Segmented Muffle Mandrel for Dental Ceramic Pressing

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Solution Overview

Problem

Current methods for producing dental restorations are inefficient and uneconomical, particularly when using lithium disilicate ceramic, and face challenges in producing complex inside corners and achieving uniform temperature gradients, leading to suboptimal surface quality and material waste.

Innovation Solution

A muffle base with a shortened muffle mandrel and interchangeable mandrel attachments allows for customizable processing, ensuring seamless transitions and efficient material pressing, reducing material waste and improving surface quality by allowing the muffle base to be reused and adapted for various manufacturing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional muffle base with a long muffle mandrel is used, then the existing equipment compatibility is maintained, but the material waste increases and surface quality deteriorates

Engineering Contradiction:
Improvesurface qualityVSAvoidmaterial waste
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The muffle mandrel is divided into two separate components: a lower portion that remains fixed in the muffle base and an upper portion that can be removed and replaced. This segmentation allows optimization of the mandrel length for each specific application, reducing material waste and improving surface quality by selecting the appropriate mandrel length for the restoration type being produced.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from a static, fixed-length mandrel to a dynamic configuration where the upper mandrel portion can be attached or detached based on production needs. This dynamic adaptability enables optimal material usage and surface quality control for different restoration types while maintaining compatibility with existing equipment.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the muffle base is designed for single-use, then the manufacturing process is simple, but the production efficiency decreases and costs increase

Engineering Contradiction:
Improveproduction efficiencyVSAvoidmuffle base structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

By segmenting the muffle mandrel into reusable lower and interchangeable upper portions, the system enables multiple production cycles with a single base structure. The lower mandrel portion remains in the reusable muffle base while upper portions can be exchanged, significantly improving production efficiency without requiring complete base replacement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention recovers and reuses the lower mandrel portion and muffle base across multiple production cycles, discarding only the expendable upper portions. This recovery approach transforms a single-use system into a multi-use system, enhancing productivity while controlling the complexity of the base structure through standardized design.

Inventive Principle:
Principle #34Discarding and recovering

3Productivity

If the muffle mandrel length is reduced, then the material pressing efficiency improves, but the temperature gradient uniformity may be affected

Engineering Contradiction:
Improvematerial pressing efficiencyVSAvoidtemperature gradient uniformity
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The segmented mandrel design allows the lower portion to remain short for efficient material pressing while the upper removable portion can be adjusted or extended when needed. This segmentation enables optimization of pressing efficiency without permanently compromising temperature uniformity, as the upper portion can be modified for different thermal requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The interchangeable upper mandrel portions can be designed with different parameters (length, thermal conductivity, geometry) to optimize both pressing efficiency and temperature gradient uniformity for specific restoration types. This parameter variability allows balancing productivity gains with thermal uniformity requirements.

Inventive Principle:
Principle #35Parameter changes

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 enables the production of high-quality dental restorations with reduced material waste and improved surface quality, making the process more economical and easier to control, especially when using lithium disilicate ceramic, while maintaining compatibility with existing equipment.

Implementation Method 1

A press furnace has a press ram that penetrates the press channel and, according to a predetermined press program, the blank(s) are further heated together with the muffle

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

A press furnace has a press ram that penetrates the press channel and, according to a predetermined press program, the blank(s) are further heated together with the muffle, for example to approximately 1,100°C for silicate or feldspar ceramics, or to 1,600°C for oxide ceramics

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 3

To minimize temperature gradients within the muffle, additional heating elements, such as an auxiliary heater in the base, are being used to achieve better temperature uniformity

Methodology Applied
Scientific EffectTemperature gradient: Temperature Gradient

Data Source

PatentEP3064169B1Method of manufacturing dental ceramic workpieces and apparatus for manufacturing dental ceramic workpieces
Publication Date: 2019.04.24 IVOCLAR VIVADENT AG
  • EP3064169B1 patent drawingFigure 1~2
  • EP3064169B1 patent drawingFigure 3~4
  • EP3064169B1 patent drawingFigure 5~6

AI summary

A muffle base (10) for dental technology is provided, with a muffle mandrel (12) as a base for attaching dental restoration preforms (positive models), in particular via pin channels, in a muffle that can be filled with a curable material. The muffle mandrel extends essentially cylindrically and has an end face (14). Connecting elements are attached to or formed in the area of ​​the end face, which detachably support at least one mandrel attachment (40). This mandrel attachment is designed to receive or forms at least one pin channel for the dental restoration preform.