Deep-Hole Drill Chip Former Layout for Easier Regrinding

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Solution Overview

Problem

Deep-hole drills with flat cutting surfaces face challenges in regrinding, particularly when machining tough and long-chipping materials, as existing methods require precise manufacturing and cannot be easily performed by users on simple grinding machines, leading to high costs and tool breakage risks.

Innovation Solution

The design incorporates one or two cutting edges with rake faces featuring multiple chip formers or troughs, allowing for regrinding by removing the drill tip to maintain consistent geometry, enabling users to reposition and regrind the drill on a simple grinding machine, retaining existing coatings and preventing chip accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single chip former extending parallel to the outer cutting edge is used, then chip formation is improved and processing speed increases, but regrinding becomes complex requiring precise CNC grinding machines and cannot be performed by users on simple grinding machines

Engineering Contradiction:
Improveprocessing speedVSAvoidregrinding capability
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The single chip former is divided into multiple discrete chip formers arranged at distances from one another along the rake face. This segmentation allows the drill tip to be reground incrementally, exposing new chip formers with each regrinding cycle, thereby enabling users to perform regrinding on simple grinding machines while maintaining effective chip formation capabilities

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple chip formers are pre-positioned at specific distances from the cutting edge during manufacturing. This preliminary arrangement ensures that as the drill tip is reground, new chip formers are progressively exposed at the correct positions and orientations, eliminating the need for complex precision regrinding operations

Inventive Principle:
Principle #10Preliminary action

2Duration of action of moving object

If the drill tip is reground to restore cutting edges, then tool service life is extended, but the existing coating on the rake face is removed and manufacturing precision is lost

Engineering Contradiction:
Improvetool service lifeVSAvoidcutting edge geometry
Core Design Contradiction:
Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The rake face is segmented into multiple zones with different chip formers positioned at distances from the cutting edge. This allows selective exposure of new chip formers during regrinding while preserving the coated rake face surface, maintaining both manufacturing precision and coating integrity across multiple regrinding cycles

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of regrounding the entire rake face, the design allows regrinding to progress in the axial direction, exposing new chip formers at different positions along the rake face. This dimensional approach preserves the coated surface and precise geometry of previously exposed chip formers while restoring cutting edges

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

Data Source

PatentEP3768452B9Deep-hole drill having a plurality of chip-forming devices and recesses in the rake face
Publication Date: 2022.07.20 BOTEK PRAEZISIONSBOHRTECHNIK GMBH
  • EP3768452B9 patent drawingFigure 1
  • EP3768452B9 patent drawingFigure 2
  • EP3768452B9 patent drawingFigure 3

AI summary

The invention relates to a single-lip drill (1) and double-lip drill having a plurality of chip-forming devices (33, 35) or hollows (37) in the rake face (23) which are arranged in succession and at a distance from one another. As soon as a cutting edge and/or the associated chip-forming device or the associated hollow is worn, the deep-hole drill according to the invention can be re-ground using simple means.