SECTION TITLE
FASTENERS & SEALING
is repeated up to 1,200 times per second, each time carefully dispensing a precise dot of material at the target location. Te high speed achieved by this ball and seat movement simply cannot be attained when using air or spring actuated valves. Additionally, jet valves gain a significant speed enhancement over pneumatic valves as they eliminate the Z-axis of movement. Te Z-axis is traditionally equipped with height and position sensing devices and operates in an “up and down” motion. In contact-based dispense valves, this combination allows the needle to move down to touch the substrate and dispense the fluid before being pulled back into start position. In contrast, high-speed jet dispensing is contactless and shoots the material repeatedly at a fixed location above the substrate. As users do not have to monitor and reposition this axis after each dispense application, they can save valuable production time and therefore achieve much higher dispense and turnover rates.
BENEFITS OF HIGH-SPEED JETTING High-speed jet valves offer several key advantages over traditional, contact-based dispensing methods. High-speed jetting does not rely on actual contact with the substrate as the material is shot rather than physically placed. Tis allows for materials to be easily dispensed into conventionally hard to reach areas, as well as those that are uneven or irregularly shaped. Te needle does not need to be dropped down onto the substrate meaning it can be easily angled to reach the desired dispense point and prevent any possible surface damage or waste of materials. Tis ability to dispense into narrow spaces is an important feature for electronics manufacturing processes such as underfills. Jet valves operate at a fixed stroke with no manual movement, which not only makes them extremely fast, but also increases process control. As jet valves do not require any Z-Axis motion device equipment, the overall setup costs are reduced and it removes the need for specially trained operators. Furthermore, contact dispensing applications require surface tension to pull the fluid from the needle tip. Te contact-free properties of high-speed jet valves eliminate this obstacle and provide a much cleaner cut off.
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Piezoelectric jetting results for UV adhesive
High-speed valves allow operators to
deposit very small and precise amounts of fluid with extremely accurate product placement. Micro dots can be achieved as small as 0.5nl, which is extremely useful for users who would traditionally struggle to achieve ultra-small dots consistently over time. For example, piezoelectric jetting is a popular choice within industries such as microelectronics, medical and automotive as operators can easily deposit these very small and precise fluids onto their substrates with improved efficiency. In addition, jet valves can create a range of dispense patterns that would not be possible with needle dispensing. From jetting multiple shots in the same location to increase dot size, to jetting fluids vertically, horizontally or in an inverted position, jet valves give operators much greater design control.
Although implementing the cutting- edge technology of piezoelectric jet valve dispensing is initially more expensive in comparison to contact-based systems, it is much more robust and requires fewer replacements and less maintenance during its lifecycle. Te ability to produce accurate and repeatable shots is primarily due to the valve’s piezoelectric actuator. Designed specifically for heavy duty and heavy cycle applications, the piezoelectric actuator maintains a consistently high performance and gives the valve an estimated lifetime of over 1,000,000,000 cycles. Additionally, piezoelectric jet valves are robustly constructed and have fewer moving parts when compared to contact valves. Tis results in considerably less downtime for system upkeep, replacements, and cleaning.
MODULAR JET VALVES Although there are many advantages to opting for a non-contact jet valve, manufacturers often need the flexibility to dispense a range of materials for different
applications and therefore would like the option to use contact-based methods too. Systems that incorporate modular
jet valves are the perfect solution for this as they can be configured for both contact and non-contact jet dispensing. Tey offer all the previously outlined advantages of non-contact, high-speed piezoelectric jetting, as well as a broad range of additional benefits. By opting for a modular jet valve, users can dispense a much wider variety of fluids and fluid viscosities. Tis includes materials such as underfill epoxies, encapsulants and conformal coatings. Modular jet valves can further improve turnover times as the same production line can be used for a multitude of different applications. Tey can be easily optimised and reconfigured to suit the new requirements without having to be removed from the production line, allowing the application to resume promptly and efficiently. When configured as a contact dispense valve, operators will be able to achieve consistent dispensing of beads or lines at a higher rate than conventional time or pressure systems due to the pumping action. Furthermore, modular dispense valves offer easy replaceability of all individual wetted parts which are subject to regular wear through usage. Tese features help keep set-up costs, maintenance and total cost of the operation to a minimum. For users looking to achieve super accurate dispensing as well as higher throughput and profitability, then high-speed piezo jet valve dispensing could be an extremely worthwhile investment.
Robert Campbell is with Fisnar.
www.fisnar.com
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