of their circuit boards must comply with strict safety standards. This includes, but is not limited to, electromagnetic compatibility, overheat protection, and fire prevention.
  4. Miniaturization: With technological advancements, many medical devices are pursuing smaller sizes and higher levels of integration. This requires circuit board designs to be more compact, with finer connections between components.

Material Selection and Performance

In the surface mounting process of medical device PCBA, the selection of PCB materials is crucial. Commonly used PCB materials include FR-4 (glass fiber reinforced epoxy resin), metal substrates (such as aluminum substrates), ceramic substrates, and so on. Different materials have different performance characteristics, and it is necessary to choose the appropriate materials according to the operating environment and requirements of medical devices.

▶ Thermal Stability: Medical devices may operate in high-temperature environments, so the thermal stability of PCBs is crucial to avoid performance issues caused by thermal expansion and contraction in high-temperature environments.

▶ Mechanical Strength: PCBs need to have sufficient mechanical strength to prevent breakage during transportation, installation, or use, ensuring the stability and durability of medical devices.

Hierarchy Structure and Design Layout

Medical devices typically require high integration, so the hierarchy structure and design layout of PCBs are particularly important. A reasonable hierarchy structure and layout design can minimize signal interference, improve circuit stability, and reliability to the maximum extent.

▶ Layered Design: For complex medical devices, multi-layer PCBs can be used to distribute different functional modules on different layers, reducing signal interference and improving the circuit’s anti-interference ability.

▶ Reasonable Wiring: A reasonable wiring design can reduce signal transmission paths, decrease signal delay, increase signal transmission speed, and avoid interference caused by signal cross-talk.

Pad Design and Process Requirements

The design of pads on the PCB and the process requirements for surface mounting are closely related. Proper pad design and process can ensure a good connection between surface-mount components and the PCB, preventing soldering defects and cold joints.

▶ Pad Size and Spacing: Different sizes and types of surface-mount components require pads of appropriate size and spacing to ensure soldering stability and reliability.

▶ Pad Shape: Different shapes of pads are suitable for different types of soldering processes, such as Surface Mount Technology (SMT) and through-hole soldering technology. Choosing the appropriate pad shape can improve soldering efficiency and quality.

Medical PCB manufacturing

Manufacturing Process of Medical PCBA

  1. PCB Design: Engineers use professional software to design the circuit board according to the requirements and specifications of the device. Once the design is completed, the PCB manufacturer produces the bare board based on the design.

  2. Component Procurement: The procurement team purchases the required electronic components based on the Bill of Materials (BOM). These components may include resistors, capacitors, inductors, ICs (integrated circuits), etc.

  3. SMT Mounting: Electronic components are precisely mounted onto the PCB using a pick-and-place machine. This process is automated to ensure speed and accuracy.

  4. Soldering: Components are soldered onto the PCB using reflow soldering or other soldering methods.

  5. Testing and Inspection: The completed PCBA undergoes quality inspection and functional testing using AOI (Automated Optical Inspection) equipment and other testing tools to ensure it meets design requirements and quality standards.

  6. Assembly and Encapsulation: The tested and qualified PCBA is assembled with other components (such as displays, batteries, etc.) to form a complete medical device.

Challenges and Trends in Medical Device PCBA

  1. Technological Challenges: With the continuous advancement of medical technology, the requirements for circuit boards in devices are also increasing. For example, many advanced imaging systems require processing large amounts of data, placing high demands on the transmission speed and processing capabilities of circuit boards.

  2. Regulatory Compliance: The medical device market is subject to strict regulatory oversight, and manufacturers must ensure that their products comply with various safety and performance standards. This requires PCBA manufacturers to have a high sense of responsibility and expertise.

  3. Supply Chain Management: Due to the uncertainty of the global supply chain and issues of component shortages, medical device manufacturers need to pay more attention to supply chain management and optimization to ensure production stability and cost-effectiveness.

  4. Sustainable Development: With the increasing environmental awareness, manufacturers need to consider sustainability issues in the manufacturing process, such as using environmentally friendly materials and reducing waste generation.

Medical  PCBA is closely related to patient health, so it is essential to maintain the accuracy and stability of the equipment. Therefore, when choosing a medical PCB manufacturer, it is necessary to consider multiple factors. If you need medical PCBs, you can choose LST, with 16 years of experience in medical PCB manufacturing and a professional team worthy of trust.

