Liquid metal ejector level sensing system and methods thereof

Abstract

A method of controlling sensing level in a liquid ejector is disclosed. The method includes filling a reservoir in communication with a liquid ejector with a printing material to a first level set point, receiving a drop out signal from a laser-based level sensor that reads from a surface of a melt pool in the reservoir, pausing an operation of the liquid ejector, adjusting the printing material level set point to a second level set point of printing material in reservoir that is higher than the first level set point, increasing a quantity of printing material in the reservoir to fill the reservoir to the second level set point, and resuming the operation of the liquid ejector.

What is claimed is: 
     
         1 . A method of controlling sensing level in a liquid ejector, comprising:
 filling a reservoir in communication with a liquid ejector with a printing material;   reading a level signal from a surface of a melt pool in the reservoir using a sensor;   coupling the level signal to the filling of the reservoir with the printing material;   receiving a drop out signal from the sensor;   pausing a jetting operation of the liquid ejector;   increasing a quantity of printing material in the reservoir until the drop out signal is no longer received from the sensor; and   resuming the jetting operation of the liquid ejector.   
     
     
         2 . The method of controlling sensing level in a liquid ejector of  claim 1 , wherein the printing material comprises a wire feed. 
     
     
         3 . The method of controlling sensing level in a liquid ejector of  claim 2 , further comprising removing the printing material feed from the reservoir. 
     
     
         4 . The method of controlling sensing level in a liquid ejector of  claim 1 , further comprising uncoupling the level signal from the filling of the reservoir with the printing material prior to increasing the quantity of printing material in the reservoir. 
     
     
         5 . The method of controlling sensing level in a liquid ejector of  claim 1 , further comprising coupling the level signal to the filling of the reservoir with the printing material prior to resuming the jetting operation of the liquid ejector. 
     
     
         6 . The method of controlling sensing level in a liquid ejector of  claim 1 , wherein the drop out signal comprises an erroneous signal from a laser-based level sensor reading scattering of light caused by contamination on the surface of the melt pool in the reservoir. 
     
     
         7 . The method of controlling sensing level in a liquid ejector of  claim 1 , wherein the printing material comprises metal, metallic alloys, or a combination thereof. 
     
     
         8 . The method of controlling sensing level in a liquid ejector of  claim 1 , wherein the printing material comprises aluminum, aluminum alloys, or a combination thereof. 
     
     
         9 . The method of controlling sensing level in a liquid ejector of  claim 1 , wherein the printing material is a powder. 
     
     
         10 . The method of controlling sensing level in a liquid ejector of  claim 1 , further comprising determining a maximum melt pool height prior to filling the reservoir with a printing material to a first level set point. 
     
     
         11 . The method of controlling sensing level in a liquid ejector of  claim 10 , further comprising confirming an absence of a drop out signal from a laser-based level sensor after filling the reservoir with a printing material to a second level set point. 
     
     
         12 . The method of controlling sensing level in a liquid ejector of  claim 11 , wherein the maximum melt pool height is higher than the first level set point and the second level set point. 
     
     
         13 . The method of controlling sensing level in a liquid ejector of  claim 12 , wherein the first level set point is from about 4 mm to about 8 mm lower than the maximum melt pool height. 
     
     
         14 . The method of controlling sensing level in a liquid ejector of  claim 11 , wherein the second level set point comprises from about 2 mm to about 4 mm relative to the first level set point. 
     
     
         15 . The method of controlling sensing level in a liquid ejector of  claim 11 , further comprising:
 adjusting the printing material level set point to a third level set point of printing material in reservoir that is higher than the second level set point; and   increasing the quantity of printing material in the reservoir to fill the reservoir to the third level set point.   
     
     
         16 . The method of controlling sensing level in a liquid ejector of  claim 1 , further comprising repeating any of the steps of:
 filling a reservoir in communication with a liquid ejector with a printing material;   reading a level signal from a surface of a melt pool in the reservoir using a sensor;   coupling the level signal to the filling of the reservoir with the printing material;   receiving a drop out signal from the sensor;   pausing a jetting operation of the liquid ejector;   increasing a quantity of printing material in the reservoir until the drop out signal is no longer received from the sensor; and   resuming the jetting operation of the liquid ejector.   
     
     
         17 . A method of controlling sensing level in a liquid ejector, comprising:
 filling a reservoir in communication with a liquid ejector with a printing material to a first level set point;   receiving a drop out signal from a laser-based level sensor that reads from a surface of a melt pool in the reservoir;   pausing an operation of the liquid ejector;   adjusting the printing material level set point to a second level set point of printing material in reservoir that is higher than the first level set point;   increasing a quantity of printing material in the reservoir to fill the reservoir to the second level set point;   confirming an absence of the drop out signal from the laser-based level sensor after filling the reservoir with the printing material to the second level set point; and   resuming the operation of the liquid ejector; and   wherein the drop out signal comprises an erroneous signal from the laser-based level sensor reading scattering of light caused by contamination on the surface of the melt pool in the reservoir.   
     
     
         18 . The method of controlling sensing level in a liquid ejector of  claim 17 , further comprising determining a maximum melt pool height prior to filling the reservoir with a printing material to a first level set point. 
     
     
         19 . The method of controlling sensing level in a liquid ejector of  claim 18 , wherein the maximum melt pool height is higher than the first level set point and the second level set point. 
     
     
         20 . A method of controlling sensing level in a liquid ejector, comprising:
 filling a reservoir in communication with a liquid ejector with a printing material;   reading a level signal from a surface of a melt pool in the reservoir using a sensor;   coupling the level signal to the filling of the reservoir with the printing material;   receiving a drop out signal from the sensor;   pausing a jetting operation of the liquid ejector;   increasing a quantity of printing material in the reservoir until the drop out signal is no longer received from the sensor;   resuming the jetting operation of the liquid ejector; and   repeating any of the preceding steps.