Traditional Gating-feeding system consists of a funnel, riser, tlacolulita, feeders, and is aimed at controlling the process of filling the shaped alloy and the creation of thermal conditions conducive to directional solidification.
The basis of the flow Gating-feeding system is the Assembly consisting of the funnel-profits. The disadvantage of such a system are the following defects: the high content of non-metallic inclusions, erosion forms and shrinkage. To eliminate these major shortcomings, this system of casting required some refinement, particularly the profitable application of the membranes and integrating them ceramic foam filter.
Technology can be used for casting of cast iron, steel and aluminum, selecting appropriate shell and profit. This technology is used for manual and automatic forming, both with horizontal and with vertical connector.
The criterion for determining the effectiveness of the application of one or another profitable sheath, it refers to the isothermal and exothermic, is considered to be the volume of profitable part of the casting. That is, the larger the cast, the more efficient use of isothermal profitable shells, and the smaller the size of the molded product, the efficiency of the exothermic shells above. Manufacturers and proponents of the use of exothermic shells, try this the criterion to maximize, justifying it by the wonderful properties of the flowing exothermic process. Often, this occurs at the expense of quality and common sense.
Features of the application shells and filter.
The main advantage of direct-flow fill is a complete isothermal profit and ceramic foam filters. Overheating the metal is often unacceptable, and due to the fact that the ceramic foam filter when passing through the jet of metal, the heat takes on its heating, thereby significantly increasing the viscosity of the melt until the metal ceases to flow into the casting (defect "underfill"). There is a need of heating the filter before pouring. Of course, exothermic profitable shell for this purpose are not suitable. There is also no need to use ceramic foam filters for cleaning metal, in the case where the quality of the casting, no one pays attention. However, the use of filtering molten metal for producing high-quality and responsible casting is undeniable. Some enterprises (for example, OJSC "Aviadvigatel", OJSC "Perm engine company") application flow casting in the "ceramic foam filter – isothermal shell" helped to increase the yield of castings. It should be noted that without pre-heating the filter, such results would be impossible.
Of course, in mass production, the heating of a large number of foundry equipment is not possible, however, the heating process of the filters can be automated, if it is economically profitable.
In addition, the use of isothermal shells for insulation of closed profits, under certain conditions, and the size of the casting, it is more expedient to use not only from an economic point of view, but also from the point of view of quality casting. The efficiency of isothermal shells, compared to exothermic, clearly begins to emerge with the tideKah weighing more than 70 kg Should take into account the fact that the exothermic shell rather capricious to storage conditions and use, in the case of "not tripping" exothermic effect, the profit will not perform its main function. In the absence of proper control, in this case, it will be difficult to identify the fact of marriage on the casting.
Manufactured by our enterprise isothermal profitable shells are fundamentally different from analogue, including the presence of a specific exothermic effect, and most importantly, reliability, which, in fact, is a profitable cover.
As for the ceramic foam filters, our preference is given to the German company "Drache". The filters of this company can be made to suit individual approach to each customer and with the same German quality.
Technology application direct fill system "ceramic foam filter – isothermal shell" improve the following indicators:
- increase the yield of metal (7-10%), due to the rejection of the use of the traditional Gating system
- significant reduction of non-metallic inclusions
- obtaining directional solidification
- improved surface quality
- reduction of repairs to the castings.
- increase in places on the model plate, reducing the size of the flask or extra casts.