Pipe Hydroforming Control for Accurate Flange Shaping
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Solution Overview
Problem
Molding a metal pipe with a flange often results in quality issues such as slack or twist due to the limited volume of the flange molding cavity, leading to suboptimal deformation of the metal pipe material.
Innovation Solution
A molding apparatus with paired molds, a servomotor-driven slide, and a control system that adjusts gas supply and slide movement speed to precisely shape and deform the metal pipe, allowing for controlled expansion and crushing of the pipe material to form a flange, with increased movement at later stages to prevent cracking and improve formability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a metal pipe is expanded and molded by supplying gas into the heated metal pipe material held between upper and lower molds, then the metal pipe material can be molded into the desired shape, but a flange portion cannot be properly formed without causing slack or twist
Solution Approach 1:
The molding process is divided into two distinct stages: first, the metal pipe material is expanded into the mold cavity by gas pressure to form the basic shape; second, the flange portion is separately formed by pressing the expanded material against the mold surface. This segmentation allows each stage to be optimized independently, preventing defects in the flange portion.
Solution Approach 2:
The metal pipe material is first expanded into the mold cavity to create a preliminary shape that fills the cavity. This preliminary expansion prepares the material in a state that is ready for the subsequent flange forming operation, ensuring the material is properly positioned and shaped before the final pressing action.
2Shape
If the metal pipe material is crushed to form a flange portion in a small volume cavity, then a flange can be molded, but slack or twist may occur in the flange portion
Solution Approach 1:
The pressing operation uses a dynamic pressing member that can move independently to apply controlled pressure to the flange portion. This dynamic action allows the pressing force to be applied progressively and uniformly, preventing slack or twist in the flange while achieving the desired shape.
Solution Approach 2:
The pressing force and pressing speed are carefully controlled and varied during the flange forming process. By changing these parameters appropriately, the material flow is controlled to achieve precise dimensional accuracy in the flange portion without causing defects.
3Ease of manufacture
If a conventional molding apparatus is used to form a flange by crushing metal pipe material, then the basic molding function is achieved, but the quality and formability of the molded article are insufficient
Solution Approach 1:
The molding apparatus is designed with separate functional components: an expansion stage using gas pressure and a flange forming stage using a pressing member. This segmentation of functions allows each component to be optimized for its specific task, improving both ease of manufacture and reliability of the final product.
Solution Approach 2:
The mold cavity serves as an intermediary that first receives the expanded metal pipe material and then guides the flange forming process. The cavity shape and surface characteristics are designed to facilitate both expansion and subsequent pressing, ensuring high quality output while maintaining manufacturing simplicity.
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 enhances the quality of the molded article by reducing the likelihood of defects like slack or twist, improving dimensional accuracy, impact resistance, and fatigue fracture resistance, while maintaining precise control over the deformation process.
Implementation Method 1
a driving section that is provided with a servomotor configured to generate a driving force for moving the slide
Implementation Method 2
a gas supply section configured to supply gas into the metal pipe material held by the holding section... controls the gas supply section so as to expand and mold the metal pipe material by supplying gas into the metal pipe material
Implementation Method 3
controls the driving section so as to mold a flange portion by crushing a portion of the expanded metal pipe material by the first mold and the second mold
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A molding apparatus capable of improving the quality of a molded article is provided. A control section (70) controls a blowing mechanism (60) so as to expand and mold a metal pipe material 14 by supplying gas into the metal pipe material (14) held between an upper mold (12) and a lower mold (11) by a pipe holding mechanism (30). The control section (70) controls a driving section (81) so as to mold a flange portion (80b) by crushing a second molded portion (14b) of the expanded metal pipe material (14) in a sub-cavity portion SC between the upper mold (12 )and the lower mold (11). In a molding apparatus (10), the control section (70) changes movement speed of a slide (82) during the molding of the flange portion (80b) by controlling a servomotor (83). Accordingly, it becomes possible to control an operation of pressing at an appropriate movement speed according to the shape or the like of the flange portion (80b). Accordingly, it is possible to improve the quality of a molded article.