marco technologies in focus: Improved metering of highly viscous media

Highly viscous media, such as thermosetting or hot-melt adhesives, are challenging to dispensing. For such media, marco previously used the string-jet dispensing process with a pressure of up to 75 bar. To improve the dot-jet capabilities, we have now increased the rigidity of the piezo drive, developed a new sealing concept and improved the temperature control.

Proven hardware and processes

Important components for dispensing highly viscous media are already standard at marco:

  • Specific sealing seats with small nozzles
  • Short valve closing times
  • Adapted design of the pins in the sealing seat

These factors provide high media speeds and shear rates, as well as powerful impact on the seal seat, which significantly improves droplet formation and detachment.

Three new components are added to these proven building blocks.

New valve
The new generation of the marco SuperiorJet (SJet) is based on its successful predecessors, but includes additional important innovations:

  • An improved, stiffer torque block with a significantly longer service life
  • A housing with a solid rear panel that increases the mechanical rigidity of the overall system

New sealing concept
In addition, a new sealing concept has been developed in the form of the rolling diaphragm, which has a better and longer-lasting sealing effect with highly viscous media.
It

Improved temperature control
As a third measure, marco offers improved temperature control. The nozzle temperature can now be set much more precisely by the user, which brings major advantages, particularly in hotmelt metering.

In addition: new valve seats and nozzles
The new sealing seats and nozzles made of ceramic or carbide complement this development. They are available with diameters from 450 μm to 15 μm and are manufactured in the carbide version on our in-house electrical discharge machines (EDM).

Convincing results
Together with the proven measures, these innovations lead to extremely convincing metering results of highly viscous media.

heat-curing-glue-dots

Heat-curing glue
(dot diameter of 150 μm)

hotmelt_dots_high_viscosity

Hot-melt glue
(dot diameter of 400 μm)

The new valve - familiar design outside - improved technology inside.
The new generation of the marco SuperiorJet (SJet) :

marco_SJet_SuperiorJet_valve_high_viscosity