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Modular Design Redefines High-Speed Dispensing

As electronics technology advances, the level of customization in consumer products has skyrocketed. At present, customizable features can be found in almost every electronic purchase. Through a wide range of electronic products, from personal computers (PCs) and cellular telephones to liquid-crystal-display (LCD) televisions and even the many electronic devices in automobiles, manufacturers of these products are acknowledging that their customers appreciate the capability to personalize these electronic product to meet their individual needs. For example, many automobile manufacturers allow additional, optional features based on each customer's specific desires. And computer companies provide flexible pricing based on how many optional features are not required. Why should this same level of customer customization not apply for dispensing systems?

Nordson EFD's PICO® xMOD valve allows customers to build an integrated valve system unique suited to their applications. Each EFD PICO xMOD component can be individually selected from a comprehensive list of optional parts to accommodate varying fluids and applications. All of the PICO xMOD components are engineered to work together as a complete, integrated system that produces fast and accurate deposits of a wide range of fluids.

Piezo Technology
A PICO xMOD valve uses piezo technology to achieve extremely fast open-and-close cycles that eject, or "jet," fluids onto a substrate target. The piezoelectric actuator inside the valve is composed of two stacks of ceramic disks that change shape as voltage is applied. This allows for more precise control of the vertical motion of the actuation needle and its attached ball. When the ball lifts off its ceramic seat, the resulting cavity fills with fluid. As the ball reseats, a fluid droplet ejects from the valve with extreme speed and accuracy. With piezo-controlled jet valves, this ball-and-seat movement typically occurs in hundreds of microseconds — speeds that cannot be achieved using traditional air- or spring-actuated valves.

Not only do PICO xMOD valves incorporate both open-and-close piezo actuation, their unusual modular design integrates exchangeable components. The xMOD valves can be used in traditional needle-based contact applications or, with a quick exchange of components, the same valve can be used in high-speed noncontact jetting. Because xMOD valves can be easily configured or reconfigured to meet changing production requirements without the need to set up or switch lines, they greatly enhance the capability and versatility of a production facility.

Modular Design
A PICO xMOD valve system has five major valve components that can easily be exchanged to meet a customer's needs. The parts are fully interchangeable and can easily be modified for different applications and just as quickly be disassembled for cleaning, repair, or maintenance. Each part can be removed and exchanged in seconds, eliminating production downtime and significantly increasing the productivity of the dispensing system. These five major valve components are the piezo actuator, the fluid body, the valve seat, the cartridge ball/stem assembly, and the heater set.

The piezo actuator is essentially the electromechanical "motor" of an xMOD valve. It controls the valve using the properties of the piezoelectric material to create precise displacement with high response speed. The PICO xMOD's piezo actuator determines the type of fluid that can be used with the valve. Different piezo actuator configurations can be set up depending on the viscosity of the fluid through the valve.

The fluid body feeds fluid from the fluid reservoir into the valve seat. Since different applications require different fluid reservoirs, an xMOD fluid body can be selected based on the required reservoir size. If an application requires heat, a fluid body can be selected for the valve that works in conjunction with an optional available heater set.

The valve seat holds the cartridge and nozzle plate. This interchangeable valve seat can greatly extend valve life and optimize the dispensing process. A trained technician can remove the valve seat for easy cleaning and maintenance in seconds rather than minutes. In addition, the valve seat can be customized for traditional contact needle dispensing or for noncontact "jet" dispensing.

The cartridge assembly is a small and compact component made of highly chemically resistant polyether ether ketone (PEEK) plastic that controls the flow of dispensed material or fluid. Internally, a special liquid gasket, applied around the PEEK cartridge body and ball stem, prevents fluid from entering the internal cartridge/spring area. The spring-loaded ceramic ball and stem move together with the piezo actuator vertical stem in up-and-down movements with extremely precise stroke control. This movement creates exact deposits of fluid with clean end-of-cycle cutoff.

An optional heater set can be included in the xMOD valve's configuration. The heater set has a copper inner sleeve and an acetal extension insulator to distribute heat gradually along its wetted path from the fluid body inlet to the valve seat nozzle plate orifice providing excellent viscosity and dispensing stability.

Dispensing assembly lines across the globe rely on consistent production in order to meet their expected quotas. When their equipment breaks or needs extensive periods of downtime for cleaning or maintenance, the process becomes bottlenecked and as a result, production suffers. The xMOD spring life exceeds 500 million cycles without failure. However, if any of the individual components listed above should become damaged and require replacement, economical replacement parts can be easily exchanged without extended assembly line downtime. This minimizes the inconvenience and expense of ordering a new valve should there be an issue with a specific component.

The xMOD valve systems use piezoelectric jetting technology to apply assembly fluids with continuous speeds to 500Hz, in amounts as small as 0.5nL. When configured for jetting, the valve does not contact the substrate, making it well suited for applying precise amounts of fluid on uneven surfaces or targets with small components, tight tolerances, or hard-to-access areas. While jetting, an xMOD valve eliminates Z-axis movement and the need for precise height positioning, resulting in fast dispensing speeds with high dot-to-dot consistency. The xMOD valves can be used for a wide variety of fluids, including ultraviolet (UV) adhesives, general adhesives and adhesive components, lubricants such as oils and grease, paints and coloring fluids, aqueous solutions, organic solvents, liquid polymers and polymer solutions, and a wide range of other liquids. The flexible, modular valve system allows for a high level of customizability with a wide array of individually maintained, serviceable parts, offering the same high deposit accuracy and excellent process control as the entire Nordson EFD PICO line.

Contact: Nordson EFD LLC, 40 Catamore Blvd., East Providence, RI 02914 401-431-7000 E-mail: Web:

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