Groove Forming Tool for Cylindrical Surface Roughening

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Solution Overview

Problem

Existing methods for mechanically roughening cylindrical surfaces of metallic workpieces, such as piston running surfaces of cylinder liners, require complex coordination of tool movements, leading to inefficiencies in producing consistent and accurate microstructures for adhesive bases under thermal spraying.

Innovation Solution

A method involving a groove forming tool that moves axially, rotates, and then returns axially to create intersecting grooves with minimal scatter, allowing for easy control and reduced time, using a tool with teeth arranged in rows for forming axial and circumferential grooves without cutting or by cutting, facilitating optimal adhesion for surface coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If complex coordination of tool movements is used to create microstructures, then manufacturing precision is improved, but device complexity increases and productivity decreases

Engineering Contradiction:
Improvemicrostructure consistencyVSAvoidtool movement coordination
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The tool is divided into multiple rows of teeth (at least two rows) arranged axially parallel, where each row independently forms grooves. This segmentation allows the complex microstructure creation to be distributed across multiple simple cutting elements, reducing the complexity of controlling individual tooth movements while maintaining high manufacturing precision through the collective action of all teeth

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The groove forming tool is designed with universal functionality to perform multiple operations simultaneously - creating both axial grooves (through forward axial movement) and circumferential grooves (through rotation at axial position). This multi-functionality eliminates the need for separate tools or complex coordinated movements, simplifying the device while achieving precise intersecting groove patterns

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

2Manufacturing precision

If complex coordination of tool movements is used to create microstructures, then manufacturing precision is improved, but productivity decreases

Engineering Contradiction:
Improvemicrostructure consistencyVSAvoidprocess time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The method enables continuous useful action by performing both axial groove formation (during forward axial movement) and circumferential groove formation (during rotation at axial position) in an integrated sequence without idle strokes. The tool continuously engages the workpiece surface, eliminating non-productive movement time while maintaining precise microstructure formation through the systematic arrangement of tooth rows

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The tool design incorporates preliminary action by pre-positioning multiple rows of teeth in specific axial configurations before engagement. The axial arrangement of teeth rows is predetermined to create the desired groove pattern, allowing the tool to immediately produce accurate microstructures upon engagement without requiring complex real-time coordination or adjustment during the machining process

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If axial and circumferential grooves are formed by separate operations, then manufacturing precision is improved, but loss of time increases

Engineering Contradiction:
Improvegroove intersection accuracyVSAvoidtool return stroke
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The method merges the formation of axial grooves and circumferential grooves into a single integrated tool engagement cycle. The tool performs axial movement to create axial grooves, then rotates at axial position to create circumferential grooves, all while maintaining continuous engagement with the workpiece. This eliminates the need for separate operations and idle return strokes, reducing time loss while preserving groove intersection accuracy through the systematic tooth arrangement

Inventive Principle:
Principle #5Merging (Combining)

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 method enables the reproducible and economical production of a defined microgroove structure with minimal scatter, ensuring optimal adhesion and interlocking for surface layers applied by thermal spraying, reducing the complexity and time required for tool movement control.

Implementation Method 1

mechanically roughening a cylindrical surface of a particularly metallic workpiece... by creating a defined microstructure of intersecting grooves... groove forming tool that moves axially, rotates, and then returns axially to create intersecting grooves... using a tool with teeth arranged in rows for forming axial and circumferential grooves without cutting or by cutting

Methodology Applied
Scientific EffectMechanical cutting: Abrasion

Data Source

PatentEP2958695B1Process and tool for mechanical roughening of a cylindrical surface
Publication Date: 2018.02.28 AUDI AG
  • EP2958695B1 patent drawingFigure 1
  • EP2958695B1 patent drawingFigure 2
  • EP2958695B1 patent drawingFigure 3

AI summary

The invention relates to a method for mechanically roughening a cylindrical surface (12) of an in particular metallic workpiece (11), e.g. the piston bearing surface of a cylinder sleeve in a cylinder crankcase, by producing a defined microstructure of mutually crossing grooves (14, 15), and by a groove forming tool (20), operating with or without material removal, for carrying out the method. A method according to the invention is characterized in that a) in a first operation, the groove forming tool (20) is moved axially along the workpiece surface (12) in such a way that at least one axial groove (14) is machined into the workpiece surface (12); b) in a second operation, following the first operation, the groove forming tool (20) is rotated about the cylinder axis (13) by a predefined rotational angle in the axial position reached in the first operation, as a result of which at least one circumferential groove (15) crossing the axial groove (14) is machined into the workpiece surface (12); and c) in a third operation following the second operation, the groove forming tool (20) is drawn back axially along the workpiece surface (12).