Patent Application
20180354023
The present invention relates to a system, apparatus, and method for continuous casting of metal, and more particularly, to a mechanism for controlling the shape of a direct chill casting mold to dynamically control a profile of an ingot cast from the mold during the casting process.
Metal products may be formed in a variety of ways; however numerous forming methods first require an ingot, billet, or other cast part that can serve as the raw material from which a metal end product can be manufactured, such as through rolling or machining, for example. One method of manufacturing an ingot or billet is through a semi-continuous casting process known as direct chill casting, whereby a vertically oriented mold cavity is situated above a platform that translates vertically down a casting pit. A starting block may be situated on the platform and form a bottom of the mold cavity, at least initially, to begin the casting process. Molten metal is poured into the mold cavity whereupon the molten metal cools, typically using a cooling fluid. The platform with the starting block thereon may descend into the casting pit at a predefined speed to allow the metal exiting the mold cavity and descending with the starting block to solidify. The platform continues to be lowered as more molten metal enters the mold cavity, and solid metal exits the mold cavity. This continuous casting process allows metal ingots and billets to be formed according to the profile of the mold cavity and having a length limited only by the casting pit depth and the hydraulically actuated platform moving therein.
The present invention relates to a system, apparatus, and method for continuous casting of metal, and more particularly, to a mechanism for controlling the shape of a direct chill casting mold to dynamically control a profile of an ingot cast from the mold during the casting process. Embodiments may provide an apparatus for casting material including: first and second opposing side walls; first and second end walls extending between the first and second side walls, where the first and second opposing side walls and the first and second opposing end walls form a generally rectangular shaped mold cavity. At least one of the first and second opposing side walls may include two or more contact regions, where each of the two or more contact regions may be configured to be displaced relative to a straight line between a first end of the at least one of the first and second opposing side walls and a second end of the at least one first and second opposing side walls in response to receiving a respective force applied externally from the mold cavity. The respective displacement at a first of the two or more contact regions may be different from a displacement at a second of the two or more contact regions, and a respective force at each of the two or more contact regions may change the curvature of the at least one of the first and second opposing side walls.
According to some embodiments, the respective force at the first of the two or more contact regions may include a force in a first direction, where the respective force at the second of the two or more contact regions may include a force in a second direction, opposite the first direction. The respective force at the first of the two or more contact regions may include a force of a first magnitude in a first direction, where the respective force at the second of the two or more contact regions may include a force of a second magnitude in the first direction, the second magnitude being different from the first magnitude. The first and second opposing side walls may include an inner casting surface and an outer surface. Each of the first and second opposing side walls may further include a flexible bladder disposed along the outer surface, where a cooling fluid chamber is defined between each respective opposing side wall and the respective flexible bladder. The casting surface of each of the first and second opposing side walls may include a plurality of orifices in fluid communication with a respective fluid chamber. A baffle may be disposed between a cooling fluid chamber and the respective side wall, where the baffle includes a plurality of flow-restricting orifices. The plurality of orifices in each of the first and second opposing side walls may be configured to direct cooling fluid from the respective cooling fluid channel toward a cast material as the cast material advances past the casting surfaces of the first and second opposing side walls.
The first and second opposing side walls and the first and second opposing end walls of example embodiments may cooperate to define a mold cavity having a shape defined by the opposing side walls and end walls. Example embodiments of an apparatus may include: first means for applying a first force to a first of the two or more contact regions; and second means for applying a second force to a second of the two or more contact regions. The first means and the second means may be controlled by a single controller to change the shape of the mold cavity according to one or more properties of the material to be cast. The first means and second means may be configured to change the shape of the mold cavity as the material is cast based on one or more of a cast material alloy, a temperature of the cast material exiting the mold cavity, a temperature profile of the cast material, or a shape of the cast material exiting the mold cavity.
