Vacuum casting machine

A vacuum casting machine has a rotary table obtaining motion from a self-contained drive and accommodating chambers with casting molds. In turning, the rotary table causes each of the chambers to register in succession with an opening in a melting chamber through which metal is being poured. This arrangement of mold chambers enables partial overlapping in time of such processes as preparing a mold for pouring, the melting of charge and accumulating melt in the melting chamber in a requisite amount, and the cooling of each mold with the casting. This all considerably increases the production rate of the machine.

BACKGROUND OF THE INVENTION 
The present invention relates to the equipment for melting and casting 
metal in a vacuum, and more specifically to vacuum casting machines. It 
may be used to advantage in vacuum metallurgy employing electric furnaces 
where the operation of preparing the molds for casting and cooling of the 
castings is a rather time-consuming one. The most expedient way of using 
the invention is the incorporation of the machine disclosed into an 
electron beam melting plant producing castings predominantly in refractory 
and chemically-active metals, such as, for example, tungsten, tantalum, 
molybdenum, niobium, titanium, and their alloys. 
There is known a vacuum casting machine comprising a metal-melting vessel 
disposed in a melting chamber fitted with means of heating the metal and a 
vacuum seal serving to close an opening through which the metal is being 
poured, a casting mold accommodated in a chamber of its own so arranged 
that an opening in this chamber in fact registers with the opening in the 
melting chamber, and a system for evacuating both the melting chamber and 
the chamber with the mold (USSR author's certificate No. 212,289). 
The known machine serves the purpose of melting metal and is capable of 
heating the casting mold to approximately 1000.degree. C accompanied by 
the degassing of the material it is made of followed by the centrifugal 
casting of metal in the mold and cooling of the casting to between 
200.degree. and 400.degree. C, all these operations being performed in a 
vacuum. 
In the known machine the melting chamber is accommodated on supports and is 
a water-cooled vessel with heaters for the melting of metal in the form, 
for example, of consumable electrodes producing an arc. The vessel is 
connected to a vapor pour pump. One of the walls of the vessel is provided 
with a manhole used for servicing the items of equipment installed in the 
vessel. This manhole is tightly closed when a vacuum is applied to the 
vessel. 
Rigidly attached at the bottom of melting chamber is a dome-shaped shell 
arranged so that its convex side faces the inside of chamber and provided 
with a centrally-located operating closed by a vacuum seal. The edge of 
shell extends beyond the chamber and forms a pipe which has a flange for 
connecting the chamber containing the mold. The space inside the shell is 
connected to a vacuum pumping system. 
The metal-melting vessel accommodated in the melting chamber is a 
water-cooled crucible provided with means of pouring the metal into the 
mold. Said means incorporates a shaft attached to the crucible with one of 
its ends whereas the other end extends through a vacuum seal beyond the 
melting chamber and is linked up with a self-contained drive. Installed in 
the melting chamber is also a funnel which both forms and directs the 
spout of molten metal as the metal is being poured into the mold. During 
this operation the funnel is inserted into the opening in the dome-shaped 
shell. 
The casting mold is disposed in a separate chamber fitted with a flange for 
connecting to the flange of dome-shaped shell so that the shell and said 
chamber form a space separated from both the atmosphere and the space of 
melting chamber. 
The mold-containing chamber is installed on a carriage and is capable of 
travelling with respect to the melting chamber along rectilinear rails 
placed under the melting chamber. Since the mold somewhat protrudes above 
the flange of its chamber, the carriage is fitted with jacks serving to 
move the mold-containing chamber vertically so as to connect its flange to 
the flange of dome-shaped shell. 
For employing the centrifugal casting process, the casting mold is held 
fast to a base plate provided at the bottom of mold containing chamber. 
The base plate is attached to the end face of a shaft extending beyond the 
chamber by means of a vacuum seal. Fitted to the outside end of the shaft 
is a pulley linked up with an electric motor through a V-belt drive. The 
motor is installed on the carriage. The chamber is also fitted with 
heaters serving to heat the mold. 
The known vacuum casting machine is provided with a self-contained vacuum 
pumping system serving to evacuate both the melting chamber and 
mould-containing chamber. 
The vacuum pumping system of the melting chamber is a two stage one 
consisting of a high-vacuum vapor pump coupled to the melting chamber 
through a vacuum seal and a rough-vacuum mechanical pump producing a 
backing vacuum for the vapor pump. 
The vacuum pumping system of the mold chamber is a single-stage one 
consisting of a rough-vacuum mechanical pump connected to the space inside 
the dome-shaped shell through a line because the mold chamber can be 
evacuated of air only if its flange is coupled to the flange of 
dome-shaped shell. All joints of the casting machine are provided with 
seals. 
By the term high-vacuum pump as employed herein is meant a pump able to 
produce a pressure not below 5.times.10.sup.-3 mm Hg whereas the term 
rough-vacuum pump denotes a pump ensuring a pressure of up to 
1.times.10.sup.-2 mm Hg. Said pumps maintain the requisite vacuum in the 
spaces evacuated throughout the operation. 
The machine operates on the following lines. On sealing and evacuating the 
space of melting chamber, a casting mold is placed into the 
carriage-mounted chamber and secured to the base plate. The carriage is 
moved along the rails under the melting chamber so as to place the flange 
of mold chamber coaxially with the flange of the dome-shaped shell of 
melting chamber. At the next stage, the mold chamber is lifted with the 
aid of jacks so as to enable said flanges to couple one to another. A 
sealing member interposed between the flanges is compressed, sealing off 
the space formed by the dome-shaped shell and mold chamber. The mould 
chamber vacuum system is set into operation, evacuating said space and 
after that heaters are turned on for heating the mold to a temperature of 
approximately 1000.degree. C. 
During the heating of mold, gases are gradually driven off the material of 
mold and to prevent the contamination of the space inside the melting 
chamber by said gases the vacuum seal in the opening of dome-shaped shell 
is closed before setting the mold chamber vacuum system into operation. 
The mechanical vacuum pump of said vacuum system removes the gases as they 
are being liberated from the material of mold. At the same time, the 
melting chamber vacuum system is set into operation. 
