Questions and answers

dispensing technology refers to the controlled dispensing of liquids or pasty liquids in exact quantities. marco specializes in precise dosing systems developed for a wide range of applications, for example in the automotive, electronics and medical technology industries.

marco offers a wide range of dosing systems that are tailored to different requirements. The most important systems include

• Contactless and contact-based dispensing: Dispensing valves are crucial for the precise control of material dispensing. With marco valves, both contact and contactless dispensing is possible with the right valve insert.
  With non-contact dispensing, liquids or pasty media are dispensed without direct contact with the substrate, allowing very fast dispensing.
  With contact dispensing, the liquid is applied directly to the substrate. This reduces the dispensing speed compared to contactless dispensing.
• DotJet dispensing: Precise application of dots or drops, ideal for applications where small and exact quantities of material are required.
• String dosing: This method is suitable for applications such as the dam-and-fill process, which is used to protect highly complex components.
• Spraying: A technique in which materials are sprayed onto surfaces in extremely fine doses, ideal for cavities and large or sensitive areas.

The various dosing systems from marco are based on highly developed piezo technology, which enables consistent, reproducible dosing accuracy. Our dosing valves and technologies are easy to integrate into existing production lines and ensure maximum automation and efficiency.

dispensing technology plays a crucial role in modern production processes, as it ensures the precise and repeatable dispensing of materials. This improves product quality, minimizes material losses and increases the efficiency of production lines. Especially in sectors such as the automotive, electronics, medical technology and food industries as well as consumer electronics and aerospace technology, the accuracy of dispensing technology is crucial to the success of production. Our dosing systems ensure that products meet the highest standards and deliver reliable results.

Contactless dispensing is a modern, time-saving process for which marco uses precision dispensing valves equipped with its proprietary TorqueBlock technology to precisely apply liquids to a carrier material or substrate - without direct physical contact. The liquids used include adhesives, greases or liquid metals, for example. At the heart of this process are piezoelectrically operated valves, also known as micro-dispensing valves, which can precisely dispense even minimal quantities.

Microdispensing is a precisely controlled process used to apply liquids in the micro and nanoliter range. This process not only ensures efficient use of the often cost-intensive dosing media, but also offers high repeat accuracy and process reliability. The micro-dosing valves used enable dosing with minimum quantities and maximum frequency. Contactless application completely eliminates the risk of damage to the carrier material.

The jet valve plays a key role in non-contact dispensing technology. Its precisely coordinated interchangeable nozzle geometry and exact control make it possible to apply minimal quantities of liquid with pinpoint accuracy and without contact. The medium supplied under constant material pressure is pressed through the replaceable nozzle/seal seat by a rapidly closing plunger. The resulting forces cause the medium to accelerate very quickly, allowing it to hit the substrate unerringly without deviating horizontally or vertically.

Viscosity is a fundamental property of fluids and describes their resistance to flow and plastic deformation. It applies not only to liquids and gases, but also to certain solid-like materials such as bulk solids. Essentially, viscosity is the opposite of fluidity and serves as a central criterion for classifying substances. In technical applications, fluids are divided into low-, medium- and high-viscosity substances. Everyday materials such as water belong to the low viscosity range, while more viscous substances gradually move into the medium and high viscosity classes. In precision and microdispensing, this transition is crucial: as viscosity increases, the flow behavior changes from a free-flowing, water-like consistency to a controlled, syrupy flow. High viscosity materials eventually reach the point where significant pressure or special systems are required for consistent dispensing.

This classification also determines which microdosing system is used:

• mtv/ssm is suitable for low-viscosity liquids
• mtv/sdm for medium viscosity liquids
• mtv/sdl for highly viscous liquids

The modular and compact valves from marco systems are particularly easy to clean, as only the components in contact with the media - the fluid body and sealing seat - need to be cleaned. 

With the compact valves, it is sufficient to loosen just three screws to remove the sealing seat.
With modular valves, the sealing seat can simply be slid out.

Inthis video, we show you how to clean the valves properly.

The operating frequency of a valve depends largely on its design - in particular on the torque block. This can be designed as a double or single torque, as well as in large or small variants.
Basically, the smaller the torque block, the higher the achievable frequency. In burst mode, frequencies of up to 1200 Hz are even possible.

The opening time refers to the period of time the valve remains open - measured in milliseconds (ms). It also includes the time (in microseconds) required to achieve full opening/stroke.
While the valve is open, the medium is discharged. The quantity discharged depends largely on the media pressure applied and the nozzle diameter.

A piezo is a component that generates electrical voltage when subjected to mechanical stress - a process known as the piezoelectric effect.
In our systems at marco, however, we use the reverse effect. When an electrical voltage is applied, the piezoelectric material (the torque block) deforms, generating a torque that triggers the opening or closing of the valve.

The pulse definition describes the characteristic shape of the control pulse that regulates the opening and closing of the valve. Precise control is particularly important for highly viscous materials.
A short, steep closing flank leads to a clean material break-off, as this is where the pulse and force are at their highest. At the same time, the opening flank can be adjusted so that the plunger opens more slowly, which prevents unwanted air pockets and enables controlled opening behavior.

Yes, our valves are designed for active temperature control. They can either:
- be heated to high temperatures of up to 200 °C or
- kept at a constant operating temperature with the aid of a 55 watt heating element (hot melt version).

Temperature fluctuations - for example due to ambient conditions or machine heat - can lead to a change in the valve stroke (piezo drift), which has a negative effect on the dispensing quantity.
Constant temperature control helps to minimize these influences and thus enables consistent dispensing accuracy.

SJet technology refers to the measurement of the valve stroke after each individual opening impulse. The stroke is measured in micrometers (µm).
To stabilize the stroke, the opening voltage (0-400 volts) is continuously readjusted - compensating for piezo drift or other tolerances. This ensures extreme precision with less than 1 % deviation.