Glass-Forming Mandrel with Diffusion Layer

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Solution Overview

Problem

The challenge in hot forming of glass products, particularly for pharmaceutical packaging, is the introduction of tungsten impurities from forming mandrels, leading to contamination and a short service life due to material removal and mechanical stress, which affects the geometry and purity of the glass products.

Innovation Solution

A forming mandrel with a diffusion layer, using high-heat-resistant materials like tungsten or its alloys as the core material and applying a diffusion layer with materials like silicon or aluminum to prevent material removal and contamination, ensuring a stable and clean glass product formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a mandrel made of tungsten or tungsten alloys is used for hot forming glass products, then the thermomechanical strength and resistance to glass evaporation products are improved, but tungsten-containing impurities are introduced into the glass product and material loss occurs on the mandrel

Engineering Contradiction:
Improvethermomechanical strengthVSAvoidtungsten-containing impurities
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The mandrel is segmented into two distinct material zones: a core material (tungsten or tungsten alloy) providing thermomechanical strength, and an outer shell material (platinum group metal or ceramic) preventing impurity introduction. This segmentation allows each material to perform its specialized function without the drawbacks of using a single material throughout.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mandrel is constructed as a composite material structure combining core material and shell material with different properties. The core provides high-temperature strength while the shell provides chemical inertness and prevents tungsten contamination, creating a composite system that delivers both mechanical performance and purity.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a mandrel made of tungsten or tungsten alloys is used for hot forming glass products, then the resistance to glass evaporation products is improved, but material loss occurs on the mandrel leading to shortened service life

Engineering Contradiction:
Improveresistance to glass evaporation productsVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The mandrel is segmented into two distinct material zones: a core material (tungsten or tungsten alloy) providing thermomechanical strength, and an outer shell material (platinum group metal or ceramic) preventing impurity introduction. This segmentation allows each material to perform its specialized function without the drawbacks of using a single material throughout.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mandrel is constructed as a composite material structure combining core material and shell material with different properties. The core provides high-temperature strength while the shell provides chemical inertness and prevents tungsten contamination, creating a composite system that delivers both mechanical performance and purity.

Inventive Principle:
Principle #40Composite materials

3Object-generated harmful factors

If a coating layer is applied on the mandrel to prevent tungsten-containing impurities, then the introduction of impurities is reduced, but the coating layer cracks or flakes under high mechanical stress reducing service life

Engineering Contradiction:
Improvetungsten-containing impuritiesVSAvoidservice life
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The mandrel is segmented into two distinct material zones: a core material (tungsten or tungsten alloy) providing thermomechanical strength, and an outer shell material (platinum group metal or ceramic) preventing impurity introduction. This segmentation allows each material to perform its specialized function without the drawbacks of using a single material throughout.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mandrel is constructed as a composite material structure combining core material and shell material with different properties. The core provides high-temperature strength while the shell provides chemical inertness and prevents tungsten contamination, creating a composite system that delivers both mechanical performance and purity.

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 diffusion layer significantly reduces tungsten contamination and extends the service life of the mandrel by minimizing material loss and corrosion, maintaining high-quality glass product dimensions and purity, especially in the interior of hollow glass products like syringes.

Implementation Method 1

a diffusion layer, using high-heat-resistant materials like tungsten or its alloys as the core material and applying a diffusion layer with materials like silicon or aluminum to prevent material removal and contamination

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3121154B1Glass-forming mandrel with a diffusion layer
Publication Date: 2020.05.06 SCHOTT AG
  • EP3121154B1 patent drawingFigure 1
  • EP3121154B1 patent drawingFigure 2
  • EP3121154B1 patent drawingFigure 3A~3D

AI summary

The invention relates generally to the manufacture of glass products. In particular, the invention relates to a forming tool comprising a mandrel, a method, and an apparatus for the hot forming of glass. The glass products obtained in this way can be used, for example, as pharmaceutical packaging. The mandrel for forming at least a section of a heated area of ​​the glass pre-product comprises a temperature-stable core material and a diffusion layer, which is in contact with the glass pre-product during the forming process.