Development board manufacturing and application guide

04/15/2024 在： /通过：

Development boards are circuit boards used for embedded system development, comprising a series of hardware components including central processing units, memory, input devices, output devices, data pathways/buses, and external resource interfaces. Typically, developers of embedded systems customize development boards according to their development needs, or users can design them on their own. Development boards serve as a means for beginners to understand and learn about both the hardware and software of systems. Additionally, some development boards provide basic integrated development environments, software source code, and hardware schematics. Common types of development boards include 51, ARM, FPGA, and DSP development boards.

The role of development boards:

Development boards serve as integrated platforms that facilitate embedded system development while reducing the barriers and risks associated with it. They play the following roles:

  1. Prototyping and validation: Development boards allow developers to quickly build prototypes of embedded systems and perform joint software and hardware debugging and testing to validate the functionality and performance of the system. They also simulate real-world environments, reducing uncertainties and risks during the development process.

  2. Application development: Development boards provide different hardware platforms and software support for various application needs, making it convenient for developers to create applications. They typically offer abundant peripheral interfaces and software libraries, enabling quick implementation of various application functions.

  3. Education and training: Development boards are also used for education and training, helping students and beginners understand the principles and development methods of embedded systems. They often have low costs and are easy to use, making them suitable for practical learning and experimentation.

  4. Enhancing learning efficiency: In terms of learning, development boards can effectively improve learning efficiency and shorten the development process.

Advantages of development boards:

  1. Rapid prototyping: Development boards assist developers in quickly designing prototypes and validating their designs efficiently.
  2. Easy portability: Development boards are highly versatile and can be easily ported to other hardware platforms.
  3. Abundant peripherals: Development boards typically offer a rich array of peripherals and interfaces, catering to diverse application scenarios.
  4. Cost-saving: Compared to designing and manufacturing hardware prototypes from scratch, using development boards can save on development costs.
  5. Default system and software support: Many development boards come with default system and software support, reducing the workload for developers.

Development board-4

Components of a Development Board

A development board is a complex assembly of multiple electronic components, each of which serves a specific purpose. The primary elements can be divided into several categories:

Microcontroller/Microprocessor
This component is the development board’s brain, running software programs and controlling other peripherals.

Memory
It includes both volatile (RAM) and non-volatile (Flash, EEPROM) storage for program code storage and execution.

Input/ Output (I/O) Interfaces
These make it possible for the board to communicate with other devices or parts. Examples include digital I/O, analog inputs, and communication interfaces such as USB, UART, and SPI.

Manufacturing Process of Development Circuit Boards

  1. Determine the requirements and functionalities of the development board: Before making a development board, it’s essential to clarify its requirements and functionalities, including the needed interfaces, operating frequency, processor type, etc. Only with a clear understanding of the board’s functions and requirements can the subsequent design and manufacturing proceed.

  2. Design the circuit schematic: Once the requirements and functionalities of the development board are determined, the circuit schematic needs to be designed. When designing the schematic, considerations must include the connection methods between various circuit modules, specific parameters of circuit modules, etc. Professional circuit design software like Altium Designer, Protel, etc., is typically used for this process.

  3. PCB layout design: After completing the circuit schematic design, the PCB layout design follows. PCB layout design involves arranging components and traces from the circuit schematic onto the actual circuit board. Factors to consider during layout design include the board’s dimensions, distances between components, trace routing, etc. Professional PCB design software like PADS, Altium Designer, etc., is used for this process.

  4. PCB board fabrication: Once the PCB layout design is completed, the designed PCB board needs to be fabricated. PCB board fabrication usually involves techniques like photolithography, etching, etc., and the process needs to be conducted in a clean laboratory environment. The fabricated PCB board needs to undergo quality testing to ensure there are no issues like copper leaks, short circuits, etc.

  5. Component soldering: After the PCB board fabrication, various components need to be soldered onto the PCB board. Soldering requires attention to factors like temperature, duration, etc., to ensure soldering quality. After soldering, testing is conducted to ensure good joint quality.

  6. Software programming: Once the hardware is completed, software programming is required. Software programming typically involves using programming languages like C, assembly language, etc., to write programs controlling various modules of the development board. The written programs need testing to ensure correctness and stability.

  7. Debugging and testing: After software programming, debugging and testing are conducted. This process involves using professional testing instruments and tools like oscilloscopes, logic analyzers, etc., to ensure the normal operation of the development board’s modules.