Embodiments of an apparatus provided herein may include a controller, where the displacement of the first contact region and the displacement of the second contact region are performed in response to at least one of an unexpected slowing of liquid into the mold cavity or feedback from an actuator applying a respective force to one or both of the first contact region and the second contact region. Embodiments may include two or more fixed position members, where the two or more fixed position members may be configured to resist movement of the first and second opposing side walls in response to a respective force applied at one or more of the two or more contact regions. The first and second opposing side walls may each include an upper portion and a lower portion. The upper portion of the at least one of the first and second opposing side walls may be displaced proximate the first contact region a first distance relative to the straight line between the first end of the at least one of the first and second opposing side walls and the second end of the at least one first and second opposing side walls. The lower portion of the at least one of the first and second opposing side walls may be displaced proximate the first contact region a second distance relative to the straight line between the first end of the at least one of the first and second opposing side walls and the second end of the at least one first and second opposing sidewalls, thereby defining a taper between an upper portion of the mold cavity and a lower portion of the mold cavity.
Embodiments described herein may provide a system for casting metal. The system may include: a controller; a mold including a first side wall, a second side wall opposite the first side wall, a first end wall, and a second end wall opposing the first end wall. The first side wall, second side wall, first end wall, and second end wall may cooperate to define a mold cavity having a mold cavity profile. The system may include a first force receiving element of the first side wall located opposite the mold cavity, where a first force applied to the first force receiving element may be controlled by the controller and cause a first displacement of the first side wall at the first force receiving element. A second force receiving element of the first side wall may be located opposite the mold cavity, where a second force applied to the second force receiving element may be controlled by the controller and causes a displacement of the first side wall at the second force receiving element. The first displacement may be different than the second displacement. The controller may be configured to adjust the first displacement of the first force receiving element and the second displacement of the second force receiving element during a casting process using the mold. The controller may adjust the first displacement and the second displacement in response to at least one of a property of the metal being cast or a profile of the metal exiting the mold.
According to some embodiments, the first side wall and the second side wall of the mold may each include a plurality of orifices for directing cooling fluid along metal exiting the mold during the casting process. A cooling fluid channel may be defined along the first side wall outside of the mold cavity, where the cooling fluid channel may be defined between the first side wall and a flexible bladder. The first force and the second force may be configured to be applied to the first force receiving element and the second force receiving element in opposite directions. Each of the first side wall and the second side wall may define therein a respective cooling fluid channel and a plurality of cooling fluid orifices. The system may include a cooling fluid supply, where the cooling fluid supply may be configured to provide cooling fluid to each of the respective cooling fluid channels to be sprayed through the plurality of orifices toward a cast material exiting the mold cavity at different angles.
Embodiments described herein may provide a component of a mold. The component may have a body extending along a length defined between a first end wall and a second end wall; an inner face defining a portion of a mold cavity and extending from the first end wall to the second end wall; and an outer surface opposite the inner face, where the outer surface is configured to receive a first force and a second force. The first end wall and the second end wall may be substantially stationary, where the component is configured to be displaced from a first shape between the first end wall and the second end wall to a second shape between the first end wall and the second end wall in response to application of the first force and the second force, where the first force and the second force are different.
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
Exemplary embodiments of the present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
Embodiments of the present invention generally relate to the design of a direct chill casting mold to facilitate a more consistent ingot profile. Vertical direct chill casting is a process used to produce ingots or billets that may have large cross sections for use in a variety of manufacturing applications. The process of vertical direct chill casting begins with a horizontal table containing one or more vertically-oriented mold cavities disposed therein. Each of the mold cavities is initially closed at the bottom with a starting block or starting plug to seal the bottom of the mold cavity. Molten metal is introduced to each mold cavity through a metal distribution system to fill the mold cavities. As the molten metal proximate the bottom of the mold, adjacent to the starting block solidifies, the starting block is moved vertically downward along a linear path. The movement of the starting block may be caused by a hydraulically-lowered platform to which the starting block is attached. The movement of the starting block vertically downward draws the solidified metal from the mold cavity while additional molten metal is introduced into the mold cavities. Once started, this process moves at a relatively steady-state for a semi-continuous casting process that forms a metal ingot having a profile defined by the mold cavity, and a height defined by the depth to which the platform and starting block are moved.
