Flow Forming Device with Integrated Cutting Tool

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Solution Overview

Problem

Existing flow-forming methods face challenges in processing workpieces with irregular wall thickness in the circumferential direction, leading to the 'whip arm effect' where the workpiece warps and the forming process is aborted due to uneven material distribution and increased length in areas of greater wall thickness.

Innovation Solution

A device and method that incorporate a cutting tool to machine the workpiece during forming, allowing for greater irregularities in wall thickness by ensuring even material distribution through the use of an outer forming tool, such as a forming roller, and an inner mandrel, which helps absorb reaction forces and maintain the workpiece's position relative to the forming tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If flow-forming method is used to reshape hollow body, then diameter and wall thickness are reduced, but wall thickness uniformity deteriorates leading to whip arm effect

Engineering Contradiction:
Improvewall thickness uniformityVSAvoidforming process stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The cutting tool performs preliminary removal of material in regions with excessive wall thickness before the forming process completes. By pre-removing material that would otherwise cause uneven distribution, the cutting tool prevents the whip arm effect from developing during forming, allowing workpieces with initially irregular wall thickness to be successfully formed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cutting tool applies localized material removal only in specific circumferential regions where wall thickness exceeds the target value. This selective intervention maintains material in regions that already have appropriate thickness while removing excess material only where needed, preserving overall workpiece integrity while achieving uniform wall thickness distribution.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If additional forming tools are added to device, then forming capability is improved, but device complexity increases

Engineering Contradiction:
Improveprocessing capabilityVSAvoiddevice structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cutting tool is integrated into the existing forming device structure, combining material removal and plastic deformation functions in a single coordinated system. The cutting tool shares the rotating frame and drive mechanism with the forming tools, eliminating the need for separate standalone machining equipment while expanding the device's processing capabilities.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The multi-functional device performs both plastic deformation (forming) and material removal (cutting) operations using a single integrated system. The rotating frame supports both forming tools and cutting tools, allowing the device to handle workpieces with varying wall thickness irregularities that would require different processing approaches.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution effectively prevents the whip arm effect by ensuring even material distribution and absorption of reaction forces, enabling the processing of workpieces with more significant wall thickness irregularities, thus stabilizing the forming process and preventing warping.

Implementation Method 1

Through plastic deformation, the material of the workpiece is initially displaced by the outer forming tools towards the inner forming tool

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

a cutting tool of the device can act on the outer contour of the workpiece at the same time as the forming tool

Methodology Applied
Scientific EffectMechanical cutting:

Data Source

PatentEP2995394B1Device and method for forming a workpiece
Publication Date: 2016.09.07 REPKON MASCH & TOOL IND & TRADE LTD
  • EP2995394B1 patent drawingFigure 1
  • EP2995394B1 patent drawingFigure 2
  • EP2995394B1 patent drawingFigure 3

AI summary

A device (1) for forming a hollow and at least substantially rotationally symmetrical workpiece (4) comprises an inner forming tool (3) for supporting an inner contour of the workpiece (4) and an outer forming tool (2) for introducing a forming force into an outer contour (10) of the workpiece (4). The workpiece (4) is rotatable about an axis of rotation (X) relative to the outer forming tool (2). The device (1) includes a cutting tool (15) and is designed such that the cutting tool (15) can engage the outer contour (10) of the workpiece (4) simultaneously with the forming tool (2).