Let's first introduce the common drilling in PCB: through hole, blind hole, buried hole. The meaning and characteristics of these three holes.
Conduction hole (VIA), this is a common hole used to conduct or connect copper foil lines between conductive patterns in different layers of the circuit board. For example (e.g. blind holes, buried holes), but do not insert component pins or other reinforcement copper plated holes. Because PCB is formed by the accumulation of many copper foil layers, each layer of copper foil will be covered with a layer of insulation layer, so that the copper layer can not intercommunicate with each other, the signal link is on the through hole (via), so there is the Chinese through hole title.
Characteristics are: in order to meet customer needs, the circuit board through the hole must be strongholds, so in the change of the traditional aluminum sheet plug process, with white mesh to complete the circuit board surface welding and plug holes, so that its production stability, reliable quality, more perfect use. With the rapid development of the electronic industry, higher requirements have been put forward for the manufacturing process and surface mounting technology of printed circuit boards. The process of plugging through holes is applied and born, and the following requirements should be met:
1. Copper can be in the through hole, welding can plug or not plug.
2. There must be tin lead through the hole, there is a certain thickness requirement (4um) shall not be solder resistance ink into the hole, resulting in tin beads inside the hole.
3. The pass-through hole must have solder resistance ink plug hole, light proof, no tin ring, tin beads and flat requirements.
Blind hole: that is, the outermost circuit in the PCB and the adjacent inner layer to connect with electroplating holes, because can not see the opposite side, so called blind pass. At the same time, in order to increase the utilization of space between PCB layers, blind holes are applied. That is, a pass hole to a surface of the printed board.
Characteristics: Blind holes are located on the top and bottom surfaces of the board and have a certain depth. They are used to connect the surface circuit to the inner circuit below. The depth of the holes usually does not exceed a certain ratio (aperture). This production method needs to pay special attention to the depth of drilling (Z axis) to be just right, do not pay attention to it will cause difficulties in the hole electroplating so almost no factory, you can also put the prior need to connect the circuit layer in the individual circuit layer when the first drilling hole, and then together, but the need for more precise positioning and alignment device.
Buried hole is the link between any circuit layers inside the PCB, but not through to the outer layer, is also not extended to the surface of the circuit board of the through hole meaning.
Features: This process cannot be achieved by drilling after bonding. Drilling must be performed at the time of individual circuit layers. The inner layer must be partially bonded before electroplating treatment, and finally, all bonding can be completed. This process is usually used only on high-density circuit boards to increase the available space of other circuit layers
In PCB production process, drilling is very important, can not be careless. Because drilling is to drill the required holes in the copper clad plate, to provide electrical connection, fixing device function. If the operation is not proper, there is a problem in the process of the hole, the device can not be fixed on the circuit board, light will affect the use of heavy, the whole board will be scrapped, so the drilling process is very important.
PCB board three anti glue what? Why should PCB board be coated with three anti - adhesive?
The PCB board mentioned in the title refers to the printed circuit board, also known as the printed circuit board, is the electrical connection provider of electronic components. It is very common in the electronics industry, and the three anti adhesive is also widely used in it. There is no PCB board three anti adhesive this type of adhesive, in fact, on the PCB coated with a layer of three anti adhesive. Today, Pulin Xiaobian to talk to you carefully!
First, easy to cause PCB board damage factors
Moisture is the most prevalent and destructive major factor to PCB boards. Excessive moisture will greatly reduce the insulation resistance between conductors, accelerate high speed decomposition, reduce Q value, and corrode conductors. Often appear PCB board metal part of the patina, is because of copper and water vapor, oxygen caused by the chemical reaction.
Two, why PCB board should be coated with three anti adhesive?
Because the use of three rubber PCB board, not only has waterproof, moisture-proof, dust-proof "three" performance, but also has cold and heat shock resistance, aging resistance, radiation resistance, salt spray resistance, ozone corrosion resistance, vibration resistance, good flexibility, strong adhesion and other properties.
The three anti adhesive coating on PCB board and parts, when affected by the adverse factors of the operating environment, can reduce or eliminate the electronic operating performance decline.
Different terminal products because of the different application environment, the performance requirements of the three proofing adhesive will be focused on. Refrigerators, washing machines, water heaters and other household appliances require high moisture resistance, outdoor fans, street lamps and other products need excellent anti-fog performance.
Three anti rubber as PCB circuit board "god of protection", it shows its professionalism. For the purchase of this kind of adhesive products have a professional demand, natural to choose a professional regular brand, the use of more assured, such as CosMolar, professional engaged in the research and development and production of three anti rubber, according to different needs, to provide customized solutions providers.
Electronic products are very afraid of damage, if you need to use electronic products in harsh environments. It is strongly recommended to coat the PCB board with three anti - adhesive, which will form a protective coating. Moisture-proof, corrosion-proof, shock-proof, protective functions. Now, you know why to apply three anti-rubber on the PCB board, have the need of the small partners do not hurry to act!