Many liquids which fit into the viscosity range can be used with piezoelectric GeSiM dispensers. Other important parameters are density and surface tension. The latter one is important for generating smooth drops when the liquid passes the orifice.
Please download the product brochure for a selection of dispensable liquids.
Adhesives often have high viscosities. There are two ways to dispense them: the design of the microdispenser can be optimized for higher viscosities or the viscosity is reduced by heating. GeSiM microdispensers should not be heated to more than 120 °C, i.e., the viscosity of the liquid should not exceed 5 mPa·s at 120 °C.
The UV-curable adhesives OG169 and UVO-114 (Epoxy Technologies) could be dispensed (viscosities at room temperature: 82 mPas and 300 – 700 mPas, resp.) The left image depicts the dependence of droplet velocity and diameter on the excitation voltage for UVO-114; the inset of Fig. 1 shows a picture of a single droplet of adhesive in front of the dispenser nozzle.
The right side picture shows an array of single epoxy spots on glass, made by the Nano-Plotter. The spot size is about 200 µm and can be varied using different piezo settings. Although the viscosity of OG169 is much lower than that of UVO-114, it needs a higher temperature for dispensing.
A number of liquids (e.g. glycerol) were successfully tested. Inthe case of two-component epoxies, the individual components must be dispensed using two different microdispensers. Mixing and curing of the epoxy then takes place on the substrate, one example being 301-2 from Epoxy Technologies.
Microdroplets ejected by the piezoelectric GeSiM dispensers fly at a speed of about 4 m/s. The high kinetic energy supports mixing of mixable liquids.
The GeSiM Droplet Collider is based on a manual swivel to host two piezoelectric microdispensers. Micrometer calipers allow to adjust position and angle of nozzles to make sure simultaneous ejected drops hit on air.
Stroboscope camera for visual alignment and drop inspection