On heating the mold to the temperature specified for the process, the rate 
of mold degassing slows down considerably, an increase in the vacuum in 
the dome-shaped shell indicating this condition. At this instant, the 
vacuum seal in the opening of dome-shaped shell is opened whereas the mold 
chamber vacuum system is disconnected and the vacuum in both the melting 
chamber and mold chamber is maintained with the aid of the high-vacuum 
vapor pump of the melting chamber vacuum system. A further increase in the 
vacuum brings about further degassing of the material of mold and an 
interval of time is required until this degassing is completed. After that 
a voltage is applied to the consumable electrodes and the melting of the 
charge, placed in advance into the melting vessel of the melting chamber, 
is started. When sufficient melt of specified chemical composition is 
accumulated in the melting vessel, a funnel serving to protect the vacuum 
seal from splashes and direct the spout of melt into the casting mold is 
inserted into the opening in the dome-shaped shell. To produce castings by 
the centrifugal casting process, the drive of the base plate shaft is set 
into operation with the casting mold secured to said base plate. The 
electrodes are removed from the melting zone and deenergized, and the 
pouring arrangement is set into operation to pour the mold. 
On completing the pouring, the funnel is returned into its original 
position and the casting in the mold is cooled to a temperature at which 
the gases of the atmosphere have no harmful effect on the material of the 
casting. The cooling takes place in a vacuum, i.e., the mold chamber 
remains connected to the melting chamber. 
During the process of cooling, the vacuum in mold chamber is maintained 
with the aid of the vapor pump of melting chamber; alternatively, if the 
vacuum seal in the dome-shaped shell is closed, the vacuum is produced by 
the mechanical pump of the mold chamber vacuum system. If necessary, the 
casting can be cooled under a blanket of an inert gas pumped into the 
dome-shaped shell while the vacuum seal is being closed. 
On finishing with the cooling of casting, the mold chamber is lowered onto 
the carriage with the aid of jacks and wheeled out from under the melting 
chamber along the rails. After that, the mold with the casting is removed 
from the base plate to which it is held down and withdrawn from the 
chamber. A new mold is placed into the chamber and the cycle is repeated. 
It will be noted that the known vacuum casting machine operates in several 
stages which are: the placing of the mold on, and securing to, the base 
plate in the chamber accommodated on the carriage; the wheeling of the 
carriage with the chamber under the melting chamber and coupling the mold 
chamber to the melting chamber in a vacuum-tight fashion; the heating of 
the mould and the degassing of mold material with the rough-vacuum pump 
set into operation; the final degassing of mold material with the vacuum 
seal in the dome-shaped shell held open and the evacuation of both the 
melting chamber and mold chamber with the aid of the high-vacuum pump; the 
melting of charge and pouring of the mold; the cooling of the casting; the 
disconnection of the mold chamber from the melting chamber and the 
wheeling of the carriage from under the melting chamber for the purpose of 
removing the casting. 
The machine may feature more than one carriage with mold chambers. In this 
case there is a practical possibility to overlap in time to some extent 
the operations of removing the mold with cooled-down casting and of 
coupling a new chamber with a mold to the melting chamber. 
The known vacuum casting machine suffers from a number of drawbacks, one of 
them being the fact that the mold chamber is of a layout which enables the 
operations of mold heating and degassing of mold material and also that of 
cooling to take place only if the mold chamber is connected vacuum-tightly 
to the melting chamber (there is no other way of evacuating the mold 
chamber except through the dome-shaped shell of melting chamber). For the 
same reason, the casting is cooled also while the chambers are connected 
one to another in a vacuum-tight fashion or otherwise the gases of the 
atmosphere will have an adverse effect on the material of the casting. 
The period elapsed in heating the mold and degassing its material and also 
that required for cooling the casting by far exceeds the melting time. 
While casting such metals as tungsten, tantalum, molybdenum and niobium, 
the mold should be heated to more than 1000.degree. C and this heating 
along with the degassing of mould material takes over one hour. The 
process of final degassing is considerably extended in time if electron 
beam guns requiring a vacuum of the order of 1.times.10.sup.-3 mm Hg in 
the melting chamber are used as the means of melting the metal. 
The period elapsed in cooling such castings to a temperature between 
200.degree. and 400.degree. C, which is regarded as harmless from the 
standpoint of illeffects of the gases of the atmosphere on the material of 
the casting, exceeds two hours and is selected depending on the size and 
shape of casting and also the material of mold. This is hardly comparable 
with some 30 to 40 minutes which are commonly required to obtain the 
requisite amount of melt in the melting vessel and so the operation of 
melting cannot be even partly overlapped in time by the operations of 
heating the mold and cooling the casting, said design features of the mold 
chamber being the cause of this disparity. 
It stands thus to reason the production rate of the known machine is in 
fact decided by the duration of the period elapsed in time-consuming 
auxiliary operations of heating and degassing the mould and cooling the 
casting, and this is a disadvantage of the known machine. 
Another disadvantage of the known machine is the fact that the mould 
chamber is of the non-split type, rendering the access to the base plate 
for securing the mould thereto difficult. Used commonly in such a chamber 
for holding down the mould is a contrivance clamping the mould due to the 
action of the centrifugal forces coming into play when the base plate is 
set spinning. Said contrivance fails to give reliable performance because 
it cannot prevent the mold from moving away from the centre of bed plate 
under the influence of radial forces coming into existence if the casting 
in the spinning mold becomes even slightly non-symmetrical. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is an object of the present invention to eliminate said disadvantages. 
Another object of the present invention is to provide a vacuum casting 
machine of a design which will considerably increase the production rate 
controlled by the period elapsed in obtaining the melt in a requisite 
amount and in pouring the mold. 
A further object of the present invention is to provide a vacuum casting 
machine which is handy and reliable in operation. 
Said objects are attained in a vacuum casting machine comprising a 
meta.sup.1 -melting vessel disposed in a melting chamber equipped with 
means of heating the metal and a vacuum seal serving to close an opening 
through which the metal is being poured, a casting mold disposed in a 
chamber of its own arranged so that its opening in fact registers with the 
opening in the melting chamber and a system for evacuating both the 
melting chamber and mold chamber, said machine incorporating according to 
the invention a rotary table with a self-contained drive and mold chambers 
rigidly attached to the table all the way around its circumference and 
each fitted with a vacuum seal; said rotary table places in turning each 
of the mold chambers in communication with the opening in the melting 
chamber whose vacuum seal connects to the vacuum seal of each of the mold 
chambers in a vacuum-tight fashion through a vacuum seal while the metal 
is being poured into the mold. 
The present invention allows preparing the next mold for pouring at the 
same time that instant the current melting is finished and additionally 
allows the cooling of the casting simultaneously with the melting of the 
next charge and preparing the next mold disposed in its chamber on the 
rotary table. In addition, there is no need to place the mold chambers 
under the melting chamber in strict succession one after another; this, in 
its turn, allows the variation, in the case such necessity does not exist, 
of the period of preparing each of the molds for pouring depending on the 
weight of casting and, consequently, allows variations in the time of the 
cooling of the castings without interfering with the procedure of 
preparing the next batch of melt in the melting chamber. 
