Modeling of Core Curing
For the prediction of the core curing process, MAGMA C+M considers the gas flow through the open pore volume of a sand core. The common curing mechanisms such as gas curing (PU cold box) or curing through drying (inorganic binders) are simulated. The program also provides information about areas in which amine first locally accumulates before it at least partially evaporates after a certain time.
Typically, the amine gas does not reach all areas of the core at the end of the active amine feed flow. However, these areas are cured during purging, when the purging air carries remaining amine gas through these areas. MAGMA C+M therefore allows for the optimization of gas curing and purging. The temperature control for thermally cured binder systems (hot box, croning, inorganic cores) is effectively supported by MAGMA C+M by means of controlled heating cartridges or through oil channel temperature control. For inorganic cores, the program calculates the drying process which leads to binder hardening in the heated core box, including the transport of water vapor by hot air.
The popularity of inorganic binders is increasing and the process is expected to reach an even higher degree of application in the future. In these systems, the core strength is achieved through a drying process - which is for the most part reversible - in a heated core box. An optimum temperature control of the core box is a significant factor for a successful core production with economically acceptable cycle times. A homogeneous temperature distribution also promotes a homogeneous skin formation which is necessary to remove the core safely from the tooling. MAGMA C+M allows the prediction of the heat flow in the core sand and the accompanying evaporation of water from the binder. Generated water vapor is absorbed by the hot air stream and carried out of the pore volume. In this process, the condensation of evaporated water in colder areas of the core is also considered.
With the simulation of the temperature control for heating the core box from room temperature and the thermal situation during cyclic operation, the positions and the required power of heating cartridges or oil lines can be tested during the design of the core box. In addition, the control of the heaters can be differentiated and analyzed effectively.