几种常用工件的焊接及焊接定义【焊接调试】
Update date：2012-6-26
Just in the electronics industry people do not know what welding is, do not know how to weld, today to share with you. Welding is to use heat or pressure, or heated and pressurized so that the surface of the gold dust a process connected together, with or without filler metal. Micro-electronics products, welding is often used the methods of soldering. Characteristic of this method are: welding of metallic materials (generally refers to the pad or metal pins) itself does not melt, relying on the melting point lower than the filler metal of the welded materials melting and wetting of the weld surface, so that the two occur proliferation, followed by After cooling and solidification and the formation of interconnect solder joints. Welding is an important microelectronic interconnect technology, chip scale package and board-level packaging of the modern electronics industry are a large number of tin-based alloy of low melting point filler metal for welding. For example, wave crest surface and the plug is fitted with the use of circular flow of molten solder components PCS welding face contact with the completion of the welding process; sucked solder paste reflow prior placed between the components and PCD pad heated through the melting of the solder paste of solder powder components and PCB connection. The electronic circuit of the welding process is an extremely complex systems engineering. Although the welding process is only the molten solder and the base metal of the welded metal binding process, but its microscopic mechanism is more complex, involving physics, chemistry, mechanics, materials, electrical, metalworking and other related knowledge.
Several commonly used workpiece welding
A printed circuit board welding
1.1 welding pre-treatment
Should first check whether the printed circuit board to meet the requirements, the surface treatment eligibility, there is no pollution, deterioration and breakage. Map
Shaped holes and 7L diameter compliance with drawings and so on; varieties, specifications, and outer packaging of the components is consistent with the drawings, the component leads with or without oxidation, corrosion. Then the oxide layer printed circuit boards, components and tin * components, printed circuit board long-term storage, the surface adsorption of the component leads and printed circuit board pad dust, impurities or oxidation , the formation of the oxide layer. Components loaded printed circuit boards, lead foot dip tin processing in order to ensure that no Weld.
To the oxide layer is: with a knife or sharp instrument along the lead direction from the root of the device leads at 2-4M out scraping side scraping, while rotating the workpiece lead, will lead the death of the oxide completely Vice net so far. Do not lead foot, not the original coating on the workpiece lead scraped to see the true colors of the original metal can, and be mindful, not too much force prevent components the lead Guaduan or the break. Will scrape components leads in a timely manner dipped in flux. Enemy tin pot dip tin, or the electric iron t: tin. Either way, the last time tin can not be too long to avoid component damage due to overheating. Semiconductor devices, clamp the clamping transistor dip tin-lead foot - wide end, to help heat dissipation.
1.2 Printed Circuit the right welding
Printed circuit board assembly and welding in the entire electronics manufacturing in the core of machine product quality members. Its quality directly affects the entire soldering printed circuit boards, in addition to complying with the essentials of the soldering. Also note that a single panel, h device should be mounted on the printed circuit board opposite (ie, the copper foil surface), leads through the holes and pad connection.
1.3 welding post-processing
① cut off the excess lead, be careful not to exert force other than the shear force of solder joint
⑦ Check the printed circuit board all allow device-lead solder joints and repair defects.
⑦ clean printed circuit boards.
(2) wire bonding
Wire bonding occupies an important position in the assembly of electronic products
(]) Wire welding, pre-treatment
In electronics assembly, commonly used to connect wires are mainly three categories: single-stranded, stranded, shielded wire.
(1) stripping insulation layer: common tools available in the manual stripping or special tools, special machinery in the large-scale industrial production. According to the need for welding, wire stripper or flat mouth clamp stripping out the wire end of the insulating layer 2-4cm. Shielded wire stripping head. Stripping sweet stripping head. The appropriate choice of the number of hole; stripping head with an ordinary flat-nose pliers, rotate to side edge scissors, forced to be uniform, the intensity of either light weight wood, or easy to damage the shield wire. In the separation of shielded wire, tweezers along the winding direction slowly peel. Do not cut with scissors.
Note: The single strands should not damage the conductor; multi-strand wire and shielded wire is not disconnected. Twisted into a spiral of multi-strand wire stripped of insulation layer attention to the line along the cores of the original direction of rotation.
中文版