Single-Crystal Ingot Pulling Control for Stable Diameter Transition
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Solution Overview
Problem
Existing single crystal ingot growth control devices face challenges in accurately controlling the diameter of ingots during the transition from the shouldering process to the body process, leading to diameter errors and quality deterioration due to rapid growth tendencies and excessive temperature corrections.
Innovation Solution
A single crystal ingot growth control device that performs real-time integral calculation of diameter errors, adjusting the pulling speed stepwise and incorporating temperature corrections using PID calculations to maintain target diameters and prevent excessive corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pulling speed is rapidly increased to decrease diameter error, then the diameter control responsiveness is improved, but the diameter overshoots and becomes smaller than target
Solution Approach 1:
The control device performs preliminary action by predicting future diameter trends based on current growth rate and acceleration before the diameter error becomes significant. This allows the system to prepare appropriate pulling speed adjustments in advance, preventing both overshoot and excessive correction.
Solution Approach 2:
The control method dynamically adjusts the pulling speed based on real-time diameter growth rate and acceleration. Instead of using fixed control parameters, the system continuously adapts the pulling speed adjustment magnitude according to the current growth state, enabling precise control during rapid diameter changes.
2Stability of the object's composition
If the pulling speed is strongly controlled to maintain target diameter, then the diameter stability is improved, but the temperature fluctuates excessively
Solution Approach 1:
The system predicts temperature trends based on current temperature and heating power before excessive fluctuations occur. This preliminary prediction allows the control device to adjust heating power proactively, maintaining temperature stability without requiring strong pulling speed control that would cause excessive temperature variations.
Solution Approach 2:
The control method implements dual feedback loops: one for diameter control and another for temperature control. The temperature feedback mechanism independently adjusts heating power based on temperature deviations, decoupling temperature control from pulling speed control and preventing excessive temperature fluctuations during diameter stabilization.
3Speed
If the control responds rapidly to diameter changes, then the diameter error correction speed is improved, but the control becomes excessive and unstable
Solution Approach 1:
The control device performs preliminary action by predicting future diameter values based on current growth rate and acceleration. This prediction allows the system to determine the optimal timing and magnitude of pulling speed adjustments before diameter errors become significant, achieving rapid yet stable correction.
Solution Approach 2:
The method implements predictive feedback by continuously monitoring diameter growth rate and acceleration, and using this information to anticipate future diameter deviations. This predictive feedback mechanism enables the control system to respond rapidly while maintaining stability by adjusting pulling speed based on predicted rather than just current error states.
Data Source
AI summary
A single crystal ingot growth control device includes: an input unit that receives a diameter error that is a difference value between a measured diameter of the ingot and a target diameter; a calculation unit that performs integral calculation on the diameter error received by the input unit in real time and calculates a final pulling speed for each set time that is increased stepwise by reflecting the diameter error integral value, and an output unit that outputs the final pulling speed calculated by the calculation unit to a pulling controller during the set time.