During the casting process, the mold itself is cooled to encourage solidification of the metal prior to the metal exiting the mold cavity as the starting block is advanced downwardly, and a cooling fluid is introduced to the surface of the metal proximate the exit of the mold cavity as the metal is cast to draw heat from the cast metal ingot and to solidify the molten metal within the now-solidified shell of the ingot. As the starting block is advanced downward, the cooling fluid may be sprayed directly on the ingot to cool the surface and to draw heat from within the core of the ingot.
The direct chill casting process enables ingots to be cast of a wide variety of sizes and lengths, along with varying profile shapes. While circular billet and rectangular ingot are most common, other profile shapes are possible. Circular profile billets benefit from a uniform shape, where the distance from the external surface around the billet to the core is equivalent around the perimeter. However, rectangular ingots lack this uniformity of surface-to-core depth and thus have additional challenges to consider during the direct chill casting process.
A direct chill casting mold to produce an ingot with a rectangular profile does not have a perfectly rectangular mold cavity due to the deformation of the ingot as it cools after leaving the mold cavity. The portion of the ingot exiting the mold cavity as the platform and the starting block descend retains a molten or at least partially molten core inside the solidified shell. As the core cools and solidifies, the external profile of the ingot changes such that the mold cavity profile, while it defines the shape of the final, cooled ingot, does not have a shape or profile that is identical to the final, cooled ingot.
While direct chill casting molds have been designed and developed to generate an ingot having substantially flat sides on its rectangular profile for the ingot portion produced during a steady-state portion of the casting process, the start-up process of direct chill casting includes challenges that distinguish the start-up casting phase process and the initial portion of the ingot formed during the start-up casting phase process from the steady-state phase of the casting process and the portion of the ingot formed during steady-state casting.
During the start-up phase of direct chill casting, high thermal gradients induce thermal stresses that cause deformation of the ingot in manners that are distinct from those experienced during the steady-state phase of casting. Due to the changes in thermal gradients and stresses experienced in the start-up phase versus the steady-state phase of casting, a constant-profile mold cavity results in a non-uniform profile of the ingot portion cast during the start-up phase, also known as the butt, and the ingot cast during the steady-state casting phase. As the portion produced during steady-state casting forms the majority of the ingot, the mold profile may be designed such that the opposed sides and ends of an ingot are substantially flat. This may result in a butt of the ingot formed during the start-up phase lacking substantially flat sides, as illustrated in the cast ingot cross-section of
The deformation of the ingot portion produced during the start-up phase 170 may not be usable depending upon the end-use of the ingot, such that the portion of the ingot formed during the start-up period may be sacrificial (i.e., cut from the ingot and repurposed/re-cast). This sacrificial butt portion of the ingot may be substantial in size, particularly in direct chill casting molds that have relatively large profiles, and while the butt may be re-cast so the material is not lost, the lost time, reheating/re-melting costs and labor associated with the lost portion of the ingot, and the reduced maximum size potential of an ingot result in losses in efficiency of the direct chill casting process Similar issues may exist at the end of a casting in forming the “head” of the ingot or billet, where casting ceases to be steady-state and may require specific control parameters to maximize the useable portion of the ingot and reducing waste.
Certain embodiments of the present invention include a direct chill casting mold that has flexible opposing side walls that may be dynamically moved during the casting process to eliminate the butt swell of conventional direct chill ingot casting molds to reduce waste and to improve the efficiency with which ingots are cast. Direct chill casting molds as described herein may include an opposed pair of casting surfaces on side walls of the mold that are flexible allowing them to change shape while the mold is casting an ingot. Each of the opposed side walls may include two or more contact portions or force receiving elements, each configured to receive a force that causes the opposed side walls of the mold to move dynamically and change shape during the casting process. The forces applied to the two or more contact regions may be independent and may include forces in opposing directions, as described further below. The contact regions may optionally be repositionable along the length of the opposing side walls to enable greater control over the shape of the side wall resulting from the forces applied.
