FASTENERS & SEALINGSECTION TITLE
DHIGH-SPEED SISPENSINGOLUTIONS
Robert Campbell reveals why piezoelectric jet valves represent a worthwhile investment
I
n many high-volume production environments where adhesives and fl uids are used, there is a continuous drive for faster dispense rates, higher
throughput and profi tability. T is creates a need for advanced dispensing technologies that can achieve all the above whilst providing highly accurate results. High- speed piezoelectric jet dispensing is a powerful alternative to traditional dispense valves and could fulfi l these requirements with ease. High-speed jet valve dispensing is a
relatively new and innovative technology that can dramatically increase dispensing rates of adhesives and other fl uids. A non- contact dispensing method, high-speed jetting is the process of material being shot from a fi xed location onto the desired substrate with outstanding consistency and repeatability. As the jet valve never comes into contact with the surface, there is a much higher degree of dispensing fl exibility, meaning it can be used in a wider variety of applications. Piezoelectric jet valves can dispense at approximately twice the speed of standard, pneumatic jet valves. Despite moving at such high rates, users of piezo jet valves are often amazed at how precisely and accurately they can dispense small, neat dots or lines. High-speed jet valves are operated via a sophisticated dispense controller. T is controller helps optimise the dispensing process as it provides a clear overview of all components and their status throughout the entire operation.
Piezoelectric jet valves are robust and long-lasting
HOW HIGH-SPEED JETTING WORKS T e high-speed functionality of the valve is initiated by the advanced piezoelectric ceramic technology. In fact, piezoelectric jet valves can operate at continuous speeds of up to an impressive 1,200Hz and burst speeds of up to 2,000Hz. Rather than relying on air pressure, the piezoelectric actuator within the valve converts an electric signal into a highly precise cycle to dispense material. High-speed jet valves with this technology can achieve very fast open and close cycles that jet fl uids onto the desired substrate. T e piezo actuator is composed of two stacks of ceramic discs that change shape as voltage is applied. T is creates a defl ection in the cantilever arm, causing the actuator stem to lift at a fi xed stroke. When the ceramic ball lifts off its ceramic seat, the resulting cavity fi lls with fl uid. T en, as the ball reseats, a fl uid droplet is ejected from the valve. T is process
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