Ergonomic Change in a Limited Space

 

Shuttle Table Equipped with Hydraulic Ball Bars and Electro-Hydraulic Lifting Platform.
There are some die transport carts on the market, usually models with low functionality. Few carts are optimized for a mold change, and in limited spaces or with high loads, most of them quickly reach their limits. This is different from automotive supplier ElringKlinger. The company has recently started using a compact model from Roemheld adapted to the individual requirements.

ElringKlinger AG is a listed automotive supplier with over 10,000 employees at 45 locations worldwide. The company headquarters are located in Dettingen/ Erms, Baden-Württemberg, Germany. At this site, the company produces cylinder head gaskets, among other products, for which ElringKlinger remains the world market leader to this day. The company also produces special gaskets for engines, transmissions, and exhaust systems as well as lightweight plastic components such as oil pans and cam covers. The latter product group is part of the lightweight construction/elastomer technology division, which is now ElringKlinger’s top-selling segment. “Over the last few years, we have grown steadily, so we needed more and more space. As a result, we are sometimes faced with very cramped conditions,” says Tobias Gerst, production engineer in the lightweight construction/elastomer technology division. He is responsible for the procurement of machines and plants as well as for the planning and optimization of production processes.

The space is particularly cramped, for example, at two injection molding machines, equipped by a common robot and running in three shifts. They are located in an enclosure that can only be entered through a comparatively narrow and low door for the mold change. Directly in front of the machine, there is hardly any space left for maneuvering a transport cart. In the past, this used to cause a challenging and physically exhausting mold change – which is now noticeably easier due to a compact transport cart from Hilma-Roemheld GmbH, Hilchenbach, Germany.

Standard Changing Cart as an Emergency Solution

On the two machines, which are positioned at an angle of about 120° to each other, among other things, transmission. gaskets are provided with sealing lips made of an elastomer. Every eight to nine days, it is time for a mold change. Since there is no overhead crane in the hall, the machines cannot be loaded from above. Instead, the plant operators used one of the many standard transport carts used in plant 1 until a few months ago. For production engineer Gerst, however, this was an emergency solution: “The existing cart types were either unsuitable for high mold
weights or too large for the limited space available. As a result, we had to maneuver awkwardly and still could not quite reach one of the two machine tables.” Therefore, the injection molding machine was approached from the side instead. However, this meant that the molds had to be pushed crosswise to the roller bars of the changing cart. A lot of muscle strength was required until the mold was finally in the right place. Therefore, two years ago, Gerst looked for an alternative that better met the special requirements.

Handling Molds Weighing up to One Ton without Shunting

The steel molds used on the two machines weigh up to one tonne and have a maximum height of 400 mm. The size of the base area varies between 300 x 300 mm and 550 x 500 mm. Of course, the new changing cart should be equally suitable for small and large molds – and still fit through the enclosure’s narrow door. “We were also looking for a system where we could push out molds in several directions,” adds Gerst. This saves the operator from having to maneuver, regardless of which injection molding machine he is changing the mold. One is located to the right of the entrance to the enclosure, and the other is opposite it. The operator can drive in a straight line, load and unload the cart forwards and to the right, and drive out in reverse gear. Through a Google search, Gerst came across the clamping and changing technology manufacturer Roemheld. The group of companies with its headquarters in Laubach, Germany, is one of the leading set up time optimizers for the plastics processing industry worldwide. They develop and distribute the die changing cart RWA 1600, which is characterized by a compact design, an electrohydraulic
lifting platform, and a shuttle table equipped with hydraulic ball bars. The cart can also be adapted to specific customer requirements. Due to the ball bars on the support surface, dies can be moved manually in any direction (Fig.1). A special mechanism ensures transport safety: during transport, the ball inserts are lowered and the die is protected against the movement. Insertable front and sidebars provide an additional safety measure.

Special Requests Quickly Considered

As standard, Roemheld offers three versions with four, six or eight ball bars and a load capacity of 1600 kg each. After a detailed consultation, however, Gerst decided on a special version with nine roller bars. This ensures that even the smallest molds used by ElringKlinger are securely supported by at least two bars. The production engineer also opted for a smaller plate 850mm wide and 750 mm deep.

 

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