Innovative spraying scheme with the highest explos

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Innovative painting scheme with high explosion-proof grade

Liebherr uses a new set of large-scale painting equipment of hydraulic excavator to walk out of the road of innovation - Parts weighing up to 20t are freely suspended on the roof controlled lifting rail conveying system through the painting equipment. At the same time, a special lifting scheme ensures the best explosion-proof grade in the paint booth and drying room

an impressive scene: accompanied by the flashing alarm lights to protect employees and the sound of regular percussion gongs, the excavator chassis passed Schw like a swallow? The workshop of bischen kirchdorf is closely followed by several brackets and rotating platforms, which are jointly transported to a suspension device. The excavator chassis weighs about 11T, and the total weight of other parts even exceeds 15t. Liebherr has been looking for a solution that can speed up the logistics process and improve economic efficiency during workpiece coating and drying. Liebherr's original suspension coating equipment is designed to bear only 4T, and heavier parts are transported manually. At that time, the company only had ground transportation technology, which increased the difficulty of painting work. At first, it seemed impossible for Liebherr to use the ceiling to transport equipment below 20t, because such equipment has not been built so far

since 1949, Liebherr has manufactured, assembled and sprayed hydraulic excavators at Baden-W ü rttemberg General Factory. The uses of this behemoth painted with typical yellow color include underground construction and tunnel excavation, industrial handling technology, demolition and waste recycling, and water industry. The product range includes the use of machines weighing 10~672t. At kirchdorf plant, the excavator currently manufactured weighs 77t, and there is still an increasing trend. Therefore, in the process of production reorganization, the coating process of heavy parts should also be automated. The workpiece in production must be thoroughly cleaned before priming and painting (Fig. 1), and the painting should also be replaced with environmentally friendly water-soluble 2-k water paint. The workshop originally used for welding parts has now been used for new construction, that is, to build a new set of equipment on a total area of 3500m2

Figure 1 the workpiece in production must be thoroughly cleaned before priming and painting.

the scheme is provided by weinsberg vollert equipment manufacturing company. This heavy-duty professional manufacturer not only provides internal logistics systems for the metal industry and automobile industry, but also provides services for the building materials industry, such as developing transportation equipment for cement manufacturers; The design principle of the new general single load lifting rail conveying system for parts weighing up to 20t comes from this industry. Vollert has been able to apply its experience from the building materials industry to this new set of equipment. In this regard, it has set up a base to promote the expansion of the base and designed similar equipment. So far, such a large bearing capacity is unique in the field of rail conveying equipment. The challenge is to develop a device. Considering the explosion-proof protection of the paint booth and other reasons, the conveying unit of this device can operate without a separate electric drive - which has also been successfully achieved

there is no need for motors and power supply equipment

the scheme is as simple as if it came from a genius: the conveying unit developed by vollert company is composed of a suspension device. According to its size and weight, the workpiece can include China, the United States, the United Kingdom and Norway classification society certification, iatf16949 automobile plate certification, EU market CE certification Budweiser beer and Coca Cola beverage manufacturer certification can also be hung on the suspension device separately, and the height can be adjusted within 2m (Figure 2)

Figure 2 at the beginning of large painting equipment, the loading and unloading controller is responsible for controlling the conveying unit (red) with suspended workpieces. According to its size and weight, the workpiece can be hung separately or multiple together on the suspension device

when the suspension device runs on the lifting rail conveying track, it passes through the whole equipment, and a fixed friction wheel drive device is installed on the equipment according to a certain distance, which is responsible for the necessary feeding. The center point is equipped with three distribution controllers, each of which has an action distance of 15.5m and a weight of 14T, and is responsible for driving the conveying unit and equipment to the specified primer room, spray room, demist room and drying room

here shows the advantages of this drive system itself: the suspension device enters and exits these workshops with the help of friction wheel technology and gear drive device, which are installed on the distribution controller. Therefore, there is no need for motors and power supply equipment components in the workshop - which is decisive for explosion-proof protection. Although it is possible to manufacture drive devices that ensure explosion-proof, such devices are very expensive. In addition, the equipment is also directly exposed to the risk of dirt, such as dirt caused by paint mist, which requires regular maintenance

on the contrary, the engineers of vollert company have found a solution with low cost, permanent function, almost maintenance free and high usability by using friction wheel drive: the new equipment runs 24 hours a day. As the general contractor, vollert company is not only responsible for the design, transportation technology and steel structure analysis and design, but also undertakes the coordination of other parts of equipment technology

