Thermal Deposition Coating Temperature Control via Cryogenic Feedback
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Solution Overview
Problem
Thermal deposition coating processes face challenges with improper temperature control leading to overheating, thermal degradation, and stress due to mismatched thermal contraction coefficients, and existing cooling methods are insufficient or detrimental to coating quality.
Innovation Solution
A process using cryogenic coolants to control temperature by simultaneously measuring temperatures at multiple locations, calculating an average temperature, and adjusting deposition rate, coolant flow, and relative speed to maintain optimal temperature ranges, while also managing standard deviations to ensure uniformity and minimize stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cryogenic cooling methods are used to remove heat fast, then heat removal capability is enhanced, but temperature control difficulty increases and thermal uniformity becomes harder to maintain
Solution Approach 1:
The patent implements a feedback control system that continuously monitors temperature at multiple locations on the workpiece and automatically adjusts coolant flow rates and deposition parameters. This closed-loop control enables the system to respond to temperature variations in real-time, maintaining thermal uniformity despite the aggressive heat removal capability of cryogenic cooling.
Solution Approach 2:
The patent divides the cooling system into multiple independent coolant delivery zones with individually controllable flow rates. By segmenting the cooling application, the system can target specific hot spots or areas requiring different cooling intensities, thereby maintaining thermal uniformity across the workpiece surface while utilizing cryogenic cooling's high heat removal capability.
2Temperature
If breaks are introduced in the process cycle for heat dissipation, then heat buildup is reduced, but process productivity decreases
Solution Approach 1:
The patent implements continuous cooling during the entire thermal deposition process rather than introducing periodic breaks. Cryogenic coolant is applied continuously at controlled flow rates, allowing heat dissipation to occur concurrently with coating deposition. This eliminates idle time and maintains continuous productivity while effectively controlling heat buildup through sustained cooling.
Solution Approach 2:
The patent changes the cooling parameter from intermittent (periodic breaks) to continuous with variable flow rates. By continuously adjusting coolant flow rates based on real-time temperature feedback, the system maintains effective heat dissipation throughout the deposition process without requiring process interruptions, thereby preserving productivity.
3Productivity
If cooling air jets are used to offset productivity loss, then process continuity is maintained, but coating quality deteriorates due to oxygen and moisture
Solution Approach 1:
The patent replaces air-based cooling with inert cryogenic gases (such as nitrogen or argon) as the cooling medium. These inert gases provide the necessary cooling effect while preventing oxidation and contamination of the coating. The cryogenic inert gas coolant thus maintains both process continuity and coating quality by eliminating the harmful effects of oxygen and moisture present in air.
Solution Approach 2:
The patent introduces cryogenic inert gas as an intermediary substance that performs the cooling function without introducing contaminants. Unlike air cooling where oxygen and moisture directly contact the coating surface, the inert cryogenic gas acts as a clean intermediary medium that transfers heat away from the workpiece while protecting the coating from atmospheric contamination.
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 enables the production of well-adhering, uniform coatings with minimized thermal stress, maintaining optimal temperatures and improving coating quality and production rates.
Implementation Method 1
Heat removal from the workpiece during thermal deposition coating is critical and one of the most popular ways of practicing heat removal during the thermal deposition coating operation is to introduce breaks in the process cycle so that the accumulated heat is dissipated to the surroundings
Implementation Method 2
Thermal deposition coating operations deposit a preheated and/or molten coating material onto the surface of a substrate
Implementation Method 3
simultaneously measuring temperatures at multiple locations
Data Source
AI summary
A process for the thermal deposition coating of a workpiece is provided that comprises the steps of:thermally depositing a coating on a metallic surface of a workpiece from a deposition head wherein at least one condition selected from the group of: coating deposition rate onto said surface, relative motion between the surface and said deposition head, and cryogenic coolant application rate onto said workpiece is controllable;substantially simultaneously measuring temperatures at a plurality of locations over the metallic surface of the workpiece;determining an average temperature of the temperatures measured in step (b);comparing the average temperature to a preselected minimum temperature and a preselected maximum temperature for the workpiece; andadjusting at least one of the controllable conditions if said average temperature is not between the preselected minimum temperature and the preselected maximum temperature for the workpiece.