초록 ▼

A compact printhead assembly is designed for employment in a soldering operation without the need for fluxes and without conducting the operation in a confined chamber. A self-contained printhead assembly has an internal reservoir and internal heating elements for raising the temperature above the m

A compact printhead assembly is designed for employment in a soldering operation without the need for fluxes and without conducting the operation in a confined chamber. A self-contained printhead assembly has an internal reservoir and internal heating elements for raising the temperature above the melting temperature of solder or other liquid to be dispensed in microdroplets from a working surface at one end of the printhead housing. A jetting device containing an electro-mechanical transducer is pulsed to produced droplets at an exit orifice located at the working surface. Inert gas is preheated by the housing and delivered to the working surface to establish an oxygen-free atmosphere around the exit orifice and between the working surface and a substrate located a working distance away, whereby microdrops can be formed and deposited without harmful oxidation.

대표청구항 ▼

[ I claim:] [1.] A compact printhead assembly adapted to operate without confinement in a controlled atmosphere chamber, the printhead being configured to eject liquid solder droplets onto a workpiece through its own controlled atmosphere designed to inhibit oxidation of the ejected droplets in a sp

[ I claim:] [1.] A compact printhead assembly adapted to operate without confinement in a controlled atmosphere chamber, the printhead being configured to eject liquid solder droplets onto a workpiece through its own controlled atmosphere designed to inhibit oxidation of the ejected droplets in a space between a working surface at one end of the printhead assembly and the workpiece, the assembly comprising:a heated housing having a reservoir for holding melted solder and an end having a working surface, the housing having a heating means;the working surface being spaced apart from the reservoir by a portion of the housing containing an internal cavity extending from the reservoir to the working surface;a solder jetting device positioned within the internal cavity of said portion of the housing, said jetting device being adapted to controllably eject droplets of melted liquid solder received from the reservoir in the housing, the jetting device comprising an electro-mechanical transducer in contact with an elongated conduit having an inlet end in communication with the melted solder and an outlet end having an exit orifice positioned adjacent said working surface, configured to emit said solder droplets outwardly away from said working surface;said working surface being a generally flat surface surrounding the outlet of the solder jetting device extending laterally a sufficient distance to confine a blanket of flowing inert gas within a gap established between the working surface and said workpiece; andmeans for uniformly distributing a flow of inert gas around the exit orifice whereby said gas flows outwardly from the working surface, traversing said gap established between the working surface and a workpiece when the printhead is positioned for soldering use over a workpiece in order to provide a sufficient protective atmosphere around solder droplets emitted from the exit orifice by the jetting device to permit solder deposition without damaging oxidation.