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    Printed circuit board manufacturing technology development trend abroad
    Time:2014-9-23 Click:1518

    A, printed circuit board manufacturing technology abroad development situation
    With the development of the miniature device fabrication and surface mount technology, led PCB manufacturing technology innovation and improve faster, especially the wire width of circuit graphics is currently widely used abroad through three wire between pin and achieve practical phase conductor width is by 4 to 5 wire between pins, and toward finer wire width.In order to meet the SMD lead more narrow spacing, realizing the PCB wiring fine lines.Technology is widely held, is that generally used CAD/CAM system, from the design data provided by the manufacturing system into production with data;In the aspect of raw material use thin thin copper foil and dry film photoresist;Because the narrow spacing requirements printed circuit board surface has smooth flat copper surface, in order to make the micro welding plate and has a thin line and its narrow spacing circuit graphics;Used by the base material should have high ability of thermal shock, to make the PCB in the process of denso after many also won't produce bubbles, layered and PanGu welding defects such as, ensure high reliability of surface mount component;Ensure that modified epoxy resin and using high viscosity copper foil and maintain its sufficient bonding strength at welding temperatures, and also should has high size stability, ensure the production process fine circuit graphics positioning of the consistency and accuracy requirements.In short, thin wire, narrow spacing of printed circuit board manufacturing technology development speed is quick, want to keep up with the world advanced technology level, we must understand the foreign developments in this area.
    Second, the key technology development trend in abroad
    1, film making and graphic transfer process
    Transfer film production and graphics quality, directly affect the quality of making fine circuit graph.So, when making the film widely used computer aided design (CAD) system, circuit design and computer aided manufacturing (CAM) system interface through the data conversion to produce high precision, high resolution, light painted film.Owing to the high wire density, conductor width and spacing of 0.10 0.05 mm, to ensure the precision and accuracy of film conductor graphics, and circuit diagram form like quality, requirements of workshop cleanliness higher, usually adopt or thousand level, to ensure the high quality of film.
    In terms of graphic transfer technique, materials used high resolution imaging of thin photosensitive resist, CD (electrophoresis) and resistance welding using liquid photosensitive resistance welding flux.Electrophoresis coating of the photo imageable etching resist layer, the thickness of 5-30 microns, controllable, its resolution of 0.05-0.05 mm.To improve the accuracy of fine circuit graph and resistance welding graphics and consistency has played a big role.
    In the process of transfer circuit graphics, in addition to strictly control the process parameters, the same to the cleanliness requirement of the workshop is very high also, reached a level standard or more small.In order to ensure the high quality of graphic transfer, but also assure indoor working conditions, such as control indoor temperature in 21 + / - 1 ℃, relative humidity of 55-60%.Negative transfer and graphic imaging of made of semi-finished products, must be 100% of the check.

