US20090308562A1

US20090308562A1 - Electrical servo driven rollover melt furnace

Info

Publication number: US20090308562A1
Application number: US12/138,892
Authority: US
Inventors: Brad L. Rauguth; James Rackley; Steven Allen
Original assignee: Zimmer Inc
Current assignee: Zimmer Inc
Priority date: 2008-06-13
Filing date: 2008-06-13
Publication date: 2009-12-17

Abstract

An apparatus and method for melting metal and casting molds. The apparatus includes a rollover melt furnace having a crucible and a mold. The apparatus also includes an electrical servomotor that drives rotation of the crucible about an axis of rotation. This rotation of the crucible causes molten metal to flow from a pour opening in the crucible into a fill opening in the mold. The apparatus may further include a controller to carry out a pouring process in compliance with a pour profile and a melting process in compliance with a melt profile.

Description

BACKGROUND

1. Field of the Invention
The present invention relates to rollover melt furnaces for melting metals and casting metals in molds. More specifically, the present invention relates to an electrical servo driven rollover melt furnace and method for utilizing the same.
2. Description of the Related Art
Casting is a manufacturing process by which molten metal is poured into a mold, allowed to solidify within the mold, and then removed from the mold, resulting in a solid fabricated part.
A rollover melt furnace is a device typically used to perform the casting process. A typical rollover melt furnace has a heated crucible that is connected to a rotating shaft. As the shaft rotates, the crucible also rotates about a horizontal axis. When the crucible is in an upright, or rest, position, a top surface of the crucible faces upward. The top surface of the crucible includes a pour opening.
In operation, the crucible is first manually rotated to a charge position. Once reaching this charge position, an ingot is loaded into the crucible.
Next, the crucible is manually rotated to an upright position. The crucible is heated in the upright position until the ingot melts. After the molten metal reaches a desired temperature, a mold is connected to the crucible with a bottom surface of the mold facing downward. The bottom surface of the mold includes a fill opening. The bottom surface of the mold is attached to the top surface of the crucible, with a device such as a clamp, so that the fill opening of the mold is in fluid communication with the pour opening of the crucible.
Then, the crucible is rotated to an inverted position. Once reaching this inverted position, the top surface of the crucible faces downward, while the bottom surface of the mold faces upward. The molten metal pours from the pour opening of the crucible into the fill opening of the mold. Finally, the mold is removed from the rollover melt furnace, and the molten metal inside the mold is allowed to solidify before being removed from the mold.
Currently, rotation of the crucible is driven by a hydraulic motor. Hydraulic rollover melt furnaces possess many disadvantages. First, the pour cycle described above is not repeatable. Hydraulic actuators are highly susceptible to process variability, especially over time as the actuators wear out. For example, from pour to pour, the pour cycle of a hydraulic rollover melt furnace may vary up to several seconds. Particular molds require particular pour cycles. If a pour occurs too quickly, inclusions may form within the hardened metal. If a pour occurs too slowly, the molten metal may not fill all areas of the mold, particularly those areas of small cross-section. If a mold is filled incorrectly, the process must be repeated.
Also, the pour cycle of a hydraulic rollover melt furnace is not reproducible from furnace to furnace. Each hydraulic rollover melt furnace has a single pour cycle setting that cannot be efficiently or easily reprogrammed to account for various molds.
Finally, the process of actually filling a mold using a hydraulic rollover melt furnace presents several challenges. For one, current devices provide one-directional rotation of the crucible. More specifically, the motor drives the crucible from the upright position to the inverted position, but the actuator is not programmable to stop at discrete positions when pouring or when driving the crucible from the inverted position back to the upright position. Therefore, the crucible must be manually rotated from the inverted position to a charge position to receive the next ingot, and then must be manually rotated from the charge position to the upright position to melt the ingot. In addition, the speed at which current devices rotate is difficult to control, often resulting in pours conducted at excessive speeds. As mentioned above, if a mold is filled too quickly, inclusions may form within the hardened metal. Finally, current devices do not allow for wetting the crucible lip with molten metal before pouring. For one, the pour speed is too fast to pause at a wet lip position, because molten metal would slosh out of the crucible. Also, the one-directional rotation prohibits the crucible from stopping at this discrete position and from automatically returning to an upright position after reaching the wet lip position.

