PCB Drill Coating Layout for Wear Resistance and Electrical Sensing
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Solution Overview
Problem
Drilling tools used for PCBs with increased inorganic filler or glass fibers face issues with wear, leading to inaccurate hole positioning, rough inner walls, and potential breakage, which can result in poor drilling quality and incorrect breakage detection due to coatings with low electroconductivity affecting electrical sensing.
Innovation Solution
A drilling tool design where the tool base material is exposed at specific points and covered with a coating film on the outer circumference of cutting edges, ensuring electroconductivity between the tool and the material being drilled, allowing for accurate sensing and minimizing drilling quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coating film with low electroconductivity is applied to the entire drilling tool surface, then wear resistance and cutting edge protection are improved, but electrical sensing accuracy and drilling depth control deteriorate
Solution Approach 1:
The patent applies different surface treatments to different regions of the drilling tool. The outer circumferential surface receives a wear-resistant coating film, while the point portion is left with exposed base material or given a different coating. This local differentiation allows the tool to simultaneously achieve wear resistance where needed and maintain electrical sensing capability at the contact point with the workpiece.
2Strength
If the amount of inorganic filler or glass fibers in PCB is increased, then heat resistance and rigidity are improved, but cutting edge wear resistance deteriorates
Solution Approach 1:
The patent employs a composite structure consisting of a cemented carbide base material and a coating film layer. This composite material system combines the hardness and heat resistance of the base material with the enhanced wear resistance properties of the coating film, allowing the drilling tool to effectively process high-strength PCB materials while maintaining extended tool life.
3Strength
If a coating film is applied to the drilling tool, then cutting edge protection is improved, but electroconductivity and breakage detection accuracy deteriorate
Solution Approach 1:
The patent implements localized surface treatment where the coating film is applied only to specific regions (outer circumferential surface) while leaving other regions (point portion) with different properties. This ensures that the coating provides cutting edge protection where required, while the exposed base material at the point portion maintains sufficient electroconductivity for accurate breakage detection through the workpiece.
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
This configuration ensures reliable electroconductivity, preventing erroneous breakage detection and maintaining drilling quality, even with low electroconductivity coatings, by allowing direct contact and effective electrical sensing, thus enhancing tool performance and extending tool life.
Implementation Method 1
PCB drills are normally covered with various coatings for the purpose of minimizing wear on the cutting edges
Implementation Method 2
contact between a PCB drill point and a copper foil layer on a PCB surface is electrically sensed (electric conduction is sensed)
Data Source
Figure 1
Figure 2~2(c)
Figure 3~3(c)
AI summary
To provide a drilling tool and a method for manufacturing the same, with which electroconductivity is ensured between a tool point and a material being drilled, and any decrease in drilling quality can be minimized more so than with a non-coated drill. A drilling tool in which one or more helical chip-evacuating flutes (2) are provided, from a tool point to a base, in an outer circumference of a tool main body (1) having a coating film (5) covering a tool base material made of a cemented carbide, and one or more cutting edges (4) are provided at intersecting ridge lines of the chip-evacuating flutes (2) and a point relief (3), wherein a point of the tool main body (1) is provided with an exposed part (6) in which there is no coating film (5) and the tool base material is exposed, and certain ranges at tool-outer-circumference sides of the cutting edges (4) are covered by the coating film (5).