PCBA aging test practices

In order to ensure the stability and use reliability of PCBA products, after the PCBA processing is completed, it is best to conduct a sampling of aging test, the main purpose of aging test is to simulate the daily use environment of the product through a combination of high temperature, low temperature, high and low temperature changes and electrical power to expose the defects of the PCBA, such as poor welding, mismatch of component parameters, and debugging process caused by In order to eliminate and improve the failure, the PCBA board without defects will play a role in stabilizing the parameters.

PCBA aging test has 3 standards, according to these 3 standards to do, the general problems can be found.

1, low temperature work: PCBA board will be placed in the temperature of -10 ± 3 ℃ for 1h, in this condition, should be with rated load, 187V and 253V conditions, power on all programs to run, the program should be correct.

2, high temperature work: the PCBA board will be placed at 80 ± 3 ℃ / h after the condition, with load, 187V and 253V conditions, power on all programs to run, the program should be correct.

3, high temperature and high humidity work: PCBA board will be placed in the temperature 65 ± 3 ℃, humidity 90-95% conditions, time 48h, with rated load power on to run all programs, each program should be correct.

The specific practices of PCBA aging test are:

1、Put the PCBA board under ambient temperature into the thermal aging equipment under the same temperature, and the PCBA board is in running state.

2、Lower the temperature inside the equipment to the specified rate to the specified temperature value, when the temperature inside the equipment reaches stability, the PCBA board should be exposed to low temperature conditions to maintain 2h.

3、Raise the temperature inside the device to the specified temperature at a specified rate, and when the temperature inside the device reaches stability, the PCBA board should be exposed to high temperature conditions for 2h.

4、Lower the temperature in the equipment to room temperature at a specified rate, repeat continuously until the specified aging time, and measure and record the PCBA board once according to the specified aging time.

PCBA board after the above process aging test, you can rest assured that bold delivery to customers, the benefits of doing so is that customers are assured that the return rate is extremely low, and the quality is more stable.

Share 5 kinds of PCB copy board disassembly IC method

In the process of PCB copy, it is necessary to disassemble the circuit board, remove the integrated circuits and other components to make the BOM list, and scan and copy the PCB bare board, therefore, in this process, the correct disassembly of the integrated circuits on the PCB board is also an important issue.

　　Not only in the PCB copy process, is in the circuit repair, often need to remove the integrated circuit from the printed circuit board, and because of the integrated circuit pins are many and dense, disassembly is very difficult, and sometimes damage to the integrated circuit and the circuit board. Here, we provide several accurate disassembly of the integrated circuit proven methods, I hope it will help you.

　　Solder suction tin demolition method: the use of solder suction demolition integrated block, which is a common professional method, the use of tools for ordinary suction, soldering soldering iron, power in 35W or more. When disassembling the integrated block, as long as the heated dual-use soldering iron head on the pins of the integrated block to be disassembled, to be melted solder joint tin is sucked into the fine tin ware, all the pins of the solder sucked after the integrated block can be taken off.

　　　Soldering iron brush with disassembly method: the method is simple and easy, as long as there is a soldering iron and a small brush can be. When disassembling the integrated block, the soldering iron is heated and the solder on the pins is melted after reaching the melting temperature, and the brush is used to sweep off the melted solder. In this way, the pins of the integrated block can be separated from the printed board. This method can be carried out in separate pins or separately. Finally, use pointed tweezers or a small “a” screwdriver to pry off the integrated block.

　Medical hollow needle removal method: take a few medical 8 to 12 hollow needles. When using the needle’s inner warp just cover the integration block pins is appropriate. When disassembled with a soldering iron to dissolve the pin solder, in time to cover the pin with a needle, and then remove the iron and rotate the needle, wait for the solder to solidify and then pull out the needle. This way the pin is completely separated from the printed board. After all the pins are done once, the integrated block can be easily removed.

