Fusing Glass Articles via Vacuum Cavity Welding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large size optics mirrors require sealing of multiple glass pieces, which often results in unbounded regions and gas bubbles due to the sealing process, typically requiring temperatures above 1700°C.
Innovation Solution
A method involving positioning glass blocks to define an interface seam, welding them to create an internal cavity, coupling a vacuum fitting, drawing a vacuum, and heating to fuse the glass blocks together, minimizing gas trapped between the blocks and reducing the need for high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple glass pieces are sealed together at high temperatures (>1700°C) to create large size optics, then the size requirement is met, but gas bubbles and unbounded regions form at the seal plane
Solution Approach 1:
The glass blocks are positioned and welded together at lower temperatures before the final high-temperature fusing step. This preliminary assembly allows the cavity to be sealed while minimizing gas entrapment, and subsequent high-temperature treatment completes the fusion without introducing additional defects
Solution Approach 2:
A cavity is intentionally created and sealed within the seal plane during the welding process. This extracted cavity allows for vacuum application to remove gas bubbles before final fusing, preventing gas entrapment that would otherwise occur in traditional direct sealing methods
2Area of stationary object
If traditional sealing processes are used to join multiple glass pieces, then large size optics can be manufactured, but temperatures greater than 1700°C are required
Solution Approach 1:
The fusing process is divided into multiple stages: initial welding at lower temperatures to form the cavity structure, vacuum application to remove gases, and gradual heating to final fusing temperature. This segmented approach avoids the need for immediate high-temperature processing that causes thermal stress and distortion
Solution Approach 2:
The processing temperature is progressively changed from lower temperatures during initial welding and vacuum application to higher temperatures for final fusing. This parameter change over time allows cavity formation and gas removal before complete fusion, reducing the peak temperature requirement compared to traditional single-step sealing
3Area of stationary object
If multiple glass pieces are sealed together to form large optics, then size requirements are met, but unbounded regions and inclusions are created at the seal plane
Solution Approach 1:
A vacuum environment is created within the sealed cavity before final fusing. This inert environment prevents gas entrapment and oxidation, eliminating the formation of bubbles and unbounded regions that would otherwise be generated during the high-temperature fusing process
Solution Approach 2:
The cavity is sealed and vacuum is applied before complete fusing occurs. This preliminary action removes harmful gases and prevents inclusion formation, and only after this preparation is the final high-temperature fusing applied to complete the bonding without generating defects
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 method reduces defects like gas bubbles and unbounded regions, allowing for efficient fusion of glass blocks at lower temperatures, minimizing distortion and equipment costs, while maintaining a high-quality seal.
Implementation Method 1
drawing a vacuum in the cavity between the first and second glass blocks
Implementation Method 2
heating the first and second glass blocks to fuse the first and second glass blocks together
Data Source
AI summary
A method of forming a glass article is provided. The method includes the steps of positioning a first interface surface of a first glass block proximate a second interface surface of a second glass block to define an interface seam, welding the first and second glass blocks together around a majority of the interface seam to define an internal cavity, coupling a vacuum fitting to at least one of the first and second glass blocks, drawing a vacuum in the cavity between the first and second glass blocks, and heating the first and second glass blocks to fuse the first and second glass blocks together.