Ultrashort Pulse Laser Machining of Zirconia With Internal Cleavage

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Solution Overview

Problem

Conventional machining methods for brittle ceramic materials, such as zirconia, are inefficient, time-consuming, and lack precision due to long processing times, tool exchange requirements, and difficulties in predicting material shrinkage and warping, leading to decreased precision.

Innovation Solution

A machining method using ultrashort pulse lasers to project laser beams from a normal direction onto zirconia-based light-transmitting materials, forming objects inside the material and creating cleavage sites, followed by separation and polishing, eliminating the need for post-machining firing and reducing physical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional machining methods are used on fully sintered ceramic materials, then machining precision can be maintained, but machining time becomes excessively long due to high material hardness

Engineering Contradiction:
Improvemachining precisionVSAvoidmachining efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces conventional mechanical cutting tools with laser beams for machining fully sintered ceramic materials. The laser beam ablates the hard ceramic material through photothermal effects, eliminating the need for mechanical contact and tool exchanges, thereby dramatically reducing machining time while maintaining precision on fully sintered materials

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the machining parameter from mechanical force to laser energy density. By controlling laser power, pulse duration, and scanning speed, the system can efficiently remove hard ceramic material through ablation without the limitations of mechanical tool wear and exchange, resolving the contradiction between machining speed and precision

Inventive Principle:
Principle #35Parameter changes

2Productivity

If half-sintered materials are used for machining, then machining efficiency improves, but additional firing time is required increasing total processing time

Engineering Contradiction:
Improvemachining efficiencyVSAvoidtotal processing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent performs laser machining on fully sintered materials before any firing process. By using laser ablation on already-sintered materials, the machining is completed in one step without requiring subsequent firing, thereby eliminating the 7-15 hour firing time while maintaining high machining efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the firing step from the conventional machining sequence. Instead of machining half-sintered materials and then firing them, the system machines fully sintered materials directly, taking out the unnecessary firing step and reducing total processing time significantly

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If machining data is prepared to account for shrinkage and warping, then machining precision can be improved, but it becomes difficult to predict contraction and warping accurately

Engineering Contradiction:
Improvemachining precisionVSAvoidprediction complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical cutting with laser ablation on fully sintered materials. Since the material is already in its final sintered state, no further shrinkage or warping occurs during or after machining. This eliminates the need for complex shrinkage prediction and compensation calculations, simplifying the machining data preparation while maintaining high precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If multiple devices are used for cutting and firing, then specialized functions are achieved, but machining precision decreases due to repeated positioning

Engineering Contradiction:
Improveprocess specializationVSAvoidpositioning precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent merges the machining and firing processes into a single sequential workflow. Fully sintered materials are machined by laser ablation and then fired in one continuous process without intermediate positioning. This eliminates cumulative positioning errors from multiple devices while maintaining the specialized functions of both machining and firing

Inventive Principle:
Principle #5Merging (Combining)

5Ease of manufacture

If cutting tools are kept in direct contact with material, then machining can be performed, but machining precision deteriorates due to contact forces

Engineering Contradiction:
ImprovemachinabilityVSAvoidcontact-induced error
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical cutting tools with laser beams for machining fully sintered ceramic materials. The laser beam ablates material through photothermal effects without physical contact, eliminating all contact-induced errors such as tool deflection, material deformation, and vibration. This maintains ease of manufacture through non-contact machining while achieving superior precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 significantly reduces machining time and enhances precision by avoiding material contraction and tool contact, allowing for high-precision fabrication of complex shapes without the need for additional processing steps.

Implementation Method 1

a laser is projected towards a material to machine the material. Projecting a laser towards a material makes machining of these materials possible without any contact

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

in a second machining step, the laser is projected to positions corresponding to cleavage data representing a cleavage site formed inside the material

Methodology Applied
Scientific EffectStress concentration and fracture: Fracture Mechanics

Data Source

PatentEP3536442B1Processing method, processing system, and processing program
Publication Date: 2025.12.10 ROLAND DG CORP
  • EP3536442B1 patent drawingFigure 1
  • EP3536442B1 patent drawingFigure 2
  • EP3536442B1 patent drawingFigure 3A~3B

AI summary

To provide machining methods with which the time required for machining can be shortened and objects can be obtained with high machining precision. A machining method for machining a material using a laser, the method including: a first machining step of forming an object inside the material by projection of the laser; and a second machining step of forming a cleavage site inside the material by projection of the laser towards outside a location in which the object has been formed.