　　Increase the solder melting disassembly method: This method is a hassle-free method, just add some more solder to the pins of the integrated block to be disassembled, so that the solder joints of each column of pins are connected, so as to facilitate heat transfer and easy disassembly. Disassembly with a soldering iron each heated column of pins with pointed tweezers or small “a” screwdriver to pry a pry, two columns of pins are heated in turn, until removed. In general, each column of pins heated twice can be removed.

　　Multi-strand copper wire suction tin demolition method: is the use of multi-strand copper core plastic wire, remove the plastic skin, the use of multi-strand copper core wire (can use short wire head). Before using the multi-stranded copper core wire on the rosin alcohol solution, to be hot soldering iron will be multi-stranded copper core wire into the integrated block pins heated, so that the tin solder on the pins will be adsorbed by the copper wire, suck on the part of the solder can be cut off, repeated several times on the pins of the solder can all be sucked away. Conditions can also use the braided wire inside the shield. As long as the solder sucked, with tweezers or a small “a” screwdriver gently pry, the integrated block can be removed

How to convert from BMP to PCB in PCB copy?

The complete steps of PCB copy board are as follows:

The first step is to get a PCB, first record on paper the type, parameters, and location of all the meta parts, especially the diode, the direction of the three machine tubes, and the direction of the IC gap. It is best to use a digital camera to take two pictures of the location of the components.

Step 2: Remove all devices and remove the tin from the PAD holes. Clean the PCB with alcohol, then put it into the scanner, start POHTOSHOP, sweep the silkscreen surface in color and print it out for backup.

Step 3: Lightly sand the TOP LAYER and BOTTOM LAYER layers with water gauze paper until the copper film is shiny, put it into the scanner, start PHOTOSHOP, and sweep in the two layers separately with color. Note that the PCB must be placed horizontally and vertically in the scanner, otherwise the scanned image will not work.

Step 4, adjust the contrast of the canvas, light and darkness, so that the part with copper film and no copper film part of the contrast is strong, and then turn the sub-image to black and white, check whether the lines are clear, if not, repeat this step. If clear, save the figure as black and white BMP format files TOP.BMP and BOT.

Step 5, convert the two BMP format files to PROTEL format files respectively, and call in the two layers in PROTEL, if the position of PAD and VIA over the two layers basically overlap, it shows that the first few steps are well done, if there is deviation, repeat step 3.

BMP into TOP.PCB, pay attention to the SILK layer, that is, the yellow layer, then you trace the lines in the TOP layer is, and according to the second step of the drawing to place the device. After drawing the SILK layer will be deleted.

BMP to BOT.PCB, pay attention to the SILK layer, that is, the yellow layer, and then you trace the lines in the BOT layer is it. After drawing the SILK layer will be deleted.

PCB and BOT.PCB into PROTEL, combined into one figure is OK.

Step 9, use a laser printer to print the TOP LAYER, BOTTOM LAYER, respectively, to transparent film (1:1 ratio), the film onto that PCB, compare whether there is a mistake, if not, you’re done.

Copy board accuracy problem

For the accuracy of the copy board, it depends on two aspects, one is the accuracy of the software and the other is the accuracy of the original image.

For software accuracy using 32-bit floating point can be said to not have any precision limits, so the main thing depends on the original scan image accuracy, let’s say, if the photo taken with 1 million pixels can be washed 5-inch photo, but if you want to wash it into a 20-inch photo that is not clear at all, the same reason, so for the high precision requirements of the circuit board, to copy out Very high precision PCB diagrams, in the scan to choose a higher DPI.

DPI is the meaning of how many points per inch. That is, the distance between each two points on the scanned image is 1000/DPI, in mil.
If the DPI is 400, then the distance between the two points on the image is 1000/400 = 2.5 mil, which means that the accuracy is 2.5 mil.
This is the most scientific basis, so some people say that the accuracy can reach 1mil or less, that is the premise. In fact, the accuracy of the copied board mainly depends on the original scanning accuracy.