It is expedient that the mold chambers are provided each with a second 
opening accommodating a vacuum seal for coupling the chamber to a pump 
additionally provided in said system for evacuation and installed on the 
rotary table. The provision of a vacuum pump on the rotary table and the 
fact that this pump can be connected to each of the chambers allow 
evacuation of the chambers to a vacuum of the same order as the vacuum 
produced in the melting chamber so that the gases driven off the material 
of molds when each of the mould chambers is vacuum-tightly linked to the 
melting chamber cannot contaminate the space of melting chamber. 
In an embodiment of the present invention, the pump installed on the rotary 
table is connected to a line of preliminary vacuum through lines so that 
the lengths of lines adjacent to the joints are disposed along the axis 
about which the table is rotating. Such a connection between movable and 
fixed lengths of lines has proved its reliability over a long period in 
service. 
In another embodiment of the present invention, each of the mold chambers 
is fitted with a base plate accommodating the mold, rigidly secured 
thereto, and attached to the end face of a shaft extending beyond the 
chamber and receiving rotary motion from a stationary drive enabling the 
centrifugal casting of metal to take place. Owing to this arrangement 
there is only one drive serving the needs of all the mold chambers 
provided on the rotary table. 
In a further embodiment of the invention, each mold chamber is of the split 
construction and consequently can be split along a plane running close to 
the junction between the mold and base plate; furthermore, the rotary 
table is provided with an opening of a diameter which somewhat exceeds the 
diameter of that portion of chamber which accommodates the base plate with 
mold and is adapted for removal. On removing this portion of the chamber 
with the base plate and there is free access to the means of securing the 
mold to the base plate and the mould can be firmly secured in place. 
Still in another embodiment of the present invention, the removable portion 
of chamber is provided with rollers at its bottom resting on circular 
rails disposed in a plane parallel to the rotary table and concentrically 
with the axis of its rotation, said rails being of split construction and 
installed so that a length of them is capable of moving in a vertical 
plane. By virtue of this arrangement, the parts of each chamber remain 
connected in a vacuum-tight fashion while the rotary table is on the move 
and, moreover, there is the capacity to mechanize the jobs of placing the 
mold into the chambers and withdrawing the mold integrally with the 
castings. 
Thus, in the vacuum casting machine disclosed, the rotary table with the 
chambers mounted thereon enables both the preparation of each mold for 
pouring and the cooling of the mold with the casting without any 
connection between the mold chamber and melting chamber. By virtue of this 
fact, the production rate of machine is controlled mainly by the time 
required to melt a charge.

The vacuum casting machine disclosed serves the purpose of casting 
predominantly refractory and chemically active metals and their alloys. It 
incorporates a melting chamber 1 (FIG. 1) with electron beam guns 2 
thereon for the purpose of melting metal. Accommodated in the melting 
chamber 1 is a vessel 3 (FIG. 2) wherein metal is being melted. For 
pouring the metal the wall of the chamber 1 is provided with an opening 4 
closed by a vacuum seal 5. The melting chamber 1 contains a pouring means 
6 for pouring metal into a casting mould 7 placed in a mold chamber 8. The 
vacuum casting machine according to the invention is provided with a 
rotary table 9 obtaining motion from a self-contained drive 10 (FIG. 3). 
Rigidly secured to the rotary table 9 all the way around its circumference 
is a plurality of chambers 8 (FIGS. 1, 2 and 3) each of which is provided 
with an opening with a vacuum lock 11 serving the purpose of in a, 
vacuum-tight fashion, the chamber 8 to the vacuum lock 5 (FIG. 2) of the 
melting chamber 1 when the mold 7 is being filled. The vacuum seals 5 and 
11 are linked up vacuum-tightly one with another by means of a vacuum seal 
12. 
The machine is provided with a system for evacuating the melting chamber 1, 
mold chambers 8 and electron beam guns 2. 
The system serving to evacuate the melting chamber 1 and electron beam guns 
2 incorporates a rough-vacuum mechanical pump 13 (FIG. 1) which is capable 
of producing a pressure of the order of 1.times.10-1 mm Hg. The pump 13 is 
connected to a receiver 16 through a line 14 with a valve 15 and the 
receiver 16, in its turn, is coupled to the melting chamber 1 through a 
line 17 with a valve 18. Line 19 with a valve 20 is connected to the 
receiver 16 thereby providing a link between a high-vacuum vapour pump 21 
fitted with a vacuum seal 22 and to the melting chamber 1. The high vacuum 
vapor pump 21 is capable of evacuating said melting chamber to a pressure 
as low as from 1.times.10.sup.-3 to 5.times.10.sup.-5 mm Hg. ln addition, 
the receiver 16 is connected to diffusion pumps 27 and 28 through a line 
23 with a valve 24 and a line 25 with a valve 26, respectively. The 
diffusion pumps 27 and 28 provide a means of evacuation the space around 
the cathodes of the electron beam guns 2 to a pressure of approximately, 
1.times.10.sup.-5 mm Hg. Each of said pumps is equipped with a vacuum seal 
29 and 30, respectively, for connecting the pumps to the respective 
electron beam guns 2. 
To create a preliminary vacuum in the mold chambers 8 mounted on the rotary 
table 9, the vacuum pumping system also incorporates a mechanical pump 31 
connected to a receiver 34 through a line 32 and valve 33, and the 
receiver 34, in its turn, is connected with the mold chambers 8 installed 
on the rotary table 9 through the intermediary of a line 35 and valve 36. 
Before entering each of the chambers 8, the line 35 (FIG. 2) is bifurcated 
and each branch is fitted with a valve 37. 
Disposed on the rotary table 9 is a vapor pump 38 additionally introduced 
into the vacuum pumping system and capable of producing a pressure of 
approximately 1.times.10.sup.-3 mm Hg in the mold chambers 8. Said pump is 
coupled to a mechanical vacoum pump 41 through a line 39 with a valve 40 
(FIG. 1). 
The melting chamber 1 (FIG. 2) is a cylindrical water-cooled vessel of 
welded construction with a flat bottom installed on supports 42. Pipes 43 
fitted into the holes at the top of the melting chamber 1 provide a 
connection with the electron beam guns 2 through vacuum seals 44. The 
vessel 3 disposed in the melting chamber 1 is a water-cooled lined 
crucible fitted to a horizontal shaft 45 (FIG. 3) extending with its other 
end beyond the melting chamber 1. The shaft 45 rest on brackets 46 with 
provision for rotation thereon and the brackets 46 are rigidly secured to 
the bottom of the melting chamber 1. The shaft 45 has drillings (not 
shown) admitted through which into the jacket of the vessel 3 is water for 
cooling and is an item of the pouring means 6 serving to pour the casting 
mould 7. Said pouring means also incorporates a hydraulic cylinder 47 
attached outside the melting chamber 1 at its bottom at right angles to 
same so that a piston rod 48 of the hydraulic cylinder 47 enters the 
melting chamber 1 through a hole in its bottom and is pivotally linked 
with the vessel 3 by means of a tie rod 49. The bottom of the melting 
chamber 1 is also pierced by the opening 4 with a pipe 50 accommodated 
wherein is the vacuum seal 5. 
