The defense and aerospace sectors are heavy users of metal fabrication and transformation solutions of all kinds for a variety of applications. The construction of ships, planes or weapons requires ever more sophisticated materials and construction methods in order to be able to offer specific, high-quality solutions.
One of the most modern techniques for manufacturing metal components, adapted to the needs of the defense industry, is shaping, or cylindrical lamination, known in the automotive and aerospace industries.
During the process, the thickness of the wall of the preform is reduced by the action of cutting tools or rollers that can move parallel to the surface of the mold or taper the outer surface according to the thickness required at each point, while the inner side diameter remains constant. The molding process takes place in the three specific areas of contact of each roller with the outside of the piece, creating specific pressures that allow the material to flow with lower forces compared to other molding processes.
Although the material to be used obviously depends on its application, steel is mainly used, although metals that can be formed in the cold state are valid (light alloys can be formed by this technique by processes at high temperatures). Complex parts with multiple curves with different thicknesses, protruding parts and always smooth surfaces can be obtained, which are difficult to manufacture using other methods. In addition, the parts are lighter than their welded or cast equivalents, the thickness of each part can be chosen, and higher fatigue resistance is achieved because there are no welded parts, with lower costs due to fewer parts and intermediate work.
A further development of this technology would be so-called free flow forming, with which parts can be produced that cannot be produced using other methods. This technology developed by the Turkish company Repkon increases the forming speed considerably and enables the more precise production of parts for components with different thicknesses. Contrary to the assumption that only lightweight components can be made with cylindrical rollers, Repkon is currently making short, medium and long range missile sections with this new technology, especially those with sections of 610mm.
Repkon is a supplier of turnkey production systems, forming machines and products based on this technology. The company also manufactures turbines and hollow drive shafts for engines and control shafts for the aerospace industry based on stamping technology. The company has forty years of metal forming experience and is able to manufacture high-precision cold stamping techniques produced by shear, hot spinning, forging and pressing for both the defense, aerospace and hydrocarbon industries and mining.
Repkon also makes small and medium barrels for pistols, assault rifles or machine guns with rotating cold forging machines and is currently working with the Turkish Defense Authorities on the development of a new 40mm barrel. for an automatic grenade launcher with flowforming. These solutions will be presented by the company at the next IDEX exhibition, which will take place in Abu Dhabi from 21-25 this month, as confirmed by the company’s Business Director and Head of Corporate Communications, Ugur Cem Gurpinar. (Jos M Navarro Garca)
Photo: Different production capacities of Repkon (Repkon)
Production by flowforming (Repkon)
Detail of the free flowforming technique (Repkon)
Examples of parts made by flowforming (Repkon)
The Repkon stand at IDEX (Repkon)
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