  8. Encapsulation and production: After completing debugging and testing, the development board can be encapsulated and put into production. Encapsulation involves placing the development board into a casing to protect it from external environmental influences. Production involves mass manufacturing of the development board to meet market demand.

Summary:

Development circuit boards play a crucial role in the electronics manufacturing field, offering excellent solutions to challenges in electronic design. If you need development circuit boards, please contact us.

The application and technical characteristics of LTCC PCB

04/11/2024 在： /通过：

LTCC (Low Temperature Co-fired Ceramic) refers to a process where multiple layers of ceramic green sheets, printed with conductive metal patterns and interconnected vias, are stacked together after precise alignment and then co-fired at temperatures below 900°C to form a monolithic multilayer interconnect structure.

This technology allows for increased wiring density and shorter interconnect distances, as well as the independent design of circuits on each layer of the substrate, enabling the realization of circuits with three-dimensional structures.

Additionally, the surface of the multilayer ceramic substrate can be used to mount bare chips by cavity mounting or to install other circuit components by surface mounting, utilizing inter-layer vias and internal circuits for connectivity. This greatly enhances the assembly density of circuits, meeting the requirements of electronic devices for circuit miniaturization, high density, multifunctionality, high reliability, and high transmission rates.

Applications of LTCC PCB

LTCC PCBs are widely used in various applications that require high performance, reliability, and operation in harsh environments. Some key application areas include:

  1. Aerospace and Defense: LTCC multilayer ceramics are used in aerospace electronic systems, radar systems, missile guidance systems, and other military applications that require high reliability, resistance to harsh environments, and high-frequency performance.

  2. Automotive Electronics: The excellent thermal performance and reliability of LTCC PCBs make them suitable for automotive applications, such as engine control units, sensors, and Advanced Driver Assistance Systems (ADAS).

  3. Telecommunications: LTCC technology is widely used in high-frequency applications in the telecommunications industry, such as RF front-end modules, power amplifiers, and antenna arrays for cellular base stations and satellite communications.

  4. Medical Devices: The biocompatibility and hermetic sealing capability of LTCC PCBs make them suitable for implantable medical devices, such as pacemakers, cochlear implants, and neurostimulators.

  5. Industrial Sensors and Controls: LTCC multilayer ceramics are used in various industrial applications due to their ruggedness and tolerance to extreme temperatures, vibrations, and chemicals. This includes pressure sensors, flow meters, and harsh environment monitoring systems.

Manufacturing Process of LTCC PCB

The production process of Low Temperature Co-fired Ceramic (LTCC) PCB typically involves the following steps:

  1. Film Removal: Remove the film layer on the surface of the glass fiber board, usually done using an alkaline solution.

  2. Drilling: Punch holes on the ceramic board according to the requirements of the circuit diagram.

  3. Shaping: Mold solder pads and component positions on the ceramic board according to the requirements of the PCB.

  4. Coating: Apply coating on the surface of the shaped PCB to enhance its mechanical strength.

  5. Sintering: Subject the coated PCB to high-temperature sintering to achieve ceramicization and hardening of the PCB.

  6. Processing: Perform processes such as adhesive application and cleaning.

Material Selection for LTCC PCB

The materials used in the fabrication of LTCC PCBs include circuit layers, inner layer vias, hook holes, solder resist films, ceramic powders, silicon nitride, etc. Among them, ceramic powder is the primary raw material for making LTCC PCBs. The quality and performance of the selected ceramic powder determine the reliability and stability of the PCB. It is recommended to choose high-purity ceramic powder to ensure that the produced PCB has sufficient mechanical strength and durability.

Testing Specifications for LTCC PCB

The produced LTCC PCBs need to undergo relevant tests to ensure their quality and stability. The main testing specifications include:

  1. Solderability Test: Assessing the soldering quality of solder pads and wires on the PCB.

  2. Insulation Resistance Test: Measuring whether the insulation resistance of the PCB meets specified requirements.

  3. Metal Adhesion Test: Evaluating the adhesion between the conductive layer on the PCB surface and the ceramic substrate.

  4. Thermal Shock Test: Assessing the stability and reliability of the PCB under rapid temperature changes.

  5. Low-Temperature Constant Stress Test: Evaluating the stability and reliability of the PCB under specified temperature and stress conditions.

