TPT November 2014

Article

Fontijne Formitt

Improving the quality of tube formed products using spinforming By Jeff Mansveld MSc, global marketing manager, Fontijne Formitt, Netherlands

End product

Spinning process Currently spinforming technology has progressed to modern CNC controlled machines. The primary objective of spinforming is to create a symmetrical shape or form from flat blanks or tube without creating a major reduction in the thickness of the parent material. Fontijne Formitt is focused on tube spinning which is a more difficult process compared to spinforming blanks, as an inner mandrel is not present to create the final spun form. From the tube shapes round and oval, it is possible to achieve a cylindrical reduced diameter of the shell. Additionally, spun shapes can be combined with cast, drawn, forged or machined parts to reduce costs and increase productivity. Spinning the tube ends can be performed concentric, eccentric and oblique. Concentric spinning Concentric spinforming machines form a reduced end profile that is concentrically aligned with the tube’s central axis. Fontijne Formitt’s concentric spinner can automatically control the part length without trimming in most cases. Dynamic length control provides accurate part length compensation for varying material parameters. A concentric spinner can be placed in a horizontal or vertical design, in which the vertical spinner uses less floor space. EST-OST spinning The Eccentric Spinning Technology (EST) and Oblique Spin- ning Technology (OST) spinning process forms a reduced end profile that is eccentric to or at an oblique angle to the tube’s central axis without rotating the part. Using advanced mechan- ical design and machine control techniques, the possibility of spinforming complex transition angles such as eccentric and oblique can be realised. With an increasing demand for quality tube shaped products, space saving solutions and cost savings in production processes, it is important to select the production process that fits your business model. This article will explain how a spinforming machine is successful in improving the quality of tube formed products and lowering the production costs.

Oblique

Eccentric

Using different types of angles is, especially in the automo- tive industry, a frequently occurring request, because of space saving solutions. The various complex shapes can be more easily connected with other components. For example cata- lytic converters can be formed by EST/OST to save space re- strictions in the engine compartment. First, the shell is loaded in the work holding clamp of the EST/ OST spinning machine where the datum positions the part on the correct depth. The shell is static and the two forming rollers rotate around the part to form the end in multiple steps. Form- ing different angles requires a movement in several ways, with in total a 4-axis machine. The shell is moved by work holder in a horizontal direction and multiple times fed in and out to form the end ( Z-axis ). Together with the movement of the two rollers ( X-axis ) the shell can be spinformed. The shell is moved off centre by work holder to form an eccentric ( Y-axis ), and the shell is angular rotated by work holder to form an oblique shape (A-axis ). The EST-OST spinning machine can be equipped with automatic trimming of the shell ends. Benefits In general, spinning is more efficient than other metalforming processes. No welding Spinforming technology eliminates the need for welded tube end-pieces, for example two circumferential welds for one piece cone ends and six (2x longitudinal and 4x axial) welds for two-piece cone ends. This enhances overall component quality and reliability, as possible leaks from weld processes are nearly eliminated. Indoor pollution created by welding is eliminated as there are no weld gases. Scrape rate One-piece end cones which are commonly made by dies in combination with a press for concentric end cones or a hydrostatic process for eccentric and oblique end cones

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N ovember 2014