War industry electron yuan the applied research that parts of an apparatus mixes outfit technology

The welder having lead of foreword 　 tradition art in the electron yuan parts of an apparatus solders mature condition already was in in exercise, the conductivity that its solder nods, stability, sex that fight corrode, tension and mechanical intensity already achieved good technology status, but the tremendous influence that pollutes pair of mankind living environments as a result of lead, the industry offers the think of a way that electronic product changes without lead in succession related international, as the European Union " the statement that uses the specific and harmful material that the electron contains in electric equipment about limitation " make, our country also was promulgated " electronic information product pollutes control government measure " , technology of electronic outfit couplet falls into disuse stage by stage lead makes Cheng, consume especially kind wait for an industry, realized electronic product basically change without lead. Current, solder without lead engineering technology is in transfer and start level, domestic and international application does not have plumbic technology to do not have uniform standard to actual application from theory, much to having the solder that lead solders to nod dependability to remain test data proves. Because the domain such as this war industry, spaceflight and medical treatment shows level to still be used,lead makes the electron below Cheng install couplet technology, and the solder on market guides a foot to use yuan of parts of an apparatus of the film that do not have lead to had been used in great quantities, supplier of partial integrated circuit already stopped the supply of traditional component having lead, make war industry industry inevitable be faced with the parts of an apparatus having lead, parts of an apparatus that do not have lead confuses the issue of outfit with solder having lead, the article will spread out application to discuss in the light of the dependability that mixes outfit technology. 2.

Solder without lead in the technological process standardization development in the craft that do not have lead, through business of chime of joint efforts of domestic industry public figure, " solder without lead standard system " what 　 finalizes the design basically already and meet through expert evaluation is authorized, if pursue,1 is shown. " solder without lead standard system " it is a basis it is mature that the tradition has lead to solder technological process and show level to solder without lead special ask and make, normative sex is strong, applicable range is wide, but the high reliability that installs couplet technology in the electron as a result of war industry, spaceflight and medical treatment domain asks, solder without lead standard system still cannot apply completely at these domains, we will draw lessons from this standard system to make piece mix install technological process, mix the 3 element that assemble craft certainly. Mix the feasibility that installs technology from practical angle analysis. 3.

3 element electron installs electronic outfit couplet 3 element are couplet respectively yuan of parts of an apparatus, solder and PCB solder dish. Use implementation of the solder that do not have lead not to have lead yuan parts of an apparatus (solder is carried or bring a foot not to have lead) do not have plumbic film solder with PCB dish the technology that install couplet is the welder that do not have lead namely art. And an any contains lead part in 3 element solder to have lead, now 3 element have lead, mix without lead outfit match a gender to include a list 1. 3.

　 of state of 1 yuan of parts of an apparatus 3.

1.

1 without lead yuan characteristic of parts of an apparatus has lead relatively yuan parts of an apparatus, without lead yuan the main characteristic of parts of an apparatus is better be able to bear or endure of lukewarm function and solder end without lead the besmear that change plating is handled. Better be able to bear or endure lukewarm function can satisfy the solder that do not have lead the character of higher melting point; And solder end is used change plating besmear without lead, it is to be in of yuan of parts of an apparatus bring a foot to eletroplate or dip besmear does not have plumbic film, improved the infiltration performance that solder carries, enhanced solder to nod dependability. Do not have lead normally yuan parts of an apparatus supplies general of chamber of commerce yuan temperature of upright film composition, heat-resisting makes clear the label do not have lead of parts of an apparatus and solder to go up at packing, so that solder when use reasonable welder art. 3.

1.

