Drill Web Thickness Variation for PCB Micro-Drilling

Solution Overview

Problem

Micro drills used in PCB fabrication face high drilling resistance due to thick web structures, leading to reduced service life and susceptibility to cutting face breakage, especially when drilling multiple layers simultaneously.

Innovation Solution

A drill structure design featuring a shank part and bit part with a cylindrical bit core, where the web thickness is reduced by tilting two sides of the web to form first and second cutting faces, and extending auxiliary cutting faces to enhance chip discharge and abrasion resistance, with the width of the prismatic web edges being smaller than the outer-side width of the primary cutting faces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the web has a larger thickness, then the drill structure has greater strength, but the drilling resistance increases and service life decreases

Engineering Contradiction:

Improvestrength of drill structureVSAvoiddrilling resistance

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The patent applies local quality by making the web thickness non-uniform along the bit core. The web has a first thickness at the tip and a second thickness at the tail, with the first thickness being smaller than the second thickness. This localized variation optimizes both strength and drilling resistance - the thinner web at the tip reduces drilling resistance while the thicker web at the tail provides sufficient strength.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameter of web thickness along the length of the bit core. By varying the thickness parameter from tip to tail, the design achieves optimal performance - reduced drilling resistance at the cutting tip while maintaining structural integrity through increased thickness toward the tail.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the web has a larger thickness, then the drill structure has greater strength, but the service life of the bit part decreases

Engineering Contradiction:

Improvestrength of drill structureVSAvoidservice life of bit part

Core Design Contradiction:

StrengthVSDuration of action of moving object

Solution Approach 1:

The patent applies local quality by making the web thickness non-uniform along the bit core. The web has a first thickness at the tip and a second thickness at the tail, with the first thickness being smaller than the second thickness. This localized variation optimizes both strength and drilling resistance - the thinner web at the tip reduces drilling resistance while the thicker web at the tail provides sufficient strength.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameter of web thickness along the length of the bit core. By varying the thickness parameter from tip to tail, the design achieves optimal performance - reduced drilling resistance at the cutting tip while maintaining structural integrity through increased thickness toward the tail.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If the cutting face structure includes only two primary cutting faces and two secondary cutting faces, then the structure is simpler, but the cutting faces are likely to break during drilling

Engineering Contradiction:

Improvecomplexity of cutting face structureVSAvoidreliability of cutting faces

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies segmentation by dividing each cutting face into multiple segments: a primary cutting face and a secondary cutting face. The primary cutting face has a first thickness and the secondary cutting face has a second thickness, with the first thickness being smaller than the second thickness. This segmentation allows each face to perform specialized functions - the thinner primary face reduces drilling resistance while the thicker secondary face provides structural support and abrasion resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making the web thickness non-uniform along the bit core. The web has a first thickness at the tip and a second thickness at the tail, with the first thickness being smaller than the second thickness. This localized variation optimizes both strength and drilling resistance - the thinner web at the tip reduces drilling resistance while the thicker web at the tail provides sufficient strength.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10661357B2Drill structure

Publication Date: 2020.05.26 TCT GLOBAL

AI summary

A drill structure comprises a shank part and a bit part. A web is formed on the front end of the bit part. Two sides of the web are tilted backward to form two cutting faces. At least one chip-discharge groove is formed on the surface of the bit part. Each cutting face includes a primary cutting face and a secondary cutting face. The thickness of the prismatic web edge of at least one primary cutting face is smaller than the outer-side width of the primary cutting face. An auxiliary cutting face is extended to the wall of the flute from the cutting edge of the primary cutting face and a portion of a blade back of the secondary cutting face of another cutting face. The present invention decreases the drilling resistance during drilling a hole and increases the service life of the drill bit.