SUMMARY

The present invention relates to an apparatus for melting metal and casting molds. The apparatus includes a rollover melt furnace having a crucible and a mold. The apparatus also includes an electrical servomotor that drives rotation of the crucible about an axis of rotation. This rotation of the crucible causes molten metal to flow from a pour opening in the crucible into a fill opening in the mold. The apparatus may further include a controller to carry out a pouring process in compliance with a pour profile and a melting process in compliance with a melt profile.
According to an embodiment of the present invention, an apparatus includes a rollover melt furnace, having a rotating shaft and a crucible, and an electrical motor. The crucible is connected to the rotating shaft for rotation therewith. The crucible has an exterior surface that includes a pour opening. The electrical motor is connected in driving relationship to the rotating shaft of the rollover melt furnace.
According to another embodiment of the present invention, an apparatus includes a rollover melt furnace having a rotating shaft, a crucible, and a mold. The crucible is connected to the rotating shaft for rotation therewith and includes a pour opening into an interior cavity. The mold has an exterior surface that includes a fill opening, which is sized to accommodate a flow from the pour opening of the crucible. The apparatus also includes an electrical motor connected in driving relationship to the rotating shaft of the rollover melt furnace. The apparatus further includes a controller. The controller is capable of sending a plurality of command signals to the electrical motor.
The present invention also relates to a method for melting metal and casting molds. Advantageously, the present method may be customized depending on the particular mold, the particular metal being used, and any other relevant factors. Also, the present method is repeatable and consistent from pour to pour, and is reproducible from apparatus to apparatus. Finally, the present method permits two-directional, electronically controlled rotation of the crucible.
According to an embodiment of the present invention, a method is provided for melting metal and casting molds in a rollover melt furnace. The rollover melt furnace includes a rotating shaft and a crucible connected to the rotating shaft for rotation therewith. The crucible includes a pour opening located on an exterior surface of the crucible into an interior cavity. The method involves loading an ingot into the interior cavity of the crucible; melting the ingot in the interior cavity of the crucible thereby forming a molten metal; attaching a mold to the rollover melt furnace, the mold having an exterior surface that includes a fill opening, the fill opening being sized to accommodate a flow from the pour opening of the crucible; and rotating the shaft using an electrical motor to transfer the molten metal from the crucible to the mold.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a front elevational view of an apparatus of the present invention;

FIG. 2 is a side elevational view of the apparatus of FIG. 1, taken along line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view of the apparatus of FIG. 1, taken along line 3-3 of FIG. 1;

FIG. 4 is a partial cross-section of the apparatus of FIG. 3 with a crucible in the charge position;

FIG. 5 is a partial cross-section of the apparatus of FIG. 3 with the crucible in the upright position;

FIG. 6 is a partial cross-section of the apparatus of FIG. 3 with the crucible in the wet lip position;

FIG. 7 is a partial cross-section of the apparatus of FIG. 3 with the crucible in the fill position;

FIG. 8 is a partial cross-section of the apparatus of FIG. 3 with the crucible in the inverted position;

FIG. 9 is a block diagram of a motion feedback loop and a temperature feedback loop of the present invention;

FIG. 10 is graphical depiction of pour profiles of the present invention; and

FIG. 11 is graphical depiction of a melt profile of the present invention.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention any manner.

