Milling Tool Fastening System Centering Pin Positioning

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Solution Overview

Problem

Existing milling and drilling tools face challenges with positional inaccuracy due to screw-based fastening systems, which can lead to increased setup and changeover times, and may not adequately absorb the forces encountered during machining.

Innovation Solution

A fastening system utilizing a centering pin and corresponding opening, along with a sliding block and groove, allows for precise positioning and force absorption, enabling quick replacement and improved accuracy without the need for multiple screws.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If screws are used to fasten the cutting element to the tool body, then the cutting element can be attached, but positional inaccuracy occurs due to play and manufacturing tolerance

Engineering Contradiction:
Improvefastening reliabilityVSAvoidpositioning accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

A centering pin is introduced as an intermediary element between the cutting element and tool body. The pin fits into a centering opening on the tool body and a corresponding opening on the cutting element, providing precise positioning and eliminating play. This mediator component resolves the positioning accuracy issue while maintaining fastening reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The fastening system is segmented into distinct functional components: the centering pin for positioning, the sliding block for rotational constraint, and the screws for fastening. This segmentation allows each component to perform its specific function optimally, with the centering pin addressing positioning accuracy independently from the fastening function.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If small-diameter screws are used to improve positioning accuracy, then positioning accuracy improves, but the forces to be absorbed cannot be absorbed by just two or three screws

Engineering Contradiction:
Improvepositioning accuracyVSAvoidforce absorption capacity
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The system separates positioning function (centering pin) from force absorption function (screws). The centering pin handles positioning with high precision, allowing the use of fewer screws optimized for force absorption rather than positioning. This segmentation resolves the contradiction by assigning different functions to different components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The centering pin acts as a mediator that takes over the positioning function, enabling the screws to focus solely on force absorption. This intermediary component allows the use of fewer, larger-diameter screws that are optimized for withstanding machining forces rather than providing positioning precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Force

If screws with larger diameter or a variety of screws are used to absorb forces, then force absorption capacity increases, but set-up and changeover times increase significantly

Engineering Contradiction:
Improveforce absorption capacityVSAvoidset-up and changeover time
Core Design Contradiction:
ForceVSLoss of time

Solution Approach 1:

The positioning function is extracted from the screw system and assigned to a dedicated centering pin. This extraction allows the use of fewer screws (reducing fastening time) while maintaining both positioning accuracy and force absorption capacity. The centering pin is pre-installed on the tool body, eliminating the need for time-consuming positioning adjustments during changeover.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The centering pin is pre-installed on the tool body before the cutting element is attached. This preliminary action ensures that positioning is already established when the cutting element is mounted, significantly reducing set-up and changeover times. The pin is positioned and secured in advance, so no time is lost during the cutting element replacement process.

Inventive Principle:
Principle #10Preliminary action

4Force

If multiple screws are used to attach the cutting element, then force absorption capacity increases, but the number of screws leads to significant increase in set-up and changeover times

Engineering Contradiction:
Improveforce absorption capacityVSAvoidchangeover speed
Core Design Contradiction:
ForceVSProductivity

Solution Approach 1:

The positioning function is extracted from the multi-screw system and assigned to a dedicated centering pin mechanism. This extraction reduces the number of screws needed from multiple to just two or three, directly improving changeover speed while maintaining force absorption capacity through the optimized screw configuration.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The centering pin automatically provides positioning when the cutting element is mounted, eliminating the need for operators to manually adjust or align multiple screws. The system serves itself by providing inherent positioning through the pin-opening interface, significantly reducing the time and complexity of changeover operations.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2300184B1Tool comprising a fastening unit
Publication Date: 2014.02.12 SANDVIK INTELLECTUAL PROPERTY AB
  • EP2300184B1 patent drawingFigure 1
  • EP2300184B1 patent drawingFigure 2
  • EP2300184B1 patent drawingFigure 3

AI summary

The invention relates to a milling or boring tool (1) which comprises a base body (2) that can be rotated about a tool axis and a cutting element that can be fastened to the base body (2) and that has a cutting section or a cutting insert seat for accommodating a cutting insert. The aim of the invention is to devise a fastening system for fastening the cutting element to the base body, which can be easily produced at low cost, allows a highly precise positioning of the cutting element on the base body and furthermore allows the cutting element to be rapidly changed. A centering pin (23) the axis of which does not coincide with the tool axis is arranged in parallel to the boring axis on a part, the base body or the cutting element and a corresponding centering opening is arranged on the other part, the cutting element or the base body.