LTCC pcb-2

Advantages of LTCC Integration Technology

Technological Advantages:

  1. Ceramic materials possess excellent high-frequency, high-speed transmission, and wide bandwidth characteristics. Depending on the composition, the dielectric constant of LTCC materials can vary within a wide range. When combined with high-conductivity metal materials as conductors, it helps improve the quality factor of the circuit system, increasing the flexibility of circuit design.

  2. LTCC can meet the requirements of high current and high temperature resistance, and it has better thermal conductivity than ordinary PCB circuit substrates. This greatly optimizes the thermal design of electronic devices, enhances reliability, and can be applied in harsh environments, extending their service life.

  3. It can produce circuit boards with a high number of layers, and multiple passive components can be embedded within them, eliminating the cost of packaging components. On high-layer three-dimensional circuit boards, integration of passive and active components facilitates increased circuit assembly density, further reducing volume and weight.

  4. It has good compatibility with other multilayer wiring technologies. For example, combining LTCC with thin-film wiring technology can achieve hybrid multilayer substrates and hybrid multi-chip components with higher assembly density and better performance.

  5. Discontinuous production processes facilitate quality inspection of each layer of wiring and interconnection holes before final product assembly. This helps improve the yield and quality of multilayer boards, shorten production cycles, and reduce costs.

  6. Energy saving, material saving, green, and environmental protection have become irresistible trends in the component industry, and LTCC meets this development demand. It minimizes environmental pollution caused by raw materials, waste, and production processes to the greatest extent.

Application Advantages:

  1. Easy to achieve more wiring layers, increasing assembly density.

  2. Convenient for embedding components internally, enhancing assembly density and achieving multifunctionality.

  3. Facilitates quality inspection of each layer of wiring and interconnection holes before substrate firing, which is beneficial for improving the yield and quality of multilayer boards, shortening production cycles, and reducing costs.

  4. Exhibits excellent high-frequency and high-speed transmission characteristics.

  5. Easy to form various structures of cavities, thus enabling the realization of high-performance multifunctional microwave MCMs (Multichip Modules).

  6. Possesses good compatibility with thin-film multilayer wiring technology. Combining the two can achieve hybrid multilayer substrates and hybrid multichip components (MCM-C/D) with higher assembly density and better performance.

  7. Easy to realize integration of multilayer wiring and packaging, further reducing volume and weight, and improving reliability.

Technical Features:

Utilizing LTCC for the fabrication of chip-type passive integrated devices and modules offers several advantages:

  1. Ceramic materials exhibit excellent high-frequency and high Q-factor characteristics.

  2. The use of high-conductivity metal materials as conductor materials helps improve the quality factor of the circuit system.

  3. It can adapt to high current and high-temperature requirements and possesses better thermal conductivity than ordinary PCB circuit boards.

  4. Passive components can be embedded into multilayer circuit boards, facilitating increased circuit assembly density.

  5. It has favorable temperature characteristics, such as a small coefficient of thermal expansion and a small temperature coefficient of dielectric constant, allowing for the production of extremely high-layer circuit boards and structures with line widths smaller than 50μm. Additionally, the discontinuous production process allows for inspections of the green substrate, thereby enhancing yield and reducing production costs.

The future development trends of LTCC technology, as an advanced passive component miniaturization technique, will focus on further enhancing integration, miniaturization, high-frequency capability, and reliability. With the increasing demand for high-performance and high-reliability electronic products in fields such as electronics, communications, and automotive industries, LTCC technology is expected to play a crucial role in more application scenarios, driving sustained and stable market growth. Additionally, with technological advancements, the layer count of LTCC technology may further increase, enabling more efficient circuit designs and superior performance.

Inspection standard for PCBA processing

04/09/2024 在： /通过：

Printed Circuit Board Assembly (PCBA) inspection is a crucial process in electronic device manufacturing. It involves examining the quality of PCBs and their components to ensure they meet necessary specifications and standards. PCBA inspection is a vital aspect of quality control as it helps prevent defects and failures in the final product. In this article, we will discuss in detail the inspection and acceptance criteria for PCBA boards.

PCBA Inspection Process

The PCBA inspection process typically involves a combination of automated and manual checks. The first step of the process is visual inspection, which includes examining the PCB for any physical defects such as cracks, scratches, or damage to solder mask layers. This is usually manually performed by trained inspectors using magnifying glasses or microscopes.

The next step is Automated Optical Inspection (AOI), which uses cameras and software to detect defects such as missing components, misaligned components, and soldering defects. AOI is a fast and accurate inspection method capable of detecting defects that may be difficult for humans to identify.

