Automobile Coating Nozzle Array Control for Overlap-Free Recoating
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Solution Overview
Problem
Conventional techniques for automobile coating using inkjet nozzles often result in overlapping or separated coating ranges between adjacent paths due to inaccuracies in nozzle trajectory and material positioning, leading to deteriorated coating quality such as streaks, especially with highly viscous materials.
Innovation Solution
A coating apparatus with a nozzle array and controller that adjusts the discharge amount from each nozzle based on coating information to minimize overlap and separation between paths, using a piezoelectric diaphragm to control the discharge of coating material, and a robot arm to move the nozzle along orthogonal paths, optimizing the recoating width and discharge amounts to enhance mixing and prevent sagging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a robot moves inkjet nozzles along multiple paths to coat a wide area, then coating productivity increases, but coating quality deteriorates due to overlapping or separated coating ranges between adjacent paths
Solution Approach 1:
The patent applies local quality by differentiating the discharge amount control based on nozzle position. Nozzles at end portions of the nozzle array that correspond to recoated portions (overlapping areas between adjacent paths) discharge less coating material compared to other nozzles. This localized adjustment prevents excessive coating thickness and streak formation in overlapping regions while maintaining adequate coverage in non-overlapping regions, thereby resolving the contradiction between wide-area productivity and coating quality.
Solution Approach 2:
The patent changes the discharge amount parameter dynamically based on the nozzle's position in the array and its correspondence to recoated portions. By adjusting the discharge amount parameter for specific nozzles (reducing it for end portion nozzles in overlapping areas), the system optimizes coating uniformity across the entire coated surface, preventing both overlap and separation issues while maintaining high productivity through multi-path coating.
2Stability of the object's composition
If the coating material is highly viscous to maintain coating properties, then coating material stability improves, but mixing between adjacent paths becomes difficult leading to streak formation
Solution Approach 1:
The patent changes the discharge amount parameter for nozzles positioned at end portions of the nozzle array that correspond to recoated portions. By reducing the discharge amount from these specific nozzles, the system creates a gradient that facilitates natural mixing at the boundaries between adjacent coating paths. This parameter adjustment allows highly viscous coating materials to mix effectively without requiring reduced viscosity, thereby maintaining both material stability and coating uniformity.
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 apparatus effectively suppresses coating quality deterioration by ensuring smooth mixing and reducing sagging between adjacent paths, improving coating efficiency and reducing costs by minimizing material scattering and enabling two-tone coating without masking.
Implementation Method 1
using a piezoelectric diaphragm to control the discharge of coating material
Data Source
AI summary
A coating apparatus includes a discharge unit, a moving unit, and a controller. The discharge unit includes a nozzle array with a plurality of nozzles, and is configured to discharge a coating material from each of the plurality of nozzles. The moving unit is configured to move a position of the discharge unit with respect to a to-be-coated surface along a plurality of paths. The controller is configured to determine, based on coating information, a width of a recoated portion on which the coating material is discharged in an overlapping manner between two adjacent paths among the plurality of paths, and determine a discharge amount from each of the plurality of nozzles so that a discharge amount from each of nozzles at an end portion of the nozzle array corresponding to the recoated portion is less than a discharge amount from each of other nozzles of the nozzle array.