As a developer and producer of fluxes for electronics production, Emil Otto Flux- und Oberflächentechnik GmbH also offers a wide range of fluxes for soldering technology in cable assembly and strand tinning. The requirements for these fluxes are as varied as the tasks involved in cable assembly.
The aim of using a flux is to achieve uniformly good tinning using leaded or lead-free solders. It must be possible to control the tinning process so that only a defined length of the strand is tinned. Any flux residues must not have any effect on the subsequent use of the end product, for example due to corrosion or low surface electrical resistance (SIR). It is also important that the flux used does not penetrate the cable and strand sheathing, as otherwise the strands and wires could corrode. Furthermore, the cable sheathing may be damaged in this case.
The fluxes must meet the temperature requirements of the respective process. If the solder bath is run at higher temperatures, the fluxes must remain active. This is particularly important if the stranded wire coatings are "burned off" during the soldering process.
Emil Otto has developed a range of fluxes that are specially tailored to the requirements of cable assembly. Among the tried and tested fluxes that are halogen-free and therefore less critical in terms of corrosion and surface resistance is PM-334, a halogen-free, low-resin flux with a very wide range of applications. Other fluxes are equally suitable for use in cable assembly. HR-D/110 and
If a pasty, halogen-free flux is to be used, the use of "Neo Cordyn" is recommended. "Neo Cordyn" is a pasty flux, also known as soldering grease, which is used when dripping of the flux is undesirable. This pasty flux is halogen-free, therefore low-corrosion and has very good soldering properties
In some applications, especially when using anoxidized materials, the activation must be increased. In this case, a flux with higher activation must be selected, which can be achieved by a different composition or a higher solids content. If increasing the amount of activator is not sufficient, fluxes from Emil Otto with a higher halogen content can be used. However, halogens increase the risk of corrosion and leakage currents. Emil Otto's development department worked out a solution to reduce the risk. "By formulating the flux accordingly, the halogenated components are broken down in the soldering process. This minimizes the risk," explains Wilfreid Berke, graduate chemist, IPC specialist and technical sales consultant at Emil Otto GmbH.
In addition to the standard fluxes, Emil Otto has developed a large number of special fluxes on customer request in recent years. For example, the Rheingau-based company also offers fluxes for classic soft soldering that are based on a mixture of zinc chloride/ammonium chloride. These fluxes are used for tinning glass penetrations in sensor production. Furthermore, Emil Otto offers fluxes that are also suitable for soldering on ceramic substrates, which are used in particular in sensor production.
The fluxes are usually applied by dipping, sponging or brushing. The latter method in particular is often used in smaller EMS companies. It is therefore important that these companies can also obtain smaller quantities of flux. Emil Otto specializes in these requests and also offers these customers very small quantities of 1 liter.
One of these customers is ES&S Solutions GmbH from Viersen on the Lower Rhine. The medium-sized company offers customized cable, circuit board and adapter solutions for almost all applications. The focus is on the processing of connectors and the production of cable assemblies for LCD displays and other electrical assemblies developed in-house.
Despite miniaturization and interface diversity, it has not been possible to reduce the variety of connectors and cables in recent years. On the contrary, the specialization of transmission features has made a wide variety of combinations possible. ES&S Solutions therefore develops and produces solutions tailored to the respective applications.
"With our "old" flux, soldering normal standard stranded wires in AWG24-28 was quite possible. However, some of our customers require thinner strands, such as AWG30. In this case, our "old" flux was not sufficient as it could not retain enough solder on the wire," explains Mr. Volker Wehnen, PCB Sales Manager, "Therefore, we had to find a supplier who could offer us a flux for this application. It was important to us that we could also purchase small packaging units."
Internal quality assurance revealed that the new flux from Emil Otto achieved the highest soldering quality. Due to the excellent price-performance ratio, ES&S Solutions decided that all customer-specific cable assemblies with particularly thin strands will only be processed with the flux 205200261 Cat No. 2052 ELM-KF. ES&S Solutions is also seeking quality approval for other strand diameters so that the use of fluxes can be standardized.