2 without lead yuan classification of parts of an apparatus reachs use attention to be in process of couplet of outfit of product of war industry electron, without lead yuan the chooses the material that should note end of yuan of solder of parts of an apparatus and parts of an apparatus humidity of parts of an apparatus is sensitive grade, enclose a form according to actual application and parts of an apparatus, we will not have lead yuan cent of parts of an apparatus is two kinds: One kind is SOP, SOJ, QFP, PLCC, its solder carries film part basically is Ag, Au, NiPb and NiPbAu, down-lead serves as with PCB solder dish electric join. Use experimental verdict [1] , the film of this kind of parts of an apparatus that do not have lead is OK and very good as compatible as solder having lead, assure the dependability that solder nods. Another kind is BGA kind, BGA kind the characteristic of yuan of parts of an apparatus depends on bringing a foot to be globose, be in noumenal bottom, common handiwork solders the outfit couplet that can't finish BGA, the article is right BGA kind yuan parts of an apparatus will not do specific technology analysis. Those who need an attention is solder carry film to contain Sn-Bi without lead yuan parts of an apparatus, use solder having lead to solder in this kind of process of yuan of parts of an apparatus, the Pb composition in solder having lead meeting and yuan 3 yuan when the Sn-Bi that solder of parts of an apparatus carries film receives an interface to form Sn-Pb-Bi in solder in all layer of brilliant low melting point (97 ℃ ) , cause solder side to come off, empty wait for a problem, serious effect solders intensity. 3.

2 solder state does not have plumbic solder is technology of electronic outfit couplet changes the core that carry out without lead, in developing a process, appeared a variety of give priority to body with Sn in all brilliant alloy does not have plumbic solder, for example Sn-Ag-Cu solder, its good fatigue sex and extensibility are close to what use at war industry industry to have plumbic solder Sn63Pb37, but tower above of melting point of the solder that do not have lead has plumbic solder 30 ℃ - 40 ℃ , and exterior pulling force is large, fluidity is poor, the long-term reliability that solder nods remains to prove. Accordingly, what war industry domain basically uses is in all Sn63Pb37 of alloy of brilliant lead stannum serves as solder material, the integral performance of this kind of solder applies in craft and a kind of any solder that do not have lead can not compare environmental test respect, its performance dominant position is here no longer give uncecessary details. 3.

3PCB solder dish film state has lead to make Cheng solder in the tradition in craft, PCB base material uses FR-4 generally model [4] , temperature of Tg(vitrification transition) the value is in commonly 130 ℃ , PCB film basically uses sirocco to make alloy of smooth stannum lead, but should solder temperature achieves 240 ℃ above (lead solders temperature is under 240 ℃ ) when, color of surface of base material of a few PCB can become deep to pale, although this is critical,temperature won't affect the quality issue such as the insulating properties of substrate, but the color that forms on the exterior is bigger difference also is unqualified element. Soldering without lead in craft, the PCB solder of theoretic relatively appropriate for military use dish film uses ENIG, namely chemical plating nickel / technology of dip gold film, frit stannum temperature is in 245 ℃ - 250 ℃ , and at present value of Tg of printed board base material all is under 260 ℃ , solder the PCB in the process board meeting as solder caloric increases, produce the warpage of different level, and be in actual application, the test method that has not united can appraisal PCB board the service mass in the technology that do not have lead. Accordingly, in view of dependability element, the PCB of product of electron of war industry domain board film still craft of tradition of continue to use. 4.

Lead mixes outfit craft to analyse without lead according to afore-mentioned is opposite the concrete analysis of yuan of parts of an apparatus, solder and PCB film and real work apply, the skill of electronic outfit couplet that shows field of spaceflight of level war industry mixes outfit technology but reduce: Use fact of traditional solder having lead to have the lead, component that do not have lead and PCB film solder, namely lead makes what Cheng falls the lead, component that do not have lead mixes outfit technology. Control the key that mixes outfit technology now and solder craft undertakes analytic summing up. 4.

1 management controls 　 4.

1.

Choose and buy of 1 yuan of parts of an apparatus is controlled in view of solder the dependability of the effect, it is in the process of choose and buy of yuan of parts of an apparatus, should choose as far as possible have lead yuan parts of an apparatus. If must be chosen,do not have lead yuan parts of an apparatus, should ask to just offer solder of parts of an apparatus to carry film stuff, limit to be able to bear or endure for goods lukewarm value, optimal weld time, damp susceptibility, smooth feeling is spent wait for parameter material specification, so that inventory management is mixed,solder corresponding measure is adopted in the process. 4.

