Machining Tool Shank Plastic Deformation Press Fit

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Solution Overview

Problem

Existing machining tools are costly to manufacture due to the need for precise pre-machining of surfaces for conventional press fits, which increases production time and expense.

Innovation Solution

A machining tool design that uses a plastically deformed tool shank with a high oversize press fit for the cutting element, eliminating the need for precise surface machining by utilizing a hard metal or cermet cutting element pressed into a steel shank with intentionally designed cross-sectional tolerances for a non-positive connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional press fit is used to join the cutting element to the tool shank, then a secure connection is achieved, but precise pre-machining of surfaces is required which increases manufacturing cost and time

Engineering Contradiction:
Improveconnection securityVSAvoidmanufacturing cost and time
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the dimensional parameters by designing the receiving opening with a cross-section that is intentionally smaller than the cutting element's cross-section. This parameter change enables plastic deformation of the tool shank material during pressing, creating a secure connection without requiring precise pre-machining tolerances. The cross-sectional area reduction of the receiving opening is the key parameter change that resolves the contradiction between connection security and manufacturing ease.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies preliminary plastic deformation to the tool shank material through the pressing process itself. By designing the press fit to cause plastic deformation rather than relying on elastic deformation with precise tolerances, the connection is established during the pressing operation without requiring preliminary precision machining of the contact surfaces. This preliminary action of plastic deformation eliminates the need for subsequent grinding or precision machining operations.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If precise surface machining is performed on the tool shank and cutting element, then manufacturing precision is improved, but production time and costs increase

Engineering Contradiction:
Improvesurface precisionVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the tolerance parameters by intentionally designing high tolerances (larger dimensional variations) for the receiving opening and cutting element interfaces. Instead of requiring tight tolerances for elastic press fits, the design accepts larger dimensional variations because the plastic deformation process accommodates these variations and still achieves a secure connection. This parameter change from tight to loose tolerances eliminates the need for time-consuming precision machining operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention treats the contact surfaces as disposable in the sense that they are not precisely machined but rather formed through the pressing process itself. The surfaces are created during assembly rather than being pre-formed with high precision, similar to how disposable components are formed during assembly rather than requiring precise pre-manufacturing. This approach significantly reduces production time while maintaining connection integrity through plastic deformation.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

This approach significantly reduces manufacturing costs and time by allowing the cutting element to be pressed in without mechanical post-processing, resulting in a robust and cost-effective machining tool with a simplified production process.

Implementation Method 1

The cross section of the receiving opening and the cross section of the pressed-in part of the cutting element are designed in such a way that the tool shank is plastically deformed by the pressing-in of the cutting element

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

a non-positive connection is produced by means of a press fit between the cutting element and the tool shank

Methodology Applied
Scientific EffectPress fit: Mechanical Force

Data Source

PatentEP3057731B1Machining tool and method of producing a machining tool
Publication Date: 2019.08.14 CERATIZIT AUSTRIA GES
  • EP3057731B1 patent drawingFigure 1a~2b
  • EP3057731B1 patent drawingFigure 3a~4b

AI summary

The invention relates to a machining tool (2a) and to a method for producing a machining tool. Said machining tool comprises, in particular a cutting, boring, drilling, rotating and/or countersinking tool. The machining tool also comprises a tool shaft (4a) which comprises an axial receiving opening (6a), and a cutting element (12a) which is inserted at least partially into the receiving opening (6a). Said receiving opening cross-section and the inserted cutting element cross-section are designed such that the tool shaft (4a) is plastically deformed by inserting the cutting element (12a).