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Rational handling of high-quality sheet metal

Articulated-jib crane and vacuum lifting device - a modular system for efficient and economical handing of sheet-metal parts.

The problem is a familiar one: sheets of metal have to be lifted from a stack and placed on a pallet as part of a customer order or on the table of a sheet-metal cutting machine.

With conventional solutions, this cannot be done without some damage to the surfaces of the metal sheets, even if they are protected by intermediate layers of paper or by adhesive films, as is often the case with stainless-steel sheets or sheets with brushed surfaces.

A further problem is the tendency of the sheets to stick together on the stack, which means that considerable mechanical forces must be applied to separate the sheets from each other. This can be done manually in the case of thin sheets, but thick sheets require the use of further aids. Even if such handling tasks occur only occasionally, they require the use of several people and additional aids, and the surfaces of the sheets are still not fully protected against damage.

It is thus necessary to look for a practical, safe and economical handling solution. The investment in a special handling device pays for itself by reducing the number of people needed for handling the parts, by decreasing the handling and transport times, by minimising the idle times of the sheet-metal cutting machines and by avoiding damage to the sheets which can result in costly complaints from customers.

 

This is particularly true when commissioning metal sheets in a sheet-metal production firm or trading company, such as a renowned trading company for semi-finished products and sheet metal.

The product range includes various sheet metals (stainless steel, aluminium, brass, copper, honeycomb and checker plates, plastic-coated metal sheets) in various formats (large: 1,500 x 3,000, medium: 1,250 x 2,500, small: 1,000 x 2,000 mm). The sheets are between 0.8 and 30mm (aluminium) thick, which means that they can weigh up to 400kg.

The task: handling thin and thick, large and small metal sheets

Neither the thick sheets nor the thin ones can be handled and commissioned rationally by hand. In addition, the company has to commission between 30 and 50 orders for metal sheets per single-shift working day, something which cannot be achieved without a sufficient number of people.

For this reason, the company management decided to reorganize their handling of metal sheets and started to look for a practical solution to the problem. Schmalz’s (represented by Millsom Materials Handling in Australia & New Zealand) articulated-jib crane and a vacuum lifting device of the type VacuMaster, was the solution. They were immediately convinced of the concept of this compact handling system, which is delivered ready for use. 

Today, the user can optimize their material flow and production operations even under the difficult conditions which exist on their premises. The advantages of the rigid articulated-jib crane, which weighs only 800kg, at its low overall height, its relatively large working area and the fact that it can be controlled easily and precisely, even when carrying a heavy load.

It permits ergonomical, longitudinal or transverse handling and is thus ideal for loading and unloading sheet-metal cutting machines, even if access from the top is restricted or impossible, and for removing sheets from stacks and placing them on pallets. The articulated jib is 3.5 metres long and can be swung out laterally to cover a working area of about 20 square metres. Equipped with a vacuum lifting device of the type VacuMaster 500-6, it is capable of lifting loads weighing up to 500 kg.


The solution: an ideal combination of an articulated-jib crane and a vacuum lifting device

The crane is thus capable of lifting the weight of the vacuum lifting device and a load of 500 kg easily and safely and at a lifting speed of either 4 or 8 meters per minute, as desired. The system has an overall height of 3,580 mm and a lifting height of 1,700 mm which means that it can master most of the material-flow requirements in a flexible manner.

The rigid load suspension system prevents the load from swinging, reduces the removal and dropping times and simplifies precise positioning. The reliable friction clutch ensures the necessary safety in the case of an overload and is supported in this by the safety elements of the vacuum lifting device.

The new material-flow and commissioning solution at the company proves its value every day and provides considerably more efficiency and productivity in the processing of orders in the central stockroom. For this, the required metal sheets are transported in stacks to the commissioning area, using ground conveyors. An operator lifts a sheet from the stack with the articulated-jib crane and the vacuum lifting device and places it on a pallet which rests on trestles. A sheet of paper is laid between the metal sheets to protect their surfaces against damage and the entire stack is wrapped in cardboard.