To sum up, when scanning the board set the DPI should be based on the actual board requirements of the precision, if the precision requirements such as cell phone board line spacing below 1mil, then the need to scan the DPI should be set at more than 1000DPI. Scanners on the market today can meet this condition.
The higher the DPI, the clearer the picture, the higher the accuracy, but the disadvantage is that the picture is too large, the hardware requirements are high, so according to the specific circumstances of the specific settings. For the general accuracy of the board generally use 400DPI is very good, cell phone board and so on can be set at 1000DPI or more.

PCB board heat treatment tips

Heat dissipation through the PCB board itself
The widely used PCB boards are copper-clad / epoxy glass cloth substrates or phenolic resin glass cloth substrates, and a small number of paper-based copper-clad boards are used. Although these substrates have excellent electrical properties and processing performance, but poor heat dissipation, as a high heat-generating components of the heat dissipation path, almost can not be expected to conduct heat from the PCB itself resin, but from the surface of the component to the surrounding air heat dissipation. However, as electronic products have entered the era of miniaturization of components, high density mounting, and high heat generation assembly, it is not enough to rely only on the surface area of very small components to dissipate heat. At the same time, due to the large number of QFP, BGA and other surface-mounted components, the heat generated by the components is transmitted to the PCB board in large quantities, so the best way to solve the heat dissipation is to improve the direct contact with the heat-generating components of the PCB’s own heat dissipation capacity, through the PCB board to conduct out or emit out.

High heat-generating devices plus heat sink, thermal conductivity plate
When there are a few devices in the PCB when the heat generation is large (less than 3), you can add heat sink or heat pipe on the heat-generating devices, when the temperature can not be lowered, you can use a heat sink with a fan to enhance the heat dissipation effect. When the amount of heat-generating devices is more (more than 3), a large heat sink cover (board) can be used, which is customized by the location and height of the heat-generating devices on the PCB board and a special heat sink or a large flat heat sink keyed to different component height positions. The heat sink is snapped onto the component surface as a whole, and each component is in contact with the heat sink. However, the heat sink is not effective due to the poor consistency of the height of the components when they are mounted and soldered. Usually a soft thermal phase change pad is added to the component surface to improve heat dissipation.

Pay attention to air convection cooling
For devices with free convection air cooling, it is best to arrange the integrated circuits (or other devices) in a longitudinal manner or in a long horizontal manner. Pay attention to make forced ventilation and natural ventilation in the same direction; the heat dissipation of the printed circuit board in the device mainly relies on air flow, so the air flow path should be studied during the design and the device or printed circuit board should be reasonably configured. Air flow always tends to flow to the place with less resistance, so when configuring devices on the printed circuit board, avoid leaving a large empty space in a certain area. The configuration of multiple printed circuit boards in the whole machine should also pay attention to the same issues.

Heat dissipation by using a reasonable alignment design
Since the resin in the board has poor thermal conductivity, and copper foil lines and holes are good conductors of heat, increasing the residual rate of copper foil and increasing the number of heat-conducting holes are the main means of heat dissipation. Placing as many metalized vias as possible, with as large an aperture and plate surface as possible, relying on the vias to help dissipate heat; planning the minimum channel width according to the current density of the device; paying special attention to the channel wiring at the joints; surfaceizing the high-current lines as much as possible; considering the use of sinks if the requirements cannot be met;

