Glass Rod Fabrication Diameter Control via Variable Acquisition
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Solution Overview
Problem
Conventional methods struggle to suppress diameter fluctuations in glass rods with large diameter reduction ratios, as direct measurement at the furnace is challenging, leading to lagged feedback control and unacceptable diameter fluctuations, especially when drawing glass preforms with high diameter reduction ratios.
Innovation Solution
An apparatus and method that control the feed and drawing speeds of a glass preform by setting a constant feed speed and determining the drawing speed based on measured diameter data from a variable diameter acquisition position relative to the furnace, adjusting the distance from the reference position to account for diameter fluctuations, thereby maintaining precise control over the drawing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the diameter is measured at a position close to the heater for feedback control, then the response speed of feedback control is improved, but the measurement is difficult to implement directly
Solution Approach 1:
The patent uses the diameter of the glass preform at a measurable position as an intermediary parameter to control the drawing process. Instead of directly measuring the diameter at the difficult-to-access position near the heater, the system measures the preform diameter at a more accessible location and uses this measurement to calculate and control the drawing speed, thereby achieving feedback control without direct measurement at the problematic position.
2Device complexity
If the diameter acquisition position is fixed relative to the furnace, then the control system is simpler, but diameter fluctuations occur with large diameter reduction ratios
Solution Approach 1:
The patent makes the diameter acquisition position dynamic by defining it relative to the glass preform rather than fixed to the furnace. The acquisition position moves with the preform during the drawing process, ensuring that the measurement always corresponds to the correct reference point regardless of the preform's position in the furnace or the diameter reduction ratio being applied.
3Productivity
If a large diameter reduction ratio is used to draw smaller glass rods, then the productivity is improved, but the diameter fluctuation becomes unacceptable
Solution Approach 1:
The patent implements a feedback control system where the diameter of the glass preform is continuously measured during the drawing process. The measured diameter is used to calculate the appropriate drawing speed, which is then adjusted in real-time to maintain uniform rod diameter. This closed-loop feedback enables high diameter reduction ratios to be used productively while keeping diameter fluctuations within acceptable limits through active control.
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 effectively suppresses diameter fluctuations in glass rods with large diameter reduction ratios, ensuring a stable and precise drawing process even for high reduction ratios, such as 60% to 95%, by dynamically adjusting the drawing reference distance based on preform diameter fluctuations.
Implementation Method 1
heating the preform in the furnace
Data Source
AI summary
The present invention provides an apparatus and a method for fabricating a glass rod from a glass preform capable of suppressing a diameter fluctuation of the drawn glass rod even when there is a relatively large diameter reduction ratio between the glass preform and the glass rod, such as 60 to 95%. The feed speed V1 of the glass preform is set to a constant value, the diameter D of the glass preform is acquired for determining the drawing speed V2 from diameter data of the glass preform measured before being drawn at a diameter acquisition position defined with respect to a reference position of the furnace. The distance from the reference position to the diameter acquisition position is defined so as to vary depending on a diameter fluctuation of the glass preform before being drawn in a longitudinal direction thereof.