STIRRI® V4-TF™ – Universal No-Clean Air-Free™ Tacky Flux

AIRfree™ Technology with HX-Booster™ for Critical Industrial Applications

V4-TF is a high-performance, universal no-clean tacky flux designed for critical industrial applications where robust soldering performance is paramount. This formulation directly addresses market feedback regarding the longevity and cleanability of V3-TF. V4-TF utilizes an improved solvent system with a higher boiling point, resulting in better cleanability and enhanced performance during hot air rework.

As an AIRfree™ material, V4-TF boasts exceptional homogeneity, virtually eliminating air bubbles that can cause splatter affecting solder joint quality or inconsistent dispensing that impairs sensitive industrial machines. This unique formulation uses a carefully balanced proprietary blend of rosin and synthetic resin, providing the benefits of both materials: the rosin contributes to excellent wetting and immediate tack, while the synthetic resin enhances electrical performance and minimizes residues. It also features a proprietary HX-Booster™ package, augmenting halogens for superior oxide stripping.

The flux exhibits excellent texture, controlled flow rate, and superior stay-in-place properties during component placement and hot air rework. Its composition meets the stringent reliability requirements of leaded aerospace and defense applications, crucial for long-endurance, high-altitude operation, while also demonstrating excellent compatibility with lead-free alloys used in modern medical, automotive, EV, eVTOL, HALE, and UAS manufacturing. It features a Visual QC-Aid™ optical tracer that glows in UV for instant visual detection of residues, and an Olfactory QC-Aid™ tracer that provides a pleasant scent, engaging the sense of smell for the purpose of such detection.

The HX-Booster™ package, which augments halogens, may cause the unactivated residue to exhibit temporary conductivity. This characteristic ensures superior soldering performance and can be fully addressed by optimizing the soldering profile with additional time and heat, or by cleaning the assembly. The activated residue is benign and fully conforms to J-STD-004C for no-clean formulations. For a halogen-free AIRfree™ assembly, please refer to our resin-based HX-ZERO™ formulation, V4-UHF-TF.

Key Performance Advantages

• Corrosion Resistance: Activated residues are non-corrosive, protecting soldered joints from long-term degradation in harsh environments characterized by temperature fluctuations, humidity, and potential exposure to chemicals or salt spray. This is particularly critical for HALEs and UASs operating in extreme altitudes and weather conditions.
• Minimal Residue: Low residue levels minimize potential issues with electrical conductivity, insulation resistance, and contamination. This is essential for high-density electronics in EVs and the sensitive sensors and avionics found in eVTOLs, HALEs, and UASs.
• Thermal Stability: This flux is engineered to withstand the rigors of both leaded and lead-free soldering processes, maintaining its integrity and ensuring effective fluxing action even at peak reflow temperatures reaching up to 250°C. Furthermore, it maintains its properties during hot air rework procedures, withstanding temperatures up to 450°C, providing an extra margin of safety and facilitating effective rework.
• Mechanical Strength: This flux contributes to robust solder joints that exhibit high resistance to fatigue from vibration and mechanical shock, crucial for applications like eVTOLs and UASs that experience significant operational stresses.
• Electrical Performance: High insulation resistance prevents current leakage and signal interference, especially important in high-voltage EV systems and sensitive avionics in aerial vehicles. Low electrical conductivity of the activated residues further mitigates the risk of short circuits and electrical failures.

Application-Specific Design Considerations

• EVs: The flux is optimized for high-temperature performance, resistance to automotive fluids, and compatibility with high-current connections in battery management systems and power inverters. Critically, it is also designed to resist any influence from the strong magnetic fields present in EV powertrains during dispensing and component placement, ensuring consistent application and preventing unwanted flux migration.
• eVTOLs, HALEs, and UASs: The flux is designed to be lightweight, resistant to extreme temperatures and altitudes, and compatible with sensitive electronic components and sensors. It is also designed to withstand the vibrations, shocks, and accelerations experienced during flight.

Compliance and Standards

• IPC Standards: The flux is designed to adhere to IPC J-STD-004C (Requirements for Soldering Fluxes) and other relevant IPC standards.
• Aerospace and Military Standards: Compliance with relevant aerospace (e.g., MIL-STD) and military standards is also being addressed, particularly for HALE and UAS applications, where specific performance requirements may necessitate adherence to MIL specifications.

Formulation Details

• Rosin/Synthetic Resin Blend: A balanced blend of reprocessed rosin crystal and fully synthetic resin provides excellent soldering performance, minimal residues, and broad alloy compatibility.
• Low-Residue Characteristics: Ideal for applications where cleaning is challenging due to component density, equipment limitations, temperature constraints, or restricted access.

Manufacturing and Application

• Flux Application Method: The flux is designed for compatibility with various modern dispensing equipment, including positive displacement and time/pressure systems. It is also being optimized for use with automated dip coating systems, stencil printing, and inkjet printing for precise and consistent flux application.
• Solder Alloy Compatibility: The flux exhibits excellent compatibility with a wide range of solder alloys commonly used in EV, eVTOL, HALE, and UAS applications, including SnAgCu and SnBi alloys, as well as specialized high-reliability lead-free alloys containing indium or antimony. Compatibility with traditional SnPb alloys used in exempted aerospace and defense applications is also considered.

Environmental Impact

The formulation is designed with a low VOC (Volatile Organic Compound) content to minimize environmental impact.

Ready for Implementation

This advanced flux is in its final validation phase, undergoing rigorous field testing to confirm its exceptional performance in demanding applications. While final feedback is being gathered, the formulation is ready for implementation and offers significant potential for improving reliability and performance in critical electronic systems. Contact us today to request samples and evaluate this next-generation soldering solution for your specific needs.

While V4-TF is designed as a no-clean flux, cleaning may be necessary prior to conformal coating to ensure optimal coating adhesion and long-term reliability, particularly in harsh operating environments. As a supplier of both fluxes and conformal coatings, we can offer expert guidance on selecting the appropriate cleaning procedures and conformal coating materials for your specific application. Contact us to discuss your requirements.

Clasificación ROL0: no limpio y no corrosivo. Sin halogenuros (<0,05%). Resistente al aislamiento superficial. Sin avance del espejo de cobre. Baja migración electroquímica (caída <1 década)

30-50 mPa/s (Malcom @ 10 RPM/25ºC (x 10³mPa/s))

“No-clean” indica el método de limpieza definido por el estándar IPC y no significa que el fundente no deje residuos. Más bien, no limpiar significa que el fundente se puede dejar en la PCB durante varios conjuntos SMT consecutivos, pero tampoco causará corrosión si se deja indefinidamente. Sin embargo, la limpieza puede ser necesaria y deseable. Los fundentes que no requieren limpieza se eliminan fácilmente utilizando solventes industriales en dispositivos ultrasónicos o usando removedores de residuos de fundente disponibles comercialmente como STIRRI HydraSweep™.

Este producto no incluye ningún kit dispensador: ¡una compra por separado!

El kit de dispensación es un complemento para la dispensación manual, que se utiliza para crear presión con un émbolo de forma similar a una jeringa médica.

Las jeringas de aire destinadas a máquinas dispensadoras neumáticas utilizan un tapón de pistón en lugar de un émbolo. ¡No retire el pistón ya que ofrece el mejor sellado evitando el contacto con el aire!

Este material está certificado conforme a REACH: no utiliza ninguna materia prima de la lista restringida de sustancias de gran preocupación de REACH.