As noted above, the opposing side walls of example embodiments described herein may include a profile that is dynamically adjustable from between two or more curvature profiles. The adjustment of the opposing side wall curvature may enable an ingot butt or billet butt produced at the start-up of the casting process to be produced without swelling or other dimensional or physical attributes that render the butt unsatisfactory for the intended purpose of the billet or ingot being cast. Example embodiments described herein allow near infinite size optimization from one mold in a given casting pit.
While the illustrated embodiments described herein generally depict two fluid chambers (460 and 465), there may be more or fewer fluid chambers based on the desired design configuration. A single fluid chamber may be used in some embodiments to provide cooling fluid flow through the side wall 211. Optionally, more than two fluid chambers may be used, particularly in an embodiment in which different flow rates or pressures may be desirable through orifices associated with each of the fluid chambers. Similarly, while three attachment points are shown for each of the force receiving members 310, embodiments may include fewer or more attachment points. According to some embodiments, the force receiving members may be attached to the side wall only at a single location, while in other embodiments the force receiving members may be attached to the side wall at two, three, or more locations.
Referring back to
According to the illustrated embodiment of
While the above-described and illustrated embodiment includes actuation plates 217, 218 that move simultaneously and in synchronization, example embodiments described herein may provide an actuation mechanism that allows the top actuation plate 218 to be moved independently from the bottom actuation plate 217. Disconnecting the fixed relationship between the top actuation plate 218 and the bottom actuation plate 217 allows a curvature in the side wall 211 to be different between the top and bottom of the side wall, such as a tapered opening from a wider curve at the top of the side wall 211 to a narrower curve at the bottom of the side wall. Through disconnection of fixed relationship between the top actuation plate 218 and the bottom actuation plate 217, the displacement of the force receiving member 310 may be different from the top of the force receiving member to the bottom force receiving member. This additional degree of freedom may enable better control over the profile of the ingot cast from the mold by permitting differing displacement along the x-axis between the top of a side wall and the bottom of the side wall. The separate actuation may include any of the mechanisms described above duplicated for top and bottom actuation plates, or using a single actuation mechanism with an adjustment allowed between the actuation mechanism and one or both of the top 218 and bottom 217 actuation plates. Such an adjustment mechanism may be a mechanism that enables a length to be altered between the actuation mechanism and one or both of the actuation plates, thereby enabling an offset to be imparted between the top actuation plate and the bottom actuation plate.
Further, while the illustrated embodiment of
In response to a bend introduced in the side wall 211 of the mold cavity through displacement of the force receiving members 310 along the x-axis shown in
The illustrated embodiment of
Also illustrated in
During the casting process, as material exits the mold cavity in response to the starter block 157 advancing downwardly as shown in
As noted above, embodiments may include any number of cooling fluid chambers, where each cooling fluid chamber may feed one or more sets of orifices for providing cooling fluid to the cast part as it exits the mold. As shown in
According to the illustrated embodiment, fluid chamber 465 may be in fluid communication with cooling orifices 264, which may each be arranged at an angle with respect to the side wall 211. In the depicted embodiment, cooling orifices 265 are arranged at an angle of forty-five degrees relative to the side wall 211, as shown by arrow 265 indicating the direction of fluid exiting the first plurality of cooling orifices 264. The second plurality of cooling orifices 266 may be arranged to direct cooling fluid at a different angle as shown by arrow 267, which is illustrated at an angle of twenty-two degrees relative to the side wall 211. However, the second plurality of cooling orifices may be in fluid communication with cooling fluid chamber 460 rather than chamber 465. In order to supply cooling fluid from the cooling fluid chamber 460 to the plurality of orifices 266, a channel 270 may be machined or otherwise formed into the back face of the side wall 211, beneath the substrate 280 on which the cooling channels are supported. A channel 270 may be present for each of the second set of cooling orifices 266, or alternatively, channels 270 may exist at a plurality of locations along the length of the side wall 211 in cooperation with a channel closer to the second set of cooling orifices 266 extending longitudinally along the side wall 211 in a manifold arrangement.
