Expert sorting from Feltre18 April 2006
After slaughter, the hides are de-haired, followed by a chemical or vegetable treatment aimed at preventing decomposition. These are standard processes, carried out regardless of the distinct characteristics of each animal. This is also the phase of the tanning process in which the hides and skins are split, separating the valued external section from the fleshy interior part, using a press to eliminate any residual liquids still present. At the end of these preliminary phases, hides are selected according to size and quality. The large hides are used in the manufacturing of sofas or garments, while smaller pieces of leather can be used for the production of footwear. During the tanning process, the whole of an animal's skin is treated, regardless of any eventual defects or faults. In fact, the animal's two flanks can present different characteristics or problems. Fire branding typically damages an entire section of a hide irreparably. But other faults can also be present on the skin, such as scars, defects due to illness, or even more commonly, signs of wear induced by the animal's habit of always sleeping on one side. Such peculiarities determine the value of each hide and, because of this factor, it is necessary to cut and separate the primary material based on its qualitative level. Feltre - based in Chiampo, in the province of Vicenza - a major exporter of tanning machinery worldwide, specialise in this very task. Everything in full view Feltre say the task of separating the hides and identifying their special characteristics cannot be performed by automatic machinery, but must be entrusted to an experienced human operator. For this reason, in the past, the person carrying out this chore had to move about in the tannery, among pallets stacked with hides which were transferred manually. This is a very demanding job from a physical point of view, with a level of productivity that is incompatible with the rhythm of modern industry. This gave rise to selection lines, which pick up previously treated individual hides and transfers them directly to the grading station. This also provides the operator with information on the size of the hide, its thickness and weight. The system saves the operator from continuous movement, lifting heavy hides and working in conditions with inadequate lighting. By simply pressing a few buttons, and focusing solely on the work at hand, the quality control operator can grade and evaluate each hide, deciding its end use accordingly. Furthermore, the operator can decide whether to cut the primary material into side leather or if it is of high quality, keep it whole. All of this takes place without the operator having to move from the work station, and depending on the operator's evaluations, the hides are then automatically conveyed onto different pallets. Fast yet controlled handling However, the rapid transfer of a hide from a processing machine to a pallet without damaging it is not a simple task. Since we are dealing with natural products, hides are completely different from each other. Handling operations are assigned to a series of conveyor belts which, advancing at different speeds and under constant control, lay down each individual hide and position it along the sloped surface of the selection station. The operator can then evaluate it, immediately identifying any faults and grading the quality of the hide by touch. Thanks to advanced handling technology, this grading process is reduced to mere seconds, and it is only at the end of the sorting phase that the fate of each hide or side leather is determined. The operator, by simply pressing a button, decides whether to dissect the hide and which stack to send it to. Feltre's field of specialisation lies in the selection of hides and their movement from the selection station to the pallet, along with an innovative cutting system. The handling of such differing varieties of hides is an especially delicate operation, since inept actions can damage the product with significant economic repercussions. Very large hides must be carefully folded, just as a great degree of care must be taken in their precise positioning on the final pallet. Unwanted folds will form if hides are not perfectly stretched out, along with cracks and cuts which will render them unusable or downgrade part of the product. In addition to performing tasks which are similar to those carried out by human operators, an automated handling system must guarantee the possibility of operating correctly and quickly. Furthermore, in order to ensure the optimum positioning of the product, the pallets rest on a platform which compensates for their height, depending on the load, and determines their removal and the immediate replacement of completed pallets. Faster with automation To fulfil such a delicate task, Feltre's management have chosen the innovative solutions proposed by Rockwell Automation, the hi-tech multinational which comprises prestigious brands in the industrial automation sector, such as Allen-Bradley, Reliance Electric, Breter, Guardmaster and Rockwell Software. Rockwell Automation's worldwide servicing network makes tracking down spare parts anywhere fast and easy when needed. Feltre machines are exported throughout the globe and are designed to last for decades. These machines are structurally designed entirely in stainless steel, guaranteeing optimal resistance. Handling speed is vital to high productivity. Automated solutions proposed by Feltre allow for the movement of hides at speeds of over 100m per minute, guaranteeing tanners excellent stability for the leather and the possibility of analysing up to six pieces per minute. In addition, as company owner Domenico Feltre explains: 'Rockwell Automation provides the security of a brand name that is recognised and esteemed worldwide, offering further guarantees of quality for those who choose to innovate their production facilities with one of our automatic handling units.' 'Of course', admits assistant marketing manager Luca Tisato, 'the decision to make use of special innovative tailor-made solutions compels us to keep our level of know-how continuously up-to-date, which is neither simple nor economic, but it does allow us to offer our customers quality solutions that are at the vanguard of technology and enable them to be competitive, above all in facing the aggressive competition posed by emerging nations.' A machine for every need By definition, a tannery is an especially hostile environment, both because of the presence of acids in a liquid and gaseous state and because, typically, the operating personnel don't concern themselves very much with the machinery. It is, therefore, fundamental to set up a system which, in addition to being robust and well-built, is also capable of offering the sort of operating simplicity that will allow personnel with a low level of training to work on it. The operator interface, which takes full advantage of the characteristics present on the PanelView 600 plus, is user friendly and immediately comprehensible, since it features commands that can be used even by operators without specific training. In fact, on some equipment designed by Feltre, the operator need only select the animal type the hides originate from to prompt the machine to automatically modify a series of operating specifications enabling it to adapt to the special characteristics of the product being treated. Automatic hide handling solutions are generally placed in production departments which are already operating and, for this reason, a standard machine does not exist, but rather each installation must be adapted to the space and needs of each and every customer. Which is why, as Tisato explains: 'We never set ourselves any design limitations, and never say no to any project prematurely. Instead, we study the needs of each and every customer, and strive for the best solution for every situation.' All of this has been made possible through the use of the invaluable solutions provided by Rockwell Automation. As Francesco Antoniazzi, electrical systems manager, explains: 'More specifically, after having successfully employed the SLC 500 series PLCs, for a few months now we've been implementing CompactLogix which, thanks to its high response speed, provides an optimum support for the functionalities of such a machine, on which up to six selection stations operating in parallel can be created. A demonstration of how, with the support of a supplier capable of guiding technological evolution, we can effectively respond to the market's needs.' Furthermore, thanks to the broad range of products available from Rockwell, Feltre's technicians can identify at any time the ideal components needed to respond to the requirements of each individual machine, without having to accept compromises or make use of inadequate solutions. This enables the realisation of particularly efficient and reliable solutions, capable of managing even the largest or most delicate product batches. Programming made easy The decision to invest in the design of customised - and therefore difficult to reproduce - machinery allows Feltre to remain competitive even in the current difficult times for the leather sector. In fact, the majority of producers are trying to contain costs and are ready to invest only in equipment providing real added value. Building and designing machines which are customised to the specific needs of each client is aided by the programming simplicity of the control system designed by Rockwell Automation. A testimony to this is the fact that software development for each new machine can be completed in just a few weeks, enabling Feltre to respond quickly to the specific needs of customers. In addition, using Ethernet systems provides the possibility of remote servicing. This feature is greatly appreciated by customers who feel reassured by the support of a technician and the immediate assistance with software problems, for which most companies do not have their own staff.