the whole system includes 17 processing stations, including 5 drying rooms, demisting and cleaning rooms, primer rooms, paint spraying rooms and cooling rooms. In addition, the terminal of the equipment is a return buffer device with 4 stations. It can be used not only as the air cooling section for spraying finish paint drying, but also to balance the fluctuations of production. The fourth controller is responsible for loading and unloading, with an action distance of 16m and a height of 10.5m. The controller is designed to be self-propelled and half door type, so there is no problem that the disturbing vertical transportation track affects the moving radius of the submitted workpiece, because the workpiece is 12.5m long, 4.5m high and 2.8m wide. After the workpiece is submitted, it is suspended on the conveying unit located in the loading controller, and then it is driven into the cleaning room

after passing through the whole production line, the first of the three distribution controllers takes over the carrier unit containing the workpiece and sends it to the degreasing station, and then to the open preparation site. Here, the surface that does not need painting, such as the turning plate of the excavator, is stripped of the tape, and the drill hole is sealed before priming. In addition, the conveying unit is also equipped with corresponding data groups to provide information about paint type, ral color, temperature, drying duration and so on (convenient for the adjustment of detection position; the servo motor drives the precision lead screw to drive the loading actuator to move along the Z axis to realize the application of experimental force, Fig. 3). The ral number can be raised on the display of the primer room and paint room, and the control of the drying room also uses this data group. After the workers respond, the system automatically starts to run, pick up and continue to transport

Figure 3 through the control system, the data and processes of all automatic electronic universal experimental machines with robots can be called at any time. The conveying unit is also equipped with corresponding data sets, which provide information about paint type, ral color, temperature and drying duration, etc.

there are 19 sets of suspension devices, each weighing up to 20t, which are constantly circulating. Due to the parallel configuration of the preparation site and the paint booth, the workpiece can be crossed and crossed at any time as required, and can also catch up, advance, throw out or reverse (Fig. 4). A buffer device passes through the workstation in parallel and arrives at the paint booth, so vollert's single load rail conveying system can provide more flexibility than other equipment. As early as the early stage of the design, the company made a virtual simulation of the technological process and calculated the best number of conveying units for smooth operation. Therefore, this scheme ensures a very fast beat time

Figure 4 the friction wheel (yellow) installed at the specified distance is responsible for the continuous transportation of 19 conveying units (red). The jobs arranged in parallel enable the workpiece to cross and cross at any time according to needs, and can also catch up, advance, throw out or reverse

environmentally friendly paint spraying technology

Heimer paint spraying equipment and industrial air technology company from Bielefeld city is a professional company equipped with paint spraying rooms and drying rooms. The two working rooms are used for priming and finishing the excavator parts. The fully automatic rolling shutter door prevents the paint mist from escaping and prevents the equipment surface from being dirty

modern filtration equipment is responsible for pumping air and cleaning it. At the same time, water-soluble 2-k water paint is used, and there is almost no solvent in the paint. Figure 5 shows that the excavator chassis (black) weighing more than 11T is suspended on the conveying unit (red) and transported to the cleaning room. In the later cooling chamber, demisting chamber and drying chamber, Liebherr also adopted an environment-friendly scheme: the drying equipment uses 90% of the circulating air, and fresh air only accounts for 10%. Secondly, using the heat exchanger in the demisting equipment can also preheat the fresh air and recover valuable energy. The dried suspension device drives to the return route, removes the workpiece at the terminal of the return section, and then sends it to the final assembly line. For labor protection reasons, the transportation speed of the traffic area in the plant is 0.2m/s, while the speed of the equipment in the closed painting area and the return road section can reach 0.5m/s

Figure 5 the excavator chassis (black) weighing more than 11T is suspended on the conveying unit (red) and transported to the cleaning room. The left part of the figure is the return buffer

although this equipment is the first of this kind, Liebherr company is absolutely convinced of this scheme. Compared with the past, they have greatly increased the load and significantly shortened the beat time. At the same time, the process of workpiece passing is more flexible. In this way, the company has a set of modern equipment that is environmentally friendly and more cost-effective. In addition, the completion time of the project is also worth mentioning: vollert engineers only need 15 months from design to final acceptance

mobile excavator expert

kirchdorf is the General Factory of Liebherr group. In 1949, the great success of the first mobile tower jib crane laid the foundation for the company, which is still owned by the family. Kirchdorf production base has been specializing in the production of mobile excavators for many years, and now it still uses the name of Liebherr hydraulikbagger GmbH. Liebherr currently has about 1600 employees in kirchdorf. The company's production plan includes manufacturing more than 3000 mobile excavators and material handling equipment for underground engineering every year; In addition, nearly 50000 hydraulic cylinders are used for various construction machinery of Liebherr company. Liebherr group has nearly 30000 employees all over the world, covering more than 100 companies on all continents. (end)

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