Drilling Entry Sheet Resin Layer Bubble Control
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Solution Overview
Problem
Existing methods for producing entry sheets for drilling copper-clad laminates face issues with bubble formation and surface roughness due to the low melting point of water-soluble resins, leading to poor hole position accuracy and surface quality, especially when drilling small-diameter holes.
Innovation Solution
A process involving a mixed solvent of water and isopropyl alcohol with a specific ratio is used to dissolve a water-soluble resin composition, applied to a base material, and then dried to form a resin layer, which effectively prevents bubble formation and achieves a smooth surface, enhancing hole position accuracy and surface flatness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aqueous solution of water-soluble resin composition is applied and dried to form a resin layer, then the resin layer provides drilling lubrication and cooling effect, but bubbles remain in the resin layer and ridges form on the surface due to continuous vaporization and self-melting during drying
Solution Approach 1:
The patent changes the chemical composition parameters of the aqueous solution by adding isopropyl alcohol to create a mixed solvent system. This parameter change modifies the drying behavior of the resin layer, preventing continuous vaporization and self-melting that cause bubbles and ridges, thereby improving hole position accuracy while maintaining drilling quality
Solution Approach 2:
The patent creates a composite aqueous solution combining water-soluble resin composition with isopropyl alcohol in a specific ratio (95:5 to 5:95 by weight). This composite solvent system leverages the properties of both components to achieve uniform drying without bubbles or surface ridges, resolving the contradiction between drilling reliability and manufacturing precision
2Ease of operation
If water-soluble resin with low melting point is used, then the resin provides good lubrication during drilling, but continuous self-melting occurs during drying causing surface ridges and bubbles
Solution Approach 1:
The patent modifies the drying parameters by introducing isopropyl alcohol to the aqueous solution. This changes the evaporation rate and drying mechanism, allowing the low melting point resin to provide lubrication without undergoing continuous self-melting that would create surface ridges and bubbles
Solution Approach 2:
Isopropyl alcohol acts as an intermediary substance in the mixed solvent system. It mediates the drying process by controlling vaporization rates and preventing direct contact between excessive heat and the resin, thereby maintaining surface flatness while preserving the resin's lubrication properties
3Ease of manufacture
If aqueous solution is used as solvent, then the resin composition is easy to apply and environmentally friendly, but bubbles and ridges form during drying reducing production stability
Solution Approach 1:
The patent develops a composite solvent system combining water and isopropyl alcohol. This composite maintains the ease of application and environmental friendliness of aqueous solutions while adding the volatility control benefits of isopropyl alcohol, eliminating bubbles and ridges to achieve stable production
Solution Approach 2:
The patent optimizes the composition parameters of the mixed solvent (water-soluble resin composition to isopropyl alcohol ratio from 95:5 to 5:95 by weight). This parameter optimization ensures easy application while achieving uniform drying without defects, thereby stabilizing production
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 process results in an entry sheet with a flat and smooth resin layer surface, improving hole position accuracy and enabling stable production of small-diameter holes, reducing the occurrence of ridges and bubbles during drilling.
Implementation Method 1
drying due to vaporization of water and self-melting due to heat continuously occur in the step of drying of an aqueous solution of such a water-soluble resin applied to a base material
Implementation Method 2
a resin layer is finally formed by cooling-solidification
Data Source
AI summary
There are provided a process for the production of an entry sheet for drilling, comprising preparing a water-soluble resin composition solution by using a mixed solvent containing water and isopropyl alcohol in a specific ratio as a solvent of a water-soluble resin composition, then applying the solution to a sheet-like base material and drying the resultant base material to form a resin layer on the base material, and a method of drilling a printed wiring board material using the above entry sheet. According to the present invention, the problems of remaining bubbles in the resin layer and a decrease in surface flatness and smoothness due to the occurrence of a ridge, which are caused because the melting point of the water-soluble resin is lower than the boiling point of water, are overcome, and an entry sheet for drilling excellent in hole position accuracy is provided.