A Covering and protection Type Porthole Die For Semi-Hollow Al-Profiles

A new structure named covering type for the semi-hollow Al-profiles was present. through a common actual case, the determination of structure parameters was introduced in detail. Mainly including the arrangement of portholes, the structure design of chamber and the selection of bearing. The method of checking the die strength was introduced. According to the extrusion results, the structure of the traditional solid die and the covering type structure were compared. The characteristics of the latter structure were simple and easy to process. The practical application shows that the new die structure can enhance the die life, improve the production efficiency and reduce the cost. The high precision and the surface brightness of the profiles were obtained. The structure is worth promoting. The aim is to provide reliable data and reference for the further research and development on the structure for semi-hollow Al-profiles.

Development of a Subpath Extrusion Tip and Die for Peripheral Inserted Central Catheter Shaft with Multi Lumen

The tip and die for manufacturing multi-lumen catheter tubes should be designed considering the flow velocity of the molten polymer and the deformation of the final extruded tube. In this study, to manufacture non-circular double-lumen tubes for peripherally inserted central catheters (PICCs), three types of tip and die structures are proposed. The velocity field and swelling effect when the circular tip and die (CTD) are applied, which is the commonly used tip and die structure, are analyzed through numerical calculation. To resolve the wall and rib thickness and ovality issues, the ellipse tip and die (ETD) and sub-path tip and die (STD) were proposed. In addition, based on the results of numerical analysis, the tip and die structures were manufactured and used to perform extrusion. Finally, we manufactured tubes that satisfied the target diameter, ovality, wall, and rib thickness using the newly proposed STD.

Hot Extrusion Processing of Al–Li Alloy Profiles and Related Issues: A Review

Al–Li alloy is a new structural material with the advantages of lightweight and high strength. The extrusion profiles of Al–Li alloy are widely used in aerospace and other fields, which can significantly reduce the weight of the aerospace equipment and improve their carrying capacity and service performance. Particular service conditions of structural components in aeronautical and space areas put forward strict requirements on microstructure, mechanical properties, and dimensional precision of Al–Li alloy profiles. Therefore, it places higher requirements on the shape forming and microstructure controlling of the Al–Li alloy profiles. The manufacturing process of the profiles involves billet homogenization, hot extrusion, solution and quenching treatments, artificial aging, and others. The parameters of each process as well as the die structure have important effects on the final performance of the profiles. This article summarizes the main applications and key mechanical properties of Al–Li alloy extrusion profiles. The technologies related to the manufacturing process of the extrusion profiles are summarized and analyzed. The related studies about the evolutions of the microstructure and mechanical properties during homogenization and extrusion processes are reviewed. The developments of the solid solution and quenching treatments as well as the aging strengthening technology for extruded Al–Li alloy profiles are also introduced. The scientific problems and key technologies that need to be solved in the manufacturing of Al–Li alloy extrusion profiles are presented, and the prospect for future development trends in these fields is given.

Friction Stir Forming of Aluminum Alloy Gear-Racks with Semi-Closed Dies

This paper reports friction-stir forming (FSF) of gear-racks of JIS A5083 aluminum alloy with semi-closed dies. FSF is a modified friction-stir process suggested by Nishihara in 2002. The process generates frictional heat and internal forces, enabling massive deformation of the material. It has been successfully utilized for mechanical joining and microforming, but seems to offer an opportunity for net-shape forming of bulk products as well. We put a material in a semi-closed gear-rack die and conducted friction stirring on its top surface. The material deformed and filled the cavity of the die due to high pressure and heat caused by friction stirring. This study investigates the forming conditions and the corresponding results, including the material fill ratio in the tooth. We also investigated the difference between this method and open-type FSF that had been conducted with an open-die structure.