Electrostatic Coating Nozzle Grounding Circuit for Residual Charge Dissipation
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Solution Overview
Problem
The existing electrostatic coating methods experience unstable film-forming states and potential errors like blurred patterns due to residual charge-induced dripping of the coating liquid after the high voltage is stopped, requiring a discharge time of several tens of seconds to several minutes.
Innovation Solution
An electrostatic coating device with a switch that grounds the nozzle after power is turned off, allowing the remaining charge to dissipate quickly, ensuring synchronized cutoff of the power and liquid supply, thereby hastening the completion of liquid dripping from the nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the high voltage is stopped, then the coating process is completed, but the residual charge causes dripping of coating liquid from the nozzle for several tens of seconds to several minutes
Solution Approach 1:
The patent extracts the harmful residual charge from the nozzle by introducing a grounding switch. When the switch is activated, it provides a direct path to ground for the accumulated charge, separating the charge discharge function from the natural passive discharge process. This actively removes the harmful factor (residual charge) that was previously trapped in the nozzle.
Solution Approach 2:
The grounding switch acts as an intermediary element between the nozzle and the ground. Instead of relying on the natural slow discharge path through the air or insulation, the switch provides an artificial conductive path that mediates the charge transfer to ground, dramatically accelerating the discharge process while isolating the rest of the coating system.
2Manufacturing precision
If the residual charge remains in the nozzle, then the coating process can be completed, but dripping of coating liquid continues causing unstable film-forming state and blurred patterns
Solution Approach 1:
The patent applies preliminary anti-action by preparing the grounding switch in advance and activating it at the appropriate moment (when coating is completed and residual charge becomes problematic). The switch is positioned to immediately counteract the harmful dripping effect once activated, preventing the unstable film-forming state and blurred patterns before they can fully develop.
Solution Approach 2:
The patent converts the harmful residual charge into a beneficial effect by using it to trigger the grounding switch. The presence of residual charge proves that the nozzle is still charged and needs grounding, so the system uses this harmful indicator to activate the corrective measure, transforming the harmful factor into a trigger for the beneficial grounding action.
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 solution enables rapid cessation of liquid dripping from the nozzle after power is turned off, stabilizing the film-forming state and reducing the likelihood of film-forming errors, allowing for smoother and more precise coating completion.
Implementation Method 1
When the nozzle is grounded by the switch, the charge remaining in the nozzle goes to the ground and the charge remaining in the nozzle disappears
Implementation Method 2
a size of droplets approximate to the nozzle diameter ejecting from the nozzle are split by repulsion of the charge stored in the droplets
Data Source
AI summary
An electrostatic coating device comprising a nozzle section that discharges a liquid to a substrate, a counter electrode that is disposed in such a way as to face the nozzle section and supports the substrate and a power source device that applies a voltage between the nozzle section and the counter electrode further comprises an instantaneous stop circuit that selectively grounds the nozzle section. When the nozzle section is grounded by the instantaneous stop circuit, a charge remaining in the nozzle section goes to the ground and the charge remaining in the nozzle section disappears. For this reason, after the power source device is turned off, dripping of the liquid from the nozzle section can be completed as quickly as possible.