Pipe End Planing With Dry Ice Cooling for Weld-Grade Surface Finish
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Solution Overview
Problem
Existing methods for machining the end surfaces of cut-to-length pipes are costly and do not consistently achieve high surface quality, particularly for pipes intended for orbital welding applications.
Innovation Solution
A processing machine with a clamping device and a cooling system using dry ice snow (solid carbon dioxide) to improve surface quality, where the dry ice snow acts as a lubricant and coolant, eliminating the need for additional lubricants and providing effective cooling by avoiding gaseous insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional machining methods are used for pipe end surfaces, then the manufacturing process is simple, but the surface quality and planeness are insufficient for orbital welding applications
Solution Approach 1:
The patent applies parameter changes by introducing cryogenic cooling conditions to the machining process. Liquid nitrogen or liquid carbon dioxide is supplied to the engagement area between the planing tool and pipe end surface, fundamentally changing the thermal parameters of the machining environment. This cryogenic parameter change enables achieving high surface quality (Ra ≤ 0.8 μm) and excellent planeness without requiring overly complex machining equipment, thus resolving the contradiction between manufacturing precision and device complexity.
Solution Approach 2:
The patent uses liquid nitrogen or liquid carbon dioxide as an intermediary substance in the machining process. This intermediary serves multiple functions: it cools the engagement area, reduces thermal deformation of the pipe end surface, improves surface quality, and acts as a lubricant. By introducing this intermediary, the patent achieves high manufacturing precision without proportionally increasing device complexity, as the same fluid provides multiple beneficial effects simultaneously.
2Manufacturing precision
If additional lubricants are supplied during machining, then surface quality improves, but environmental pollution and health hazards increase
Solution Approach 1:
The patent converts the typically harmful effect of extreme cold into a beneficial factor. Liquid nitrogen or liquid carbon dioxide, which are extremely cold substances, are used to cool the machining area. This cryogenic cooling reduces thermal deformation, improves surface quality, and simultaneously eliminates the need for harmful lubricants. The harmful effect of extreme cold is transformed into a benefit that achieves both high surface quality and environmental friendliness.
Solution Approach 2:
The patent makes the cooling fluid serve multiple functions simultaneously. The liquid nitrogen or liquid carbon dioxide not only cools the engagement area but also acts as a lubricant, reducing friction and wear between the planing tool and pipe end surface. This self-service approach eliminates the need for separate lubricant supply systems and harmful chemical lubricants, achieving both high surface quality and pollution reduction with a single substance.
3Temperature
If liquid carbon dioxide is expanded directly without proper nozzle design, then gaseous insulation occurs reducing cooling effectiveness, but proper nozzle design complexity increases
Solution Approach 1:
The patent utilizes phase transitions of carbon dioxide to achieve effective cooling. The nozzle is designed to expand liquid carbon dioxide into solid dry ice particles rather than directly into gas. This controlled phase transition from liquid to solid prevents the formation of gaseous insulation layers, maintains effective thermal contact with the machining area, and provides superior cooling effectiveness. The phase transition mechanism is integrated into the nozzle design, achieving both effective cooling and practical device complexity.
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
The machine achieves improved surface quality and reduced costs by using dry ice snow for cooling and lubrication, ensuring precise machining and efficient processing of pipe end surfaces.
Implementation Method 1
the cooling of the engagement area between the tool and the workpiece, i.e., the pipe, with dry ice snow (solid carbon dioxide (CO2))
Implementation Method 2
the cooling of the engagement area between the tool and the workpiece, i.e., the pipe, with dry ice snow (solid carbon dioxide (CO2)) also brings about a lubrication that results in an optimized surface quality
Implementation Method 3
an insulation due to gaseous carbon dioxide (Leidenfrost effect) between the pipe to be cooled and the liquid carbon dioxide is avoided
Data Source
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AI summary
The present invention relates to a processing machine (1) and to a method for planing an end surface (13) of a pipe (14). The known methods for machining the end surfaces of a pipe therefore prove to be disadvantageous since they make the required surface quality available only with great expense. The present invention therefore has the problem of making a processing machine and a method available that make it possible to process the end surface of a finished pipe with improved quality. To this end the invention suggests a processing machine (1) for planing an end surface (13) of a pipe (14) with a clamping device (2) for the pipe to be processed, with a tool holder (3) with a planing tool (4), whereby the tool holder (3) is driven by a motor and can rotate about an axis of rotation (6), whereby the clamping device (2) and the tool holder are driven by a motor and can move toward one another in a direction parallel to the axis of rotation (6) of the tool holder, and whereby the processing machine (1) comprises a cooling device that is arranged in such a manner that it cools the pipe (14) to be processed and/or the planing tool (4) with the aid of liquid and/or solid carbon dioxide during the operation of the device.