Patent Publication Number: US-11396042-B1

Title: Serial multi-cavity high pressure casting apparatus and high pressure casting method using the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Korean Patent Application No. 10-2021-0090189, filed on Jul. 9, 2021, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     Field of the Disclosure 
     The present disclosure relates to a high pressure casting apparatus and a high pressure casting method capable of producing a casting product twice in one mold. 
     Description of Related Art 
     Assuming that one product is conventionally produced in one mold when a product is produced by a high pressure casting, to produce two products in one mold, 1) a parallel multi-cavity structure, 2) an increase in a casting area, and 3) an increase in the tonnage of a high pressure casting machine due to an increase in a mold-clamping force should be applied. 
     A mold-opening force (P) is a value obtained by multiplying a casting pressure (p) by a casting area (A), and the mold-opening force is proportional to the casting area. 
     A general casting pressure has a slight difference according to products but has about 600 to 800 bar, the casting pressure does not greatly vary even if the size of the mold or the size of the product is changed. Instead, as the casting area increases, the mold-opening force that opens the mold increases and a high pressure casting machine with a mold-opening force larger than the mold-opening force such that the mold is not opened is selected. For example, a 2-cavity casting method compared to a projection area of a 1-cavity casting method requires a projection area of about 1.8 to 2 times. In other words, when a 500 t high pressure casting machine is required to produce a product of the 1-cavity casting method, a 1,000 t high pressure casting machine is arithmetically required to produce the 2-cavity casting product. 
     For example, Japanese Patent Application Laid-Open No. 2001-321887 discloses that two multi-cavity casting methods have been designed by the three stage mold (fixed/medium/operation) and each cavity has been filled using two sleeves and the plunger. 
     The method may simultaneously produce two or more products with the same tonnage of the high pressure casting machine, but has no choice but to fill each sleeve/the plunger with molten metal, and therefore, there is no choice but to use a method for sequentially injecting the molten metal using a ladle in one melting furnace, or simultaneously injecting the molten metal in each of two melting furnaces. The former increases a cycle time, and the latter increases an investment cost due to the construction of an additional melting facility, thereby affecting productivity and product costs. 
     The contents described in Description of Related Art are to help the understanding of the background of the present disclosure, and may include what is not previously known to those skilled in the art to which the present disclosure pertains. 
     SUMMARY 
     The present disclosure has been made in an effort to solve the above problem associated with the related art, and an object of the present disclosure is to provide a serial multi-cavity high pressure casting apparatus and a high pressure casting method using the same, which may produce a product twice as much as the convention in one mold without increasing a mold-clamping force of the high pressure casting apparatus. 
     According to one aspect of the present disclosure, a serial multi-cavity high pressure casting apparatus includes a three stage mold including a fixed mold, an operation mold, and a medium mold disposed between the fixed mold and the operation mold, a main sleeve penetrating a lower portion of the fixed mold, and having molten metal injected thereinto, a main runner formed to extend upward from the main sleeve, an auxiliary sleeve branched to both directions from the main runner, an auxiliary runner formed to extend upward from each of both ends of the auxiliary sleeve and connected to each of a first cavity formed between the fixed mold and the medium mold, and a second cavity formed between the medium mold and the operation mold, and a sleeve core disposed on a lower portion of the medium mold, and having the main sleeve, the main runner, and the auxiliary sleeve inserted thereinto. 
     Further, a pair of bisected sleeve cores are provided, and the main sleeve, the main runner, and the auxiliary sleeve are inserted into a core cavity formed between the pair of sleeve cores. 
     Furthermore, each of the auxiliary runners connected to the first cavity and the second cavity is divided into a plurality of auxiliary runners from the auxiliary sleeve, and the first cavity and the second cavity are formed as many as each of the auxiliary runners is divided. 
     Alternatively, the serial multi-cavity high pressure casting apparatus may further include a pair of core cylinders coupled to side surfaces of the pair of sleeve cores, respectively, and coupled to both side surfaces of the medium mold perpendicular to a longitudinal direction of the main sleeve, to operate the pair of sleeve cores by a hydraulic pressure in a direction perpendicular to the longitudinal direction of the main sleeve. 
     Further, the serial multi-cavity high pressure casting apparatus may further include a pair of hydraulic cutters coupled to an upper end of the medium mold, and each of the hydraulic cutters including a cutting blade extending toward the sleeve core inside the medium mold to move the pair of hydraulic cutting blades upward or downward by a hydraulic pressure. 
     Therefore, when the cutting blade moves downward by the pair of hydraulic cutters, the pair of cutting blades cut the auxiliary sleeve. 
     In particular, the pair of cutting blades cut each of symmetric points with respect to a branched point where the auxiliary sleeve is branched from the main runner. 
