Drilling Entry Sheet Resin Surface Free Energy Adhesion
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Solution Overview
Problem
Existing entry sheets for drilling in laminated or multi-layer boards face issues with weak adhesion strength between metallic foils and resin composition layers, leading to poor hole position accuracy and frequent drill breakage, especially when an adhesion layer is not used.
Innovation Solution
An entry sheet comprising a metallic foil with a resin composition layer that has a specific surface free energy range (27.0 to 37.0 mJ/m2 dispersion term and 0 to 5.0 mJ/m2 polar term) without an adhesion layer, utilizing a combination of water-insoluble and water-soluble resins to achieve strong adhesion and improved hole position accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an adhesion layer is not provided between metallic foil and resin composition layer, then material costs and production complexity are reduced, but adhesion strength becomes weak causing layer peeling during drilling
Solution Approach 1:
The invention changes the surface free energy parameters of the resin composition layer by controlling the dispersion term (20-40 mJ/m²) and polar term (0-10 mJ/m²) within specific ranges. This parameter optimization enables the resin composition layer to achieve strong adhesion to the metallic foil without requiring an additional adhesion layer, thus resolving the contradiction between manufacturing simplicity and adhesion strength.
2Ease of manufacture
If an adhesion layer is not provided between metallic foil and resin composition layer, then material costs are reduced, but hole position accuracy deteriorates due to layer peeling and drill stepping
Solution Approach 1:
By optimizing the surface free energy parameters (dispersion term: 20-40 mJ/m², polar term: 0-10 mJ/m²) of the resin composition layer, the invention prevents layer peeling during drilling processing. This ensures the drill bit follows the intended path accurately without stepping on peeled layers, thereby maintaining hole position accuracy while eliminating the need for an adhesion layer and reducing material costs.
3Device complexity
If adhesion strength between metallic foil and resin composition is weak, then production complexity is reduced, but drill breakage frequency increases
Solution Approach 1:
The invention optimizes the surface free energy parameters of the resin composition layer (dispersion term: 20-40 mJ/m², polar term: 0-10 mJ/m²) to achieve adequate adhesion strength. This prevents the resin composition layer from peeling off during drilling, which would otherwise cause the drill bit to step and break, thereby reducing drill breakage frequency without increasing production complexity.
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 provides strong adhesion between the metallic foil and resin composition, enhancing hole position accuracy during drilling while eliminating the need for an adhesion layer, thus reducing material costs and production complexity.
Implementation Method 1
the adhesion strength between the metallic foil and the layer of the resin composition is weak, and therefore the layer of the resin composition is peeled during drilling processing
Data Source
AI summary
An entry sheet for drilling comprising: a metallic foil; and a layer of a resin composition, the layer formed on the metallic foil without interposing an adhesion layer, wherein the surface of the layer of the resin composition, the surface being in contact with the metallic foil, has a dispersion term γSD of surface free energy in a range from 27.0 to 37.0 mJ/m2 and a polar term γSP of the surface free energy in a range from 0 to 5.0 mJ/m2.