The vacuum seal 5 consists of a hollow body 51 (FIG. 4) with an opening 
closed by a water-cooled cover 52 attached to a rod 53 whose other end 
extends beyond the body 51 so as to be capable of reciprocating back and 
forth integrally with the cover 52 in the direction coinciding with the 
direction of the longitudinal axis of the rod 53. The cover 52 has a boss 
pierced by a hole which enables the rod 53 to pass through the cover. 
Accommodated on that portion of the rod 53 which is inside said hole there 
is an eccentric 54 serving to hold down the cover 53 to a seal 55 disposed 
in the body 51 concentrically with the opening provided therein. The 
vacuum seal 11, 22, 29, 30 and 44 referred to above are of the same 
construction. 
The space inside the body 51 communicates with the receiver 34 (FIG. 1) 
through a line 56 with a valve 57. The body 51 (FIG. 4) is fitted with a 
flange 58 disposed coaxially with the opening in the body and attached to 
said flange is the vacuum seal 12 comprising two coaxially arranged 
bellows 59 and 60 with a flange 61. The space between the bellows 59 and 
60 communicates through a pipe 62 contacting the flange 58 with a source 
of liquid (not shown) kept under a pressure. The lower (as shown in the 
drawing) end face of the flange 61 is provided with an annular groove to 
accommodate a sealing ring 63. 
Inside the melting chamber 1 (FIG. 2) in front of the opening in the body 
51 (FIG. 4) of the vacuum lock 5 (FIG. 2) there is disposed a funnel 64 
serving the purpose of directing the spout of metal into the casting mold 
7 and protecting the locks 5 and 11 from splashings of molten metal. The 
funnel 64 is arranged in the melting chamber 1 with provision for 
reciprocating up and down along its axis by means of a rack 65 fitted to 
the tundish 64 and meshing a pinion 66 disposed at an end of a shaft 66a 
extending beyond the melting chamber 1 through a vacuum seal (not shown). 
Running coaxially with the tundish 64 inside the melting chamber 1 there 
is a heater fitted to an end of a rod whose other end extends beyond the 
melting chamber and serves to apply voltage to the heater 67. The length 
of the rod 68 is selected so that the upper portion of the tundish 64 
embraces (as shown in the drawing) the heater 67. 
The vessel 3 is charged from a hopper 70, using a feeder 69. The feeder 69 
rests on the support 42 and a part of it extends into the melting chamber 
1 through a side port. A vacuum seal 71 of a construction similar to that 
of the vacuum seal 5 (FIG. 4) is interposed between the hopper 70 and 
feeder 69. The feeder 69 (FIG. 2) is fitted with a telescopic screw which 
overhangs the vessel 3 during the operation of charging but is retracted 
into the feeder 69 during the operation of melting. The hopper 70 is 
provided with a lid 72 closing it in a vacuum-tight fashion. The hopper 70 
is connected with the receiver 34 (FIG. 1) through a line 73 with a valve 
74. An inspection window 75 (FIG. 2) in the melting chamber 1 enables the 
monitoring of the melting process. In addition, the temperature of the 
melt in the vessel 3 can be monitored by means of a transducer 76 
available at the top of the melting chamber 1 as shown in the drawing. 
The rotary table 9 (FIG. 1) of the vacuum casting machine is a horizontal 
plate resting on rollers 77 (FIGS. 2 and 3) fitted at its bottom as shown 
in the drawing all the way around the circumference and travelling over 
circular rails 78 accommodated on supports 79. 
Spaced uniformly around the plate of the rotary table 9 (FIG. 1) there are 
openings each containing a chamber 8 with a casting mold 7. In an 
embodiment disclosed, the rotary table 9 carries six chambers 8. In 
general, the number of the mold chambers 8 accommodated on the rotary 
table 9 is decided by the ratio of the time elapsed in preparing a mold 
and cooling the casting contained therein to the time elapsed in preparing 
a next batch of melt in the vessel 3 for pouring another mold 7. 
For fitting the mould chambers 8 into the openings of the rotary table 9, 
locating shoulder 80 is provided on the side surface of each chamber next 
to the mating side surface of opening (FIG. 4) and somewhat above the 
shoulder each chamber 8 has a flange made integrally with the chamber, 
said shoulder resting on the plate of the rotary table 9 and fixed to same 
by bolts (not shown). The rotary table 9 is so disposed with respect the 
melting chamber that in turning it enables the vacuum lock 11 of each 
mould chamber 8 to register with the vacuum lock 5 of the melting chamber 
1. 
The rotary table 9 is set into motion with the aid of the drive 10 (FIG. 3) 
accommodated on one of the supports 79. Fitted to an output shaft 82 (FIG. 
2) of the drive 10 is a pinion 83 meshing a gear ring 84 attached to the 
side surface of the rotary table 9. For accurate positioning of the table 
9 after it has been turned, use is made of an actuating cylinder 85 (FIG. 
4) with a piston rod 86 arranged vertically and rigidly secured to one of 
the supports 79. Cylindrical through holes 87 provided in the plate of the 
rotary table 9 between the adjacent mold chambers 8 serve to accommodate 
the piston rod 86 of the cylinder 85. It will be noted that the support 79 
is turned in FIG. 4 so as to be superimposed on the plane of drawing. The 
tip of the piston rod 86 is a conical one to facilitate the centering of 
each hole 87 in the table 9 with respect to the piston rod 86. 
Each of the mould chambers 8 communicates with the vapor pump 38 (FIG. 2) 
attached to the rotary table 9 by way of an intermediate vessel 88 
accommodated directly on the table 9. Each of the mold chambers 8 has a 
hole with a pipe 89 and a vacuum seal 90 of the same construction as the 
vacuum seal 5 (FIG. 4) considered above through which each of the mold 
chambers 8 is connected to the intermediate vessel 88 and, consequently, 
to the pump 38. The intermediate vessel 88 is fitted with pipes whose 
number corresponds to the number of mould chambers 8 available, each of 
these pipes being disposed coaxially with the pipe 89 of the corresponding 
mold chamber 8 on the other side of its vacuum seal 90 and serving to 
connect the intermediate vessel 88 to the corresponding mold chamber 8. 