According to the illustrated embodiment, the cooling fluid flow through each of the first plurality of orifices 264 and the second plurality of orifices 266 may be independently fed by a respective cooling fluid chamber 460, 465. This configuration enables a cooling profile to be generated according to the type of material being cast with the appropriate flow rates and spray patterns from the respective set of cooling orifices. Optionally, cooling fluid temperatures may be separately controlled to provide even further control over the cooling of the material exiting the mold. Further, while the arrows 265 and 267 depict a general direction of cooling fluid exiting the orifices 264, 266, respectively, the spray patterns and fluid flow rates may be designed according to a preferred spray pattern based on the cooling requirements of the material being cast. Cooling fluid may also be selected based on the cooling requirements of a particular material being cast. Such cooling fluid may include, for example, water, ethylene glycol, propylene glycol, Organic Acid Technology (OAT) cooling fluid, or other fluid suited for drawing heat away from the cast part. The angle of the cooling orifices 264 and 266 may each also be configured for a specific angle of impingement on the cast part, which may be at an angle to encourage laminar flow at the orifice exit and turbulent cast part cooling fluid flow as the cooling comes into contact with the cast part. The angle of flow from the cooling orifices 264 and 266 may be in the range of about 0 degrees (directed down, substantially parallel to the side of the cast part exiting the mold) to about 90 degrees (directed perpendicular to the side of the cast part exiting the mold toward the cast part). This angle may be established based on characteristics of the material to be cast in the mold, for example.
According to some embodiments, fluid conduit block 260, as shown in
Each of the fluid chambers 460 and 465 may be defined by a flexible bladder 462, such as a heat-resistant silicone or similar material. While a separate flexible bladder may be used to define each cooling fluid chamber, according to the illustrated embodiment, a single flexible bladder 462 is used to define both cooling fluid chambers 460, 465, where the flexible bladder webbing may be captured between fasteners 450 and their corresponding fastener holes within the side wall 211. The baffle plate 261 may also be captured between the flexible bladder webbing and the side wall 211 using those same fasteners. The flexible bladder webbing may also be adhered to the baffle plate 261 using an adhesive or high-temperature sealant. Optionally, the flexible bladder material may be fiber-reinforced, multi-material, or geometrically layered to improve life of the chambers 460, 465. The bladders may be flexible to accommodate the bending of side wall 211, though sufficiently resilient to enable a fluid pressure to be applied to the fluid within the chambers to facilitate the appropriate flow rate and spray pattern from the orifices 264, 266.
In addition to providing cooling fluid to the orifices 264, 266, the cooling fluid chambers 465 and 466 provide a cooling effect on the side wall 211 itself. Cooling fluid chambers 465 and 466 are arranged in a manner that facilitates heat extraction from the back face of the side wall 211 into the cooling fluid. This side wall cooling effect further reduces the temperature of the side wall 211 proximate the lubricating fluid channel 261 to avoid over heating the lubricating fluid which can result in premature evaporation or burning of the lubricating fluid. Cooling of the side wall 211 using cooling fluid chambers 460 and 465 further reduces the likelihood and degree to which lubricating fluid would burn or evaporate as it flows down along side wall 211 with the cast material.
Example embodiments have been described and illustrated herein as incorporating flexible side walls of a direct chill casting mold with fixed profile end walls. However, embodiments described herein with respect to the side walls may optionally include end wall assemblies having constructions similar to those of the sidewalls described herein. End walls that are sufficiently long to result in swell of the cast material during a start-up phase of the casting process, or in need of profile correction may be configured to be flexible in the same or a similar manner as described herein with respect to the side walls. The flexibility of end walls may further reduce swelling of the ingot butt during the start-up phase and may decrease waste while increasing the efficiency and output of a direct chill ingot casting mold.
