Patent Application
20220324016
The present disclosure relates to an apparatus for low-pressure casting of metallic products.
As is known, the production of metallic alloy castings using the low-pressure casting process involves the use of forming dies that have impressions, into which is poured a metallic mass which is first melted by way of adapted smelting furnaces.
The forming dies are normally constituted by two or more parts that can be moved relative to each other, known in the sector as “half-dies”, which can pass from an open configuration, in which they are mutually spaced apart, to a closed configuration, in which they are in mutual contact so as to define the above-mentioned impressions together.
In more detail, at the start of the process the half-dies are mutually moved apart, so as to enable an operator to carry out a series of preliminary preparatory operations on the forming impressions.
Once the preparatory operations are concluded, the two half-dies are closed, to form the forming die, and are arranged at the smelting furnace which introduces the molten metal inside them.
When the casting has solidified and cooled sufficiently, the forming die is moved to an ejection area and the two half-dies are opened to allow the castings thus formed to be ejected.
In moving the half-dies, the use is known of manipulators in which the movements are actuated by a series of hydraulic actuators.
Such solution, although facilitating the movement of the half-dies, increases the safety risks for the operators and for the environment.
The possible consequences of an oil leak in a high-temperature environment like that in a foundry are to be, for example, considered.
Furthermore, such manipulators have considerable weight and encumbrances, and feature construction solutions that are complex and, therefore, have particularly high final costs.
It must likewise be considered that manipulators of the hydraulic type are generally slow, as well as being non-flexible and rather imprecise in their movements.
In fact, hydraulic actuators cannot execute rotations of upper half-dies of more than 90°, so defining only two positions for them.
The present disclosure provides an apparatus for low-pressure casting of metallic products that overcomes the drawbacks of the cited known art.
Within this aim, the disclosure provides an apparatus that makes it possible to move in a precise, rapid and highly repeatable manner the parts that make up the forming die.
The disclosure also provides an apparatus that is particularly flexible, that makes it possible to simplify the layout of the entire plant in which it is inserted, and is capable of being easily adapted to any changes in the latter.
The disclosure provides an apparatus that is safe for the users and the persons working in the vicinity of the plant, and also for the environment.
The above aim and the above and other advantages, which will become better apparent hereinafter, are achieved by providing an apparatus for low-pressure casting of metallic products, which comprises at least one forming die which is provided with a cavity which is adapted to receive a molten metallic mass, said forming die comprising at least two parts which can move between an open configuration, in which said two parts are mutually spaced apart, and a closed configuration, in which said two parts together define said cavity, said forming die being supported and moved by a manipulator with multiple degrees of freedom, said apparatus being characterized in that said manipulator comprises a plurality of movable parts which are actuated by electric motor means which are driven by a control unit.
Further characteristics and advantages of the disclosure will become better apparent from the description of a preferred, but not exclusive, embodiment of an apparatus according to the disclosure, illustrated by way of non-limiting example in the accompanying drawings wherein:
With reference to the figures, an apparatus for low-pressure casting of metallic products is generally designated by the reference numeral 1.
The apparatus 1 comprises a forming die 2 which is constituted by two parts 4a, 4b, also called “half-dies”, which can move between an open configuration, in which they are mutually spaced apart, and a closed configuration, in which they are in mutual contact.
More specifically, in the closed configuration, the two parts 4a, 4b together define a cavity 3 that is adapted to receive a molten metallic mass.
For example, the metallic mass can be heated and brought to the liquid or semisolid state by a smelting furnace 6, which is conventional and is not described in detail.
The two parts 4a, 4b of the forming die 2 are supported and moved by a manipulator 10 with multiple degrees of freedom.
According to the present disclosure, all the movements of the movable parts of the manipulator 10 are obtained with transmission means which are actuated by motor means of the electric type, driven by an adapted control unit.
More precisely, the rotating movements of the manipulator 10 are obtained with high-torque reduction gears actuated by brushless motors, while the linear movements are obtained with linear screw actuators which are also actuated by further brushless motors.
Preferably, in the manipulator 10 electric motors are used with a degree of protection at least of the order of IP65, powered with cables protected by sheaths that can withstand high temperatures.
In the example shown, the manipulator 10 has a stationary base 5 and a post 11 mounted thereon so that it can rotate about a first axis 100 which is oriented vertically.
Advantageously, in a variation of embodiment not shown in the figures, the base 5 can be hung from the ceiling and the post 11 can extend downward therefrom.
The post 11 and the stationary base 5 are mutually connected by way of a first joint 21, which is associated with a first electric motor 31 with the interposition of a first reduction gear 41.
A first articulation element 12 is mounted on the post 11 and can oscillate about a second axis 200 which is transverse to the first axis 100 and is oriented horizontally.
The first articulation element 12 is connected to the post 11 by way of a second joint 22 and is moved by a second electric motor 32 through a second reduction gear 42.
An arm 13 extends from the first articulation element 12 and is adapted to support and move the two parts 4a, 4b of the forming die 2.
In other embodiments, not shown in the figures, the apparatus 1 can comprise multiple arms 13, all connected to a single post 11.
In more detail, the arm 13 comprises an elbow-shaped portion 15 which is connected to the first articulation element 12 by way of a third joint 23, which enables that arm 13 to rotate about a third axis 300 which is transverse to the second axis 200.
Such rotation is controlled by a third electric motor 33 which is coupled to a third reduction gear 43.
Advantageously, the arm 13 is composed of a first segment 14a, which is fixed along a fourth axis 400, which is substantially parallel to the third axis 300, and of a second segment 14b, which can move along the fourth axis 400.
The segments 14a and 14b are mutually coupled by way of sliding means 24, for example constituted by a slider-and-guide system, which is conventional and not described in detail.
