Page 43 - Апрель

FOUNDRY PRODUCTION

In this form, the assembled model, lined with a film of the bag, can be removed from the
mold, using it to make a mold from a self-hardening bulk or bulk mixture by feeding and curing
the mixture first from the outside of the bag, and then feeding and curing the mixture inside
the bag. From this form, the foam model should be burned out at temperatures above 400-
5000 ºС using the burn-out casting method, because the film of the bag will deteriorate the gas
permeability of the form for LFC.
There are options without evacuating the bag, when, after loading the polyhedrons, a
self-hardening molding mixture is also fed into the bag in form 2, which keeps them assembled,
and the bag film serves as a separating coating. After removing from the reusable mold 2, the
assembled model in a coma of the hardened sand mixture is removed from the bag and molded
by conventional methods using the LFC method, which is acceptable for polyhedrons with a
partition thickness of more than 6 - 10 mm.
It is even easier to make a prefabricated
model in a disposable sand mold 2 without
removing and without using a bag 3. This mold is
made from a mixture with a binder on a wooden
model. Model polyhedrons are poured into the
resulting cavity; their compaction in all cases is
possible by using a removable weight 4 and /
or vibration, which contributes to their optimal
placement, tight pressure edges of faces with
partial cutting of edges of edges and vertices
into adjacent polyhedra. After compacting the
model, the through holes of the polyhedrons
are fed sand and completing the mold by known
molding methods, combining the model with a
gating system and forming a sand layer in the
mold above model.
Alternatively, a frame made of model
polyhedrons can be combined with a solid
gasified model, or with individual polyhedrons covered with a synthetic film without access to
their pores of the sand mixture (such a film of a part of the frame is possible for other types
of frame castings), and obtain a frame casting with monolithic parts or inserts at a given
location. The analogy of frame structures with the microstructure of amorphous metals, the
atomic configuration of which looks like the indicated polyhedrons as the most dense packing,
according to crystallography data, it makes it possible to transfer some properties, for example,
isotopy, to cast metal cellular structures.

Stanochniy park 43