The above described and illustrated example embodiments include a plurality of force applying members which, responsive to a force received, induce a bend in a side wall (or end wall) of a mold.
The forces applied to the force receiving elements 510 may be different across a side wall. For example, as shown in
The adjustment of the curvature of a side wall or end wall of a direct chill mold during the casting process may be controlled using a plurality of different methods. For example, a cast material may have a casting profile that dictates parameters with respect to casting speed (e.g., flow rate of the liquid cast material and descent speed of the starter block), the temperature of the liquid cast material entering the mold cavity, the flow rate/pressure of the cooling fluid through the cooling orifices, the flow rate/pressure of the lubricating fluid through the lubricating orifices, and a curvature profile for the material at each phase of the casting process. The curvature profile may be adjusted from a first position during the start-up phase of casting, to another curvature profile during the steady-state phase, to another curvature profile during the end phase, and any number of curvature profiles between these phases (e.g., a dynamic steady change between the different phases). In such an embodiment, a controller may dictate the shape of the curvature of the side walls and/or end walls throughout the casting process responsive to the phase of casting. Feedback of properties of the material being cast may not be necessary in such an embodiment.
According to some embodiments, the curvature profile of the walls of the mold may be determined based on a closed-loop feedback system. A controller may receive temperature information (e.g., of the liquid casting material, the cast material exiting the mold, mold temperature, etc.), casting speed (e.g., the speed of descent of the starter block and platform), dimensional information (e.g., dimensions of the cast part as it exits the mold cavity or a predefined distance below the mold cavity exit), stress and/or strain feedback, or other information related to the casting process, and use this information to establish the appropriate curvature profile of the wall. A plurality of sensors may be dispersed around the exit of the mold cavity, such as thermal sensors to detect the temperature of the casting exiting the mold, or distance sensors configured to measure the dimensions of the casting exiting the mold. These sensors may provide feedback to the controller to determine the appropriate curvature profile given the data with respect to the casting exiting the mold cavity.
While example embodiments described herein may be implemented to reduce or control butt swell of a cast part, example embodiments may optionally be implemented to preclude or mitigate cast parts getting stuck within the mold. For example, butt curl and excessively hot casting conditions of a cast part such as an ingot during the casting process may cause an interference fit of the cast part within the mold, where the mold walls (side walls, end walls, or both) become engaged by the cast part in a manner that precludes the cast part 160 from exiting the mold assembly 200 as the starter block 157 descends into the cast pit. These conditions which lead to an interference between mold and cast part may lead to catastrophic failure, such as a mold over flow if not quickly corrected or mitigated. During the steady-state portion of the casting process, various factors may contribute to a cast part becoming hung up in the mold, such as improper lubrication, abnormal cooling, or the like. During the end of the casting process, the cast part may experience “reduced head shrinkage” and the flexible walls of the mold of example embodiments may be controlled to accommodate this shrinkage. During the movement of the side walls of the mold, a binding condition may occur where the cast part becomes stuck or hung up in the mold. In each of these cases, while the causes may be different, a cast part may become stuck within the mold which can lead to catastrophic failure if not mitigated quickly.
Example embodiments described herein may provide feedback from the mold to a controller indicating when a condition arises where the cast part is stuck or hung up in the mold. The feedback to the controller may include one or both of two detected changes. A first change that occurs in the casting process when the cast part is hung up within the mold is that the casting fluid flow slows while movement of the starter block continues downward into the casting pit. The casting fluid flow is controlled by the control pin and spout orifice size based upon metal level feedback, such that if fluid flow is rising while the starter block continues to descend, it is an indication that the cast part may be stuck in the mold. The level of the molten metal in the mold may be maintained at a constant or near constant level during casting through feedback of the level in the mold to a valve, such as a control pin in a fluid flow tube, to adjust the flow according to the fluid level in the mold. If this fluid flow control has to reduce fluid flow to maintain fluid level unexpectedly, it may be a symptom of a cast part stuck in the mold cavity.
