Drill Cutting Head Web Thinning for Sharp Entry and Edge Strength

Solution Overview

Problem

Drill cutting heads with short chisel edges are weak and prone to wear, while those with longer chisel edges are difficult to enter the workpiece and require more torque, leading to poor hole quality and increased wear, especially in longer drills relative to their diameter.

Innovation Solution

A drill cutting head design featuring a central web thinning that acts as both a rake surface for the innermost cutting-edge section and a secondary clearance surface for the leading cutting edge, creating a strong and sharp drill point that easily enters the workpiece without compromising strength or increasing primary clearance angle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the chisel edge is made shorter to create a sharper drill point, then the drill enters the workpiece more easily, but the cutting edge becomes weaker and more prone to wear and breaking

Engineering Contradiction:

Improveease of entering workpieceVSAvoidstrength of cutting edge

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent applies local quality by creating different web thicknesses at different locations: the web is thinned in the region of the main cutting edges to create a sharp, easy-to-enter drill point, while the web remains thicker in the central chisel edge region to maintain strength. This localized variation in web thickness allows the drill to simultaneously achieve ease of entry and cutting edge strength.

Inventive Principle:

Principle #3Local quality

2Strength

If the chisel edge is made longer to increase strength, then the cutting edge becomes stronger and less prone to wear, but the drill requires more feed force and torque to enter and rotate the workpiece

Engineering Contradiction:

Improvestrength of cutting edgeVSAvoidtorque and feed force required

Core Design Contradiction:

StrengthVSPower

Solution Approach 1:

The patent applies local quality by creating different web thicknesses at different locations: the web is thinned in the region of the main cutting edges to create a sharp, easy-to-enter drill point, while the web remains thicker in the central chisel edge region to maintain strength. This localized variation in web thickness allows the drill to simultaneously achieve ease of entry and cutting edge strength.

Inventive Principle:

Principle #3Local quality

3Length of moving object

If the drill has an extended length relative to its diameter (L > 5 x D), then the drill can reach deeper holes, but the reduced stiffness makes the drill weaker and more prone to wear

Engineering Contradiction:

Improvedrill lengthVSAvoidstiffness and wear resistance

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The patent applies local quality by creating different web thicknesses at different locations: the web is thinned in the region of the main cutting edges to create a sharp, easy-to-enter drill point, while the web remains thicker in the central chisel edge region to maintain strength. This localized variation in web thickness allows the drill to simultaneously achieve ease of entry and cutting edge strength.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP4484037A1Drill cutting head

Publication Date: 2025.01.01 SANDVIK COROMANT

Figure 1~2
Figure 3~4
Figure 5

AI summary

The present invention relates drill cutting head wherein each main cutting edge comprises an innermost cutting-edge section creating an obtuse angle in the main-cutting edge towards the central edge, and in that a central web thinning forms an inner rake surface for the innermost cutting-edge section wherein, for each of the pairs of cutting edges, the central web thinning is formed between and borders the primary web thinning of the trailing main cutting edge and the primary clearance surface of the rotationally leading main cutting edge.