Cold-Forming Tool Holder Motion for Precise Surface Profiling

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Solution Overview

Problem

Existing cold-forming methods for producing profiling in solid or hollow parts are inflexible, require significant tool changes for different diameters, and often result in low surface quality due to momentary tool contact and multiple axial processing steps.

Innovation Solution

A method utilizing a tool holder with synchronized rotating and orbital movements, allowing for a complex movement that includes rolling and sliding components, enabling continuous profiling close to workpiece projections and reducing the need for multiple tool interventions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a profiling tool is moved axially relative to the hollow part at a constant radial feed depth, then the desired profile length is reached, but a slight scale-like roughness is created on the surface

Engineering Contradiction:
Improveprofile length precisionVSAvoidsurface quality
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The profiling tool is oscillated in a direction perpendicular to the longitudinal axis of the hollow part, creating a periodic back-and-forth movement on the surface. This periodic action distributes the material removal more evenly and prevents the accumulation of scale-like roughness that occurs with continuous axial feeding, thereby improving surface quality while maintaining profile precision

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The profiling tool combines axial movement with perpendicular oscillation, creating a dynamic two-dimensional motion pattern. This dynamic approach allows the tool to engage and disengage from the workpiece periodically, reducing continuous contact stress and minimizing surface roughness generation while achieving the desired profile length

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If rotating tools hammer the workpiece periodically to create a profile, then flexibility for different products is achieved, but profiling close to a radially outwardly projecting shoulder is not easily possible

Engineering Contradiction:
Improveproduct specification flexibilityVSAvoidprofiling near shoulder capability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The profiling tool is given freedom of movement in a second dimension perpendicular to the longitudinal axis, in addition to the axial direction. This two-dimensional motion capability allows the tool to navigate around obstacles like radially outwardly projecting shoulders while maintaining profiling capability, enabling operation in previously inaccessible areas

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If multiple tools are distributed around the circumference to form profile gaps in a single step, then production time is reduced, but the device requires significant reconfiguration for different diameters

Engineering Contradiction:
Improveprofile formation speedVSAvoiddevice reconfiguration requirement
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Instead of using multiple fixed tools distributed around the circumference, the invention employs a single profiling tool that can dynamically move in multiple directions (axially and perpendicular to the axis). This dynamic single-tool approach achieves the same profile formation capability as multiple tools while eliminating the need for complex device reconfiguration when changing workpiece diameters

Inventive Principle:
Principle #15Dynamics

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 enhances surface quality and productivity by allowing extensive profiling in a single intervention, reducing post-processing needs and tool changes, while maintaining flexibility for adapting to different product specifications.

Implementation Method 1

the tool movement on the workpiece includes a rolling motion

Methodology Applied
Scientific EffectRolling motion: Roller

Implementation Method 2

The tool movement can have both a rolling and a sliding component

Methodology Applied
Scientific EffectSliding motion: Friction

Implementation Method 3

Device and method for the cold-forming shaping of workpieces

Methodology Applied
Scientific EffectCold-forming: Cold-forming

Implementation Method 4

a first tool (2) is fed, in a complex movement comprising at least a rolling movement and a sliding movement, into the outer surface (11a) of a machining area (11) of a workpiece (1)

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3880384B1Device and method for the cold-forming shaping of workpieces
Publication Date: 2024.02.07 ERNST GROB AG
  • EP3880384B1 patent drawingFigure 1~8
  • EP3880384B1 patent drawingFigure 2A~2D
  • EP3880384B1 patent drawingFigure 3~4

AI summary

The invention relates to a method and to a device for producing a shaped body with shaping by cold-forming a workpiece (1), the workpiece having a longitudinal axis (Z) and an outer surface (11a), for example a cylindrical outer surface, which extends along the longitudinal axis (Z) in a working area (11), and to which the shaping (P) is applied. The workpiece (1) carries out a rotational movement (R1) about the longitudinal axis (Z) and is worked by a tool (2) in multiple forming actions, during each of which an operative part (21) of the tool (2) comes into contact with the working area (11). The tool (2) is held by a tool holder (5), and the tool holder (5) is rotationally mounted in a rotating member (8) about an axis of rotation (W) and is driven to perform a rotary movement (R5) about its axis of rotation (W), and is driven by the rotating member (8) to perform a rotating movement (R8). The rotational movement (R1) of the workpiece (1) is synchronized with the rotating movement (R8) of the tool holder (5), and the rotary movement (R5) of the tool holder (5) is synchronized with the rotating movement (R8) of the tool holder (5).