Conical Tube Blank Expansion Using a Preheated Single Mandrel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for expanding cylindrical tube blanks into conical shapes are complex and require multiple steps, including reheating and cooling, and often involve interactions between multiple elements, which can lead to cracking and inefficiencies.
Innovation Solution
A method and apparatus using a single mandrel to expand tube blanks by preheating, pressing, and then pulling out the mandrel while optionally using compressed air or mechanical stripping, eliminating the need for additional elements and simplifying the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple steps including reheating and cooling are used to expand tube blanks, then the expansion process can be completed, but the process complexity increases and the risk of cracking occurs
Solution Approach 1:
The mandrel is preheated to a target temperature before insertion into the tube blank. This preliminary heating action ensures that the mandrel transfers sufficient heat to the tube blank during the expansion process, eliminating the need for subsequent reheating steps and reducing overall process complexity while maintaining reliability
Solution Approach 2:
The heating and expansion operations are merged into a single integrated process. The preheated mandrel performs both the heating function (by transferring heat to the tube blank) and the forming function (by mechanically expanding the tube) simultaneously, thereby reducing the number of separate process steps and equipment requirements
2Device complexity
If a single mandrel is used for expansion, then the device complexity is reduced, but the mandrel must perform multiple functions including heating and forming
Solution Approach 1:
The mandrel is designed as a multi-functional tool that simultaneously performs heating (through preheating and heat transfer during insertion), forming (through mechanical expansion), and potentially cooling (through material properties or design features). This universal design reduces the number of separate components needed while maintaining all necessary functions
Solution Approach 2:
The mandrel's temperature parameter is changed and controlled to achieve different functions at different stages. By adjusting the mandrel's temperature (preheated to target temperature), it can transfer heat to the tube blank for heating, then maintain structural integrity for forming, and potentially facilitate cooling or stripping, thereby achieving multiple functions through parameter variation
3Ease of operation
If the mandrel remains in the expanded tube blank, then the tube blank can be held in position, but removal becomes difficult without additional steps
Solution Approach 1:
Compressed air is introduced through the mandrel to create an air cushion or pressure differential between the mandrel surface and the tube blank interior. This pneumatic action reduces friction and adhesion forces, allowing the tube blank to be easily stripped or pushed off the mandrel without additional mechanical removal steps, thereby maintaining holding stability during expansion while simplifying removal
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
Simplifies the production of conical tube blanks by reducing the number of steps and minimizing the risk of cracking, while allowing for efficient expansion and easy removal from the mandrel.
Implementation Method 1
a first mandrel preheated to a first target temperature is inserted into the initial tube blank... the first mandrel is pressed into the interior of the initial tube blank to a predetermined depth and held in the pressed-in position for a predetermined heating period, so that at least part of the tube blank is expanded
Implementation Method 2
when the first mandrel is pulled out of the expanded tube blank, either compressed air is blown into the interior of the conical tube blank through the first mandrel provided with at least one corresponding first air channel
Data Source
AI summary
SUMMARYThe invention relates to a method and a device for expanding at least a section of an initial tube blank (2) made of plastic or metal in such a way that an expanded tube blank (1) is obtained which tapers in the direction of an end of the tube blank that is not affected by the expansion process. The initial tube blank is fixed in a holding device (4) in a first position (6a), a first mandrel (3) is inserted into the initial tube blank, pressed therein and held in the pressed-in position for a predetermined heating time period, so that at least a part of the tube blank is expanded, and finally the first mandrel is pulled out of the expanded tube blank (1), wherein, when the first mandrel is pulled out of the tube blank, either compressed air is blown into the interior of the expanded tube blank through the first mandrel provided with at least one corresponding first air channel (5), or the expanded tube blank is mechanically stripped off.