1.

2 inventory management control a basis to offer money data specification, cent opens buy to have lead yuan parts of an apparatus and without lead yuan parts of an apparatus, and the basis does not have lead yuan susceptibility of moisture of parts of an apparatus, smooth feeling is spent wait for index to ask to adopt moistureproof, shading to wait deposit measure, a few make clear clearly bear the material with pressure too little value is deposited alone, avoid other the mutual extruding of yuan of parts of an apparatus is caused special the property damage of yuan of parts of an apparatus. 4.

2 craft control 　 4.

2.

1 yuan of parts of an apparatus go wet processing basically is aimed at without lead yuan the humidity of parts of an apparatus is sensitive parts of an apparatus, solder in high temperature in the process, damp of interior of parts of an apparatus will be quick vaporization, destroy its in-house insulation, mechanical intensity to wait thereby, generation " popcorn " phenomenon, the influence damages even function of parts of an apparatus. Accordingly, technology design personnel should make the humidity in equipment of form a complete set affirming before beginning in welder sensitive parts of an apparatus, arrange parts of an apparatus alone go current technology. 4.

2.

2 have lead to change processing [5] 　 does not have lead yuan of parts of an apparatus lead changes processing to include to insert those who assemble yuan of parts of an apparatus or appliance to lead changes processing and surface to stick of outfit lead changes processing, distinction is being stuck at the surface install solder of yuan of parts of an apparatus end is immediate with PCB solder dish stick solder, and insert yuan of parts of an apparatus to use continuously bring foot and PCB board the Kong Pei that go up closes, two kinds of yuan of parts of an apparatus lead changes processing the process is roughly same, but operation detail should be handled carefully. Insert outfit without lead yuan of parts of an apparatus lead changes processing is to bringing a foot to undertake having lead is changed namely, the process is: Burnish of sand paper of metallographic of use W28 date makes the film of the foot that do not have lead, film ply between M of μ of M-7 of about 3 μ , in burnish process, strength should even and should not be too big, avoid to cause excessive burnish, affect yuan of parts of an apparatus intensity of electric connective machinery. The place that crosses the burnish that cite a base next undertakes evade stannum handles (attention: Transistor and get together ministry of the root when the down-lead evade stannum of stupid ethylene electric capacity should leave 2mm-4mm not evade stannum) , its purpose is bringing the remains of place of the burnish on the foot not to have plumbic film at keeping clear of, but evade stannum frequency should be restricted in two the following, control of evade stannum time is in 1S-2S, the thermal shock that relapses in case affects the performance of yuan of parts of an apparatus. The surface is stuck outfit without lead yuan of parts of an apparatus lead changes processing is solder end undertakes lead is changed notting have, operation difficulty is opposite bigger, burnish and evade stannum process need more careful. Because the watch sticks solder of yuan of parts of an apparatus to carry the sex that fight caustic poorer, the process that this asks to using burnish of sand paper of W28 date metallographic exerts oneself to do sth. lighter, had taken a little with sand paper can. Evade stannum process should reduce iron to use temperature appropriately, as far as possible one-time finish, can use drop in temperature appropriately measure. 4.

2.

3 solder means is aimed at the line of the products in real work the industrial characteristic with much, little amount, the domain such as war industry, spaceflight and medicine basically solders with handiwork means is given priority to. Solder especially the otherness that different type parts of an apparatus answers to ask to temperature in the process, solder by hand can change neatly soldering-iron head and solder solder with satisfying requirement, be aimed at experiment, outdoors, cramped space and other and special environment, can produce the advantage that solders by hand more. 4.

2.