DETAILED DESCRIPTION

Referring to FIGS. 1-8, apparatus 10 is provided for melting metal and casting molds. Apparatus 10 includes rollover melt furnace 12. Rollover melt furnace 12 includes frame 14, rotating shaft 16, clamp 18, crucible 20, and mold 22. Frame 14 supports rollover melt furnace 12.
As shown in FIG. 1, crucible 20 is connected to rollover melt furnace 12 for rotation along with rotating shaft 16. In other words, crucible 20 may be directly or indirectly connected to rotating shaft 16. Crucible 20 includes exterior surface 24, which may include top exterior surface 26 and bottom exterior surface 28. Crucible 20 also includes interior cavity 30. Exterior surface 24 includes pour opening 32, which comprises an aperture in exterior surface 24 that provides access into interior cavity 30 of crucible 20. In an exemplary embodiment, top exterior surface 26 includes pour opening 32. Lip 34 is formed between exterior surface 24 and interior cavity 30. Crucible 20 may be heated by any method known in the art including, but not limited to, induction. In one form thereof, interior cavity 30 of crucible 20 has a capacity of up to approximately 50 pounds. In another form thereof, crucible 20 is approximately 0.5 inches thick between interior cavity 30 and exterior surface 24.
As shown in FIG. 5, mold 22 includes exterior surface 36, which may include top exterior surface 38 and bottom exterior surface 40. Mold 22 also includes interior cavity 42. Exterior surface 36 includes fill opening 44, which comprises an aperture in exterior surface 36 that provides access into interior cavity 42 of mold 22. In an exemplary embodiment, bottom exterior surface 40 includes fill opening 44. Fill opening 44 should be sized to accommodate a flow from pour opening 32, as discussed in more detail below.
Returning to FIG. 1, apparatus 10 also includes electrical servomotor 46. Electrical servomotor 46 is connected in driving relationship to rotating shaft 16 of rollover melt furnace 12. Electrical servomotor 46 is capable of rotating shaft 16 about axis 48. Crucible 20 is non-rotatably connected to rotating shaft 16, so electrical servomotor 46 is also capable of rotating crucible 20 about axis 48.
Referring to FIGS. 9 and 10, to control the rotation of crucible 20, apparatus 10 may further include controller 52. Controller 52 controls the actual movement of crucible 20 about axis 48 based on pour profile 58. Pour profile 58 is a set of instructions for the operation of rollover melt furnace 12. Over a set time interval 62, pour profile 58 indicates the desired movement of crucible 20 about axis 48 in terms of a set position 64 of crucible 20, a set velocity 66 of crucible 20, and/or a set acceleration 68 of crucible 20 about axis 48, for example.
In an exemplary embodiment of the present invention, controller 52 may be capable of storing more than one pour profile 58 and accessing a desired pour profile 58 based on user command 70. Controller 52 may include an input device for receiving user command 70 such as, but not limited to, a keyboard or a bar code reader. A user may inform controller 52 of the particular job being performed by, for example, entering a command on the keyboard or scanning a bar code.
According to an embodiment of the present invention, apparatus 10 may further include motion feedback loop 49, as shown in FIG. 9. Motion feedback loop 49 includes electrical servomotor 46, motion feedback device 50, and controller 52. Motion feedback device 50 may be incorporated within electrical servomotor 46, or motion feedback device 50 may be remotely mounted on rollover melt furnace 12, such as on rotating shaft 16. Motion feedback device 50 may be any device, such as a transducer, capable of monitoring at least one output variable 54 of electrical servomotor 46 and sending feedback signals 56 to controller 52. In an exemplary embodiment, motion feedback device 50 includes a resolver or an encoder which provides position and/or velocity feedback. Output variable 54 to be measured by motion feedback device 50 depends on the location of motion feedback device 50. Ultimately, output variable 54 corresponds to the actual position, the actual velocity, and/or the actual acceleration of crucible 20 about axis 48 at a given time.
The following two examples illustrate the function of motion feedback device 50. If motion feedback device 50 is mounted on rotating shaft 16, output variable 54 may be the velocity of rotation about axis 48 of rotating shaft 16. The velocity of rotation about axis 48 of rotating shaft 16 corresponds equally to the velocity of rotation about axis 48 of crucible 20. If, on the other hand, motion feedback device 50 is incorporated within electrical servomotor 46, output variable 54 may be the position of electrical servomotor 46. The position of electrical servomotor 46 corresponds to the position of rotating shaft 16, and in turn the actual position of crucible 20 about axis 48. For example, a single rotation of electrical servomotor 46 may correspond to a certain degree of rotation of crucible 20 about axis 48, depending on the gear reduction (if any) used between electrical servomotor 46 and crucible 20.
