The modern uses of sheet metal require higher quality cut products, while on the other hand globalisation means that it is now possible to purchase sheet metal coils virtually everywhere in the world. The cutting lines must always provide the best quality results, also in the case of defects and characteristic inconsistencies within the same lot of coils.
The search for the maximum added value is nowadays an objective obsession of the most modern economies, which are faced with a globalisation that puts a lot of strain on the choice and the production methods for each industrial product. The environmental and energy developments drive companies to look for lighter solutions, whilst at the same time there is also an interest in finding design and production methods that ensure shorter times and processes. As far as sheet metal is concerned, the choice is very wide: high resistance, cold and hot rolled, pre-painted, stainless steel, galvanised sheet metal. Precision and productivity requirements means that there is a strong need for finding levelling lines capable of processing, quickly and with high precision, high volumes of coils, often with different characteristics. Thanks to its performance characteristics, the high precision levelling line for the processing of 0.5 to 3.00 mm thick sheet metal produced by CAMU of Bressanvido (VI) for an important Service Centre is today the state of the art of the sector. It consists of a coil pay-off reel, feeding table, leveller, flying shears, stacking and transport unit for the unloading of scrap, stacking unit for the storage of “delicate” materials, weighting system. The specifications were clear. As it is typical with a Service Centre, the expected lots are small and diversified, and it is therefore important to be able to quickly move from one lot to the next as soon as possible. Therefore, the line needs to be, above all, extremely flexible and versatile.
The leveller: the queen of coils
Experts are aware that sheet metal exceeding 2 mm in thickness must be stress relieved before the levelling operation. The feeding table is equipped with two rubber rollers for feeding and pulling, and three stress relieving rollers. CAMU has paid particular attention to the mechanical processing of all the components of the line. However, the leveller remains the most critical element, because it fundamentally affects the planarity characteristics of the sheet metal, and therefore its quality. As explained by Fabio Basso, co-owner together with his brother Loris, for years CAMU has concentrated its attention on the technological and quality development of this machine, and the current results of the company mean that the automatic levelling lines are among the best on the market in terms of quality. The main characteristics are: 19 rollers (9 top and 10 bottom rollers), and counter rolling in 7 points (6th to avoid ruining the material). The seven bottom counter rollers are independent, movable on wedges. The 9 top rollers are the same (6th), and the 7 counter rollers may be manually calibrated during the annual calibration, unlike the bottom roller, which have motorised calibration. Our solution, ensures Fabio Basso, results in more even unloading, and prevents flexion in the row of counter rollers. Just as important, is the independence of the tilting movements on half moon with cam, thanks to the individual electric motors, programmed and displayed on the control desk. The vertical movement of the top bank is controlled by 4 large screws, 2 on the right and 2 on the left, independently controlled to ensure better inclination on the operator side, or on the opposite side. The level of rigidity needs to be particularly high, for the processing of high resistance steel, while a typical characteristic of levellers is their elongation during operation. As usual, the company from Vicenza has matched its know-how with the specifications of the materials, and although the starting point have been the latest consolidated standard solutions, it has been able to practically redesign the machine to adapt it to the specific use. Thanks to the latest structural analysis information systems, the columns have been strengthened, and rigidity has been maximised on the bottom bench and the top bridge. “At this point, it is important to mention that each line, and most of all each important machine, is continually reassessed, to ensure perfect suitability to the usage requirements of the customer. Of course, this always entails a redesign activity, and therefore also a commitment from our staff of technical designers. But on the other hand, it is what gives the possibility of customising all our applications, obviously starting from fundamentally standardised solutions, which have therefore already been tested, and have also already proved competitive. Our leveller is a machine that is particularly suitable for use with materials with inconsistent characteristics, which makes it very sought after both in highly industrialised countries, and also in emerging markets. I would also like to emphasise that for the purpose of quality, the cleaning of the rollers is performed automatically, by an attached felt that moves alternatively from right to left, and which may be soaked with specific detergent. Also our attention to detail is clearly very high”.
The study of the stacking activity
The cutting of the rolled metal coil using flying shears is another fundamental characteristic of the line. CAMU shears are the result of a consolidated know-how, clearly recognised by the market. Thanks to these extremely fast shears that move on rotating ball bearings with ground racks, and are therefore very precise, the cutting quality is very good, with very limited burring. After the unloading of the sheets and the waste material, the product is moved by two transporting units with different speeds, with the faster one also fulfilling the task of moving the piece away, and ensure better stacking efficiency. This solution is particularly suited to short pieces. In addition, the pneumatic movement rotating arm stacking unit has been conceived to handle delicate materials. For the purpose of the productivity of the operation, the approaching movements to adapt to the various sizes of the programmed formats are ensured by motors and encoders. From one of the control desks along the line, the operator can follow the programmed operation on the display. We witnessed the movements and we were impressed by their fluidity and speed. Thanks to a photocell, the oil pressure driven platform moves down with the increase in the number of stacked sheets, with the sheets not falling on top of each other, but rather being supported by lateral rollers, also capable of handling wide pieces without “sagging”. On a construction point of view, the higher unloading speed, in order to increase the speed of movement of the stacking unit, has been obtained thanks to a pneumatic system with rigid tubes and accumulators. A special shock absorber at the level of the head stop prevents edge damage, extremely important when cutting thin and delicate materials. The unloading area is motorised and uses chains. When full stacking capacity has been reached, the platform lowers to the level of the chains for unloading, and then moves away. Pneumatic palletizing units can be found on the sides of the stacking unit. Weights are shown on the control desk. Lastly, it is explained to us that the whole line is equipped with a very efficient high lubrication system, and therefore wear of components is very limited, maximising reliability and continuity of operation.
The CAMU company
For over 35 years, CAMU of Bressanvido (VI) has been designing and manufacturing sheet metal coil processing lines: longitudinal cut slitters and transversal cut lines, for low and high thicknesses. Also press and special machine feeding lines. CAMU (www.camu.it) is today extremely well received and recognised at international level, a position that is becoming stronger and stronger thanks to word of mouth. In order to increase its capability in meeting the requirements of the market, the company is expanding its design and manufacturing activities even further. A staff of committed technicians, driven by the success of the solutions offered, is always available to analyse and develop new automatic applications, simple and easy to manage, in order to provide customers with practical, efficient, and cost effective lines.