    2, drilling technology
    Quality first to ensure the plating through hole drilling high reliability and high quality, we must strictly control the quality of drilling.In this area have attached great importance to both at home and abroad.Especially in surface encapsulation of multilayer printed circuit board thickness and aperture is higher, so the quality of the plating through hole is the key to improve surface encapsulation PCB percent of pass.Currently abroad on choosing the hole diameter, the diameter of 0.25-0.30 mm.Trail of hole is the key to the development of high precision, high stability, nc drilling machine and use, in recent years abroad has been developed and used to drill diameter of 0.10 mm hole CNC drilling machine and special tools.In drilling, experience tells us that in the base material of physical and chemical properties, on the basis of correctly selecting drilling process parameters is very important.While the right choice of auxiliary materials and matching tooling (such as: top and bottom plate, positioning method, drill bit, etc.).In order to adapt to the micro aperture also USES laser drilling technology.
    3, hole metallization technology
    In hole metallization technology, in order to ensure the hole metallization quality of high reliability, in after pretreatment using new type of pitting and drilling process method to stain the low alkaline potassium permanganate method, provide very good hole wall surface, and eliminates the slot wedge and crack defects.And USES the advanced direct plating process, vacuum metallization process and other process method, adapt to various types of printed circuit boards, micro hole, blind hole buried and distributed metallization.
    4, vacuum laminating process
    Especially manufacturing multilayer printed circuit board, generally used vacuum multilayer press abroad.This is due to the internal graphics have a characteristic impedance surface installation of multilayer printed circuit board (Z0) requirements.Because of the characteristic impedance is related to the thickness of the dielectric layer and wire width (see the following formula:
    Z0 = 60 / epsilon. LN. 4 h/D0 note: epsilon as the dielectric constants of materials
    H, the thickness of the dielectric materials
    Do as the actual width of the wire
    The dielectric constant and wire actual width is known, so the thickness of the dielectric materials, is becoming the key factor of the characteristic impedance.Using vacuum laminating equipment and computer control, the lamination quality is significantly improved.Because before vacuum laminating multilayer printed circuit board has vacuum exhaust between layer and layer, removal of low molecular volatiles, make the layer pressure has reduced obviously, so it is just regular multilayer printed circuit board laminating pressure 1/4-1/2, so that the multilayer printed circuit board line graph layer between the dielectric material thickness, high precision, small tolerance, ensure the characteristic impedance Z0 technical indicators within the scope of the design requirements.At the same time, the laminated vacuum technology, to improve the surface roughness of multilayer printed circuit board, the decrease of multilayer printed circuit board quality defects, such as lack of glue, layered, white spot and dislocation, etc.).
    Three, detection technology is to ensure that the implementation of the important means
    According to denso technology by pin instrumentation technology to surface encapsulation technology (bare chip installed directly technology and fine spacing) - multichip module (MCM) or more chip packaging technology development, make a multi-layer PCB circuit graphics detection more difficult.To this end, both at home and abroad in the development and use of high precision, high stability testing equipment.At present there are two kinds of non-contact detection equipment and contact.
    1, non-contact detection technologies
    Detection is a printed circuit board of physics and chemistry performance data provided by the weight method.As printed graphic precision and density change, in the past by adopting the method of artificial vision has been quite a long time don't meet the needs of rapid development of high-tech, testing technology and equipment has been rapid development, gradually replaced the human visual from the use function to judge the quality of our products and the appearance of it from the circuit graphic detection to the inner circuit graphics, so as to push the simple detection process quality monitoring and repair of the defect combined between the direction of development.Its main features are: the use and application of computer software and hardware technology, high-speed image processing and pattern recognition technology, high-speed processing hardware, automatic control, precision machinery and optical technologies, is a product of comprehensive variety of high technology.To detect parts no contact, no damage, no damage, can reach of the inspection contact.The equipment has the following kinds:
    Bare plate surface testing technology and equipment
    The AOI (optical tester).Mainly adopts test test of two dimensional digital graphic design specification, use with surface mount technology and three-dimensional moulded printed circuit board, design specification test will have different connotation.It can not only detect wire width and line spacing, can detect the height of the conductor.So the existence of three dimensional layout, is bound to more advanced sensors and imaging technology.Non-contact AOI test technology is a set of X - ray, infrared technology, and other detection technology in one product.
    X-ray inner perspective detecting technology
    Early use of X-ray because of the extent of the focal length to 300 microns, the detection accuracy can reach 0.05 mm.At present, the focal length has reached micron grade, can into the measuring accuracy of 10 micrometers.With image processing and use, to the lining of the multilayer printed circuit board circuit graphics for high-resolution perspective and detection.
    2, contact detection technology and equipment
    Detection method of printed circuit board, mainly adopts on-line tester is also called the static functional test.At present there are many types of models, advanced equipment can quickly for the error of a manufacturing process to produce quality defects (including open circuit, short circuit).With the general type of circuit tester, special on-off tester and pin type mobile on-off tester.The latter is suitable for small batch of high-density, high-precision double-sided and multi-layer printed circuit board e-test.

    Company name :Meizhou Hongli circuit board Co., Ltd.
    Address:Meizhou city Manila Manila ridge industrial park
    Contact us:Mr Fu
    Copyright @ www.ericmassa.com All Right Reserved property in copyright Meizhou Hongli circuit board Co., Ltd.
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