Stencil Printing Curing Low-Viscosity Materials
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Solution Overview
Problem
Standard rotary screen-printing technologies are limited in printing low-viscosity materials, often resulting in messy edges, merged features, and are unable to produce tall features or print elastic materials effectively due to viscosity constraints and material separation issues.
Innovation Solution
The method involves a stencil printing system where a substrate is in intimate contact with a stencil shell, allowing a coating material to be cured in place before separation, enabling improved feature topology control and the use of low-viscosity materials, including elastic materials, by using a curing mechanism and a gasket layer to maintain feature thickness and prevent material spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If low-viscosity coating material is used in standard stencil printing, then material flow and coverage are improved, but feature topology control deteriorates resulting in messy edges and merged features
Solution Approach 1:
The coating material is cured in place before the stencil is separated from the substrate. This preliminary curing action prevents the material from spreading or merging after deposition, thereby maintaining sharp feature edges and topology control even when using low-viscosity materials that would otherwise flow excessively.
Solution Approach 2:
The patent changes the physical state parameter of the coating material by curing it in place. This parameter change (from liquid to cured state) occurs while the material is still confined by the stencil, preventing subsequent spreading and maintaining precise feature topology.
2Length of moving object
If standard stencil printing is used for tall features, then feature height can be achieved, but material separation issues occur resulting in stringing and threads during film split
Solution Approach 1:
The coating material is cured before the stencil separation (film split) occurs. This preliminary curing prevents elastic materials from forming threads or strings during separation, as the material has already set in its final position. This enables clean separation even for tall features made from elastic materials.
Solution Approach 2:
The patent utilizes a phase transition (curing) of the coating material from liquid to solid state before separation. This phase change eliminates the elasticity-induced stringing problem that occurs during film split, allowing clean separation of even highly elastic materials.
3Adaptability or versatility
If elastic materials are printed using standard methods, then material flexibility is achieved, but printing quality deteriorates due to stringing and thread formation during separation
Solution Approach 1:
The elastic material is cured in place before the stencil is removed. This preliminary curing action prevents the material from retracting or forming strings during separation, thereby maintaining high printing quality. The material retains its elasticity and flexibility in the final cured state while avoiding defects during the printing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the printing of low-viscosity materials with improved feature topology control, achieving higher feature heights and preventing defects like stringing, while enabling the use of elastic materials by curing the coating in place, resulting in straighter, flatter features suitable for applications like adhesives.
Implementation Method 1
at least partially curing the coating material in contact to the major surface of the substrate at a curing zone where the major surface of the substrate is in contact with the first major surface of the stencil shell
Data Source
AI summary
Methods and apparatuses for screen or stencil printing a pattern on a substrate are provided. The substrate (2) has its major surface in contact with a first major surface (112) of a stencil shell (111) having apertures (116). A coating material is disposed onto the second major surface (114) of the stencil shell (111) to flow through the apertures (116) to contact the substrate (2), where the coating material is at least partially cured. The substrate (2) is separated (C) from the first major surface (112) of the stencil shell (111) after the curing (142) and a pattern (42) of the at-least-partially-cured coating material is formed on the substrate (2).