Similarly, if the casting fluid flow of a first mold cavity from among a plurality of mold cavities is different and slower than the remaining cavities, this may be an indication of a stuck cast part. A second change that may occur during casting that may be indicative of a cast part stuck in a mold is resistance or feedback experienced by the actuation mechanism that provides a curvature in the mold side walls. The mold side walls may be held in a predetermined position by the actuation mechanism, and when the cast part becomes stuck or hung up in the mold, a force may be applied by the cast part onto the mold walls. In the case of an electric actuation mechanism, the actuation mechanism may experience a rise or spike in amperage or current draw at the actuation mechanism indicating a resistive force opposing the actuation mechanism. This spike may be indicative of the hanging up of a cast part in the mold. In the case of a hydraulic actuation mechanism, a spike in pressure or current draw on a hydraulic pump may similarly be indicative of a cast part being hung up in the mold.
Still another mechanism to detect a cast part stuck in the mold may be through a weight or force on the starting block 157 and platform 159 (as shown in
Responsive to an indication of a cast part being hung up in the mold, whether through one or both of an unexpected slowing of the casting fluid flow or a spike or increase in the hydraulic pressure or electrical current of the actuation mechanism, the controller may adjust the shape of the walls of the mold, such as the side walls, in an effort to cause the cast part to break free or separate from the mold, allowing lubricant to reach between the cast part and the mold walls. This change in shape may be caused by the controller actuating the actuation mechanism in such a way as to encourage the cast part to descend from the mold cavity along with the starting block down into the casting pit.
The actuation mechanism for inducing the appropriate curvature profile is described and illustrated above to include a pair of actuation plates and an actuation mechanism to move the actuation plates. However, other mechanisms may be employed to provide forces to the force receiving members to impart a curvature to the side walls or end walls of a mold.
In an example embodiment in which the actuators 530 function as described with respect to
The dynamically adjustable side walls of example embodiments described herein may be used to establish the profile of the cast part as it exits the mold cavity and cools. However, according to some embodiments, the dynamically adjustable side walls may optionally be used to aid in aligning the starting block to the mold cavity. Alignment of the starting block with the mold cavity is important to ensure no casting fluid leaks at the start to the casting process. While a mold frame may be moved to align with a starting block through, for example, electric, pneumatic or hydraulic actuator means, embodiments described herein may use the dynamic flexibility of the mold side walls to align the mold cavity to the starting block. The starting block 157 may be positioned on a platform 159. The interface between the starting block 157 and the platform 159 may be a reduced friction interface, such as through use of a lubricating material (e.g., grease, oil, graphite, etc.) or using an air cushion with air fed through the platform to between the platform 159 and the starting block 157. One or more alignment features may extend below the mold cavity to be used as guides to guide the starting block 157 into engagement with the mold cavity. Prior to casting, as the platform is raised to engage the starting block 157 with the mold cavity, or as the mold is lowered into engagement with the starting block, the side walls of the mold cavity may be adjusted to open the mold cavity. Opening of the mold cavity using the dynamically adjusted side walls may provide a larger area into which the starting block 157 may be received, helping ease alignment.
Bringing the starting block into engagement with the mold cavity may be aided by alignment features of the mold, and once the starting block 157 is within the mold cavity, the dynamically adjusted side walls may be adjusted to a smaller opening to provide proper clearance with the starting head for cast start. In the event the starting block is not properly aligned or centered within the mold cavity, the adjustment of the side walls of the mold cavity may move the starting block such that it is centered within the mold cavity. The reduced friction surface between the starting block 157 and the platform 159 may facilitate this movement. Through this mechanism, alignment between the starting block 157 and the mold cavity may be more easily achieved.
Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
