Continuous Laser-Heated Ceramic Kiln Surface Treatment

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Solution Overview

Problem

Conventional ceramic sintering processes face challenges in achieving high surface temperatures without overheating the material, leading to mechanical tensions and cracking, which limits the production of ceramic materials with improved properties.

Innovation Solution

A method involving the use of a laser beam to selectively heat the surface of ceramic materials in a continuous kiln, where the kiln heats the material to a lower temperature than the surface during laser contact, and the laser moves in a pendular fashion to prevent cracking, while a galvanometric system ensures efficient energy distribution and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional kilns heat the ceramic material uniformly to high temperatures, then the material integrity is maintained without cracking, but the surface temperature cannot be increased beyond the bulk material temperature limit

Engineering Contradiction:
Improvesurface temperatureVSAvoidmaterial cracking
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by using laser radiation to heat only the surface layer of the ceramic material to high temperatures (above melting point), while the bulk material remains at lower temperatures (below melting point) through controlled kiln heating. This localized thermal treatment allows surface melting and restructuring without causing bulk material cracking or excessive thermal stress.

Inventive Principle:
Principle #3Local quality

2Strength

If the surface temperature is increased to improve ceramic properties, then material performance is enhanced, but mechanical tensions and cracking occur

Engineering Contradiction:
Improvematerial performanceVSAvoidmaterial stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention achieves improved material performance by locally melting and restructuring only the surface layer through laser heating, while maintaining the bulk material stability at lower temperatures. This creates a gradient structure where the surface has enhanced properties (higher density, improved morphology) without compromising the overall structural integrity of the ceramic piece.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs periodic action through controlled heating and cooling cycles, where the laser provides rapid surface heating followed by controlled cooling. This periodic thermal treatment allows the surface to melt and restructure repeatedly, forming dense, well-organized crystalline structures while the bulk material undergoes minimal thermal cycling, preventing cracking.

Inventive Principle:
Principle #19Periodic action

3Temperature

If conventional heating methods are used to increase surface temperature, then energy consumption increases, but the process remains economically viable

Engineering Contradiction:
Improvesurface temperatureVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent replaces conventional thermal conduction heating with laser radiation heating. The laser provides direct, concentrated energy delivery to the surface, achieving much higher surface temperatures with significantly lower overall energy consumption compared to conventional kiln heating that would require heating the entire bulk material to the same temperatures.

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 approach allows for high-temperature surface treatment without material cracking, enabling the production of ceramic materials with enhanced mechanical and functional properties while reducing energy consumption and CO2 emissions.

Implementation Method 1

the use of a laser beam to selectively heat the surface of ceramic materials

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

laser radiation focused on the piece... can reach very high temperatures (up to 3000°C) on the surface

Methodology Applied
Scientific EffectAbsorption of electromagnetic radiation: Absorption (EM radiation)

Implementation Method 3

Heating a ceramic material in a continuous kiln, at a first heating temperature which is less than the melting point of the material

Methodology Applied
Scientific EffectConventional thermal heating: Conduction (thermal)

Implementation Method 4

cooling the ceramic material, after heating the ceramic material after applying the laser beam

Methodology Applied
Scientific EffectThermal cooling: Cooling

Data Source

PatentEP1992445B1Continuous furnace with coupled laser for the surface treatment of materials
Publication Date: 2019.08.07 CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS (CSIC)
  • EP1992445B1 patent drawingFigure 1
  • EP1992445B1 patent drawingFigure 2
  • EP1992445B1 patent drawingFigure 3

AI summary

A continuous furnace 4 to which a laser is coupled by conventional optical means that allows the surface treatment of a part, with which it is possible to achieve temperatures of up to 3000°C on said surface whilst the remainder of the part is at a substantially lower temperature. The part in the furnace is heated to a temperature of the order of 500°C and, via an opening 5, a laser-beam bundle is applied to the part, scanning a line perpendicular to the direction of movement of the part such that the entire surface is scanned by means of the mechanical advance of the part. This scanning should extend beyond the lateral ends of the part. This type of laser-beam generator must be made compatible with the various colours with which the surface of the part is decorated. The furnace is divided into different zones, with independent temperature controls, for successfully achieving the desired values, both for heating and for cooling. The system that generates laser radiation and its deflector comprises a radiation generation/emission cavity (CO2 laser, around 10.6 mm, or diode or Nd lasers in different varieties thereof) and the emitted-beam-handling system, which may consist of a system of galvanometers or a series of combinations of lenses for successfully shaping the beam and applying it in a manner suited to the type of process, material treated and laser used.