High-Viscosity Insulating Varnish for Flat Wire Uniform Coating
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Solution Overview
Problem
Forming a uniform insulating coating film on flat electrical wires is challenging due to the effects of surface tension, leading to uneven film thickness and reduced space factor, especially when using conventional coating dies designed for round wires.
Innovation Solution
An insulating varnish with a viscosity of 10 Pa·s or more is applied to the conductor, which maintains its shape and solidifies uniformly, even under high shear stress, preventing flow and ensuring consistent film thickness without the need for a die specifically designed for the conductor shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a coating die with an opening shape similar to the conductor cross-section is used, then the coating process is simple, but the insulating coating film thickness becomes uneven on flat conductors
Solution Approach 1:
The invention changes the viscosity parameter of the insulating varnish from conventional low viscosity to high viscosity (10 Pa·s or more at 30°C). This parameter change prevents the varnish from flowing into corners under surface tension during the coating process, thereby achieving uniform film thickness on flat conductors while maintaining the simplicity of using a standard coating die.
2Ease of operation
If conventional low-viscosity insulating varnish is used, then the varnish flows easily during application, but the coating film thickness becomes uneven due to surface tension effects on flat conductors
Solution Approach 1:
The invention changes the viscosity parameter of the insulating varnish from conventional low viscosity to high viscosity (10 Pa·s or more at 30°C). This parameter change prevents the varnish from flowing into corners under surface tension during the coating process, thereby achieving uniform film thickness on flat conductors while maintaining the simplicity of using a standard coating die.
3Reliability
If the insulating coating film thickness is increased to ensure adequate insulation, then the space factor decreases due to unnecessary spaces formed by uneven coating on flat conductors
Solution Approach 1:
The invention changes the viscosity parameter of the insulating varnish to prevent surface tension-driven flow into corners during coating. This results in uniform film thickness that eliminates unnecessary spaces in wound cables, thereby improving the space factor while maintaining adequate insulation through optimized rather than increased film thickness.
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 high-viscosity varnish achieves a uniform insulating coating film with a variation ratio of 20% or less, effectively addressing the issue of uneven thickness and improving the space factor in flat electrical wires.
Implementation Method 1
an insulating varnish having a viscosity of 10 Pa·s or more at 30° C.
Implementation Method 2
an insulating varnish easily flows in corners of a flat conductor due to the surface tension of the insulating varnish
Implementation Method 3
subsequently passes through a die to remove the excess applied insulating varnish, and is then dried or baked to form an insulating coating film
Implementation Method 4
The applied varnish is then baked through a baking furnace to form an insulating coating film on the surface of the conductor
Data Source
AI summary
An insulating varnish forms an insulating coating film having a shape that corresponds to the shape of an opening of a die, having a uniform thickness. The insulating varnish is applied onto a surface of a conductor, subsequently passes through a die to remove the excess applied insulating varnish, and is then dried or baked to form an insulating coating film on the surface of the conductor. The insulating varnish has a viscosity of 10 Pa·s or more measured by a B-type viscometer at 30° C. The insulating varnish preferably contains no filler, and is preferably a polyimide precursor solution. Since the insulating varnish has a high viscosity, baking and solidification can be performed while maintaining a shape formed when the insulating varnish passes through a die.