Application Technology

HMI provides specific solutions for specific technological challenges. Below are some of the innovative and adaptive components of HMI printers and systems that address production requirements for various product types:

Aqueous Squeegee Drive

A low cost, effective means of moving the squeegee across the substrate. By utilizing the dynamic compression of the aqueous material, the movement of the squeegee is uniform and fluid. No pump is required in this closed-loop system. The lack of chatter in the print stoke provides a more effective print for fine line applications or thin deposition over larger areas where surface features in the print should be minimized.

Print Mode Selection

HMI printers come with a print mode selection switch, allowing the printer to have several different printer setups and, therefore, to be used for several different products. The printer can be set for Flood-Print to accommodate a conductive paste application, and then to Print-Print for a stubborn epoxy print.

Tooling

HMI can provide a custom toolplate for a ceramic substrate that can be centered or three-pin located for registration to the screen. Our porous stone tooling is ideal for LTCC applications where vacuum hold-down during printing is provided without substrate deformation.

Vision Alignment

HMI’s fully automated vision system allows fiducial alignment between screen and substrate for accurate image deposition. The HMI vision system uses the actual printed image to calibrate the alignment. This eliminates the need to fill the fiducials in the screen. It also takes into effect any screen shift during the print process–showing where the dynamic image actually prints, not where the screen is statically held when at rest. Whether printing a multilayer hybrid or a wafer mask, the HMI vision system will help the printer put the image where it needs to go.

Handling Systems

HMI handling systems use a variety of methods to move the substrate. Most importantly, the systems can be integrated to maximize economy and performance. As an example, a stack of solar cells can be loaded to a printer using a stack loader. The parts are printed, dried, fired and then unloaded into a partitioned magazine that protects the printed surface of the wafer. The magazine can be used to transport the parts to another part of the process. In a resistor network assembly process, that might be a laser trimming system. HMI is capable of “hand-shaking” with many other types of manufacturing equipment, allowing integration of our handling system throughout an assembly operation–and not just at the printer.

Print Head

HMI has a selection of print head assemblies to match the process requirements of the operation at hand. In an SMT application, HMI can provide a dual squeegee head, which allows the paste to be printed by two parallel squeegee blades. Each squeegee can be adjusted for level, print pressure and snap-off. The head alternates squeegee blades to keep the paste between them as they print in one direction and then the other, minimizing cycle times and maximizing throughput.

Service

Service, while not something that comes in a box, has a quality and a performance expectation, nonetheless. HMI service–whether it be field service, customer service, engineering design service or parts service–is based on decades of experience. While specific design details are customer confidential, there are few electronic screen printing applications in which our team has not been involved. Substrates running the range of green tape, flex-tape, PCB, wafer and glass. Pastes that are coating, conductive, frit, epoxy, solder, and powder. Handling from the top, the edge, the bottom, by hand, by robot or belt. We may not have seen it all, but we have seen a lot. Over 30 years of detailed records on file, consulting resources on design and process, and all of our experience in-field. It is all available for your use.