Issue link: https://iconnect007.uberflip.com/i/1348195
MARCH 2021 I DESIGN007 MAGAZINE 83 during reflow. It thus prevents the formation of a metal-to-metal bond. Even if this oxide layer is removed using etchants and fluxes, a new layer forms in situ upon exposure of clean alu- minum to the atmosphere. is prevents the use of conventional SMT methods for attach- ing SMDs to assemble PC boards. Dunn: Can you expand on a couple of ways that Mina could be utilized in automotive applica- tions? Kadiwala: Integrating electronics with the alu- minum body and chassis of the car is an inte- gral part of its manufacturing and design. Since aluminum is not easy to solder to, mechanical "crimp" and "pigtail" connections are common options. Mina™ can provide a soldered joint instead of these mechanical connectors. It can help attach aluminum wire or PCB to aluminum chassis for grounding or other such connections. It can also help with attaching copper to aluminum PCB where applicable. Dunn: is is exciting. With any new process, reliability is always a concern. What type of reliability data has been gathered? Kadiwala: Flexible PCBs were made using an Al 9-mm/PET 38-mm substrate and compo- nents were soldered using low temperature Sn/Bi/Ag solder paste. e fully assembled PCBs were then subjected to these tests: • K-09 — "Damp Heat, Cyclic (with Frost)" • M-04 — "Vibration" Both these come under the LV-124 Euro- pean automobile standards. 1. Characteristics of the Test K09 — "Damp Heat, Cyclic (with Frost)" • Chamber temperature: without cold phase: 23°C to 65°C; with cold phase: –10°C to 65°C • Chamber humidity: 95% RH • Duration: 10 d = 10 cycles at 24 h • Cycling: 5 cycles with cold phase, then 5 cycles without cold phase • Operation of samples: here not operated (usually intermittent operation = 30 s on, then 30 s off ) 2. Characteristics of the Test M-04 — "Vibration" • Chamber temperature = 8 h, profile between -40 and 80°C • Broadband random vibration according to vibration profile D in LV-124 → 5-2000Hz → 30.8 m/s² → X-axis, Y-axis, Z-axis → 8 h each axis Dunn: What materials does Mina work well with? Rigid, flex materials, others? Kadiwala: Mina works well with both—flex and rigid materials. e alloys of aluminum that we have proven for our customers include Al1235, Al6061 and Al5052. Dunn: Understanding the benefits of aluminum over copper and understanding the benefits of flexible materials such as polyester, the combi- nation seems like a natural fit for automotive applications and a wide range of other applica- tions. Which markets do you see as the early adopters of Mina taking advantage of the sim- plification of the soldering process for these materials? Kadiwala: In addition to automotive, we see significant interest from the LED, SmartTag and heat-sink and high-power industries. e LED industry would not only benefit from lower costs due to cheaper Al-PET sub- strate but also it would be a better product. A soldered LED operates much cooler compared to one attached using conductive epoxy. Based on information from a large LED manufacturer, the lifetime of an LED doubles with every 10°C reduction in operating temperature. us, sol- dered LED panels will be more reliable. SmartTags have more components and are larger in size compared to generic RFID tags.