Synthetic Quartz Glass Blank Centering During Vitrification
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Solution Overview
Problem
Existing methods for producing synthetic quartz glass blanks often result in unforeseeable bubble inclusions or dislocations during the shaping process, leading to fusion defects that impair the quality of the final product, particularly in hollow-cylindrical shapes, and fail to maintain rotation-symmetrical property profiles.
Innovation Solution
A method involving the vitrification and shaping of full cylindrical SiO2 soot bodies in a joint furnace system, where the vitrified quartz glass body is centered on a bottom plate with a trough-like recess and guided by a holding device, ensuring controlled shaping without intermediate cooling, to maintain homogeneous rotation-symmetrical profiles and prevent tilting or displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the vitrified quartz glass body is shaped by softening in the melt mold directly after vitrification without intermediate cooling, then the production efficiency is improved and the risk of fusion defects is reduced, but the control of shaping precision and prevention of tilting or displacement becomes more difficult
Solution Approach 1:
A holding device acts as an intermediary between the vitrified quartz glass body and the melt mold during the shaping process. This holding device centers and secures the glass body, preventing tilting or displacement while allowing controlled softening and shaping. The holding device is removed after shaping completes, having served its mediating function during the critical transition from vitrification to shaping.
Solution Approach 2:
The melt mold is designed with a bottom plate that provides uniform support and centering for the vitrified quartz glass body. By creating an equipotential support surface, the system ensures uniform heat distribution and prevents localized stress concentrations that could cause tilting or displacement during the softening process.
2Manufacturing precision
If a holding device is used to center and guide the vitrified quartz glass body during shaping, then the manufacturing precision and prevention of defects are improved, but the device complexity increases
Solution Approach 1:
The holding device is designed as a temporary, removable component that is extracted from the system after completing its centering function. This allows the complex centering mechanism to be separated from the final product and the main processing system, reducing overall system complexity while maintaining precision during the critical shaping phase.
Solution Approach 2:
The holding device is designed to automatically center and position the vitrified quartz glass body through its geometric configuration and interaction with the melt mold, rather than requiring complex active control systems. The device self-adjusts to provide precise centering through passive mechanical means.
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 produces high-quality, bubble-free, and striae-free synthetic quartz glass blanks with reproducible rotation-symmetrical property profiles, minimizing the risk of fusion defects and maintaining the purity and homogeneity required for optical and semiconductor applications.
Implementation Method 1
vitrifying the SiO2 soot body in the heating zone at a vitrification temperature so as to form a full cylindrical, completely vitrified, transparent quartz glass body
Implementation Method 2
shaping the vitrified quartz glass body by softening in the melt mold so as to form a viscous quartz glass mass
Data Source
AI summary
One aspect relates to a method for producing an optical blank from synthetic quartz glass by vitrifying and shaping a porous, cylindrical SiO2 soot body having a longitudinal axis, in a heating zone including a melt mold with bottom plate. The SiO2 soot body vitrified in the heating zone at a vitrification temperature so as to form a full cylindrical, completely vitrified, transparent quartz glass body. Subsequently, the vitrified quartz glass body is shaped by softening in the melt mold at a softening temperature so as to form a viscous quartz glass mass which partly fills the volume of the melt mold, and cooling the quartz glass mass and removal from the melt mold so as to form the optical blank. During shaping in the melt mold, the full cylindrical quartz glass body is brought into contact by way of controlled supply with a centering means of the bottom plate.