December, 2017


www.us- tech.com The Art of Efficient Enameled-Copper Wire Soldering By Florian Schildein


Tightening thermal requirements for copper wire and connectors, especially in the automotive sup- ply and consumer goods industries, are driving innovation in selective soldering. For more than 20 years, EUTECT® GmbH has been developing and manufacturing selective soldering modules for pro- cessing copper wire. “We’re basically dealing with a classic tortoise-


and-the-hare race,” explains Matthias Fehren bach, managing director of EUTECT. Due to these tight- ening thermal requirements, enameled copper wire is being developed further, in order to guarantee optimum thermal resistance through improved insulation. Further advan - ces in wire technology minimize the structural shape and reduce costs. “We work regularly on our selective soldering process to adapt to new materials and developments. Im - prove ments in copper wire technology are particularly welcome in the auto- motive supply industry, so we conduct frequent evaluations,” continues Fehrenbach.


Optimizing the Soldering Process


This soft soldering process can


have temperatures that exceed 842°F (450°C). This is without leaving oxide residue on the product or drastically influencing the soldering systems’ service lives. EUTECT developed ways to use protective gases to pre- vent oxide formation. “Years ago, we began to optimize


our selective soldering process for sol- dering enameled copper wire. Not just the formation of oxides should be pre- vented, but soldering beads and solder sprays should be avoided, as well as reducing the entire process cost,” says Fehren bach. It’s also critical to know which fluxes, solders, and protective gases are being used in the soldering process. The soldering system has to be


adapted to the special requirements of enameled copper wire soldering. Module components, such as solder nozzles, pumps, and solder tanks are especially stressed in high-tempera- ture applications. “Selecting the right materials for these components dur- ing the soldering module’s develop- ment is important, because our cus- tomers expect a long service life from our products,” says Fehrenbach. EUTECT uses steel, titanium, ceram- ics, special composites, and specially- developed coatings to build its machines. Soldering through the diverse


materials that are used to insulate cop- per wires, without prior stripping, poses a special challenge. Besides polyurethanes, polyurethane-butyral, polyesterimide, polyesterimide-polya - mide, esterimide, triple-insulated Tex- E wires in modified polyester construc- tion, and many other kinds are used. Natural silk, nylon and ketron


are generally used as sheathing mate- rials to give enameled copper wire flex- ibility. Without additional mechanical stripping, the customer’s machine investment is reduced and processing time is decreased by a factor of 2 to 4, depending on wire thickness.


Waste Reduction During soldering, the insulating


enamel is removed by dipping into the flowing solder wave. The solder wave also ensures that oxides, greas-


12:01:04


Selective Conformal Coating - Protective coating of electrical components


EUTECT specializes in soldering enameled- copper wires, without mechanical stripping.


es and other impurities are removed. At tempera- tures above 842°F (450°C), the solder wave con- stantly provides oxide-free solder, and the process site is washed, cleaned, and ultimately tinned or soldered. Since heat is transferred quickly, adja- cent plastics and casting compounds may only be subjected to a light thermal load. This ensures that connections and pins remain in their intended positions. EUTECT often deploys special grippers or masking techniques that raise process repeata- bility, guaranteeing high, uniform quality.


Continued on page 67


Page 61


› Greatest possible process reliability › Up to 4 heatable nozzles › Highest coating accuracy › All-in-one lacquering


Protecto Dispensing


For more information visit www.rehm-group.com or call + 1 770 442 8913


Jetting


Dispensing Spraying


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