Should such necessity arise, each of the mold chambers 8 can be provided 
with a vacuum pump 91 (FIGS. 5 and 6) installed also on the rotary table 9 
and serving only one said chamber. In this case, each such pump 91 is 
separated from the respective mold chamber 8 by a vacuum seal 92. For 
connecting each of the pumps 91 to the mechanical vacuum pump 41 (FIG. 1), 
the line 39 is bifurcated at the entry into each of the pumps 91 (FIG. 6) 
in the same way as the line 35 and each of the branches is fitted with a 
valve 93. 
Each of the mold chambers 8 is a vessel of cylindrical shape cooled with 
water. For employing the centrifugal casting process, disposed in each 
chamber 8 is a base plate 94 attached to an end face of a shaft 95 
extending beyond the mold chamber 8, said base plate accommodating one of 
the mold 7 rigidly secured thereto. Arranged at the opposite end of the 
shaft 95 is a gear 96 meshing a gear 97 (FIG. 2) of a drive 98 when the 
vacuum lock 11 of a mold chamber 8 is linked up with the vacuum lock 5 of 
the melting chamber 1. The drive 98 is a stationary one and is disposed on 
a platform 99 secured to the corresponding support 79. 
Spaced equidistantly around the circumference of each base plate 94 there 
are cams 100 (FIG. 4) serving to hold the mould 7. This mold is also 
located in the central position by means of projections 101 arranged on 
the base plate 94 diametrically opposite each of the cams. Each of the 
cams 100 is disposed in a radial recess 102 of the base plate 94. Each 
recess is dovetailed in cross-section and provided with a tapped hole in 
its end face which accommodates a screw 103 also passing through a hole in 
the cam 100. 
Each of the mold chambers 8 is of split construction and consists of an 
upper portion 104 as indicated on the drawing and a lower one shown at 
105. The split is located in close proximity to the junction between the 
mold 7 and base plate 94. Said construction of the mold chamber 8 enables 
reliable securing of the mold 7 to the base plate 94. A point to be noted 
is that the diameter of the openings in the rotary table 9 somewhat 
exceeds that of that poriton 105 of the chamber 8 which accommodates the 
base plate 94 with the mold 7. 
Each of the shafts 95 of the base plates 94 receives support from a bracket 
106 which has a housing 107 made integrally with the lower portion 105 of 
the mould chamber 8. Fitted in the bore of the housing 107 is a journal 
bearing 108 and a journal thrust bearing 109. Interposed between the 
stationary races of the bearings 108 and 109 is a distance piece 110 and 
the static outside race of the bearing 109 is held in place by a flange 
111 provided on the lower end face, as shown in the drawing, of the 
housing 107 accommodated on the bracket 106. 
Each of the shafts 95 has a blind axial drilling provided with a partition 
112 which runs diametrically along the geometrical axis of the shaft 95 
and has a horizontal portion at its bottom as indicated in the drawing. 
Both parts of the drilling in the shaft 95 comminicate with the water 
jackets of the base plate 94 circulating through which is cooling water. 
The wall of the shaft 95 in close proximity of the horizontal portion of 
the partition 112 is pierced on both sides of the partition with holes 113 
and 114. On the inside surface of the distance piece 110 level with said 
holes 113 and 114 there are provided annular grooves 115 and 116, 
respectively. Passing through the distance piece 110 level with the 
grooves 115 and 116 are radial tapped holes accommodating pipes 117 and 
118, respectively, which, in their turn, pass through the housing 107 by 
way of an opening. Connected to each of the pipes 117 and 118 are flexible 
hoses 119, serving as the inlet and outlet for cooling water. To keep 
water out of the bearings 108 and 109 use is made of sealing rings 120 
which are held down each by a flange 121 abutting against a step on the 
inside surface of the distance piece 110. 
Interposed between the space inside each of the mold chambers 8 and the 
space inside the corresponding housing 107 of the bracket 106 is a cup 122 
disposed in an annular recess machined in the upper portion of the housing 
107 as indicated in the drawing coaxially with the opening. Each cup 122 
is held down to the base of recess by a flange 123. 
Each of the mold chambers 8 is equipped with a water-cooled induction coil 
124 serving the purpose is heating-up the mold 7 and is attached to the 
inside of chamber. The leads from each induction coil 124 pass through a 
vacuum seal 125 inserted into an opening in a side wall of the upper 
portion 104 of the mold chamber 8 which remains stationary with respect to 
the rotary table 9. Contactors 126 accommodated on brackets 127 which are 
rigidly secured to supports 79 are provided for connecting the induction 
coils to a stationary source of power (not shown) after each turn of the 
rotary table 9. 
The lower separable portion 105 of each mold chamber 8 rests on rollers 128 
(FIG. 7) arranged so that the axes of their rotation are parallel to the 
plane of the rotary table 9. The rollers 128 travel over circular rails 
129 disposed in a plane parallel to the plane of the rotary table 9 
concentrically with the axis of its rotation and serve the purpose of 
pressing the lower separable portion 105 of the mould chamber to the upper 
portion 104 and assuring tightness of the joint between said portions. The 
rails 129 rest on supports 79 (FIGS. 1 and 2). 
Each of the rollers 128 is attached with the aid of a sleeve 130 secured to 
the bottom of the lower portion 105 (FIG. 7) of each mold chamber 8 with 
its end face and accommodating a rod 131 in its bore. Rigidly fitted to 
the other end of the rod 131 is a yoke 132 with a hole passing through 
which is a fulcrum pin 133 of the roller 128. That portion of the rod 131 
which is inside the sleeve 130 is provided with an axially running 
rectangular slot inserted into which is a pin 134 whose ends rest in holes 
provided in the sleeve 130. A spring 135 is slipped on the rod 131 so that 
one of its ends comes abutting against the yoke 132 and the other against 
the end face of the sleeve 130. The attachment of the rollers 128 to the 
lower portion 105 of each mold chamber 8 (FIG. 2) allows to offset any 
inaccuracy in the disposition of the rails 78 and 129 one with respect to 
the other. 
The lower portion 105 of each mold chamber 8 can be separated from the 
portion 104 of the same chamber for removing the mould 7 with a casting 
and replacing it by a new mold 7 by means of the rails 129 which are made 
up of sections installed so that one section can be moved vertically. This 
movable section of rails between two adjacent supports 79 is placed on a 
flat 136 resting, in its turn, on piston rods 137 of actuating cylinders 
138. The cylinders 138 are disposed on a round turn table 139 given the 
shape of a truncated cone carrying a gear ring on its side surface. The 
gear ring meshes a gear 140 fitted to an output shaft 141 of a drive 142 
intended to turn the turntable about its axis so as to register the 
section of the rails 129 arranged on the flat 136 with rectilinear rails 
143 which are disposed radially with respect to the rotary table 9 at a 
height corresponding to the lowermost position of the flat 136. The rails 
143 are accommodated on props 144 and serve the purpose of withdrawing the 
separable lower portion 105 of the mold chamber 8 integrally with the base 
plate 94 and the mold 7 resting thereon from under the rotary table 9 so 
as to make the mold 7 accessible. 
