Improved dosing and control at Handtmann

The globally-positioned Handtmann Group operates 44 Westomat dosing furnaces at its headquarters in Biberach, Germany. Its extensive experience with light alloy dosing technology enabled the casting manufacturer to carry out a successful modernisation programme with the help of the StrikoWestofen specialist team. Together, the two partners modernised the tried and tested PneuCo system with a flanged riser tube. This modernisation project led to great improvements in dosing system availability and process stability.

Handtmann Group (Biberach) believes the three key factors to success are: pioneering technology, innovation and commitment to quality. The light metal casting expert was able to observe all three of these principles during the recent modernisation project. Over a 24 month period, StrikoWestofen carried out a comprehensive upgrade of 44 Westomat dosing furnaces. The switch to flanged riser tubes with pneumatic measurement of the liquid metal level - PneuCo system, and the installation of the ProDos3 control systems means the furnaces are now well equipped for the challenges ahead.

To optimise dosing system availability and process stability, and to further minimise scrap rate, all 44 Westomat dosing furnaces at Handtmann were upgraded with flanged riser tubes that boast replicable conditions and straightforward handling. One clear condition was imposed, pointing out the extremely good experience of the PneuCo system over the years, Handtmann made it clear that it did not wish to sacrifice this when switching from classically-casted to flanged riser tubes.

A small flow of air from the output of the pneumatic control is directed to the scanning point in the riser tube. As soon as the rising level of the liquid metal in the riser tube covers the air outlet, the pressure in the PneuCo system rises suddenly. This rise is detected by a pressure switch and transmitted to the dosing control as a dosing contact. This pressure switch process corresponds to the dosing contact used in classical electrode scanning. Light metal foundries benefit in two ways: there are no wear parts for the dosing contact and the scrap rate is minimised by eliminating possible interference with molten metal. Handtmann’s commitment to quality led it to choosing the PneuCo system with flanged riser tubes. The new solution is currently being tested during production and the company is extremely happy with the results.

In addition to the PneuCo upgrade, Handtmann also decided to improve furnace control with the ProDos3 high precision control system for high pressure die casting. Holger Stephan, who manages the Service and Spare Parts division at StrikoWestofen, explains: "Our ProDos3 with integrated biscuit correction increases the dosing accuracy of the Westomat. In addition, pressure fluctuations can be compensated, and reproducibility improved using a number of different correction factors": The optional web server is another new feature that allows the integration of the ProDos3 control into the local company network. This means that all relevant information, e.g. the furnace pressure and performance data, can be accessed conveniently from your office.

The modernisation programme also included joint testing of new refractory replacement parts for Westomat. A clear reduction in downtime during refractory repairs to the furnace with similar quality results supports Handtmann's three principles. As a result, the product will be used in the future when repairs are carried out on the lining of dosing furnaces. Finally, a new StrikoWestofen heating station increases the level of occupational safety when handling hot ceramic components, and a special assembly bench has simplified the fitting of flanged riser tubes with PneuCo. 

Stephan added: "We are extremely happy with the successful modernisation programme and are proud that we were able to meet the specific requirements of our customer in such a flexible and cooperative way".