Large-format molded rubber parts require large elastomer presses. 

WICKERT, Landau, developed and produced one of the largest, if not the largest, rubber molding presses in the world for Semperit, Austria. The press with a pressing force of 100,000 kN went into operation at the end of 2015. 

With a hot platen size of 3,300 x 3,600 mm, parts measuring 11 m² can be produced. The respectable size of the WKP 100 000 lower plunger frame press is also clear from its weight of around 384 tons with dimensions of 5 m x 5 m x 8 m.The WKP 100 000 press, installed at the Wimpassing plant in Lower Austria, enables the particularly economical production of elastomer membranes for filter plates thanks to a range of functions. 

The specialists for the development and production of these customized large-scale products can be found in the SEMPERIT ENGINEERED SOLUTIONS business unit.

The tool to be changed is simply brought in front of the press using a transport cart or forklift. The tool change is easy and quick: A crane function on the lifting unit for the upper tool part handles the lifting task. The tool to be changed is moved to the "slide table extended" position. The locked-together upper and lower tool parts are attached to the lifting unit for the upper tool part using chains and lifted. Once the tool is sufficiently raised, the slide table moves underneath, and the tool is lowered onto the table. The lifting unit for the upper tool part also benefits regular operation.

Since the upper tool part would not be accessible in the press, it moves outward together with the lower part on the slide table. In the "slide table extended" position, the upper tool part is lifted, allowing the operator to inspect and – if necessary – clean it. If required, the lower tool part can be moved back into the machine with the slide table; this would also make the upper tool part accessible from below, improving access even further. This hydraulically driven slide table enables ergonomic and convenient operation of the machine.

To allow for quick loading and unloading of tools, two roller tables are provided.

One roller table is used for unloading. The finished molded part is pulled onto the roller table and moved away from the machine. At the same time, the other roller table, already prepared with blanks, is brought to the machine so that the tool can be quickly reloaded with the prepared blanks.

Energy-saving hydraulics

The hydraulic drive using an axial piston high-pressure pump with an electric control system for pressure and flow allows free preselection of force and speed for all movements. At the same time, the closed control loop ensures maximum reproducibility. Free preselection of increasing and decreasing force curves is possible. A hydraulic accumulator maintains constant pressure in the main cylinder during the heating phase, saving energy. This allows energy savings of approximately 25 kW/h per operating hour compared to a conventional drive.

Precise temperature distribution

Typical for WICKERT is the special design of the heating plates. Divided into four zones with two temperature sensors per zone, a homogeneous temperature distribution and precise regulation are achieved. A temperature distribution of ± 2°C over the entire (!) surface of the heating plates is reached.

Each heating plate has its own steam control valve, allowing the top and bottom temperatures to be adjusted individually according to the shape and material. The max. steam temperature is 180°C.

Tilt monitoring made easy

At the four corners of the WKP 100 000, a precise displacement measurement system detects any possible tilting of the press. On the screen, the operator or technician can define the tilt level at which the press motion should stop.

Parallelism under full load better than 0.2 mm

Parallelism under full load is a key quality criterion for rubber molding presses, as it affects thickness variation in the final product. Record-breaking for the large area of 3,300 x 3,600 mm is the achieved parallelism of 0.2 mm. This extremely high precision is made possible by a very stiff and precise mechanism, along with the ability to control each of the 9 main cylinders individually.

Switching from fast to slow closing saves cycle time

A light barrier below the upper heating plate detects when the tool reaches the "almost closed" position. At this point, the system automatically switches from fast to slow closing speed. This enables an optimal press closing profile and saves up to 20 seconds per cycle.

Additionally, the height of the tool does not need to be entered manually. This provides more convenience and eliminates the theoretical possibility of incorrect input. As soon as the press opens to a gap of about 100 mm, it pauses briefly to ensure efficient extraction.

The elastomer press built using the "WICKERT modular system" sets new standards in terms of size and energy efficiency. The high standard of production quality regarding temperature and pressure control remains, as does economic efficiency, proven through intelligent, energy-saving measures in the hydraulic design and closing profile.

About the press user

The listed company Semperit AG Holding is an internationally oriented group that develops, produces, and distributes highly specialized rubber products in the medical and industrial sectors to over 100 countries worldwide: examination and surgical gloves, hydraulic and industrial hoses, conveyor belts, escalator handrails, construction profiles, industrial molded parts, ropeway rings, and railway superstructure products. The headquarters of this Austrian company, which has existed since 1824, is located in Vienna. The Semperit Group employs over 7,000 people worldwide, nearly 4,100 of them in Asia and more than 800 in Austria (Vienna and the production site in Wimpassing, Lower Austria). The group has 22 production sites and numerous sales offices in Europe, Asia, Australia, and the Americas. In the 2015 financial year, the group achieved revenues of EUR 915 million and an EBITDA of EUR 96 million.