Molten solder injection head with vacuum filter and differential gauge system

An injection head, comprising:

• a reservoir;
• an injection port on a bottom of the injection head connected to the reservoir;
• a vacuum port adjacent to the injection port on the bottom of the injection head connected to a vacuum source, wherein the vacuum port is offset from the injection port such that the injection head has straight vertical sidewalls exposed on opposite sides of the reservoir at an exterior of the injection head;
• a differential vacuum gauge connected to the vacuum port and to the vacuum source;
• multiple heaters arranged side-by-side one another on the exterior of the injection head along the straight vertical sidewalls on the opposite sides of the reservoir;
• a filter disposed between the injection port and the vacuum source at a workpiece surface, the filter comprising a heat-resistant material with a porous microstructure that allows air flow but prevents molten solder from flowing therethrough, wherein the filter is disposed on the bottom of the injection head next to the injection port such that the vacuum port is adjacent to a top surface of the filter and the injection port is adjacent to a side of the filter that is perpendicular to the top surface of the filter;
• a first material, which is conformable, disposed on the bottom of the injection head;
• a second material, which reduces friction as the injection head is moved over the workpiece surface, disposed on the first material,
• wherein the first material and the second material have a same outer footprint as the bottom of the injection head and surround both the injection port and the filter to provide a bottommost surface of the injection head that is flat, with a portion of the first material and the second material separating the injection port from the filter along the bottommost surface of the injection head, and wherein the filter is in direct contact with the first material and the second material and separates the vacuum port from the first material and the second material;
• and
• a computer-based monitoring system having a processor device, connected to a memory, and a user interface, wherein the computer-based monitoring system is configured to display on the user interface a current vacuum pressure from the differential vacuum gauge along with feature fill properties that specify a percent that workpiece features are filled with solder at different vacuum strengths.