Segmented Dental Firing Table with Harder Support Rods

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Solution Overview

Problem

Firing tables used in kilns for dental ceramics are prone to destruction due to high temperature gradients and shrinkage, exacerbated by the weight of kiln furniture and materials being fired, leading to frequent tearing and reduced mechanical stability.

Innovation Solution

A firing table constructed from multiple parts with support rods made of harder materials, such as densely sintered aluminum oxide, embedded in softer material to absorb weight and reduce temperature stresses, allowing for different mechanical properties and thermal expansion/shrinkage in each part, and featuring a shoulder for improved insulation and thermal decoupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the firing table is made from a single piece of high-temperature-resistant material, then it provides good thermal stability, but it is prone to destruction due to high temperature gradients and shrinkage

Engineering Contradiction:
Improvethermal stabilityVSAvoidresistance to destruction
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The firing table is divided into multiple parts (first part and second part) that can be manufactured separately and assembled together. This segmentation allows each part to be optimized for its specific temperature conditions, reducing overall thermal stress and preventing destruction while maintaining thermal stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the firing table are made from materials with different properties adapted to their specific ambient temperatures. The first part uses material adapted to higher temperatures while the second part uses material adapted to lower temperatures, optimizing both thermal stability and resistance to destruction in each region.

Inventive Principle:
Principle #3Local quality

2Temperature

If the firing table is made from softer high-temperature-resistant material, then it provides good thermal resistance, but it lacks mechanical stability and is prone to tearing

Engineering Contradiction:
Improvethermal resistanceVSAvoidmechanical stability
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The firing table uses composite construction combining softer high-temperature-resistant material (porous aluminum oxide) with harder material (densely sintered aluminum oxide or calcium oxide) in specific regions. This composite approach provides both thermal resistance and mechanical stability where needed.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Harder material inserts are provided in specific regions (such as the underside) where mechanical strength is most needed, while the surrounding softer material provides thermal resistance. This localized application of different material properties optimizes both thermal and mechanical performance.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the firing table is made as a single piece, then it is simple to manufacture, but temperature stresses cause frequent tearing

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidresistance to tearing
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The firing table is segmented into multiple parts that can be manufactured separately using standard processes and then assembled together. This segmentation reduces temperature stresses and prevents tearing while maintaining reasonable manufacturing complexity through standardized connection methods.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design incorporates connection elements and structural features that preemptively accommodate and cushion thermal stresses before they can cause tearing. The segmented structure with proper connection methods provides built-in stress relief mechanisms.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Productivity

If heavier kiln furniture and materials are placed on the firing table, then more material can be fired simultaneously, but the firing table shrinks due to the weight

Engineering Contradiction:
Improvefiring capacityVSAvoiddimensional stability
Core Design Contradiction:
ProductivityVSShape

Solution Approach 1:

The firing table is divided into multiple parts with independent support structures. This segmentation allows the table to better accommodate heavy kiln furniture and materials without excessive shrinkage, as each part can independently support the load and maintain its shape.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The use of harder material inserts and composite construction provides additional structural support to counteract the shrinkage caused by heavy loads. The harder material regions provide rigidity that prevents dimensional changes under heavy weights.

Inventive Principle:
Principle #40Composite materials

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 solution enhances the durability and stability of the firing table by distributing weight and temperature stresses, reducing tearing, and providing effective insulation and thermal decoupling, thereby protecting the softer material from destruction and maintaining structural integrity under high temperatures.

Implementation Method 1

The support rods are advantageously used to support kiln furniture, so that the weight of the kiln furniture and the weight of the material to be burned on the kiln furniture is absorbed by the rods made of harder material

Methodology Applied
Scientific EffectWeight absorption:

Implementation Method 2

the individual parts are smaller than a one-piece firing table. This gives them the opportunity, independently of one another, to expand or shrink depending on the temperature

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

the individual parts are smaller than a one-piece firing table. This gives them the opportunity, independently of one another, to expand or shrink depending on the temperature

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 4

the firing table preferably has a shoulder which rests against an insulation of the furnace when the furnace is closed. This achieves a particularly good insulation of the interior of the furnace

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 5

The height of the ring is preferably greater than the height of the shoulder so that there is clearance between the top of the ring and the firing table. This results in a thermal decoupling between the top of the ring and the firing table

Methodology Applied
Scientific EffectThermal decoupling: Thermal Insulation

Data Source

PatentEP2240117B1Combustion table for an oven
Publication Date: 2012.08.08 DEKEMA DENTAL KERAMIKOFEN GMBH
  • EP2240117B1 patent drawingFigure 1
  • EP2240117B1 patent drawingFigure 2
  • EP2240117B1 patent drawingFigure 3

AI summary

The invention relates to a combustion table for an oven for dental ceramics made of solid, highly temperature-resistant material, having a base, a top side, and a wall, wherein the combustion table is formed of at least two parts in order to improve the temperature resistance of the combustion table.