ISO-Flux® “ClearWave” – The Innovative Flux Series for Electronics Manufacturing

In modern electronics manufacturing, the demands for process reliability, efficiency, and environmental sustainability are constantly increasing. With the development of the ISO-Flux® “ClearWave” no-clean flux series, FELDER GMBH Löttechnik offers state-of-the-art solutions that comprehensively meet these requirements and set new standards in the field of machine soldering.

Versatile for use in assembly production

ISO-Flux® “ClearWave” and ISO-Flux® “ClearWave S” are halogen- and rosin-free, alcohol-based fluxes designed for the machine soldering of assemblies with THT and SMD components. They were developed specifically for high-quality, lead-free manufacturing of commercial electronic assemblies and deliver outstanding soldering results for mixed-component circuits. They also deliver equally good soldering results in lead-containing soldering processes.

They are ideally suited for the high soldering temperatures used in lead-free soldering, as they remain stable even at soldering temperatures of up to 300 °C until the soldering process is complete. Both products exhibit excellent activation and wetting properties on all common solder surfaces.

Clear Advantages in the Soldering Process

ISO-Flux® “ClearWave” and ISO-Flux® “ClearWave S” were developed with the goal of achieving optimal inerting of metal printed circuit board surfaces during the automated wave soldering process.

A major advantage is the low solids content of just 2.0% (ISO-Flux® “ClearWave”) or 2.2% (ISO-Flux® “ClearWave S”), which results in virtually residue-free soldering. The low acid number (12.9) and the extremely low halide levels (<0.01%) ensure a high level of electrical safety. This is also confirmed by the excellent results in SIR and E-corrosion tests.

Thanks to their water-clear to slightly translucent beige color, residues are barely visible—a decisive advantage in no-clean processes. Thanks to their optimal formulation, ISO-Flux® “ClearWave” and ISO-Flux® “ClearWave S” also effectively prevent the formation of solder beads—even with photopolymer solder resist, uncoated printed circuit boards, and two-component solder resist masks.

Perfectly tailored to modern soldering systems

Both products can be applied using all standard fluxing methods, such as spraying, jetting, dipping, or foaming. Their strengths are particularly evident when used undiluted in spray and jet fluxing systems:

• The ISO-Flux® “ClearWave” product is ideal for wave soldering systems with spray fluxers as well as for state-of-the-art selective soldering systems with dropjet fluxers, since it does not cause the jet nozzles to clog and does not produce a sticky spray mist. 
• The ISO-Flux® “ClearWave S” product , with a low resin content (0.2%), is ideally suited for selective soldering with spray flux systems as well as for use in wave soldering systems with foam flux application. The minimal resin content ensures a very fine-pored foam crown and uniform wetting. Flux residues that have not fully reacted are physically encapsulated by the resin.

For open fluxing systems such as foam, spray, and immersion fluxers, the acid number must be checked daily. This can be done quickly and easily with the convenient FELDER titration kit (Item No. 27900099). If necessary, the acid value can be optimally adjusted using the VF-2 diluent (Item No. 258001..).

Process Parameters at a Glance

• Optimal preheating temperature: 100–130 °C (lead-free), 80–110 °C (lead-containing) — measured on the component side of the printed circuit board

• Solder bath temperature: max. 300 °C (lead-free), max. 250 °C (lead-containing)

• Soldering speed: 0.8–1.6 m/min

These parameters ensure optimal wetting while reducing thermal stress on the components.

Maximum Security and Compatibility

ISO-Flux® “ClearWave” and ISO-Flux® “ClearWave S” offer maximum safety in electronics manufacturing. In standardized tests (according to IPC-B-24), they achieved excellent results for insulation resistance and migration —both in their uncleaned and cleaned states. Even after 21 days at 85 °C and 85% relative humidity, the samples showed no signs of electrochemical corrosion.

The fluxes have been tested for compatibility with materials commonly used in electronics manufacturing. In principle, the electronic circuit can be coated with commercially available insulating varnishes. Further processing by coating with insulating varnishes is also possible in principle. However, it is recommended that the user test for specific interactions with plastics, paints, or varnishes in advance.

Storage and Form of Delivery

The product should be stored at temperatures between +5 °C and +25 °C. When unopened, the shelf life is 24 months from the date of manufacture. Both products are available in the following sizes:

• 1,000 ml bottle

• 10-liter canister

Item Numbers

• ClearWave: Item No. 25 72 00..

• ClearWave S: Item No. 25 71 00..

Conclusion: Innovative Strength Meets Practical Value

With ISO-Flux® “ClearWave” and ISO-Flux® “ClearWave S,” FELDER GMBH Löttechnik offers two high-quality no-clean fluxes that deliver impressive performance in electronics manufacturing thanks to their efficiency, cleanliness, and compatibility. They ensure reliable process control, deliver outstanding soldering results, and require minimal post-processing. As a result, they make a decisive contribution to the quality and cost-effectiveness of modern soldering processes.

With these two products, FELDER GMBH Löttechnik once again demonstrates its expertise as an innovative partner for the electronics industry.