Jet dispensing

The inherent simplicity of the jetting mechanism enables it to adapt to a wider variety of adhesive fluids, dispense patterns, and circuit board geographies than is possible with a needle dispenser. This simplicity facilitates multiple processes using a single jetting dispenser. 

Jet dispensing can deliver advantages in speed, accuracy, and repeatability in many die attach applications. 

Jet dispensing is becoming a preferred technology for more sophisticated applications such as flat panel displays... 

Voxeljet Technology GmbH [39] offers a systems base on ink-jet dispensing of binder fluid onto particles, similar to the technology developed by MIT except the binder is not burned off after the part is printed. The build envelope is 85 cm x 45 cm x 50 cm. They also have a system that prints a water soluble wax that is ink-jet printed to form the boundary of a poured (in layers) wax part. 

Jet dispensing, also known as jetting, is a direct-dispensing process whereby the adhesive paste is forced through a fine nozzle and programmed to flow onto selected areas controlled from a computer database. It is an automated method that differs from syringe/needle dispensing in that contact with the surface is not required to produce the dots, lines, or patterns. 

Jet-dispensing equipment uses a closed-loop, positive shut-off piston to dispense the adhesive. The adhesive is pressurized at the syringe to assure constant flow. Using a spring-driven ball and seat mechanism, the adhesive fills the void left when the ball retracts from the seat. When the ball returns, the force due to acceleration breaks the stream of adhesive, which is then jetted through the nozzle in precisely controlled amounts onto the printed-circuit board (Figure 4.14). Unlike contact automated... 

Figure 4.14 Jet-dispensing concept, DispenseJet DJ-2100 valve. Courtesy Asymtet a Nordson Co.)...

Adhesives for jet dispensing must have relatively low viscosities of approximately 120,000 cP at 5 rpm, or 20,000-40,000 cP at 10 rpm, and fast recovery of thixotropic properties after dispensing (narrow hysteresis in viscosity loop). Examples of SMT adhesives that are jet dispensible are Henkel s Loctite 3621 and Epoxy Technology s Epo-Tek H70E. ... 

Adamson SJ. Jet dispensing - a paradigm shift in technology. MEPTEC Report. Jul. 2003. 

Henkel Loctite 3536 / flow printed wiring boards auger, linear piston, and jet dispensing chip, and EGA... 

Jet dispensing (low-viscosity adhesive), True volume positive dispensing wide range of solder paste and adhesives, TmFlow auger valve for medium viscosity adhesives, and time-pressure for low-to-medium viscosity adhesives. NA - Not Available. ... 

Jet-dispensing equipmentuses a closed-loop, positive shut-offpistonto dispense the adhesive. The adhesive is pressurized at the syringe to assure... 

Amicon E1330LV/ Emerson Cuming Unfilled, no-flow fluxing underfill (reworkable) Not applicable Nickel-gold and OSP finishes Syringe, jet dispense, or stencil print Flip-chip, CSP, EGA modest post-reflow cure (offline) required. Reworkable, 300 second reflow cycles 225°C peak. Variable fi-equency microwave curable. 

The immobilized spots used in protein microarrays may contain protein molecules or smaller molecules such as inhibitors or ligands with which a protein in solution may interact. Very small spots are advantageous in that higher detection throughput can be achieved with minimal amounts of printed material and sample. Spots are typically deposited either by contact methods, such as printing arrayers that use needles to deposit droplets directly on the surface, or by non-contact methods, including the use of capillaries or ink jet dispensers to deposit droplets with nanoliter-picoliter volumes. 

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