Efficient inhouse paint shop for forklift trucks

Jungheinrich has started manufacturing forklift trucks at its new plant in Chomutov, Czech Republic. Part of the new plant is a modern and highly efficient in-house paint shop.

Picture: Editorial Departmend A total of 100 trolleys are in circulation on 3.5 km of chain, each trolley is 7 m long.

Jungheinrich has started manufacturing forklift trucks at its new plant in Chomutov, Czech Republic. Part of the new plant is a modern and highly efficient in-house paint shop.

Jungheinrich has built an energy-efficient and CO2-optimised new building for forklift truck production on an area of around 37,000 m2. The plant is used to powder-coat steel components for forklift trucks with a maximum body size of 6.5 m x 1.5 m x 2.1 m (LxWxH). The new plant is modularly expandable and can be adapted to a different range of components if required. In the area of conveying technology, the empty trolleys for main components are returned to the respective feed stations, sorted by type, with the necessary suspension devices.

The drying and curing area is very flexible with three separate oven lines. Heating can be gas or electric, and different dwell times and temperatures – depending on the component – can be realised. The workpieces are suspended from trolleys on a P&F conveyor system via lifting and lowering stations. The components are then transported to the various process steps of blasting (incl. cleaning), powder coating (incl. suction to create colour-free surfaces) and baking (incl. cooling) before they are also suspended again at the lifting and lowering stations. The lifting frames are fed to and removed from the lifting and lowering stations via gravity roller conveyors.

Flexible P&F conveyor system

The P&F conveyor system is used for flexible control of the trolleys. A total of 100 carriages are in circulation, each carriage is 7 m long. The chain length is approx. 3.5 km. This is distributed over two levels. The lower level is the component level, the upper level is the empty trolley level. There are empty trolley stores for allocation to the feeding stations, as the suspension devices remain on the trolleys. In addition, a separate maintenance station is installed for the trolleys,” Schulz emphasises the special features of the installed conveyor technology. 

The workpieces are mechanically pre-treated. A round grain with a diameter of 1 mm is used as the blasting medium. Afterwards, the blasted parts are vacuumed to efficiently remove adhering abrasive. The cleaning of the carriage is automatically integrated. After the mechanical pre-treatment, the powder coating is applied. For this purpose, parallel application lines are installed, which are equipped with system technology from Gema. In line 1, the house colour grey is applied, in line 2, the house colour yellow and a primer for the cold storage vehicles are applied.

Powder coating with dynamic contour recognition

An automatic booth with pre- and post-coating stations is installed in line 1. Automatic coating is carried out with 24 automatic powder guns, which are moved to the components via feed axes, controlled by laser scanners for dynamic contour recognition. In addition, a manual coating booth is available. Here, lifting/lowering stations ensure optimum positioning of the components and the work contents are visualised via a 65-inch monitor.

After application, the components arrive at a height-adjusted work area. Here, surfaces that have to be colour-free are visually displayed on monitors and then created by means of suction, with the aid of suction nozzles specially created in 3D printing. In line 2, the house colour yellow and a primer for the cold storage vehicles are applied manually. For this purpose, a coating booth with lifting/lowering station is available for optimal positioning of the components; the tasks at hand are displayed to the worker via a 65-inch monitor.

Three oven lines

Three oven lines are installed for drying and curing, which can be parameterised independently of each other. The natural gas burners are additionally protected by a current heating register.

The cooling zone is divided accordingly due to the different dwell times. By cascading the air flow, the required air volume is reduced. Afterwards, the coated components are sent for acceptance. In the course of quality assurance, the roughness depth after blasting and the powder layer thickness before baking are regularly checked with a layer thickness measuring device. In addition, oven curves are measured.

More information: www.jungheinrich.de

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