TPT May 2011

T ube M ills & R oll F orming M achines

New tube mill installed in Yekaterinburg

ATTL a spol sro, Czech Republic, has installed and commissioned a new tube mill in Yekaterinburg, Russia, to produce longitudinally welded tubes and profiles from steel and galvanised material, 102x5mm. The mill features new semi-automatic coil end welder and shear NPA, fast change of forming and calibration sections RVS system, and an ALDA Combi flying cut-off which can cut by flying shear for speed or flying cold saw when quality of the cut-off face is of prime importance. The ALDA Combi enables both operations on one machine, with changeover time of around 15 minutes. The mill includes an Attl AUT 8000 fully automatic bundling machine, and is also equipped with a Thermatool HF welding generator. Attl a spol sro – Czech Republic Fax: +420 271 960 414 Email: attl@attl.cz Website: www.attl.cz Orbital milling cut-off from Oto Mills Attl a spol has installed a new tube mill in Yekaterinburg, Russia

THE welded tube market continues to move towards the production of very large and thick tubes. For this industry Oto Mills has developed the new cut-off model TOAC40616, designed specifically for tube lines that require cuts without burr on a wide production range. If just the thickness of the tube is to be cut, a small diameter blade can be used: this means greater rigidity, lower level of vibrations and consequently improved finishing and longer life of the blades. The carriage consists of a steel structure that supports the parts making up the cut-off. It is driven by a pair of electric motors with reduction gear that operate just as many toothed pinions engaged in turn with the rack on the bed. The outfeed vice and the outfeed tube guide are fitted on a mobile structure (vice detachment carriage) that moves the tube away from the blades as soon as the cut is completed (with blades still inside the tube): in this way they are protected against feasible scraping/breakages if the tube should move due to internal tensions or to the imperfect alignment of the tube itself or even due to synchronisation errors caused by excessive oscillations in the line speed. The bed also houses the mobile tube supports: their stroke is based on the stroke of the carriage and in particular, in view of the type of connection of the cables to the carriage, the support moves at half the speed of the carriage, guaranteeing suitable support of the tube throughout the cycle. The cut-off houses the rotating part on which the four cutting heads and relevant

oil-hydraulic clearance reduction cylinders are fitted, which annul vibrations that could possibly arise during the cutting phase. The drives are installed at the back end of the rotating part, protected from chips and emulsion water, which rotate the blades, as well as the relevant blade traversing mechanisms (by means of linear actuators) and the cable carrying chain. The vices are designed so that, within a specific shape (round or square/ rectangle) they are able to cover the whole dimensional range of the machine without having to re-tool. What’s more, the part of the clamps that comes into contact with the tube is lined with an insert in plastic material to eliminate vibrations that could arise during the cutting phases and also to compensate any alignment anomalies of the tube between the infeed and outfeed vices. The vice is the quick changeover type: when you need to change profile (for example from round to square/rectangle) the whole vice is removed and replaced with another vice offline, on which the clamps suitable for the new profile to be cut are fitted. To ensure lasting life of the blades, the cutting parameters used must be suitable for the type of tube being produced (size, thickness and material of the tube). To help the operator in this choice and to make it easier to enter these parameters, the cut-off is equipped with dedicated software (the cut-off manager). When you enter the data of the tube and the type of blade (HSS or TCT), the

program suggests the best tooth range. This range is based on calculations that take into consideration the shape of the contact range and the filling of the compartment of the teeth. Once the best blade has been identified, the user selects the type of entrance in the tube and the relevant safety positions, in other words the quick approach and slow approach distances and the penetration inside the tube. At this stage, the dynamic data are entered, ie the PS (peripheral speed in m/ min) and the material removal parameter. The program suggests some default parameters that ensure cutting in safe conditions but that do not optimise the cutting time and therefore the speed of the line. Starting from these, however, the operator can select various types of preset parameters and subsequently modify the values, using the limit curves calculated as reference. The program also provides: indication of the minimum blade diameter to complete the cut with the parameters selected; and possibility to select operation with two or four blades based on the parameters selected. The oscilloscope function is also available (optional) that allows you to monitor the current and speed references, throughout all the cutting phases, of the motors, and namely: carriage launch motors, rotation motor of rotating part, blade rotation motors and lade traversing motors. Oto Mills – Italy Website: www.otomills.com

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M ay 2011

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