The thin sheets are placed on the pallet first and the thicker sheets are placed on top of them in order to provide more protection and stability.

In the past, two persons had to manhandle the sheets from the stack, a procedure which frequently resulted in damage to their surfaces. Heavy sheets had to be separated with the aid of iron bars and then lifted, moved and deposited with the aid of a fork-lift truck, a process which also often caused damage.

Today, in contrast, one person carries out the handling with the combined crane and vacuum handling system and damage to the sheets is a thing of the past.

Due to the fact that the six suction pads are spring-mounted and flexible and have special sealing lips which leave almost no marks on the sheets, the handling of both thin, non-rigid sheets and thick sheets is very easy and safe, particularly since the large vacuum reservoir and the electronic warning device ensure safe handling even in the case of a power failure.

 

Expensive pianos and luxury furniture are highly polished before they leave the factory. But even the production of unusual furniture elements and piano components must be carried out economically. It is no wonder that production is almost fully automated. This is certainly true for a company who are manufacturers and suppliers of high-quality furniture and components for the bodies of pianos.

 

Work piece handling.

Realizing that the purchase of a CNC woodworking centre is only the first step, which must be accompanied by the optimum design of the peripheral equipment for material flow and handling, the piano manufacturer soon considered the automated loading of the new woodworking machine. Loading by hand simply took too long and in many cases required two people. Partially automated loading of the woodworking machine with the aid of sheet-handling device, on the other hand, promised time savings and a better utilization of the available machine capacity.
The idea was to permit loading of the machine with raw sheets of laminated wood with easily damaged surfaces and the removal of the finished piano covers, which still weighed up to 30kg, by a single person. In addition, the risk of damage to the surfaces of the parts should be minimized and it should, at the same time, be possible to position the sheets quickly and precisely. Handling of the raw materials and finished parts with the vacuum handling technology offered by the vacuum specialists Schmalz (represented by Millsom Materials Handling in Australia & New Zealand), was found to be the best solution. Therefore they decided to purchase a vacuum lifting device of the type VacuMaster Light 100-4.

 

Universal handling of different parts

This vacuum lifting device is a universal and flexible device for very easy handling of unwieldy and heavy sheet materials weighing up to 35kg. Depending on the task and the dimensions of the work pieces, the four suction pads, which are mounted on cross-beams, can be adjusted individually and quickly. This avoids waiting times in the flexible CNC machining of a wide range of different components. The vacuum lifting devices of the type VacuMaster Light can be suspended from cranes, resulting in a relatively large working area which extends over the working space of the machine and its surroundings. The light weight of the VacuMaster Light means that the maximum load of the crane is reduced only slightly. The lifting device can also be moved around easily, since the vacuum is generated with the aid of compressed air, which means that only a compressed-air hose has to be moved with the device. The four suction pads are mounted on flexible mountings, allowing them to tilt to match the orientation of the workpiece surface.

 

Return on investment in a very short time

The special materials used for the suction pads make them very hard-wearing and, at the same time, leave almost no marks on the work pieces. The suction pads are designed with extremely high stability to ensure quick and precise positioning of the work pieces on the clamping system of the machining centre. The operation of the lifting device is also very easy, since the ejector which generates the vacuum is switched on and off with a safety switch on the basic unit. Installation is also simple: the device is hung on its crane, the compressed-air hose is connected, and the system is ready for use. An integrated warning system provides a high level of operational safety and the handling of the parts with the vacuum lifting device VacuMaster Light is absolutely free of problems. In contrast to the old way of working, one person is now sufficient for loading and unloading the machine and can also operate the CNC machine. Damage to the work pieces is also a thing of the past. The investment was very cheap, as there were no additional installation costs. The return on investment time was thus correspondingly short and the purchase of the vacuum lifting device was very worthwhile.

 

For further information visit Millsom Materials Handling at http://www.millsom.com.au