In this case, the second segment 14b is mounted telescopically on the first segment 14a and can slide along the fourth axis 400.
Preferably, the second segment 14b is moved along the fourth axis 400 by way of a linear actuator 44 which is actuated by a fourth electric motor 34.
Second articulation elements 16a, 16b are mounted respectively on the segments 14a, 14b, and can oscillate about fifth axes 500a, 500b which are arranged transversely to the fourth axis 400.
The connection between the second articulation elements 16a, 16b and the segments 14a, 14b is obtained by way of fifth joints 25a, 25b which are moved by fifth reduction gears 45a, 45b which are associated with fifth electric motors 35a, 35b.
The second articulation elements 16a, 16b have respectively a first head 17a and a second head 17b, each of which can oscillate about a sixth axis, respectively 600a and 600b.
The sixth axes 600a, 600b, about which the heads 17a, 17b oscillate, are arranged transversely to the fifth axes 500a, 500b and are defined by sixth joints 26a, 26b which connect those heads 17a, 17b to the second articulation elements 16a, 16b.
Conveniently, sixth electric motors 36a, 36b are mounted on the second articulation elements 16a, 16b and are adapted to actuate the sixth joints 26a, 26b by way of sixth reduction gears 46a, 46b.
The heads 17a, 17b support respectively a first flange and a second flange 18a, 18b which are mounted so that they can rotate about seventh axes 700a, 700b which are transverse to the sixth axes 600a, 600b.
The parts 4a, 4b, of the forming die 2 can rotate independently of each other, about the seventh axis 700a, 700b thereof, by way of seventh brushless motors 37a, 37b which are connected to seventh, precision reduction gears 47a, 47b, ensuring the coupling between them.
The flanges 18a, 18b are connected to the heads 17a, 17b by way of seventh joints 27a, 27b which are associated with the seventh electric motors 37a, 37b with the interposition of seventh reduction gears 47a, 47b.
Each flange 18a, 18b is adapted to support one of the two parts 4a, 4b of the forming die 2, which therefore can be moved in an effective and precise manner using the manipulator 10 according to the disclosure.
Conveniently, the above mentioned motors 31-37b, i.e. the respective joints 21-23 and 25a-27b, or the sliding means 24, are associated with transducers, for example encoders, for controlling the position of the movable parts 11-18b of the manipulator 10.
The movements of the manipulator 10 and the handling of the forming die 2, such as for example the transition of the two parts 4a and 4b from the open position to the closed position, and vice versa, are managed by a control unit which is controlled by an operator.
Conveniently, such control unit has a microprocessor system which is connected to the electrical/electronic parts of the apparatus 1, and is configured to control the manipulator 10 in various different operating modes, such as for example an automatic mode and a manual mode.
With reference to
In other embodiments not shown in the figures, the ejector 38 is constituted by a hydraulic actuator.
Operation of the apparatus according to the disclosure is as follows.
In an initial step of the casting process, the two parts 4a and 4b of the forming die 2 are in the open configuration, i.e. they are spaced apart from each other in order to allow the operator to carry out any necessary operations in preparation of the cavity 3.
Simultaneously, in the smelting furnace 6 a metallic mass is heated until it reaches a liquid or semisolid state.
Subsequently, the two heads 17a, 17b of the manipulator 10 are moved mutually close together, bringing the two parts 4a and 4b of the forming die 2 to the closed configuration, in which they define the cavity 3 together.
By way of the manipulator 10, the forming die 2 is then positioned at the smelting furnace 6 so as to allow the introduction of the molten metallic mass into the cavity 3.
Once the metallic mass has solidified completely it is possible to open the two parts 4a and 4b of the forming die 2 and eject the desired casting.
In practice it has been found that the disclosure achieves the set aim and advantages, an apparatus for low-pressure casting of metallic products having been provided that makes it possible to move in a precise, rapid and highly repeatable manner the parts 4a and 4b that make up the forming die 2.
In fact, since the movable parts 11-18 of the manipulator 10 are actuated by electric motors 31-37, all the movements occur with high precision and repeatability, as well as very rapidly.
It should be noted that the apparatus 1 is considerably versatile in that it makes it possible to carry out various different operations and/or functions with a same motor and/or actuator via a same movement.
By way rotations of the motors 32-37b it is in fact possible to rotate the parts 4a and 4b of the die 2 in different configurations as shown in
The use of electric motors, instead of hydraulic actuators, makes it possible to rotate the parts 4a, 4b, even through 360°, thus defining four positions for them.
For example, it is possible to rotate through 90° the parts 4a and 4b in order to bring them from a position in which they are facing each other (
By rotating the parts 4a, 4b from the graphitizing position (
As a consequence, the forming die 2 can be brought to different stations and positioned very easily, thus simplifying the layout of the plant where the apparatus 1 is installed, as well as simplifying any modifications to it.
In addition it should be noted that there is a considerable energy saving by using the electric motors 31-37b.
From experimental tests it has emerged that with an apparatus according to the disclosure power consumption in the order of 3 kW is achieved, against consumption in the order of 10 kW for similar, conventional apparatuses that use hydraulic actuators.
Last but not least, it has been found that the apparatus 1 according to the disclosure is safe for the users and the persons working in the vicinity of the plant, and also for the environment.
The apparatus for low-pressure casting of metallic products according to the disclosure is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; furthermore, all the details may be substituted by technically equivalent elements.
Naturally, the materials employed, as well as the dimensions and the shapes, may be any according to requirements and to the state of the art.
The disclosures in Italian Patent Application No. 102019000007824 from which this application claims priority are incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102019000007824 | Jun 2019 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/055231 | 6/3/2020 | WO |