Referring still to FIG. 9, after motion feedback device 50 measures and/or computes output variable 54, it then sends feedback signal 56 to controller 52. Like output variable 54, feedback signal 56 also corresponds to the actual position, the actual rotation velocity, and/or the actual rotation acceleration of crucible 20 about axis 48 at a given time. Controller 52 may be any device, such as a computer, capable of receiving feedback signals 56 from motion feedback device 50, comparing those feedback signals 56 to pour profile 58, and sending command signals 60 to electrical servomotor 46.
Referring again to FIG. 9, upon receiving feedback signal 56 from motion feedback device 50, controller 52 compares feedback signal 56 to a desired pour profile 58. More specifically, controller 52 compares the actual position, the actual velocity, and/or the actual acceleration of crucible 20 about axis 48 at a given time (based on feedback signal 56) to set position 64, set velocity 66, and/or set acceleration 68 of crucible 20 about axis 48 at the corresponding time from set time interval 62 (based on pour profile 58).
Referring still to FIG. 9, after comparing feedback signal 56 to pour profile 58, controller 52 determines a command signal 60 and sends command signal 60 to electrical servomotor 46. Command signal 60 may correspond to the desired velocity and/or the desired acceleration of electrical servomotor 46. More generally, command signal 60 controls the movement of electrical servomotor 46.
In operation, controller 52 conforms the actual movement of crucible 20 about axis 48 to pour profile 58. If feedback signal 56 does not conform to pour profile 58, controller 52 sends command signal 60 to electrical servomotor 46 to alter the behavior of electrical servomotor 46. For example, if, at a given time within set time interval 62, crucible 20 has not yet reached set velocity 66, controller 52 may send command signal 60 to electrical servomotor 46 directing electrical servomotor 46 to accelerate. Motion feedback loop 49 between electrical servomotor 46, motion feedback device 50, and controller 52 may include any closed-loop control devices known in the art, such as a resolver or an encoder which provides position and/or velocity feedback, and may operate throughout the pouring process, as described in more detail below.
According to another embodiment of the present invention, an open-loop control system may be utilized during a portion of or the entire pouring process. Without necessarily receiving feedback signals 56 from motion feedback device 50, controller 52 may send command signals 60 to electrical servomotor 46 based on pour profile 58. In this embodiment, pour profile 58 may indicate the amount of power to be supplied to electrical servomotor 46 over set time interval 62, such that controller 52 sends command signals 60 to electrical servomotor 46 in the form of power inputs to rotate electrical servomotor 46 at a desired rate. The open-loop control system may be less precise than the closed-loop control system of motion feedback loop 49.
Referring to FIGS. 9 and 11, controller 52 may also control the melting of metal within crucible 20 based on melt profile 74. Melt profile 74 is a set of instructions for the heating of crucible 20 of rollover melt furnace 12. Over a set time interval 80, melt profile 74 indicates, for example, the desired set temperature 82 of crucible 20 or of its contents within interior cavity 30 and/or the power supplied to heat crucible 20. Ultimately, set temperature 82 should reach melting point 83 of the particular material being poured.
In an exemplary embodiment of the present invention, as with pour profile 58, controller 52 may be capable of storing more than one melt profile 74 and accessing a desired melt profile 74 based on user command 70. Controller 52 may include an input device for receiving user command 70 such as, but not limited to, a keyboard or a bar code reader. A user may inform controller 52 of the particular job being performed by, for example, entering a command on the keyboard or scanning a bar code. In another exemplary embodiment, controller 52 will access both a desired pour profile 58 and a desired melt profile 74 based on a single user command 70.
According to an embodiment of the present invention, apparatus 10 may further include temperature feedback loop 72, as shown in FIG. 9. Temperature feedback loop 72 conforms the actual temperature of crucible 20, or its contents, to a melt profile 74. Temperature feedback device 75 measures the temperature of crucible 20, or its contents, and sends temperature reading 76 to controller 52. Temperature feedback device 75 may include an infrared pyrometer or an immersion thermocouple, for example. Controller 52 may be capable of receiving temperature readings 76 from temperature feedback device 75, comparing those temperature readings 76 to melt profile 74, and sending temperature commands 78 to crucible 20. In an exemplary embodiment, controller 52 receives temperature readings 76 from temperature feedback device 75 and sends temperature commands 78 to crucible 20 by controlling the power output to crucible 20.