Following AOI, the circuit board may undergo X-ray inspection, which is used to detect defects in hidden areas such as solder joints beneath surface-mounted components. X-ray inspection is particularly useful for detecting defects like voids in solder joints, which may be challenging to detect using other methods.

PCBA Component Design and Inspection Specifications

Inspection Preparation: Inspectors must wear anti-static gloves and wristwatches and prepare tools such as calipers, electrical performance parameter instruments, etc.

  1. Technical Requirements

1.1 PCBA component boards must use materials with a flame retardancy rating of 94-V0 or above, with corresponding UL yellow cards.

1.2 The appearance of PCBA component boards should be free of rough burrs, poor cutting, and layer cracking.

1.3 The dimensions, apertures, and margins of PCBA component boards must comply with the engineering drawings’ requirements, with a tolerance of ±0.1mm unless otherwise specified. The thickness of the boards should be 1.6±0.1mm unless otherwise specified.

1.4 PCBA components must print the production (design) date, UL symbol, certificate number, 94V-0 character, factory logo, and product model. If the PCBA component consists of multiple PCB boards, the rest of the PCB boards should also print the above content.

1.5 The printed symbols and font sizes should be clear and distinguishable.

1.6 If PCBA components use resistor-capacitor voltage reduction circuits, they must use half-wave rectification circuits to improve circuit safety and stability.

1.7 If PCBA components use switch-mode power supply circuits, the standby power consumption must be less than 0.5W.

1.8 European products using PCBA must have standby power consumption less than 1W. For the US version of PCBA, if customers have special requirements, standby power consumption should be executed according to technical requirements.

1.9 Except for power indicator lights using φ5 amber high-brightness scattering, the rest should use full green or full red φ3 high-brightness scattering.

1.10 PCBA components specify the live wire (ACL), neutral wire (ACN), relay common terminal wire (ACL1), high-grade or continuous wire (HI), and low-grade wire (LO).

1.11 The solder fuse and CBB capacitor (resistor-capacitor circuit) of PCBA components must be on the live wire (ACL).

1.12 ACL1 must be connected to the live wire, HI or LO must be connected to one end of the heating body each, and the common terminal of the heating body must be connected to the neutral wire.

1.13 The solder joints of PCBA components must not have virtual soldering, continuous soldering, or desoldering. The solder joints should be clean, uniform, and free of bubbles, pinholes, etc.

  1. Component Selection

2.1 PCBA component elements should be prioritized from reputable brand manufacturers, followed by manufacturers that meet international or industry standards; manufacturers with proprietary standards should not be used.

2.2 Integrated circuit (IC) components should be industrial-grade ICs.

2.3 Connector plugs and terminals must have UL certification and provide certificates.

2.4 Resistor components should use metal film resistors with clear color bands, and manufacturers should meet industry standards.

2.5 Electrolytic capacitor components should use explosion-proof capacitors with a working temperature of -40 to 105°C, and manufacturers should meet industry standards.

2.6 Crystal oscillator components should use crystal elements; RC or chip-embedded options are not recommended. Manufacturers should meet international standards.

2.7 Diodes or transistors should be selected from reputable domestic brands that meet industry standards.

2.8 Tilt switches should use infrared photoelectric types and avoid mechanical types.

2.9 Specified component surfaces must be printed with clear and visible UL/VDE/CQC symbols, trademarks, parameters, etc.

2.10 Relevant wires must have UL/VDE symbols, wire specifications, certification numbers, manufacturer names, etc., clearly visible.

  1. Testing and Inspection

3.1 PCBA components are mounted on the corresponding test fixtures, and voltage frequency parameters are adjusted accordingly.

3.2 Verify whether the self-check function of the PCBA components meets the requirements of the functional specifications. Check for abnormal sounds in relay outputs and uniform brightness in fully lit LEDs.

3.3 Verify whether the placement of the tilt device and the output function during tilting comply with the functional specifications.

3.4 Check whether the output function and fault indication of the PCBA components meet the functional specifications when the temperature probe is disconnected or shorted.

3.5 Verify whether the output of each button function of the PCBA components meets the requirements of the functional specifications.

3.6 Check whether the temperature indicated by the environmental temperature indication LED or digital display of the PCBA components complies with the functional specifications.