If each of the molds 7 and, consequently, the chambers 8 accommodating same 
are of comparatively small size, preference is given to split mould 
chambers of less intricate construction as indicated in FIG. 4. In each of 
said mold chambers 8, the joint between its portions 104 and 105 is 
rendered vacuum-tight with the aid of clamps 145 spaced equidistantly all 
the way around the circumference. 
Serving the purpose of withdrawing the separable portion 105 of each mold 
chamber 8 integrally with the base plate 94 and mold 7 accommodated 
thereon, are sleeves 146 disposed vertically so as to contact the bottom 
of each separable portion 105 as indicated in FIG. 2 and contain the ends 
of the piston rods 137 of the actuating cylinders 138 in their bores. 
The pump 38 installed on the rotary table 9 is connected in accordance with 
the invention to the mechanical pump 41 (FIG. 1) through the line 38. 
Since the pumps 38 and mold chambers 8 move integrally with the rotary 
table 9 when said table turns, certain lengths of the line 35 serving to 
create a preliminary vacuum in the mold chambers 8 and also those of the 
line 39 also rotate with the table 9. Each of the joints between the 
moving and static lengths of the lines 35 and 39 is fitted with a coupling 
device shown in FIG. 8. It will be noted that the device consists of a 
static socket 147 and a movable socket 148 disposed coaxially and facing 
each other with their end faces. The sockets 147 and 148 are installed 
along the axis of rotation of the table 9. The bottom of the static socket 
147 is pierced with a centrally located axial hole fitted into which is 
the static length of the line 39 also disposed along the axis of rotation 
of the table 9. The socket 147 is attached rigidly and vacuum-tightly to 
said length of the line 39. The bottom of the movable socket 148 is also 
provided with a centrally located axial hole and said length of the static 
line 39 extends into this hole without being attached thereto. The length 
of the line 39 rotating integrally with the table 9 is provided with a 
flange 149 rigidly secured to the end of the line. The flange 149, in its 
turn, is attached to the bottom of the movable socket 148 and is provided 
with a locating projection engaging a recess in the bottom of the socket 
148. Also accommodated in said recess is a sealing ring 150 held down to 
the bottom of the recess and the side surface of the line 39 by a 
projection on the flange 149. 
The static socket 147 is also provided with a side hole rigidly fitted 
wherein in a vacuum-tight fashion is the end of a static length of the 
line 35. The movable socket 148 is provided with a similar side hole 
fitted into which in the same way is the end of a rotating length of the 
line 35. The end face of the static socket 147 has a cylindrical 
projection which is a loose fit into the movable socket 148. An annular 
recess in the end face of the movable socket 148 accommodates a seal 151 
embracing said cylindrical projection of the static socket 147. The seal 
151 is held down to the bottom of the recess by a flange 152 attached to 
the end face of the socket 148. 
Both the static socket 147 and movable socket 148 are provided with flanges 
153 and 154, respectively, which are located in close proximity to the end 
faces of sockets. The upper end face of the flange 153, as shown in the 
drawing, has an annular groove disposed wherein is a plurality of balls 
155 held down to the bottom of the groove by the end face of the flange 
154. The upper end face of the flange 154, as shown in the drawing, has 
also an annular groove disposed wherein is a plurality of balls 156 held 
down to the bottom of the groove by a slip-on flange 157. Provided along 
the periphery of the flanges 153 and 157 are bolt holes fitted into which 
are hold-down bolts 158. 
The vacuum casting machine is equipped with a service platform 159 (FIG. 3) 
arranged close to the melting chamber, which is provided with a service 
manhole 160. Accommodated on the service platform 159 is a control desk 
161 with all the instruments and controls required for monitoring and 
controlling the process. 
In the accompanying drawings the six mold chambers of the vacuum casting 
machine are designated as 8a, 8b, 8c, 8d, 8e and 8f, whereas the positions 
assumed by the mould chambers 8 in the course of the rotary movement of 
the table 9 are designated by the letters A, B, C, D, E, and F. 
In the initial position preparatory to the operation as shown in FIGS. 1, 2 
and 3, the mold chamber 8d is at A and the mold chamber 8a is at D where 
molds 7 are being placed into their respective chambers 8. 
All the valves and vacuum seals are closed and the piston rod 48 of the 
hydraulic cylinder 47 is in its lowermost position. This indicates that 
the vessel 4 is placed so that its bottom is horizontal. The telescopic 
screw is retracted into the feeder 69 and the hopper 70 is free of the 
charge. The funnel 64 is in its uppermost position. The mold chambers 8 
are free of the molds 7. The lower separable portion 105 of the mold 
chamber 8a integrally with the base plate 94 is on the rectilinear rails 
143, the piston rods 137 of the actuating cylinders 138 are in their 
lowermost position along with the flat 136 and the section of the circular 
rails 129 disposed on the flat 136 register with the rails 143. The piston 
rod 86 of the actuating cylinder 85 is inserted into the hole 87 of the 
rotary table 9 between the mold chambers 8d and 8c. 
Before starting operation, the cooling system is turned on followed by the 
mechanical vacuum pumps 13, 31 and 41 and then the valve 15, 20; 24, 26 
and 40 are set open to provide backing vacuum for the vapor pumps 21, 27, 
28 and 38. Also to be opened at this stage is the valve 18 of the melting 
chamber 1. If each of the mold chambers 8 is served by the vapour pump 91 
of its own, also the valves 93 of each such pump are to be opened. Next to 
be opened are the vacuum seals 44 which connect the space of the electron 
beam guns 2 to the melting chamber 1. On attaining a pressure of around 
1.times.10.sup.-1 mm Hg in the spaces evacuated, the heaters of the vapor 
pumps 21, 27, 28 and 38 (91) are turned on, the heating-up of the oil in 
said pumps lasting between 30 and 45 minutes depending on the type of 
pumps and grade of oil used. 
At the same time, a mold 7 is placed on the base plate 94 of the lower 
portion 105 of the mold chamber 8a disposed on the rectilinear rails 143. 