In operation, temperature feedback loop 72 conforms the actual melting process to melt profile 74. If a temperature reading 76 at a given time does not conform to set temperature 82 of melt profile 74 at the corresponding time, controller 52 sends temperature command 78 to crucible 20 to alter the temperature of crucible 20. For example, if, at a given time within set time interval 80, crucible 20 has not yet reached set temperature 82, controller 52 may send temperature command 78 to crucible 20 directing crucible 20 to increase its temperature. Temperature feedback loop 72 may include any closed-loop control devices known in the art, such as an infrared pyrometer, and may operate during the melting process, as described in more detail below.
According to another embodiment of the present invention, an open-loop control system may be utilized during a portion of or the entire melting process. Without necessarily receiving temperature readings 76 from temperature feedback device 75, controller 52 may send temperature commands 78 to crucible 20 based on melt profile 74. In this embodiment, melt profile 74 may indicate, for example, the amount of power to be supplied to crucible 20 over set time interval 80, such that controller 52 sends temperature commands 78 to crucible 20 in the form of power inputs to melt metal ingot 86 at a desired rate. At some point during the melting process, such as when the metal ingot 86 is expected to approach melting point 83, temperature feedback loop 72 may take over for the open-loop control system.
Referring to FIGS. 1-8, a method is provided for melting metal and casting molds. In the following paragraphs, the rotation of crucible 20 about axis 48 is described relative to a vertical plane. As shown in FIG. 1, crucible 20 is in an upright position 84 when top exterior surface 26 of crucible 20 faces upward. Upright position 84 is associated with an angle of 0 degrees from a vertical plane. Although the drawings depict rotation of rotating shaft 16 and crucible 20 in a clockwise direction, rollover melt furnace 12 may permit rotation of rotating shaft 16 and crucible 20 in a counter-clockwise direction, or in both clockwise and counter-clockwise directions.
As illustrated in FIG. 4, metal ingot 86 is loaded into interior cavity 30 of crucible 20. In an exemplary embodiment of the present invention, this loading step takes place at charge position 88. At charge position 88, crucible 20 is positioned approximately 90 degrees from a vertical plane. In other words, top exterior surface 26 of crucible 20 faces sideways. Charge position 88 makes interior cavity 30 easily accessible to a user for loading metal ingot 86.
As illustrated in FIG. 5, after loading metal ingot 86 (FIG. 4) into crucible 20, crucible 20 is heated to melt metal ingot 86. Crucible 20 may be heated at an uneven rate to reduce spitting as metal ingot 86 melts. Crucible 20 may be heated until metal ingot 86 is within approximately 5 degrees of melting point 83 or until metal ingot 86 becomes molten metal 90. As discussed above, this melting process may be carried out in compliance with melt profile 74 (FIG. 11), such as by using temperature feedback loop 72 (FIG. 9). Upon reaching the desired temperature, a user may be notified, such as via an alarm or an indication on a monitor, that the melting process is complete. Along with temperature feedback loop 72, the point at which metal ingot 86 becomes molten metal 90 may be verified manually with an immersions thermometer.
After metal ingot 86 is melted, mold 22 is attached to rollover melt furnace 12. Mold 22 is secured to rollover melt furnace 12, and more specifically to crucible 20. Mold 22 may be secured to crucible 20 by manually or automatically pressing clamp 18 against top exterior surface 38 of mold 22, by locking mold 22 and crucible 20 together, or by any other known method. Mold 22 is positioned onto crucible 20 such that fill opening 44 of mold 22 is in fluid communication with pour opening 32 of crucible 20. In other words, mold 22 is positioned onto crucible 20 such that interior cavity 42 of mold 22 is in fluid communication with interior cavity 30 of crucible 20.
In an exemplary embodiment of the present invention, the attachment of mold 22 to crucible 20 takes place in upright position 84. Also, according to this exemplary embodiment, bottom exterior surface 40 of mold 22, which includes fill opening 44, is secured to top exterior surface 26 of crucible 20, which includes pour opening 32.
