Eltville, April 27, 2015

Application-specific cable connections are an important component in electronics production. Many EMS companies have integrated cable assembly into their service portfolio. The custom production of cables and wires imposes stringent requirements on production and the products used for it. Joining technology plays a decisive role precisely here, because the application areas of specific cables can be very different.

As a developer and producer of fluxes for electronics production, the firm of Emil Otto Flux and Oberflächentechnik GmbH also offers a broad spectrum of fluxes for soldering technology in cable assembly and strand tinning. The requirements imposed on these fluxes are as different as the cable assembly’s task descriptions.

The goal when using a flux is uniformly good tinning using leaded or lead-free solders. The tinning must be controllable here so that only a specified length of the wire is tinned. Any flux residues possibly present are not permitted to have any effect on subsequent use of the end product, for instance through corrosion or lower electrical surface resistance (SIR). Moreover it’s important that the flux used not penetrate into the cable and wire jacket; otherwise the strands and wires could become corroded. Furthermore the cable’s jacket can be damaged in this case.

The fluxes in this connection must suffice for the respective process’s temperature requirements. The flux must remain active if the solder bath would be damaged at higher temperatures. This is particularly important when the strand jackets are „burnt off“ in the soldering process.

Emil Otto has developed a series of solders specially tailored to the requirements of cable assembly. PM-334 flux is among the practice-proven fluxes that are halogen-free and thus less critical with regard to corrosion and surface resistance. A halogen-free, low-rosin flux with a very broad application spectrum is involved here. Other fluxes lend themselves just as well for application in cable assembly. HR-D/110 and SSK-15 are halogen-free fluxes with enhanced rosin or solids content that have a very broad process window and can therefore be used across a greater temperature range.

‚Neo Cordyn‘ is recommended if the intent is to apply a pasty, halogen-free flux. ‚Neo Cordyn‘ is a pasty flux, also called solder grease, that is used when dripping flux is undesirable. This pasty flux is halogen-free, thus low-corrosion, and has very good soldering properties.

The activity must be intensified in a few application cases, particularly when using preoxidized materials. In this case a flux material must be selected with higher activation, which can be created via a different composition or greater solids content. Fluxes from Emil Otto with higher halogen content can be used if increasing the activator quantity proves insufficient. However halogen enhancement increases the risk of corrosion and leakage currents. Emil Otto’s Development department has worked out a solution to reduce the risk. ‚Appropriate flux formulation decomposes the halogenide components during the soldering process. The risk can be thereby minimized‘, explains Wilfried Berke, graduate chemist, IPC specialist, and technical sales consultant at Emil Otto GmbH.

Besides the standard fluxes, Emil Otto has developed a large number of special fluxes tailored to customer desires in past years. Thus the company from Rheingau also offers fluxes for traditional soft-soldering that are based on a mixture of zinc chloride/ammonium chloride. These fluxes are used when tinning glass penetrations during sensor production. Moreover Emil Otto offers fluxes that are also suitable for soldering on ceramic substrates, which are used particularly in sensor production.

The fluxes are mostly applied using dipping, sponge, or brush methods. Precisely the last method is frequently used in smaller EMS companies. So it’s important that these companies also be able to order smaller quantities of flux. Emil Otto has specialized in these requests and also offers these customers minimum amounts of 1 litre.

stainability and lower consumption. While the flammability of conventional fluxes based on alcoholic solutions represents a risk during transport and handling, water-based fluxes are subject to labelling requirements neither for transport nor in the production process. Thus transport costs diminish and storage on premises without explosion protection is possible. Use of the fluxes in production is likewise simplified, because neither special handling nor employee training with respect to the use of hazardous substances is necessary.