July, 2016
www.us-
tech.com
Page 57 Soldering for Aerospace’s Harsh Environment By Yusaku Kono, Marketing Director, Japan Unix Co. Ltd. E
nvironmental conditions are harsh at the edge of space. The temperature is extremely cold, reaching –50°C (–58°F) and ultra-low
air pressure of 240 hPa at altitudes above 10,000 meters (33,000 feet). Winds whip at speeds up to 190 mph (300 kph) in the jet stream. Aircraft must be able to fly safely at their own speeds of 500 mph (800 kph) in this unforgiving place. Like military equipment, aircraft and space-
craft are precision machines built to withstand the most demanding conditions. Their designs must meet the highest engineering, quality and safety standards for components and electronic assemblies. Accurate flight control is of primary impor-
tance for communication, navigation, recording, and safety systems. Inside the cabin, environmental equipment such as pressurization and HVAC systems are important for passenger comfort. Entertainment systems and food service equipment also add even more electronic equipment, all of which must have high-reliability sol- der connections that are expected to last, in many cases, for decades.
Lead-Free Solder a Challenge Aircraft electronics are charac-
terized by thick substrates and large currents. Moreover, components are small and susceptible to heat, and difficulties arise when they must be placed with high-density narrow pitches. Today, many assembly hous- es use laser soldering systems to meet these demanding requirements. To date, robotic and laser soldering have been used primarily for mass production. However, as the technol- ogy advances, it is becoming an increasingly attractive option for high-reliability soldering. The global aircraft and aero-
space market is moving toward 100 percent lead-free solder, a market that had been exempt from RoHS compatibility requirements. Although lead-free solder has
been successfully applied in home appliances and consumer electronics, the aviation industry has been reluc- tant to adopt lead-free due to reliabil- ity concerns. But the exemptions will be ending soon, and lead solder will be banned altogether in 2018, which will force the global industry to com- ply with RoHS. Many Japanese manufacturers in the electronics and automotive
The global aircraft and
aerospace market is mov- ing toward 100 percent lead-free solder, a market
that had been exempt from RoHS compatibility requirements.
industries have promoted lead-free soldering since the inception of RoHS in 2006, and have now almost com- pletely made the transition. Since then, Japan Unix has built up the expertise in lead-free robotic solder- ing that comes from working with its customers. In particular, major clients in the automotive and indus- trial machinery sectors have prod- ucts that are used in environments that are nearly as harsh as the aero- space sector. This type of soldering is now being used by many aerospace and aircraft industries. In order to automate the solder-
See at SEMICON West, Booth 5562
ing process by adopting laser technology, a manu- facturer should be able to use a combination of sev- eral technical capabilities: a distinct knowledge of lasers, soldering expertise, and robot integration and control. A conventional soldering iron and a soldering
laser are based on different concepts of heat trans- fer. A soldering iron conducts heat, while a solder- ing laser generates it. When metals such as tin or copper are soldered, flux and other chemical sub- stances react upon heating and solidify. Solid metal is melted and flows into through-holes or along a surface to form a solder fillet. To achieve proper and consistent soldering joints, optimal sol-
An example of irradiation pattern marks. Continued on page 59
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96