Surgical Milling Cutter Geometry for Better Chip Removal

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Solution Overview

Problem

Existing surgical milling cutters face issues with inefficient chip removal, high heat generation, difficulty in cleaning, and limited visibility during surgical procedures due to their design, leading to impaired cutting performance and potential tissue damage.

Innovation Solution

A surgical milling cutter with a symmetrical design featuring two diametrically opposed teeth and cutting edges that facilitate axial and lateral tissue ablation, providing large interdental spaces for efficient chip removal and reduced heat generation, ensuring easy cleaning and improved visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple teeth with cutting edges are arranged closely together in the milling head, then the cutting performance and tissue ablation capability are improved, but the chip space between teeth becomes insufficient leading to poor chip removal

Engineering Contradiction:
Improvecutting performanceVSAvoidchip removal efficiency
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The milling head is divided into multiple teeth with cutting edges arranged around the circumference, allowing simultaneous engagement with tissue at multiple points. This segmentation enables effective tissue ablation while maintaining adequate spacing between teeth for chip removal, resolving the contradiction between cutting performance and chip removal efficiency.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the interdental space between teeth is reduced to increase the number of cutting edges, then the cutting performance is improved, but the chip space becomes clogged and heat generation increases

Engineering Contradiction:
Improvecutting performanceVSAvoidheat generation
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The teeth are designed with specific geometric characteristics including optimized rake angles and clearance angles that vary locally along the cutting edge. This local quality optimization ensures adequate chip space between teeth while maintaining effective cutting performance, preventing heat buildup by ensuring proper chip ejection paths.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If the milling head design obstructs the view of the working area, then the structural integrity and cutting stability are improved, but the visibility during surgery is reduced

Engineering Contradiction:
Improvecutting stabilityVSAvoidvisibility
Core Design Contradiction:
Stability of the object's compositionVSIllumination intensity

Solution Approach 1:

The milling head is designed with a transparent or translucent portion that allows visualization of the working area from the proximal end. This inverted approach to opacity enables surgeons to observe tissue interaction and chip removal in real-time while maintaining the structural integrity and cutting stability provided by the rigid milling head structure.

Inventive Principle:
Principle #13The other way round (Inversion)

4Productivity

If the cutting edges are designed with sharp geometry for effective tissue ablation, then the cutting performance is improved, but the tendency for chattering and uncontrolled jumping increases

Engineering Contradiction:
Improvecutting performanceVSAvoidcutting control
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The cutting edges are designed with optimized geometric parameters including rake angles between -10° and -40° and clearance angles between 40° and 70°. These parameter optimizations balance sharpness for effective cutting with sufficient strength to prevent chattering and uncontrolled jumping, resolving the contradiction between cutting performance and cutting control reliability.

Inventive Principle:
Principle #35Parameter changes

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 effective cutting performance, particularly in the axial direction, with minimal heat generation, easy cleaning, and enhanced visibility, making it suitable for high-speed medical applications without tissue damage.

Implementation Method 1

at least two teeth, each with cutting edges for rotary ablation of tissue... designed for ablation of tissue in both axial and/or lateral directions

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP4057919B1Surgical milling cutter with improved chip removal
Publication Date: 2026.04.01 AESCULAP AG
  • EP4057919B1 patent drawingFigure 1~2
  • EP4057919B1 patent drawingFigure 3~8
  • EP4057919B1 patent drawingFigure 9~10

AI summary

The present invention relates to a surgical milling cutter (16, 34, 46, 56) with a shaft (17, 35, 47, 57) for rotary-driven coupling to a drive unit about a rotation axis (19, 37, 49, 59) extending in the longitudinal direction of the shaft (17, 35, 47, 57) and with a milling cutter head (18, 36 48, 58) arranged distally on the shaft (17, 35, 47, 57), wherein the milling cutter head (18, 36, 48, 58) has at least two teeth (21, 22, 39, 40) with respective cutting edges (23, 24, 41, 42, 50a, 50b, 60a, 60b) for rotary subtractive machining of tissue, wherein the cutting edges (23, 24, 41, 42, 50a, 50b, 60a, 60b) are each designed for subtractive machining of tissue both in the distal direction and in the lateral direction, wherein a chip space (30a, 30b, 54a, 54b) is formed as a free space between circumferentially adjacent teeth (21, 22, 39, 40), wherein each chip space (30a, 30b, 54a, 54b), on the side of the rotation axis (19, 37, 49, 59) facing towards the respective cutting edge (23, 24, 41, 42, 50a, 50b, 60a, 60b), extends from the cutting edge (23, 24, 41, 42, 50a, 50b, 60a, 60b) into a region on the side of the rotation axis (19, 37, 49, 59) facing away from the cutting edge (23, 24, 41, 42, 50a, 50b, 60a, 60b).