Horizontal Preform Coating Device for Uniform Barrier Layers
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Solution Overview
Problem
In existing preform coating systems, the coating layer on plastic bottles becomes thicker at the bottom and is prone to bubble formation, leading to non-uniformity.
Innovation Solution
A preform coating device with a rotary holder that rotates the preform horizontally, a deaeration module using hollow fiber membranes to remove gases from the coating solution, and a dispenser that adjusts the coating solution discharge to ensure uniform coverage, including pulling the solution back into the dispenser and controlling the rotational speed based on slot width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the coating solution is coated on a preform held in a vertical state using a dipping system or blow system, then the coating process can be performed, but the coating layer becomes thicker toward the bottom part of the preform, resulting in non-uniform coating
Solution Approach 1:
The patent inverts the conventional vertical coating approach by holding the preform horizontally during coating. This inversion of the preform orientation eliminates the gravitational effect that causes thicker coating at the bottom, resulting in uniform coating thickness across the entire preform surface.
Solution Approach 2:
The patent changes the operational parameters by controlling the rotational speed of the preform and the discharge rate of the coating solution. By adjusting these parameters, the system achieves uniform coating distribution while maintaining the horizontal preform position, resolving the thickness uniformity issue.
2Manufacturing precision
If the coating solution is applied using conventional systems, then coating can be performed, but bubbles are easily formed in the coating solution on the preform, leading to defects
Solution Approach 1:
The patent incorporates a deaeration module that removes bubbles from the coating solution before it is applied to the preform. This preliminary action of deaerating the coating solution prevents bubble formation during the coating process, ensuring defect-free coating quality.
Solution Approach 2:
The patent replaces conventional mechanical deaeration methods with a deaeration module that uses hollow fiber membranes. This substitution provides more effective bubble removal through the membrane filtration mechanism, eliminating the harmful bubbles that would otherwise be trapped in the coating layer.
3Manufacturing precision
If the longitudinal width of the slot is reduced to control coating amount, then coating precision can be improved, but the rotational speed must be slowed down, reducing productivity
Solution Approach 1:
The patent implements a feedback control system that monitors the coating application and dynamically adjusts the rotational speed of the preform. This feedback mechanism allows the system to maintain precise coating control while optimizing the rotational speed to prevent bubble formation, thereby resolving the conflict between precision and productivity.
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 solution achieves a more uniform coating layer on the preform by preventing bubble formation and ensuring consistent thickness across the preform, enhancing the quality of the barrier coating.
Implementation Method 1
a deaeration module using hollow fiber membranes to remove gases from the coating solution
Implementation Method 2
A preform coating device with a rotary holder that rotates the preform horizontally
Implementation Method 3
a dryer arranged separated from the dispenser and drying the coating solution coated on the preform
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
The present invention provides a preform coating device (5) provided with: a rotating and holding part (9) that holds a preform (1) in a horizontal direction, and rotates the preform (1) about an axis (A) of the preform (1); and a dispenser (6) that has a slot (62) and discharges a coating liquid in a plane form from the slot (62) to the preform (1), wherein the discharge direction of the coating liquid is the direction of the normal to an outer peripheral surface of the preform (1).