PCBA Tech - ​Advantages of pcba online water cleaning machine

The welding technology of the fine-pitch QFP of the PCBA online water cleaning machine is very mature, but it also encounters some new challenges, such as how to use laser cleaning to remove the white residue between the fine-pitch QFP pins, and how to deal with PCBA components Perform boundary scan tests, etc. In this article, the new technology and new methods to solve these problems are introduced in detail.

According to practice, the use of these new technologies can solve some of the problems encountered in fine-pitch QFP welding, and improve the success rate and reliability of fine-pitch QFP assembly.

One, PCBA online water cleaning machine laser welding fine pitch QFP.

Fine-pitch QFP due to the very small pin pitch, when smt stencil printing solder paste, due to various reasons, the solder paste on the pins often bridges.

2. Pressure of PCBA online water cleaning machine,

Often the solder paste will collapse. In addition, the gravity of the QFP itself will also cause the solder paste to collapse, which will cause the solder paste to overlap. When the bridged solder paste is reflowed, it often causes the solder joints of the pins to short-circuit, forming defective solder joints.

Three, PCBA online water cleaning machine three-dimensional wiring technology based on Pro/E software

The 3D wiring technology of the batch cleaning machine based on Pro/E software is a process technology that simulates the wiring of electronic equipment through its Pro/Cabling module based on the 3D model. Three-dimensional wiring can be divided into automatic wiring and manual wiring. Automatic wiring is actually not very "automatic". It needs to use the Pro/Diagram module to create symbols for a large number of non-parametric connectors and components before automatic wiring, and perform specified operations on connectors of the same specification. Automatic routing is actually to transfer a lot of work to the design Pro/Diagram, and can not greatly improve work efficiency. In many cases, automatic wiring is completely successful and the wiring rate is not high, and manual wiring is needed to complete its "automation". The wiring process is very inflexible, so automatic wiring loses the meaning of "automation" to a large extent.

Advantages and disadvantages of PCBA online water cleaning machine

1. Excess objects that cause insulation failure.

The metal residues of the batch cleaning machine refer to the metal substances (such as wire, tin beads) produced or introduced during the PCB production process. These substances themselves are conductive and overlap between the solder joints that are mutually insulated, forming a fundamental problem. There should be a current channel, causing a short circuit. Flux residue refers to the non-volatile components and residual active components and metal salt substances generated after PCB processing and soldering. These residues can be divided into polar residues and non-polar residues. If there are polar residues on the PCBA surface, these residues have "polar" characteristics due to the eccentric electron distribution, which can ionize ions under certain conditions, and the ions will undergo directional migration to form current channels, thereby causing insulation Performance degradation is the phenomenon of electrochemical migration. Although non-polar residues are non-polar, they can cause an increase in contact resistance and even an open circuit. It can be seen that, in addition to affecting the appearance of the product, the residue, more importantly, causes the failure of the product function.

2. Reliability management of batch cleaning machine

Reliability management of batch cleaning machines refers to the general term for various management activities required to determine and achieve the required product reliability characteristics. It is from a systematic point of view, through the formulation and implementation of a scientific plan to organize, control and supervise the development of reliability activities to ensure that fewer resources are used to achieve the product reliability required by users. in the text. After the PCBA product has acquired inherent reliability through the design stage, if no management measures are taken, and there is no advanced technology to guarantee it, the reliability of the product will be degraded.

One of the reasons is that the main contents of reliability management at the manufacturing stage are as follows:

1. Establish and implement a quality responsibility system from the factory director to each employee, and have a strict quality organization system;

2. The quality assurance system is complete, and the original records of various quality are complete, which can ensure the realization of reliability goals and reliability growth;

3. Manufacturers that supply major outsourcing and outsourcing parts must conduct quality reviews, formulate management methods and order contracts that should have reliability indicators and inspection sampling plans;

1. Determination of the printed conductor size of the batch cleaning machine:

According to the size of the current flowing into the PCBA board and the allowable temperature rise range, determine the size of the printed conductor. It is the relationship curve between the conductor width (or area), temperature rise and current of the conductor in the multilayer board. For example, when the allowable current is 2A, the temperature rise is 10°C, and the thickness of the copper foil is 35μm, the conductor width is less than 2mm. In addition, the width of the ground wire of the printed circuit board should be appropriately widened, and the ground wire and bus bar should be fully utilized for heat dissipation. In order to carry out high-density wiring, the conductor width and line spacing should be reduced. In order to improve its heat dissipation capacity, the thickness of the conductor should be appropriately increased, especially the inner conductor of the multilayer board. The epoxy resin glass plate mainly used at present has a low thermal conductivity of 0.26W/(m· degree Celsius) and poor thermal conductivity. In order to improve its thermal conductivity, a heat-dissipating PCBA board can be used. The heat-dissipating PCBA board includes: the heat-conducting strip (board) PCBA board with metal (Cu, Al) strips (or plates) with high thermal conductivity on the ordinary PCBA board;

2. What kind of performance combination should the ideal coating have?

Is the batch cleaning machine easy to use? As the operating environment of electronic PCBA components becomes more and more demanding, the performance requirements of the three anti-paint coatings are getting higher and higher, and the challenges they have to face are getting bigger and bigger. The perfect three-proof paint coating can maintain good elasticity in the extreme conditions of high and low temperatures at the same time, and at the same time can maintain its characteristics at high temperatures without exhausting outward. In a humid environment, the PCBA components are at risk of being splashed by liquid water. Therefore, the three-proof paint coating also provides very good moisture resistance. It has strong resistance to solvents and corrosive gases, and the coating can be easily removed when repairing or modifying the coating., The perfect coating will be an automatically applied, intelligent, uncharged coating, which is completely different from what we have seen! More importantly, the ideal coating should also be solvent-free. An innovative non-volatile organic compound (VOC), fast curing, high-performance two-component tri-proof paint coating can now provide selective coating coating methods. The two-component (2K) solvent-free selective coating process is a technological breakthrough with a wide range of applications, which can give full play to all the advantages of the three-proof paint coating.