Ceramic Cutting Insert Tumbling for Edge Rounding

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Solution Overview

Problem

Ceramic cutting inserts produced by powder metallurgical methods face issues with sharp edges breaking easily and sinter skin containing surface defects, requiring expensive and precise post-sintering treatments like grinding to achieve the desired edge rounding and surface smoothness.

Innovation Solution

A method involving tumbling of ceramic blanks with ceramic chips in a vibratory tumbler to remove sinter skin and achieve edge rounding with specific W/H ratio and surface smoothness, reducing the need for multiple post-sintering steps and expensive equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional grinding wheels are used to shape ceramic insert blanks and remove sinter skin, then the desired final shape and surface smoothness are achieved, but the procedure becomes expensive requiring precision grinding equipment and extensive manual handling

Engineering Contradiction:

Improvesurface smoothness and final shapeVSAvoidprecision grinding equipment and manual handling

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical grinding systems with a vibratory finishing system that uses controlled vibration and abrasive media to achieve surface smoothing and shape refinement. This substitution eliminates the need for expensive precision grinding equipment while maintaining manufacturing precision through a simpler mechanical process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces abrasive media (such as ceramic beads or granules) as an intermediary substance between the ceramic insert blanks and the finishing surface. These media particles act as intermediaries that remove sinter skin and smooth surfaces through controlled abrasion during vibratory motion, replacing the direct contact of grinding wheels and reducing equipment complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If multiple post-sintering steps are performed to achieve edge rounding and surface treatment, then the cutting insert quality is improved, but the production time and process complexity increase

Engineering Contradiction:

Improvecutting insert quality and edge durabilityVSAvoidproduction time for multiple post-sintering steps

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent combines multiple post-sintering operations (sinter skin removal, surface smoothing, and edge rounding) into a single integrated vibratory finishing process. By merging these previously separate steps into one continuous operation using abrasive media in a vibratory environment, the patent reduces production time while maintaining cutting insert quality and edge durability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The vibratory finishing process with abrasive media serves multiple functions simultaneously: it removes sinter skin, smooths surfaces, and rounds edges. This multi-functional approach eliminates the need for separate specialized equipment for each operation, reducing both production time and process complexity while ensuring comprehensive treatment of the ceramic insert blanks.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Strength

If sharp cutting edges are maintained from the pressing operation, then the initial cutting performance is high, but the edges break too easily when used

Engineering Contradiction:

Improveedge strength and durabilityVSAvoidedge sharpness

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent applies preliminary surface treatment and edge rounding to ceramic insert blanks before they are mounted and used. By pre-rounding the sharp edges through vibratory finishing with abrasive media, the patent strengthens the edges against chipping and breakage during subsequent machining operations, while still maintaining sufficient sharpness for effective cutting performance.

Inventive Principle:

Principle #10Preliminary action

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 method effectively removes sinter skin and achieves the desired edge rounding and surface smoothness in a single operation, improving the durability and reducing edge chipping of ceramic cutting inserts, while maintaining the circular shape and achieving the required W/H ratio and surface roughness values.

Implementation Method 1

tumbling the ceramic blank

Methodology Applied

Scientific EffectVibration: Vibration

Implementation Method 2

remove sinter skin and provide an edge rounding

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS9238285B2Ceramic cutting insert and method of making same

Publication Date: 2016.01.19 SANDVIK INTELLECTUAL PROPERTY AB

AI summary

The present invention relates to a method of manufacturing a ceramic cutting insert, based on an oxide ceramic or a nitride ceramic or a mixed ceramic material, possibly containing whiskers, in a process comprising the powder metallurgical steps of providing a ready-to-press ceramic powder, pressing the ready-to-press powder into a compact of desired shape, sintering the compact to dense a ceramic blank followed by tumbling the ceramic blank, to remove sinter skin and provide an edge rounding.