In another exemplary embodiment of the present invention, clamp 18 is automatically positioned to receive mold 22. More specifically, clamp 18 is automatically positioned far enough away from crucible 20 to receive mold 22 but near enough to crucible 20 to be automatically and quickly pressed against mold 22 once mold 22 is attached to rollover melt furnace 12. To facilitate even filling of mold 22, mold 22 may be preheated, such as in a furnace, before receiving molten metal 90. The preheated mold 22 should be filled quickly to avoid significant cooling of mold 22. Based on user command 70, controller 52 may automatically direct clamp 18 to the desired receiving position by operating, for example, a hydraulic cylinder. The positioning of clamp 18 may occur at or near the time that controller 52 accesses a desired pour profile 58 and/or a desired melt profile 74. Once mold 22 is attached to rollover melt furnace 12, controller 52 may again operate the hydraulic cylinder to press clamp 18 against mold 22.
Referring to FIGS. 6-8, the present method involves pouring molten metal 90 to cast mold 22. As discussed above, this pouring process may be carried out in compliance with pour profile 58 (FIG. 10), such as by using motion feedback loop 49 (FIG. 9). In an exemplary embodiment, the pouring process is initiated after molten metal 90 forms within crucible 20 (FIG. 5).
As illustrated in FIG. 6, crucible 20 is rotated to wet lip position 92. Wet lip position 92, as used herein, is the position of crucible 20 at which molten metal 90 contacts lip 34 of crucible 20 just before exiting interior cavity 30 of crucible 20 through pour opening 32. Depending on the amount of molten metal 90 within crucible 20, the position of crucible 20 relative to a vertical plane may vary between 0 and 90 degrees. For example, as shown in FIG. 6, crucible 20 is positioned approximately 45 degrees from a vertical plane. If interior cavity 30 of crucible 20 contained a smaller amount of molten metal 90, crucible 20 would have to be rotated further before reaching wet lip position 92. Contacting lip 34 of crucible 20 with molten metal 90 promotes even pouring by preheating lip 34 and by cleaning residue from lip 34. Crucible 20 may pause at wet lip position 92 to more fully achieve these benefits.
In an exemplary embodiment of the present invention, shown graphically in FIG. 10, crucible 20 may be rotated back to upright position 84 after reaching wet lip position 92. Crucible 20 may then return to and pause at wet lip position 92 once again before undergoing the rest of the pouring process. This motion between wet lip position 92 and upright position 84 may be repeated any number of times before undergoing the remainder of the pouring process.
As illustrated in FIG. 7, crucible 20 is rotated to fill position 94. At fill position 94, crucible 20 is positioned approximately 160 degrees from a vertical plane, and mold 22 is located at least partially beneath crucible 20. Because fill opening 44 of mold 22 is positioned in fluid communication with pour opening 32 of crucible 20, molten metal 90 flows into interior cavity 42 of mold 22.
In an exemplary embodiment of the present invention, shown graphically in FIG. 10, crucible 20 briefly pauses at wet lip position 92. From this stopped position, crucible 20 may rotate about axis 48 with increasing velocity until reaching fill position 94.
As illustrated in FIG. 8, crucible 20 is rotated to fully inverted position 96. At inverted position 96, crucible 20 is positioned 180 degrees from a vertical plane such that top exterior surface 26 of crucible 20 faces downward and bottom exterior surface 40 of mold 22, which is located beneath crucible 20, faces upward. Molten metal 90 continues to flow into interior cavity 42 of mold 22 until interior cavity 30 of crucible 20 is essentially empty.
In an exemplary embodiment of the present invention, shown graphically in FIG. 10, crucible 20 reaches a maximum velocity at fill position 94, and then crucible 20 rotates about axis 48 with decreasing velocity until reaching inverted position 96. By slowing the rotation of crucible 20 at the end of the pour cycle, the rate at which molten metal 90 flows into mold 22 is reduced.
A remaining step of the present method involves loosening clamp 18 and removing mold 22 from crucible 20. Molten metal 90 inside mold 22 should be allowed to solidify before being removed from mold 22. Finally, crucible 20 is returned to charge position 88 in preparation for receiving another metal ingot 86.
Advantageously, the method described above may be customized depending on the particular mold 22, the particular metal being used, and any other relevant factors. For example, melt profile 74 and pour profile 58 may be customized based on these factors to minimize the presence of inclusions and gaps in a solid fabricated part. Also, the method described above is repeatable and consistent from pour to pour, and is reproducible from apparatus 10 to apparatus 10. Finally, the method described above permits two-directional, electronically controlled rotation of crucible 20.
While this invention has been described as having preferred designs, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Claims