Reasonable layout
The devices on the same printed board should be arranged as much as possible according to their heat generation size and heat dissipation degree partition, the devices with small heat generation or poor heat resistance (such as small signal transistors, small-scale integrated circuits, electrolytic capacitors, etc.) are placed in the uppermost stream of the cooling airflow (entrance), and the devices with large heat generation or good heat resistance (such as power transistors, large-scale integrated circuits, etc.) are placed in the most downstream of the cooling airflow. Can also consider the high heat generation, radiation components specifically designed to be installed on a printed board;
In the horizontal direction, high-power devices are arranged as close as possible to the edge of the printed board in order to shorten the heat transfer path; in the vertical direction, high-power devices are arranged as close as possible to the top of the printed board in order to reduce the impact of these devices on the temperature of other devices when working. The devices with the highest power consumption and the highest heat generation are arranged near the best location for heat dissipation. Do not place the higher heat-generating devices in the corners and around the edges of the printed board, unless there are heat sinks arranged near it. When designing power resistors, choose larger devices as much as possible, and adjust the layout of the board so that it has enough space for heat dissipation.
Temperature-sensitive devices are best placed in the lowest temperature areas (such as the bottom of the device), never place it directly above the heat-generating devices, multiple devices are best staggered layout on the horizontal plane.

Process method
For some double-sided equipped with devices in the area prone to local high temperature, in order to improve the heat dissipation conditions, you can mix a small amount of fine copper material in the solder paste, and then after the flow of solder in the device below the solder joint on a certain height. So that the gap between the device and the printed board increases, increasing the convection heat dissipation.

Pay attention to the selection of materials
As the components installed on the printed board also emits part of the heat, affecting the operating temperature, the choice of materials and printed board design should take these factors into account, the hot spot temperature should not exceed 125 ℃; choose a thicker copper-clad foil as much as possible; special circumstances can choose aluminum-based, ceramic-based and other small thermal resistance of the plate; the use of multilayer board structure helps PCB thermal design; RF amplifier or LED PCB using metal Base substrate.

Avoid hot spot concentration
Avoid the concentration of hot spots on the PCB, as far as possible, the power is evenly distributed on the PCB board to maintain uniform and consistent temperature performance of the PCB surface. Often the design process to achieve a strict uniform distribution is more difficult, but be sure to avoid areas of too high a power density to avoid excessive hot spots affect the normal operation of the entire circuit.

PCB circuit board copy of the skills and methods of speaking

People in the industry are well aware that one of the necessary skills of electronic engineers for pcb copy board is circuit design, which shows the importance of circuit design. There are two main aspects of circuit design, namely the design of the circuit schematic and the design of the printed circuit version.

In the process of creating the list, we need to clarify the contents of the label and the relevant data required. In fact, in the list making, a seemingly simple thing but there are a lot of hidden learning. First of all, we need to do the corresponding preparatory work. First get a piece of PCB, with a better camera to take two photos of the location of the meta-part, the effect of the shot must be clear, or not. Then we need to write down on paper all the components of a series of models, parameters, and location, especially the diode, the direction of the three machine tubes, etc. must be remembered especially clearly. The next step is to disassemble the version of the record. We first remove all the devices one by one.

It is important to note that after our knowledge also to several relevant devices and parameters, each component is removed, corresponding to its location number with double-sided tape or the like to paste it on white paper. To remind you is that in the process of splitting the board, the numbering of components must be arranged with special care, because a small detail may lead to the whole project before it is abandoned, affecting the final cloning effect. The last step to be carried out is the component test. First of all, we get the relevant data list from the hands of the demolition of the board, you can formally enter the BOM single production process, that is, through a variety of tests and analysis, all the relevant parameters of the components into a system of tables of the process. This time we need to use an advanced instrument, this instrument is called bridge tester. This tester is mainly for the impedance analysis of various components a measurement instrument, it uses the advanced comparison method to measure the resistance, capacitance and inductance of components. Of course, different levels of bridge test equipment with different test results and accuracy.