The mold 7 is centered on the base plate 94 with the aid of the 
projections 101 and held down by the cams 100, using the screws 103. The 
lower portion 105 of the mold chamber 8a with the mould 7 secured to its 
base plate 94 is moved along the rectilinear rails 143 so as to enable the 
rollers 128 to come on the section of the circular rails 129 disposed on 
the flat 136. On setting into motion the drive 142, the flat 136 with the 
section of the rails 129 is turned through 90.degree. by means of the gear 
140 which is in mesh with the gear ring of the turntable 139. As soon as 
compressed fluid is being applied to the actuating cylinders 138, the 
piston rods 137 of said cylinders start moving upwards so that the section 
of the rails 129 registers with the static section of said rails disposed 
on the supports 79. 
While the movable section of the rails 129 registers with its static 
counterpart, the rods 131 move upwards with respect to the pins 134, the 
yokes 132 compress the springs 135 and the action of these springs 
transmitted through the sleeves 130 presses the lower portion 105 of the 
mold chamber 8a to the upper portion 104 so as to keep vacuum tight the 
joint between them. 
If the mold chambers 8 are split as shown in FIG. 4, the lower portion 105 
of the mold chamber 8a is pressed to the upper portion 104 in a 
vacuum-tight fashion by means of the clamps 145. 
The valves 33, 36 and the valve 37 of the mold chamber 8a are opened in the 
succession indicated to place the space in the mold chamber into 
communication with the mechanical vacuum pump 31 through the line 35, 
receiver 34 and line 32, and to evacuate said chamber. 
When the pressure in the mold chamber is approximately 1.times.10.sup.-2 
mm Hg, the contactors 126 fitted to the bracket 127 in close proximity to 
position D are energized, applying voltage to the leads of the induction 
coil 124 of the mold chamber 8a. The heating-up and degassing of the 
material of the mold 7 is started while the vacuum in the mold chamber 8a 
is being maintained by the mechanical vacuum pump 31. 
A compressed fluid applied to the actuating cylinder 85 causes its piston 
rod 86 to move downwards so that the rod 86 disengages the hole 87 in the 
rotary table between the mold chambers 8d and 8e. On cutting in the drive 
10 imparting rotary motion to the table 9 with the aid of the pinion 83 
and gear ring 84, the table 9 starts rotating clockwise until the mold 
chamber 8a will move to the position E, being replaced by the chamber of 
arriving at D. If mold chambers of the layout illustrated in FIG. 1 are 
used, the piston rods 137 of the actuating cylinders 138 are withdrawn 
from the sleeves 146 preparatory to each turn of the table 9. 
Temporarily interrupted while the rotary table 9 is on the move, the flow 
of current to the induction coil 124 of the mold chamber 8a is resumed as 
the chamber arrives at E where the leads of the induction coil 124 become 
connected to the contactors 126 fitted to the brackets 127 in close 
proximity to position E which become energized after the rotary table 9 
completes its turn. The contactors 126 in proximity to position D are 
de-energized. Compressed fluid applied to the actuating cylinder 85 causes 
its piston rod 86 to move upards so as to enter the next hole 87 and 
locate the rotary table 9 in the requisite position. 
Compressed fluid applied to the actuating cylinders 138 causes their piston 
rods to move downwards so that the section of the rails 129 disposed on 
the flat 136 also moves downwards until it is level with the rectilinear 
rails 143. The drive 142 is turned on and the flat 136 with the section of 
the rails 129 is turned through 90.degree. so that the rails 129 register 
with the rails 143. The lower portion 105 of the mold chamber 8f is 
wheeled from under the rotary table 9 along the rails 143, a casting mold 
7 is placed on the base plate 94 and then all the operations described 
above when dealing with the mold chamber 8a are repeated. 
If use is made of mold chambers 8 of the layout shown in FIG. 4, the piston 
rods 137 of the cylinders 138 are inserted into the sleeves 146, the 
clamps 145 are screwn out, the lower portion 105 of the mold chamber 8f is 
lowered by means of the piston rods 137 and a mold 7 is placed on the base 
plate 94 of the chamber; the next operations are the same as in the case 
of the mold chamber 8a described above. 
On rendering vacuum tight the joint between the portions 105 and 104 of the 
mold chamber 8f which is at D, the valve 37 of the mold chamber 8a 
positioned at E is closed and the vacuum seal 90 of said chamber is opened 
to provide connection to the vapor pump 38 through the intermediate vessel 
88. For opening the vacuum seal 90, it is necessary to turn the rod 53 
through 180 degrees about its axis so that the eccentric 54 attached 
thereto moves the cover 52 towards the axis of the opening it closes and 
away from the seal 55. The rod 53 (FIG. 4) is then moved upwards as shown 
in the drawing with the result that the cover 52 is also moved upwards, 
opening the opening that the cover 52 is also moved upwards, opening the 
opening in the body 51 of the vacuum seal 90. 
In an embodiment of the invention shown in FIGS. 5 and 6, it is necessary 
to open the vacuum seal 92 which connects the mold chamber 8a to the vapor 
pump 91 of said chamber. 
On closing the valve 37 of the mold chamber 8a, the valve 37 of the mold 
chamber 8f is opened to evacuate said chamber by means of the mechanical 
vacuum pump 31. After that the sequence of events is repeated as outlined 
above for the mold chamber 8a placed at D. 
Next, the rotary table 9 is again turned and locked as described above with 
the result that the mold chamber 8a is moved to position F, the mold 
chamber 8f to E and the mold chamber 8e to D. Voltage is applied to the 
contactors 126 in proximity to position F which are in contact with the 
leads of the induction coil 124 of the mold chamber 8a when the rotary 
table 9 is in said position. The heating-up of the mold 7 is going on 
while the vapor pump 38 maintains a pressure of approximately 
1.times.10.sup.-3 mm Hg in the mold chamber 8a. 
A mould 7 is placed into the mold chamber 8c in the same way as described 
above when a mold was placed into the mould chamber 8f at D. 
Short of the last turn of the rotary table 9, the valve 18 is closed and 
the vacuum seal 22 opened, connecting the vapor pump 21 to the melting 
chamber 1. Also to be opened are the vacuum seals 29 and 30 which connect 
the vapor pumps 27 and 28 to the space inside the electron beam guns 2 and 
said space is evacuated. Before manipulating with the valves and seals, 
the heater 67 of the funnel 64 is turned on. 
After the mould chamber 8a has shifted to position F, the operations 
connected with the melting of metal are started. The lid 72 is opened and 
the hopper 70 loaded with a charge taken in an amount sufficient to obtain 
the requisite amount of melt. After that the lid 72 is closed and the 
joint between the lid and the hopper 70 is rendered vacuum tight. The 
valve 74 is turned open, placing the hopper 72 in communication with the 
pump 31 through the line 73 and receiver 34, and, on evacuating the hoppr 
72, the valve 74 is closed. The vacuum seal 71 of a construction similar 
to that of the seal 90 is opened and the charge from the hopper 70 enters 
the feeder 69, filling the screw. The vacuum seal 71 is closed and the 
screw is withdrawn so as to enable the charge to drop into the vessel 3. 
