Deep-Hole Drill Head With Integrated Guide Pad for Hole Accuracy

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Solution Overview

Problem

Conventional drill heads for deep-hole drilling experience a loss of pressure balance and stability due to faster abrasion of the margin portion compared to guide pads, leading to deterioration in roundness, cylindricality, and straightness of the cutting hole, especially with increased drilling operations.

Innovation Solution

A drill head design featuring a cutting blade tip with a wide guide pad portion and a separated margin portion, both made of super hard materials, where the guide pad portion is positioned to distribute load evenly and is designed to reduce abrasion, allowing the cutting blade tip to serve as both a guide and a cutting element, maintaining stability and accuracy over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional drill head with a narrow margin portion is used, then the initial cutting accuracy is achieved, but the margin portion abrades faster than guide pads during drilling operations, leading to loss of pressure balance and deterioration of cutting hole quality

Engineering Contradiction:
Improvecutting hole roundness and cylindricalityVSAvoidservice life of margin portion
Core Design Contradiction:
Manufacturing precisionVSDuration of action of stationary object

Solution Approach 1:

The outer end surface of the cutting blade tip is divided into distinct functional zones: a margin portion for initial cutting and a separate guide pad portion for guiding. This segmentation allows each portion to be optimized independently - the margin portion can be narrower while the guide pad portion provides sufficient contact area, preventing the pressure balance loss that occurs when the margin portion abrades quickly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extends the functional surface in the axial direction by adding a guide pad portion that is axially offset from the margin portion. This dimensional extension creates a longer effective guide surface, distributing the guiding function over a greater distance and reducing the wear rate on any single area, thereby maintaining pressure balance and cutting accuracy over extended service life.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If the margin portion is made narrow to improve initial cutting precision, then accurate hole formation is achieved, but the margin portion becomes more susceptible to rapid abrasion during drilling operations

Engineering Contradiction:
Improvecutting accuracyVSAvoidstability of cutting state
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

By separating the margin portion and guide pad portion into distinct functional zones on the cutting blade tip, the invention allows the margin portion to remain narrow for precise initial cutting while the separate guide pad portion provides a larger, more durable contact surface. This segmentation prevents the coupling of precision and durability that plagues conventional designs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide pad portion acts as an intermediary element that takes over the primary guiding function from the margin portion. This intermediary structure protects the narrow margin portion from excessive wear while maintaining the precision cutting capability, as the guide pad portion absorbs the majority of the contact and guiding stresses.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If additional guide pads are added to maintain pressure balance, then cutting stability is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvepressure balanceVSAvoidstructure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention merges the guide pad function directly into the cutting blade tip structure by forming the guide pad portion as an integral part of the cutting blade tip's outer end surface. This integration eliminates the need for separate guide pad components and their associated mounting structures, maintaining pressure balance without increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cutting blade tip is designed to serve multiple functions: the margin portion performs initial cutting while the integrated guide pad portion provides guiding and stability. This multi-functionality within a single component reduces the overall number of parts needed and simplifies the device structure while maintaining the required pressure balance and cutting stability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design ensures a stable cutting state with reduced runout and prolonged high-accuracy drilling performance by distributing load evenly and minimizing abrasion, maintaining excellent roundness, cylindricality, and straightness of the cutting hole over a long period without the need for additional structural changes or increased manufacturing costs.

Implementation Method 1

a guide pad portion (4) having an arc surface that slide-contacts with the inner circumference of a cutting hole (H)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

one or a plurality of cutting blade tips (2A, 2B, and 2C) mounted by brazing

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP2711114B1Drill head for deep hole cutting
Publication Date: 2021.09.08 BOTEK PRAEZISIONSBOHRTECHNIK GMBH
  • EP2711114B1 patent drawingFigure 1(a)~1(b)
  • EP2711114B1 patent drawingFigure 2(a)~2(c)
  • EP2711114B1 patent drawingFigure 3(a)~3(c)

AI summary

Provided is a drill head for deep-hole drilling to which a cutting blade tip (s) is brazed, capable of maintaining a very stable cutting state even if the number of drilling works increases, capable of continuously forming a cutting hole excellent in roundness, cylindricality, and straightness, etc., for a long period of time, and having extremely high accurate processing performance and excellent durability. In a drill head D1 for deep-hole drilling including cutting blade tips 2A to 2C brazed to cutting chip discharge ports 11 and 12 opened on a head distal end surface 1a, guide pads 3A and 3B mounted on a plurality of positions of the circumferential surface 1b at the head distal end side, and a hollow inside portion made into a cutting chip discharge passage 10 communicating with the cutting chip discharge ports 11 and 12, wherein a guide pad portion 4 having an arc surface that slide-contacts with the inner circumference of a cutting hole H is formed on the outer end surface of the circumferential portion cutting blade tip 2B.