It is well known that the shell, as soon as it is completely dry, is not yet a real ceramic and at that point, it only has the so-called green strength. It is not yet ripe and firm. This strength is reached after the burning process. Pouring hot melt is much less critical and more or less a mere formality. Particularly critical is the moment before burning, when the wax must be removed from the fragile shell, i.e. when it has to be melted. If this process is too slow or if the pressure and temperature are not correct, the wax can expand and burst the shell or at least cause fine cracks.

Exactly these cracks will then lead to a flaking of the shell, to inclusions in the cast and finally determine the reject rate. This is why so-called steam autoclaves are used worldwide, because 180-degree steam, which is generated at a pressure of up to 10 bar, most quickly couples with the mold shell, condenses and suddenly releases the energy stored in it, thus allowing almost stress-free dewaxing. All other methods, such as the so-called Flashfire, in which the green solid shell is heated directly to 1,000 degrees Celsius, the heat transfer is slower and usually cause more rejects or require firmer, i.e. thicker, mold shells. That is the theory. But what does it mean when the part is huge, and the required autoclave must be a monster machine? It is a major challenge regarding the component, and there is only one company in the world that dares to build such a device with an inner diameter of 10 feet, i.e. 3 meters: MK Technology.