Modern microdispensing possibilities make undreamt-of innovations possible, but at the same time increase producers' expectations. Faster, tinier and more precise are the factors that challenge the international marco group of companies day after day to overcome limits in micro-scale dispensing. The in-house development of specific piezo technology constantly opens up new ways for marco to satisfy all requirements.

Whether for medium- or high-volume mobile device assembly, LED, consumer electronics or medical devices, microdosing has become an essential production factor for many industries. This is understood to be the dispensing of flowable media such as adhesives, silicones, greases, solvents and other liquids, in volumes of less than one microliter. The interesting thing here is that there are various application principles for microdispensing processes. Whether it's contact dispensing, better known as dosing, non-contact jetting, or printing via inkjet technology, where inks are projected as droplets with precisely defined volumes in the range of 1 to 100 picoliters from nozzles onto paper to create the individual dots.

marco is dedicated to dispensing and jetting. For extremely fast dispensing and low rejects, our product range includes special jet valves based on our own piezo technology. The special feature: while a pneumatic jet valve keeps the speed at 1,000 percent compared to contact-based valve technology, a jet valve with marco piezo technology improves values even more significantly.

Dispensing or contact dispensing

Which application principle is used with which valve type depends on the area of application, customer requirements and the volume of investment. marco mainly implements contact dispensing for automated standard processes. The material is applied by pressing it out of a dispensing needle. This means that the medium is deposited on the substrate by a pressing process. The needle diameter is a parameter that can be used to influence dispensing quality, and in turn defines the size of a dispensed dot or line. In this process, the dot will always be at least as large as the inner diameter of the needle. The distance between the needles is also decisive for dispensing quality, as are time, pressure and dosing speed: pressure and time determine the dispensed quantity whereas the speed regulates whether a line is drawn or a dot is set. Developers like marco are experts on the numerous physical factors which can be adjusted to optimise a dispensing solution to the dot.

Non-contact jetting - high dispensing speeds possible

This is particularly noticeable in contactless jetting. Here, producers have extraordinary market advantages if the technology is right. Jet valves are in demand when very high cycle times and extreme precision are required.
Jet valves work without compressed air. The material is abruptly displaced by an electrical impulse and flung out of the jet nozzle, i.e. applied without contact. Depending on the application and speed, the so-called dots or lines (strings) are created without contact. Marco uses various valve systems in the area of contactless dispensing - including pneumatic ones, of course. However, special highlights and technological innovations are jet valves based on our own piezo technology. marco is at an advantage when tasks cannot only be carried out with standard diaphragm pumps. Piezoelectric microvalves are the number one solution where more viscous liquids requiring higher forces are to be dispensed.

Thanks to marco piezo technology, viscous liquids are not a dispensing problem

A piezoelectric actuator converts the electrical signal into a precise movement, allowing the desired pattern to be dispensed much faster than a mechanical-pneumatic solution which needs to be opened, closed and reset. marco saves at least 20 milliseconds per dispensing step with its piezo technology. In some cases, speeds up to 2,000 per cent faster than contact-based systems can be achieved. They achieve speeds two times faster than pneumatic jet dispensing solutions. Unmatched is the ability of marco's piezo technology to achieve the smallest dots or lines with micro-applications as small as 0.5 nanolitres without contaminating materials.
Another advantage of marco jet dispensing systems based on piezo technology are dispensing frequencies up to 1,500 Hz. Taking into account viscosity, surface tension and density, the systems generate perfect, small droplets reliably, with repeat accuracy and without dripping. This even works for dispensing processes that take place over a long distance or in hard-to-reach nooks and crannies. marco can angle the nozzles to reach exactly the point where the material is to hit. Thanks to the entire procedure working contact-free, manufacturing products with complex geometries are not damaged. In this way, marco technologically prevents rejects and downtime. That cannot be guaranteed with a contact-based valve that touches the surface.

The right dispensing technology depends on each customer's requirements. Our company has developed various valve systems for both dispensing technologies. The spectrum ranges from needle valves for pneumatic contact dispensing to pneumatic jet valves and torque block needle valves for contact dispensing.