Drill Core Geometry for Regrinding Without Precision Loss

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Solution Overview

Problem

Drilling tools, especially small drills used in printed circuit board production, suffer from reduced precision and performance due to tip bluntness, requiring frequent regrinding which alters the tool's geometry and reduces its service life.

Innovation Solution

A drilling tool design featuring a base body with a constant cross-sectional area core at the tool tip and an increasing cross-sectional area further from the tip, allowing for more frequent regrinding without significant geometric changes, maintaining cutting edge geometry and conveyor helix efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the drilling tool is reground after tip bluntness, then the tool can be reused, but the tool tip geometry changes and precision is lost

Engineering Contradiction:
Improveservice lifeVSAvoidtool precision
Core Design Contradiction:
Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The core is divided into a first section with constant cross-sectional area and a second section with increasing cross-sectional area. This segmentation allows the front portion to maintain geometric consistency through multiple regrinds while the rear portion provides structural support and gradual area increase.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the core have different cross-sectional area characteristics - the first section has constant area for precision maintenance at the tool tip, while the second section has increasing area for structural support. This local differentiation resolves the contradiction between reuse and precision.

Inventive Principle:
Principle #3Local quality

2Duration of action of moving object

If the tool tip is reground multiple times, then service life is extended, but the cross-sectional area of the core changes and performance degrades

Engineering Contradiction:
Improveservice lifeVSAvoidtool performance
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

Dividing the core into two functional sections enables the first section to serve as a stable reference for multiple regrinds without performance degradation, while the second section provides the necessary structural foundation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cross-sectional area parameter is designed to be constant in the first section and increasing in the second section. This parameter distribution ensures that regrinding operations do not alter the critical geometry at the tool tip, maintaining reliability throughout extended service life.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional drills are reground, then they can be reused once or twice, but precision and performance are significantly reduced

Engineering Contradiction:
Improvetool reuse capabilityVSAvoiddrilling precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The segmented core structure with constant area in the first section allows multiple regrind cycles while preserving the critical tool tip geometry, enabling extended productive use without precision loss.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The local constant cross-sectional area at the tool tip region ensures that regrinding operations maintain consistent cutting geometry, while the increasing area in the second section provides structural support for repeated use.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3535080B1Drilling tool
Publication Date: 2021.06.09 HPTEC
  • EP3535080B1 patent drawingFigure 1~2
  • EP3535080B1 patent drawingFigure 3

AI summary

The invention proposes a drilling tool (1) for drilling workpieces, comprising a tool tip (2), a base body (3) and a core (14), wherein the base body (3) has at least one primary facet (7, 8) as at least one spiral depression, in particular two spiral depressions (11, 12), each forming a conveying spiral. To extend the service life, the core (14), in a first section (I) that starts at the tool tip (2) and/or extends to the tool tip, has a constant cross-sectional area perpendicular to the axis of rotation (A) and has, in an adjacent second section (II) counter to the feed direction (V), a cross-sectional area that increases, at least in sections.