4 solder methodological 　 (1) surface sticks assemble yuan of parts of an apparatus or appliance: Solder to assure quality, before soldering, answer first the solder printed board dish place, yuan parts of an apparatus is brought even daub aids welding flux on the foot; Aid welding flux to answer solder of Tu Yi piece together; Printed board solder dish go up aid welding flux daub to should accomplish the position moderate of accurate, dosage, lest pass to aid welding flux inpour more yuan in underside of parts of an apparatus and printed board aperture, cannot clean clean, the influence solders quality. (2) piece type yuan parts of an apparatus: Should locate yuan of parts of an apparatus, solder by hand again. Fixed position can be used special and gooey receive, sheet or one also can choose when small lot is produced or bring a foot a few times to solder first fixed position. (3) piece type integrated circuit: Use commonly pull solder. When operation pulling solder, should use special electric iron head and special solder cream, and the basis cites crural span and strength, use certainly transverse pull solder (the direction with edge and perpendicular down-lead) or suitable to pull solder () of edge down-lead direction. The avoid by all means when pulling solder is brought about greatly too forcibly bring a foot to be out of shape. Microscope answers to bring a foot to whether have after be over connect by accident, be in repeatedly by accident use line suction stannum to give cleared. 4.

3 processes control 　 4.

3.

1 environment controls yuan of parts of an apparatus to solder operation environment must shipshape. Relative humidity maintains in 30% ～ 75% . When relative humidity under 30% when, should adopt antistatic measure, detect regularly electrostatic discharge is sensitive the kilter of function of parts of an apparatus. Solder platform should have good ground connection system. System of electronic ground connection maintains nice electric link through ground connection body and earth, ground connection resistor should satisfy each use technology requirement, and Yue Xiaoyue is good, should not be more than 10 Ω commonly. Avoid system of thunder ground connection and system of electronic ground connection should apart is not less than 20m, its receive terrestrial electricity block to should be less than 4 Ω . 4.

3.

2 temperature control solders environmental temperature should be controlled in 15 ℃ - 30 ℃ . There is lead in the tradition yuan of parts of an apparatus in soldering, electric iron temperature is average do not answer prep above 370 ℃ , and solder without lead normally tower above has temperature lead solders 20 ℃ - 30 ℃ , soldering without lead yuan when parts of an apparatus, because bring,evade stannum has lead to change, solder temperature can be in enclose a requirement to solder 10 ℃ are reduced on temperature foundation - 15 ℃ (in case solder carries remain to arise thereby without plumbic film " empty solder " phenomenal) . The size that the weld time that every solder chooses inspects solder to nod, medicinal powder the power of hot property and electric iron, temperature and calm, when the power in electric iron, temperature chooses to become, solder a solder nods heat time is 1s-5s commonly. Exorbitant temperature and too long weld time will are opposite PCB board base material is caused not repairable influence, form PCB board base material local color affects its insulating properties too greatly even, so temperature control is to mix outfit welder art crucial control parameter. 4.

3.

3 solder sequence control is made in welder before beginning, should according to have lead yuan parts of an apparatus, without lead yuan parts of an apparatus, solder temperature asks will yuan parts of an apparatus undertakes classified, next according to " there is lead after having lead first, first the low temperature after high temperature " the principle undertakes welder is made, reason is to prevent taller solder temperature is right other yuan of parts of an apparatus (the requirement solders temperature is relatively inferior) generation thermal shock, affect the performance characteristics of yuan of parts of an apparatus. 5.

Integrated above analyses conclusion, be based on solder to order the high requirement of dependability, solder without lead the technology still does not have applied requirement in the domain such as war industry, spaceflight and medicine. The basis has technical condition and real work experience, can control through handling of goods, process only, without lead yuan parts of an apparatus has lead to change and mix outfit solder the significant step such as control technology, control has lead to make what Cheng falls have the lead, application reliability that mixes outfit technology without lead, what realize solder to nod dependability as far as possible is the biggest change, assure yuan of application characteristics that parts of an apparatus issues in harsh environment and working exhaustion limit. Anyhow, lead makes what Cheng falls mix outfit technology is the transition that special domain shows level place to use technology, the unit such as domestic a lot of war industry, spaceflight is changing engineering technology respect to all the application of different level studies without lead, dependability evaluation and establish a standard still skimble-scamble, realize an electron to install couplet technology truly " green is made " still need us to more academic sexes are broken through and use sexual research. CNC Milling CNC Machining