Lacquer Coating Particle Removal via Solvent Spraying
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Solution Overview
Problem
In micro- and nano-fabrication processes, lacquer particles form during spraying, leading to irregularities and local defects on substrates with topographies, as the lacquer dries and impinges on the substrate, causing issues during further processing.
Innovation Solution
A method and apparatus where the lacquer is sprayed onto a substrate and then treated with solvent to dissolve and level out lacquer particles, ensuring an even surface by controlling the solvent proportion and using separate nozzles for lacquer and solvent application, with optional heating to increase viscosity and prevent flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lacquer is sprayed onto the substrate, then the lacquer can be applied economically and homogeneously on substrates with topographies, but lacquer particles form and adhere to the substrate causing local defects
Solution Approach 1:
The process is divided into two separate spraying operations: first spraying the lacquer onto the substrate, then spraying solvent onto the applied lacquer. This segmentation allows each operation to be optimized independently - the lacquer spray achieves homogeneous coverage while the solvent spray subsequently removes particles and irregularities without interfering with the initial deposition process.
Solution Approach 2:
Solvent is introduced as an intermediary substance that mediates between the lacquer application and the final surface quality. The solvent temporarily redissolves lacquer particles and irregularities after deposition, allowing them to be redistributed and smoothed into the lacquer layer, thereby improving surface quality without requiring a complete redesign of the spraying process.
2Manufacturing precision
If solvent is sprayed onto the applied lacquer, then lacquer particles are dissolved and irregularities are levelled out, but the solvent proportion must be precisely controlled to maintain proper viscosity
Solution Approach 1:
The solvent proportion in the lacquer is dynamically adjusted through the two-stage spraying process. Initially, the lacquer is applied with its original solvent content for proper flow and coverage. After deposition, additional solvent is sprayed to dissolve particles, and the overall solvent proportion is then reduced through evaporation or removal to restore appropriate viscosity. This parameter change approach allows particle removal while maintaining processability.
Solution Approach 2:
The spraying process uses periodic action by applying lacquer and solvent in alternating sequences. The lacquer is sprayed first to form the base layer, then solvent is sprayed periodically to dissolve and redistribute particles. This periodic application of solvent allows controlled particle removal while preventing excessive solvent accumulation that would compromise viscosity and lead to defects.
3Stability of the object's composition
If the solvent proportion is reduced to make the lacquer set, then the lacquer stops flowing and covers edges reliably, but the lacquer particles can no longer be dissolved effectively
Solution Approach 1:
The solvent is sprayed onto the applied lacquer as a preliminary action before the lacquer fully sets. This timing is critical - the solvent is applied while the lacquer is still sufficiently fluid to allow particle dissolution and redistribution, but after the initial deposition is complete. This preliminary solvent treatment removes particles before the lacquer viscosity increases to a point where particles can no longer be effectively dissolved.
Solution Approach 2:
The viscosity of the lacquer is dynamically controlled throughout the process. Initially, the lacquer has lower viscosity for easy application and flow. After deposition, solvent is added to temporarily reduce viscosity for particle dissolution. Then the solvent proportion is reduced through evaporation or removal to increase viscosity and stop flowing, achieving reliable edge coverage. This dynamic viscosity control allows both particle removal and proper setting.
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
The method achieves a smooth, particle-free lacquer layer on substrates with topographies, enhancing processing quality and preventing defects by maintaining the lacquer's viscosity and ensuring consistent solvent application.
Implementation Method 1
the lacquer particles which have become attached to the substrate are dissolved so that the surface of the substrate is even and (at least substantially) free of lacquer particles
Implementation Method 2
the substrate and/or the applied lacquer is heated during and/or after spraying-on the lacquer, whereby the solvent proportion of the applied lacquer can be reduced in a simple manner
Data Source
AI summary
A method for coating a substrate with a lacquer includes spraying lacquer onto the substrate and subsequently spraying the applied lacquer with solvent. In some embodiments, before the solvent is sprayed the lacquer is heated. Also disclosed is a corresponding coating device for lacquering substrates.