3.7 Verify whether the power status indication LED of the PCBA components meets the functional specifications.

3.8 Check whether the smart control operation mode of the PCBA components complies with the functional specifications.

3.9 Verify whether the continuous operation mode of the PCBA components complies with the functional specifications.

3.10 Check whether the standby power consumption of the PCBA components complies with the functional specifications.

3.11 Adjust the voltage to 80% of the rated voltage, and check for abnormal sounds in relay outputs and uniform brightness in LEDs.

3.12 Adjust the voltage to 1.24 times the rated voltage, and check for abnormal sounds in relay outputs and uniform brightness in LEDs.

PCBA General Appearance Inspection specification

  1. Solder Joint Contact Angle Defect: The wetting angle between the angle solder fillet and the terminal pad graphic endpoint exceeds 90°.

  2. Standing: One end of the component is raised or standing up from the solder pad.

  3. Short Circuit: The solder between two or more solder joints that should not be connected, or the solder of the solder joint is connected to adjacent wires.

  4. Open Solder: The component leads are not soldered to the PCB solder pads.

  5. False Solder: The component leads are seemingly connected to the PCB solder pads but are not actually connected.

  6. Cold Solder: The solder paste at the solder joint is not fully melted or does not form a metal alloy.

  7. Insufficient Solder (Insufficient Fill): The solder area or height of the component terminal and PAD does not meet the requirements.

  8. Excessive Solder (Excessive Fill): The solder area or height of the component terminal and PAD exceeds the requirements.

  9. Solder Joint Blackening: The solder joint is blackened and lacks luster.

  10. Oxidation: Chemical reaction has occurred on the surface of components, circuits, PADs, or solder joints, resulting in colored oxides.

  11. Displacement: The component deviates from the predetermined position in the plane of the solder pad horizontally, vertically, or rotationally (based on the centerline of the component and the centerline of the solder pad).

  12. Polarity Reversal: The orientation or polarity of components with polarity does not match the requirements of documents (BOM, ECN, component position diagram, etc.).

  13. Float Height: There is a gap or difference in height between the component and the PCB.

  14. Wrong Part: The specifications, models, parameters, and forms of the components do not match the requirements of documents (BOM, samples, customer data, etc.).

  15. Solder Tip: The component solder joint is not smooth and has a pulled tip condition.

  16. Multiple Parts: The positions of parts that should not be mounted according to the BOM, ECN, or samples, or there are surplus parts on the PCB.

  17. Missing Parts: The positions on the PCB where parts should be mounted according to the BOM and ECN or samples, but no parts are present.

  18. Misalignment: The position of the component or component pin has shifted to other PADs or pin positions.

  19. Open Circuit: PCB circuit is disconnected.

  20. Side Mounting: Sheet-like components with differences in width and height are mounted sideways.

  21. Reverse Side (Upside Down): Two symmetrical faces of components with differences are swapped (e.g., faces with silk screen markings are inverted vertically), common in chip resistors.

  22. Solder Ball: Small solder points between component pins or outside PADs.

  23. Bubbles: There are bubbles inside solder joints, components, or PCBs.

  24. Soldering (Solder Climb): The solder height of the component solder joint exceeds the required height.

  25. Solder Cracking: The solder joint has a cracked condition.

  26. Hole Plugging: PCB plug-in holes or vias are blocked by solder or other substances.

  27. Damage: Components, board bottom, board surface, copper foil, circuits, vias, etc., have cracks, cuts, or damage.

  28. Unclear Silk Screen: The text or silk screen on the component or PCB is blurry or has broken lines, making it unrecognizable or unclear.

  29. Dirt: The board surface is unclean, with foreign objects or stains, etc.

  30. Scratches: Scratches or exposed copper foil on the PCB or buttons, etc.

  31. Deformation: The component or PCB body or corners are not on the same plane or are bent.

  32. Bubbling (Delamination): PCB or components delaminate from the copper plating and have gaps.

  33. Glue Overflow (Excess Glue): Excessive amount of red glue (or overflow) exceeds the required range.

  34. Insufficient Glue: The amount of red glue is insufficient or does not meet the required range.

  35. Pinhole (Concavity): There are pinholes or concavities on PCBs, PADs, solder joints, etc.

  36. Burr (Peak): The edge or burr of the PCB board exceeds the required range or length.

  37. Gold Finger Impurities: There are dots, tin spots, or solder resist oil abnormalities on the surface of the gold finger plating.

  38. Gold Finger Scratches: There are scratch marks or exposed copper on the surface of the gold finger plating.