Axial Cryogenic Spindle Cooling for Aerospace Tool Changers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Machining of advanced aerospace materials with low thermal conductivity, such as ceramic matrix composites, is challenging due to heat dispersion issues at the tool-chip interface, leading to high costs and slow production times, and existing cooling systems are not compatible with commercial tool changers.
Innovation Solution
A cryogenic cutting fluid delivery system that uses a rotary coupling to convey cryogens like liquid nitrogen along an axial path to the tool-chip interface through a standard spindle, ensuring compatibility with automatic tool changers and enhancing machining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional cooling systems are used, then heat dissipation at the tool-chip interface is limited, but the system is incompatible with commercial tool changers and requires complex fluid delivery mechanisms
Solution Approach 1:
Instead of delivering cooling fluid through the tool holder from the spindle, the invention reverses the delivery path by injecting cryogenic fluid axially through the spindle itself. This inversion allows the fluid to reach the tool-chip interface directly through the spindle's internal passage, achieving both effective cooling and compatibility with standard tool holders that remain unchanged.
Solution Approach 2:
The invention extracts the cooling function from the tool holder system and relocates it to the spindle. By providing cooling through the spindle's internal passage rather than through the tool holder, the system separates the cooling delivery mechanism from the tool changing interface, allowing standard tool holders to be used without modification while still achieving effective cooling.
2Temperature
If cryogenic fluid is delivered axially through the spindle, then cooling effectiveness at the tool-chip interface is improved, but the spindle structure becomes more complex
Solution Approach 1:
The spindle is designed to serve multiple functions: it provides rotational drive to the tool holder and simultaneously acts as a cryogenic fluid delivery conduit. By integrating the cooling function into the existing spindle structure rather than adding separate cooling mechanisms, the invention achieves effective cooling while minimizing additional structural complexity.
3Object-affected harmful factors
If conventional cutting fluids are used, then cooling is provided, but environmental pollution increases and machining costs rise
Solution Approach 1:
The invention changes the physical state and temperature parameters of the cooling medium by using cryogenic fluids (liquid nitrogen or liquid helium) at extremely low temperatures. This parameter change enables effective cooling of the tool-chip interface while eliminating the environmental pollution associated with conventional cutting fluids, as cryogenic fluids evaporate into inert gases.
Solution Approach 2:
By using inert cryogenic fluids like liquid nitrogen, the invention creates an inert atmosphere at the tool-chip interface that provides effective cooling without the environmental and health hazards of conventional cutting fluids. The inert nature of these fluids eliminates pollution while maintaining superior cooling performance.
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
Enables high-speed machining of hard, low thermal conductivity materials and reduces environmental impact by eliminating the need for conventional cutting fluids, improving tool life and production efficiency.
Implementation Method 1
a small diameter vacuum insulated delivery tube 26 that has an upper portion that is surrounded by a larger diameter vacuum insulated section 27
Implementation Method 2
a cryogen such as liquid nitrogen (LN 2) to be conveyed to the tool-chip interface during machining operations
Implementation Method 3
By more effectively cooling the tool-chip interface, machining speeds and tool life can be increased
Data Source
Figure 1~7
Figure 2~3
Figure 4~5
AI summary
Cryogenic fluids are delivered along an axial path through a machine tool spindle to a cutting tool that is mounted in a standard tool holder. An external source of cryogen is delivered via an insulated line to a junction block housing where the cryogen flows into a vacuum insulated coolant delivery tube mounted on the axis of rotation of the spindle. The coolant delivery tube couples with a cryogenic manifold located in a standard tool holder in the end of the spindle. The cryogenic manifold couples the cryogen to a tool that is mounted in the tool holder. Before a tool change operation, the coolant delivery tube is raised to disconnect it from the cryogenic manifold, and to turn off the flow of cryogen to the delivery tube.