Generally speaking, there is a small shortcut to learning circuit design, which is to analyze the classical design. There are many applications of classical designs, such as mass-produced electronic products is one of them, and displays are also. Analysis of classic design generally has the following steps, which generally include copy board, reverse schematic, simulation analysis (this can be excluded) and modify the design to suit your application. Among them, the copy board is a kind of learning, the first step, but also a relatively important step. Copying is the study of the designed PCB board using reverse technology. We will first introduce you to the PCB copy method and the steps to follow. PCB copy can also be described as cloning, which is the reverse engineering part of PCB design. This requires the PCB circuit board components are removed, and then the empty board will be scanned into a picture by the copy board software processing to restore the pcb board diagram file, through the PCB copy board and reverse technology can be any electronic product imitation or electronic product cloning.

Generally speaking, the bridge tester is divided into many kinds according to different levels, the use of this instrument can not only ensure a higher accuracy rate, but also improve the intensity and efficiency of the measurement. Therefore, PCB circuit board copy is more complex and requires certain skills.

PCB copy board makes biometric technology more advanced

Fingerprint identification is the most widely used biometric technology in all corners of society, such as criminal investigation, attendance, banking and so on. Now, “iris”, “face” and other identification technologies are also listed as new identification modes by banks and put into research and development. There is no doubt that the popularity and gradual upgrade of biometric technology will make people’s life more convenient, efficient and safe.

The new market opportunity will definitely bring new technical challenges for PCB copy board industry, on the contrary, PCB Copy Board will also provide technical support for the further popularization and development of biometric technology.

PCB Copy Board makes biometric identification more accurate The so-called biometric identification technology is a close combination of computer and high-tech means such as optics, acoustics, bio-sensors and biometric principles, using the inherent physiological characteristics of the human body (such as as fingerprints, face, iris, etc.) and behavioral characteristics (such as handwriting, voice, gait, etc.) for personal identification. Since biometric identification technology has the advantages of uniqueness, stability and high security, its development prospect is very promising.

How to ensure the feasibility and effectiveness of biometric technology in practical applications, it is necessary to continuously improve and upgrade the relevant hardware products such as biometric sensors. PCB copy board using reverse research technology, the original circuit board for reverse analysis, the original product PCB files, bill of materials (BOM) files, schematic files and other technical documents, as well as PCB screen printing production files 1: 1 reduction, and then use these technical documents and production files for PCB board, component welding, flying probe test, circuit board debugging, complete the original circuit board template complete copy . In this process, you can not only get the whole set of technical information of electronic products, but also check and update the original circuit board, and modify the unreasonable parts, so as to realize the rapid upgrade and improvement of electronic products.

PCB Plate-Reading extends the application scope of biometric technology Nowadays, fingerprint recognition has been widely used. Based on the current technology and market conditions, face recognition is one of the more popular biometric technologies at present and will gradually replace fingerprint recognition. Perhaps in the distant future, fingerprint, voice, iris, face and other identification technologies have become the style of the past, replaced by more advanced identification technologies such as genetic and brain wave.

With PCB Copy board, biometrics will be interfered by objective reasons in application, thus improving the accuracy of recognition.

PCB Plate-Reading extends the application range of biometric technology. Nowadays, fingerprint recognition has been widely used, and based on the current technology and market conditions, face recognition is one of the more popular biometric technologies and will gradually replace fingerprint recognition. Perhaps in the distant future, fingerprint, voice, iris, face and other identification technologies have become the style of the past, replaced by more advanced identification technologies such as gene, brain wave and so on.

At present, many international and domestic electronic product manufacturers, application software developers and system integrators have launched software and hardware products based on biometric technology, how to quickly improve and upgrade biometric technology and accelerate the popularity of biometric technology. Life and people’s life, but also a professional board company, trying to solve the problem. Of course, PCB copy board if only know blind imitation, do not pay attention to product upgrading and re-innovation, it is easy to fall into the “cottage” whirlpool. The computer as a representative of the professional read board company timely reform and transformation, focusing on PCB copy board secondary development, that is, the industry called PCB modification board. PCB modification board refers to the extraction of PCB files for line adjustment or re-layout, in order to achieve the original circuit board function modification, can quickly achieve product updates and upgrades, to meet the personalized needs of some customers and special application needs. Therefore, through PCB copy board, combined with the actual, appropriate increase in innovative elements, reasonable changes to the board and upgrades, is currently an important means for PCB board companies to seek sustainable innovation and development

Screw pile construction recorder circuit board copy

Helical pile construction recorder purpose: accurate display of pumped grout volume versus depth graph; construction guidance for rig operators; objective monitoring of the foundation pile construction process to reduce construction time and cost. It is suitable for all types of drilling rig construction forms (swing or fixed guide column).

