ZPF Dosing Furnace – saves space and up to 50 percent of energy
In addition to melting, holding and chip melting furnaces, ZPF Group has extended its furnace range for the aluminium industry by the acquisition of Foundry4 GmbH the German manufacturer of ThermDos dosing furnaces. Standard ThermDos furnaces are available in capacities from 350 to 3250 kg and can be used for high pressure diecasting, as well as sand casting and gravity diecasting. The robust design is simple to operate and ideal for repeatable and accurate pouring. Furthermore, in the latest models, the supply launder for liquid aluminium has been optimized and the floor space required of the dosing furnace reduced by changes in the interior geometry. Thanks to the heating and insulating systems, the energy consumption of the ThermDos is up to 50 percent below that of conventional bale-out crucible furnaces.
The heart of the furnace is its controller that guarantees a high dosing accuracy and short cycle times by synchronization with the diecasting machine. The basis for that is a standard Profibus interface that enables simple communication between furnace and diecasting machine. The system is operated via touch panel. Unambiguous graphics and a machine-oriented command structure facilitate the intuitive handling of the dosing furnace. For example, the dosing weight is entered directly in kilograms. On the display pressure histories can be displayed graphically for easier process monitoring. The data of the last 350 dosing processes are automatically stored and can also be transmitted to an external archive medium if required.
High Metal Quality and Long Service Life
The design of the dosing furnace is such that a filling is possible even during dosing so that it can work without interruptions. Charging and discharge of the aluminium always occur below metal level. In this way, introduction of air into the melt, which would influence the quality of the casting, is prevented. Instead, liquid metal is discharged almost oxide-free. The aluminium is heated by silicon carbide (SiC) heating elements together with the highly efficient insulation that keep the energy consumption of the furnace very low. In order to guarantee long endurance and long service life in continuous operation, only high-quality materials are used in the furnace construction. Moreover, replacement parts are interchangeable those of other manufacturers. The ThermDos has a height-adjustable scissor-type tilting/lifting rack which simplifies the emptying and cleaning of the furnace. Also, alloy changes can be carried out quickly and easily thanks to this facility.
When selecting the suitable dosing furnace for high pressure die casting, the clamping force of the machine, shot weights and cycle times are particularly influential. For sand and gravity diecasting applications, the furnace choice and its configuration depends on the weight range of the castings, the metal quality requirements and the space available. Eight standard sizes are available and every dosing furnace may also be adapted individually to the customer’s special requirements.