On completing the charging of the vessel 3, the telescopic screw is 
retracted into the feeder 69. 
Immediately upon the closing of the vacuum seal 71, another batch of charge 
is loaded into the hopper 70 as described hereinabove. The electron beam 
guns 2 are set into operation and the charge is melted in the vessel 3, 
the process being watched through the inspection window 75 and monitored 
by means of the transducer 76 indicating the temperature of melt and other 
transducers supplying data to the instruments accommodated on the control 
desk 161. 
Short of the instant the melt in the vessel 3 is ready for pouring, the 
rotary table 9 is turned again so that the mold chamber 8a is at A and the 
vacum seal 11 of said chamber is disposed coaxially with the opening 4 of 
the melting chamber 1 closed by the vacuum seal 5. As a result of this 
turning of the table 9, the gear 96 fitted to the shaft 95 giving support 
to the base plate 94 of the mold chamber 8a engages the gear 97 of the 
drive 98. 
The mold 7 contained in the mold chamber 8a continues being heated-up 
because the leads of its induction coil 124 are connected to the 
contactors arranged close to position A. 
On turning the table 9, to be repeated as outlined above are all the 
operations connected with the placing of a mould 7 into the mould chamber 
8d now at F and repeated are also all the operations with respect to the 
mould chambers 8e and 8f now at E and F, respectively. 
Before pouring the metal from the vessel 3 into the mould 7 contained in 
the mould chamber 8a, a compressed fluid is admitted into the space 
limited by the flanges 58, 61 and bellows 59, 60 through the pipe 62. As a 
result, the sealing ring 63 is pressed against the vacuum seal 11 of the 
mould chamber 8a, separating from the atmosphere the seals 5 and 11, and 
the space therebetween. The valve 57 is opened, connecting said seals and 
space to the mechanical vacuum pump 31 through the line 56 and receiver 
34. On evacuating the seals and space to approximately 1.times.10.sup.-2 
mm Hg, the valve 57 is closed. The vacuum seal 5 is opened in the same way 
as described above in connection with the seal 90, enabling the vapor pump 
38 (91) to remove the remnant gases from the space between the seals 5, 11 
and maintain a pressure of approximately 1.times.10.sup.-3 mm Hg in the 
mould chamber 8a. Next, the vacuum seal 5 is opened and the funnel 64 is 
introduced into the melting chamber 1 through the hole 4, using the rack 
65 and pinion 66 in mesh one with the other, so that the funnel 64 is 
disposed coaxially with the opening of the mold 7 and in close proximity 
to same. While the drive 98 serving the purpose of spinning the base plate 
94 integrally with the mold 7 is turned on, the electron beam guns 2 and 
induction coil 124 are turned off, and a compressed fluid is applied to 
the actuating cylinder 47 causing its piston rod 48 to move upwards. The 
piston rod 48 in cooperation with the tie rod 49 turns the vessel 3 about 
the axis of the shaft 45 resting on the brackets 46. The metal contained 
in the vessel 3 is poured into the mold 7 through the funnel 64 and is 
distributed over the spaces in the mould on reaching same, forming a 
casting under the action of the centrifugal forces coming into play when 
the mold is being rotated. 
After that the vessel 3 and tundish 64 are returned into the original 
position, the vacuum seals 11 and 5 are closed, and no compressed fluid is 
further admitted into the space between the bellows 59 and 60, the joint 
between said seals no longer being vacuum tight; the vacuum seal 90 of the 
mold chamber 8a is also closed and the drive 98 is turned off. 
Next come all the operations connected with charging the vessel 3 and 
melting the metal as outlined hereinabove. Before the next melt is ready, 
the rotary table 9 is turned again so that the mold chamber 8f is at A 
prepared for pouring the mold 7. This is followed by the operations 
connected with closing the vacuum seals 5 and into in a vacuum tight 
fashion and pouring the metal into the mold in the same way as described 
above for the mold chamber 8a. After the turn of the rotary table 9, the 
mold chamber 8c arrives at D where a casting mold 7 is placed therein 
whereas the mold chamber 8a with a casting is at B, where the cooling of 
the casting goes on inside the space of the chamber closed vacuum tightly. 
On pouring the metal into the casting mould 7 accommodated in the mold 
chamber 8f of the rotary table 9 is turned again so that the mold chamber 
8e is moved to A and arriving at D is the last free mold chamber 8b loaded 
with a mould 7 at this position. The castings in the mold chambers 8a and 
8f cool down at C and B, respectively. 
As soon as the next batch of melt is ready in the vessel 3, poured is the 
mould 7 contained in the mold chamber 8e and then the table 9 is turned 
again so that arriving at A is the mold chamber 8d and the mold chambers 
8e and 8f become stationed at B and C, respectively. The mould chamber 8a 
containing a ready casting comes at D whereas located at E and F are the 
mold chambers 8b and 8c, respectively, wherein the heating-up and 
degassing of the material of the molds 7 take place. 
At D, the removable portion 105 of the mold chamber 8a is removed 
integrally with the base plate 94 and mold 7 secured thereto and 
containing a ready casting and transferred onto the rails 143 in the same 
sequence of events as described for the mould chamber 8f. The mould 7 with 
a casting is removed and taken to a station where the casting is withdrawn 
from the mould 7 and a new mould 7 is placed on the base plate 94. After 
that come the operations described above. 
On pouring the metal into the mold contained in the mould chamber 8d, the 
rotary table 9 is turned so that at A is the mould chamber 8c and at D, 
the mould chamber 8f where the mould with a ready casting is removed from, 
and a new mould is placed into, the chamber as this was described above 
for the mould chamber 8a. After that the casting cycle of the machine is 
repeated. 
Thus, each of the casting molds 7 is loaded into the respective mold 
chamber 8 at D and it is at this position and positions E and F where each 
mold is heated-up and degasses in a vacuum. This operation lasts 
approximately as long as the time of three sucessive meltings in the 
vessel 3 less the period elapsed in loading a new mold 7 at D and accounts 
for about an hour and a half. After that the metal is being poured in the 
mold 7 at A and then the casting is cooled down at A, B and C for about 2 
hours. 
In the vacuum casting machine disclosed, the six-mold rotary table 9 
enables the operations of preparing each of the moulds 7 and cooling the 
castings to be carried out simultaneously with the melting in the melting 
chamber 1. The result is that the period during which each successive 
casting can be produced under the conditions of steady operation of the 
machine is controlled only by the time elapsed in melting a charge in the 
melting chamber 1. This time amounting to some 30 to 40 minutes a 
considerable increase in the production rate is obtainable.