Heat Exchanger Header Orifice Cutting After Additive Manufacturing
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Solution Overview
Problem
Additive manufacturing faces limitations in accurately forming certain structures, particularly in micro-channel heat exchangers, due to challenges in precisely creating orifices that communicate between headers and heat transfer tubes.
Innovation Solution
A method involving additive manufacturing to form an inlet and outlet header with heat transfer tubes, followed by precise cutting techniques such as laser drilling, water jet, electro-discharge machining, or mechanical machining to create orifices, and using bosses to fill and close access holes, ensuring accurate orifice sizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If additive manufacturing is used to form heat exchanger structures, then manufacturing flexibility and integration are improved, but manufacturing precision of orifices deteriorates
Solution Approach 1:
The manufacturing process is divided into two distinct stages: first, additive manufacturing is used to create the header with initial access holes; second, traditional precision machining methods (laser drilling, water jet, electro-discharge machining, or mechanical machining) are used to create the final precise orifices. This segmentation allows each method to be used for what it does best.
Solution Approach 2:
The additive manufacturing process creates preliminary access holes in the header that serve as starting points for subsequent precision machining. These preliminary holes enable the later precision operations to be performed more easily and accurately, combining the advantages of both manufacturing approaches.
2Ease of operation
If access holes are cut through the inlet header wall to form orifices, then communication between headers and heat transfer tubes is enabled, but orifice size control deteriorates
Solution Approach 1:
Bosses are introduced as intermediary structures that protrude into the heat transfer tubes from the header walls. These bosses serve dual purposes: they provide a foundation for precision orifice machining and they act as flow control elements that regulate fluid passage through the orifices, enabling both ease of formation and precise size control.
Solution Approach 2:
The patent employs various advanced machining technologies (laser drilling, water jet cutting, electro-discharge machining) to replace traditional mechanical drilling methods. These substitution methods provide superior orifice size control and precision while maintaining ease of operation.
3Device complexity
If additive manufacturing forms the complete heat exchanger, then manufacturing integration is improved, but reliability of micro-channel structures deteriorates
Solution Approach 1:
The heat exchanger manufacturing is segmented into two parts: the header and support structures are additively manufactured for integration benefits, while the critical orifices are created using precision traditional machining methods to ensure reliability. This hybrid approach maintains manufacturing integration while improving micro-channel structure reliability.
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 the formation of heat exchangers with controlled pressure drops and uniform fluid flow by maintaining precise orifice sizes, addressing the limitations of additive manufacturing in micro-channel designs.
Implementation Method 1
the cutting step is provided by laser drilling
Implementation Method 2
the cutting is performed by a water jet
Implementation Method 3
the cutting is provided by electro-discharge machining
Implementation Method 4
the access holes are closed using welding
Data Source
AI summary
A method of forming a heat exchanger includes the steps of forming an inlet header having a hollow interior formed by a wall, forming heat transfer tubes of a diameter smaller than a diameter of the inlet header and extending away from the inner wall of the inlet header, the heat transfer tubes having a hollow interior, with the hollow interior of the inlet header being blocked from communication with the hollow interior of the heat transfer tubes, forming an outlet header having a hollow interior formed by a wall, the outlet header formed at an opposed end of the inlet header, and the hollow interior of the outlet header being in communication with the hollow interior of the heat transfer tubes, cutting access opening through the wall of the inlet header at a location opposed to the heat transfer tubes, and cutting through an opposed side of the wall of the inlet header to form orifices to communicate the interior of the inlet header to the interior of the heat transfer tubes, then closing the access openings. A heat exchanger arrangement is also disclosed.