Segmented Reamer Groove Cutter Reduces Cutting Load

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Solution Overview

Problem

Conventional reamers require time-consuming two-stage machining and suffer from high cutting loads, limiting their use to softer materials to avoid premature tool breakage.

Innovation Solution

A reamer design with a groove cutting edge positioned ahead of the main cutting edge, allowing the main cutting edge to be guided in a spiral groove without initial cutting load, enabling single-stage machining and use with stronger materials by coordinating rotational and feed movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional reamer design with main cutting edge merging into front chisel edge is used, then material removal capability is achieved, but cutting load becomes excessively high causing premature tool breakage

Engineering Contradiction:
Improvetool strengthVSAvoidcutting load
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The cutting edge is segmented into two distinct parts: a groove cutting edge positioned ahead that creates a spiral groove, and a main cutting edge that follows in the groove. This segmentation allows the main cutting edge to operate without the excessive cutting load it would experience if it were the leading edge, thereby preventing premature tool breakage while maintaining material removal capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The groove cutting edge performs a preliminary action by creating a spiral groove ahead of the main cutting edge. This preliminary groove creation reduces the material resistance that the main cutting edge must overcome, effectively preparing the path for the main cutting edge and reducing the cutting load to acceptable levels.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If two-stage machining process is used with conventional reamer, then surface quality is improved, but machining time increases significantly

Engineering Contradiction:
Improvesurface qualityVSAvoidmachining time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The invention merges the groove creation function and the surface finishing function into a single cutting tool and a single machining pass. The groove cutting edge and main cutting edge work in sequence during one continuous operation, eliminating the need for separate machining stages while maintaining the surface quality benefits of groove-based machining.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The machining process achieves continuity of useful action by having the groove cutting edge and main cutting edge operate in sequential succession during a single continuous pass. The main cutting edge immediately follows the groove cutting edge in the spiral groove, ensuring that the useful machining action continues without interruption or intermediate steps, thereby reducing total machining time.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3204180B1Drilling tool, in particular reamer
Publication Date: 2020.01.29 AUDI AG
  • EP3204180B1 patent drawingFigure 1
  • EP3204180B1 patent drawingFigure 2
  • EP3204180B1 patent drawingFigure 3

AI summary

The invention relates to a drilling tool, in particular a reamer, for drilling out a workpiece core drilling (3) to a nominal diameter (dN) by means of a main cutter (19) formed on a drill body (9), said main cutter (19) having a radially external cutter edge (35) which extends along a drill-body longitudinal axis (L) as far as a cutter corner (37) arranged at the drill tip (11), wherein during the drilling-out operation, the drilling tool is drivable into the workpiece core drilling (3) with a rotary movement (R) and a feed movement (V). According to the invention, the drilling tool has at least one groove cutter (21) which is mounted upstream of the cutter corner (37) of the main cutter (19) in the direction of rotation (R) of the tool. During the drilling-out operation, the groove cutter (21) produces a groove (43) in the inner wall (1) of the core drilling (3), the cutter corner (37) of the main cutter (19) being guided in said groove (43) with an at least reduced cutting load.