PCB Blogger-China PCB Factory,HOYOGO

In PCBA processing, it is more common to apply solder paste for soldering by wave soldering or reflow soldering, but sometimes a dispensing technology is also required. So what is the use of the PCB dispensing technology?       1.  Underfill While the miniaturization of chips in electronic product is becoming more and more popular, miniaturization also brings solder joint reliability issues. Although the components and substrates are soldered with solder paste, due to the small size, the solder joints are more prone to stress and fall off, so the underfill technology is introduced. In this technology, underfill is applied to one side of the solder joints by dispensing, and all solder joints are filled under capillary action. Underfill can also effectively reduce the problem of uneven stress and solder joint failure caused by mismatched thermal expansion coefficients. Underfills are used widely in electronic packaging.     2.  M aking  S older  J oints Similar to printing techniques, th

During  PCB assembly, bubbles sometimes appear  during  PCB  soldering , which usually occurs  during  reflow soldering and wave soldering.  Excessive  bubbles will cause damage to the  board . So how to avoid bubbles during PCB  solder ing?       1. Bak e Baking PCB and SMD exposed to air for a long time may affect the moisture removal of PCBA processing.     2.  Solder Paste Solder paste contains moisture and is also prone to bubbles during PCB soldering.  For solder paste, you need to choose high-quality. The temperature and stirring of the solder paste need to be strictly implemented in accordance with the requirements of electronic processing production. The exposure time of the solder paste to the air should be as short as possible, and after the solder paste is printed, reflow soldering should be carried out in time.     3.  H umidity Monitor the humidity of the workshop in a planned way, and control it between 40-60% as much as possible.     4. Furnace Temperature Curve Test th

     The PCBA processing process is a very precise process, and it is more complicated and cumbersome, so there will be relatively high defects in the PCBA processing process.  In order to avoid the occurrence of undesirable phenomena and improve the production efficiency of PCBA, various inspections will be carried out in the production process.  first article inspection  and AOI inspection are relatively common. What is the difference between them?       1.  First Article Inspection    The  first article inspection   is done before the mass production of PCBA , and is the   inspection of the   first sample or the first few samples after PCBA processing. Therefore, the so-called "first piece" of the  first article inspection   does not specifically refer to the first product, but usually refers to the first few proofing products after the processing is completed, or it can be the inspection quantity required by the customer.   If the customer does not have a requirement for

     In the PCBA processing process, welding is a very important process.   If there is a slight negligence in the operation and the relevant process regulations are not implemented, it will cause poor welding. The more common welding defects are: cold joint, false welding, continuous welding, cold welding, less welding, etc. So what is false welding? Why does false welding occur?       False welding means that during the PCBA welding process, although the manual visual inspection has already shown the effect of successful welding, sometimes the leads and solder joints can be separated by  gently poking with your fingers.   That is, it seems that the welding is successful, but in fact the welding fails. Because the false welding phenomenon is difficult to distinguish with the naked eye, it is generally found during AOI inspection.     The main reasons for false welding are welding iron tips, flux, component pins and welding tin quality problems. When the amount of flux is insufficient,

      With the development of science and technology, the volume of PCBA is getting smaller and more precise, and some defects in processing cannot be distinguished with the naked eye, so AOI has appeared.  So what PCBA problems can AOI inspect?       The working principle of AOI is to first collect and input parameters such as images, component positions, solder joints and other parameters of the good-quality board.   During the inspection, the instrument automatically scans the circuit board and automatically captures the image, and then compares the collected data with the pre-entered parameters to determine whether the characteristics of solder joints, components and other aspects are consistent. If the data is inconsistent, the d efect  will be flagged through the display for maintenance personnel to repair.     AOI is mainly used to inspect solder paste printing, component placement and soldering. For example: too much or too little solder paste,   solder paste printing offset; 

      Wave soldering is one of the important links in PCBA processing. It has certain requirements for PCBA, which are mainly reflected in PCB design, component placement, PCB and flux and so on. What are the specific requirements for these aspects?       1.  PCB Design Component layout and arrangement direction should follow the principle of smaller components in the front and try to avoid mutual occlusion.     2.  C omponents  plug-in mounting Components should be able to withstand the temperature shock of more than two wave soldering; components after soldering should have no cracks, no discoloration, no deformation, no brittleness, etc. It is necessary to ensure that the changes in electrical performance parameters of components after wave soldering meet the specifications requirements defined by the book.     3.  C omponents  Placement Using the short-insertion one-time welding process, the component pins should be exposed to the welding surface by 0.8~3mm.     4.  PCB The PCB sho

      PCB pad  falling off   is a  relatively  common  bad   phenomenon in   the   PCBA processing process , that is, the phenomenon that the pads are separated from the PCB. As a necessary medium for welding and assembling electronic components and PCB boards, once the pads fall off, the PCBA products will fail to be used normally. So what are the reasons for the PCB pads to fall off?       PCB and soldering problems are the main cause of PCB pads falling off.     PCB problem:   The poor adaptability of the copper foil and the resin of the PCB substrate will lead to the mismatch between the copper foil and the resin system, causing the PCB pad to fall off.   In the PCB manufacturing process, excessive etching of the circuit leads to copper throwing or deformation of the pad due to the collision of the pad position during the processing process, which will also cause the PCB pad to fall off.     Welding problems :  If the soldering process is too many times or the temperature is too hi

The application of PCB in today's electronic products can be seen everywhere, and there are different shaped  pads on the PCB. As the basic unit of PCB moun ting, what is the role of the pad?       The PCB pad  refer s to the lead hole on the PCB board and the surrounding copper foil of various shapes.   The types of pads are different, the common ones are square pads, round pads, oval pads, etc., and some special pads, such as teardrop pads, cross pads, and plum pads.     Take the teardrop pad as an example .   I t looks like a drop of water.   It is generally used when the electronic components on the PCB are relatively small.   If it is directly connected to the circuit on the PCB board, it will be more difficult, and even if the connection is successful, as long as the PCB board is slightly impacted in the future, it will cause the original connection to loosen or even fall off directly.   To prevent this from happening, the teardrop pad was invented.     Whether it is a soft b