1. An apparatus for melting metal and casting molds comprising:

a rollover melt furnace comprising a rotating shaft and a crucible connected to the rotating shaft for rotation therewith, the crucible having an exterior surface that includes a pour opening; and

an electrical motor connected in driving relationship to the rotating shaft of the rollover melt furnace.

2. The apparatus of claim 1, further comprising a motion feedback loop that controls the electrical motor, the motion feedback loop comprising a controller and a feedback device, wherein:

the feedback device is capable of sending a plurality of feedback signals to the controller; and

the controller is capable of receiving the plurality of feedback signals from the feedback device, comparing the plurality of feedback signals to a pour profile, and sending a plurality of command signals to the electrical motor, the command signals comprising attempts to minimize a difference between the feedback signals and the pour profile.

3. The apparatus of claim 2, wherein:

the crucible has an actual position, an actual velocity, and an actual acceleration, about an axis of rotation; and

the plurality of feedback signals correspond to at least one of: the actual position of the crucible, the actual velocity of the crucible, and the actual acceleration of the crucible about said axis of rotation.

4. The apparatus of claim 2, wherein the plurality of command signals correspond to at least one of: a velocity of the electrical motor and an acceleration of the electrical motor.

5. The apparatus of claim 1, further comprising a temperature feedback loop that controls a temperature of the crucible.

6. An apparatus for melting metal and casting molds comprising:

a rollover melt furnace comprising a rotating shaft, a crucible connected to the rotating shaft for rotation therewith, the crucible having a pour opening into an interior cavity, and a mold having an exterior surface that includes a fill opening, the fill opening being sized to accommodate a flow from the pour opening of the crucible;

an electrical motor connected in driving relationship to the rotating shaft of the rollover melt furnace; and

a controller, the controller being capable of sending a plurality of command signals to the electrical motor.

7. The apparatus of claim 6, further comprising a feedback device capable of sending a plurality of feedback signals to the controller.

8. The apparatus of claim 7, wherein the feedback device is incorporated within the electrical motor.

9. The apparatus of claim 7, wherein the feedback device is remotely mounted on the rollover melt furnace.

10. The apparatus of claim 7, wherein:

11. The apparatus of claim 6, wherein the plurality of command signals correspond to at least one of: a velocity of the electrical motor and an acceleration of the electrical motor.

12. The apparatus of claim 6, further comprising at least one pour profile, the at least one pour profile representing a set time interval and at least one of: a set position of the crucible, a set velocity of the crucible, and a set acceleration of the crucible about an axis of rotation over the set time interval, wherein the controller is further capable of:

storing the at least one pour profile;

receiving a user command;

accessing a desired pour profile based on the user command;

determining a command signal based on the desired pour profile; and

sending the command signal to the electrical motor.

13. The apparatus of claim 12, wherein the controller is further capable of:

receiving a plurality of feedback signals from a feedback device; and

comparing the desired pour profile with the plurality of feedback signals and determining a command signal therefrom, the command signal comprising an attempt to minimize a difference between the feedback signals and the desired pour profile.

14. The apparatus of claim 6, wherein the controller is further capable of:

storing and accessing at least one melt profile, the at least one melt profile representing a set time interval and a set temperature of the interior cavity of the crucible over the set time interval; and

sending a temperature command to the crucible.

15. The apparatus of claim 14, wherein the controller is further capable of:

receiving a plurality of temperature readings from a temperature feedback device; and

comparing the at least one melt profile with the plurality of temperature readings and determining the temperature command therefrom, the temperature command comprising an attempt to minimize a difference between the temperature readings and the at least one melt profile.

16. A method of melting metal and casting molds in a rollover melt furnace comprising a rotating shaft and a crucible connected to the rotating shaft for rotation therewith, the crucible having a pour opening into an interior cavity, the pour opening being located on an exterior surface of the crucible, comprising the steps of:

loading an ingot into the interior cavity of the crucible;

melting the ingot in the interior cavity of the crucible thereby forming a molten metal;

attaching a mold to the rollover melt furnace, the mold having an exterior surface that includes a fill opening, the fill opening being sized to accommodate a flow from the pour opening of the crucible; and

rotating the shaft using an electrical motor to transfer the molten metal from the crucible to the mold.

17. The method of claim 16, further comprising the step of automatically positioning a clamp to receive the mold.

18. The method of claim 16, wherein the step of melting the ingot comprises controlling a temperature of the crucible based on a melt profile.

19. The method of claim 16, further comprising the steps of:

rotating the shaft so that the crucible reaches a wet lip position; and

after reaching the wet lip position, rotating the shaft so that the crucible returns to the upright position before reaching an inverted position.

20. The method of claim 16, wherein the step of rotating the shaft using an electrical motor comprises accelerating rotation of the shaft until the crucible reaches a set velocity.

21. The method of claim 16, wherein the step of rotating the shaft using an electrical motor comprises:

rotating the shaft so that the crucible reaches a fill position, in which molten metal flows from the crucible to the mold; and

after reaching the fill position, decelerating rotation of the shaft until the crucible reaches an inverted position.

22. The method of claim 16, wherein the step of rotating the shaft using an electrical motor comprises controlling rotation of the shaft based on a pour profile.

23. The method of claim 16, further comprising the step of inputting a command into a controller to automatically control rotation of the shaft.