Spiral pile construction recorder parameters:
Small size 80x150x220 (mm)
Light weight 1.3 kg
Power supply 12V or 24V DC
Operating temperature range 0～40℃ Storage temperature range -20～65℃
High contrast LCD touch screen
PCMCIA flash memory card for data storage (≥40MB)

RayMing Technology Company is a model of success in the field of electronic equipment pcb copy, chip decryption, prototype copy cloning, production and prototype debugging. At present, we can provide customers with a full range of services in the field of this series of products. We can not only provide cloning and secondary development of this series of products, but also provide many vertical services such as PCB design, PCB copy board, chip decryption, prototype production, prototype debugging, SMT processing, etc., so as to save resources to the maximum extent and maximize customer benefits.
We will upgrade and expand the functions as the market demand changes and the technology progresses, and we can provide customized services according to your specific needs. We look forward to actively cooperating with customers who have needs in this series of products, please call us for details.

PCB solder resist design on PCBA

Solder resist layer in the control of PCBA soldering process during the role of welding defects is very important, PCB designers should minimize the spacing or air gap around the pad features. Inappropriate PCB solder resist design can lead to the following PCBA defects:

1. solder resist film is too thick than the thickness of the PCB copper foil pads, and then flow soldering will form a suspension bridge and open circuit. 2. solder resist processing and pad alignment is poor, which leads to contamination of the surface of the pad, resulting in poor solder joints eat tin or produce a large number of solder balls. 3. between two pads with wires through the PCB solder resist design should be taken to prevent soldering 4. when there are more than two close to the SMD, the pads share a common wire, the application of solder resistance to separate them, so as not to produce stress when the solder shrinkage SMD shift or pull crack.

Introduction of PCB anti-distortion design

PCB deformation on the production of printed circuit boards is very large, warpage is also one of the important issues in the process of circuit board production, loaded with components of the board after welding bending, component feet is difficult to neatly. The board also can not be mounted to the chassis or machine socket, so the PCB deformation will affect the normal operation of the entire post-process PCBA process. So is there any way to prevent PCB deformation?

The impact of PCB deformation

PCB deformation, also known as warpage, has a great impact on the welding and use. In particular, communication products, single board installation using plug box installation, there is a standard spacing between the inserts, with the narrowing of the panel, the gap between components on adjacent inserts is getting smaller and smaller, if the PCB is bent, it will affect the plugging and unplugging, will touch the components. On the other hand, the deformation of the PCB has a great impact on the reliability of BGA-type components. Therefore, it is very important to control the deformation of PCB during and after the completion of welding.

PCB anti-deformation design requirements

The degree of PCB deformation is directly related to its size and thickness. General aspect ratio ≤ 2, width-thickness ratio ≤ 150.

Multi-layer rigid PCB is composed of copper foil, semi-cured sheet and core board. In order to reduce the deformation after press fit, the laminated structure of the PCB should meet the symmetry design requirements, that is, the thickness of the copper foil, media category and thickness, graphic distribution category (line layer, plane layer), press fit, etc. are symmetrical with respect to the centerline of the PCB thickness direction.

For large size PCB, should be designed to prevent deformation reinforcement or liner plate (also known as fireproof board) which is a mechanical reinforcement method.

for the local installation, PCB deformation is likely to cause structural components, such as CPU card holder, should be designed to prevent PCB deformation liner.