     Meanwhile, the serial multi-cavity high pressure casting apparatus may further include a sliding shoe coupled to a lower side of the medium mold to guide a movement operation of the medium mold. 
     Further, a guide rail extending toward the operation mold and formed with a guide hole in a longitudinal direction is coupled to one side of the fixed mold, and a stopper inserted into the guide hole protrudes and is coupled to one side of the medium mold. 
     Further, the serial multi-cavity high pressure casting apparatus may further include a hydraulic fastener coupled to one side of the operation mold and to one side of the medium mold to fasten the operation mold to the medium mold. 
     Next, a high pressure casting method using a serial multi-cavity high pressure casting apparatus according to one aspect of the present disclosure includes injecting molten metal into the main sleeve of the serial multi-cavity high pressure casting apparatus and filling the molten metal in the first cavity and the second cavity by moving a plunger provided in the main sleeve forward. 
     The high pressure casting method may further include opening the first cavity by operating the medium mold and the operation mold when the molten metal is filled by the filling of the molten metal and then the molten metal is solidified to complete the casting and moving a pair of sleeve cores toward the pair of core cylinders by operating the pair of core cylinders. 
     Further, the serial multi-cavity high pressure casting apparatus includes a pair of hydraulic cutters coupled to an upper end of the medium mold, and each of the hydraulic cutters including a cutting blade disposed to extend toward the sleeve core inside the medium mold to move the cutting blade upward or downward by the hydraulic pressure, and the high pressure casting method may further include cutting the auxiliary sleeve by operating the pair of hydraulic cutters. 
     The serial multi-cavity high pressure casting apparatus further includes the hydraulic fastener coupled to one side of the operation mold and to one side of the medium mold to fasten the operation mold to the medium mold, and the high pressure casting method may further include releasing the constraint of the operation mold and the medium mold by operating a hydraulic fastener and opening the second cavity by operating the operation mold. 
     The present disclosure may minimize the increase in the projection area by disposing the product in series other than the conventional parallel multi-cavity high pressure casting method, and improve the productivity twice without increasing the tonnage of the high pressure casting machine. 
     In other words, the present disclosure simultaneously injects the molten metal into the multi-cavity, thereby not increasing the cycle time, and does not inject the molten metal into each of the multi-cavity and therefore does not increase the investment cost due to the construction of the additional melting facility, thereby improving the productivity and reducing the cost. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  illustrates a serial multi-cavity high pressure casting apparatus according to the present disclosure. 
         FIG. 2  illustrates a cross-sectional shape of  FIG. 1 . 
         FIGS. 3, 4, 5, 6, and 7  illustrate the serial multi-cavity high pressure casting apparatus according to the present disclosure partially and schematically for explaining a specific configuration and operation thereof. 
         FIG. 8  sequentially illustrates a high pressure casting method using the serial multi-cavity high pressure casting apparatus according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     To fully understand the present disclosure, the operational advantages of the present disclosure, and the object achieved by the practice of the present disclosure, reference should be made to the accompanying drawings illustrating preferred exemplary embodiments of the present disclosure and the contents described in the accompanying drawings. 
     In describing preferred exemplary embodiments of the present disclosure, a description of well-known techniques or repetitive descriptions that may unnecessarily obscure the gist of the present disclosure will be reduced or omitted. 
       FIG. 1  illustrates a serial multi-cavity high pressure casting apparatus according to the present disclosure and  FIG. 2  illustrates a cross-sectional shape of  FIG. 1 . Further,  FIGS. 3 to 7  illustrate the serial multi-cavity high pressure casting apparatus according to the present disclosure partially and schematically for explaining a specific configuration and operation thereof. 
     Hereinafter, a serial multi-cavity high pressure casting apparatus according to an exemplary embodiment of the present disclosure will be described with reference to  FIGS. 1 to 7 . 
     The present disclosure relates to a technology that may minimize an increase in a projection area by disposing a product in series other than the conventional parallel multi-cavity high pressure casting method, and improve productivity twice without increasing the tonnage of a high pressure casting machine. 
     To this end, a serial multi-cavity high pressure casting apparatus according to an exemplary embodiment of the present disclosure has a three stage mold structure in which a medium mold  121  is disposed between a fixed mold  111  and an operation mold  112 , in which a first cavity C 1  is formed between the fixed mold  111  and the medium mold  121 , and a second cavity C 2  is formed between the operation mold  112  and the medium mold  121 . 
     A mold support device  130  has the mold support device at the fixed mold side coupled to the fixed mold  111  to support the fixed mold  111 , and the mold support device at the operation mold side coupled to the operation mold  112  to support the operation mold  112 , and at the same time, to operate the operation mold  112  toward the fixed mold  111  forward or backward. 
     For such a placement, support, and operation, a hydraulic fastener  150 , a sliding shoe  160 , a guide rail  171 , a stopper  172 , a core cylinder  180 , a hydraulic cutter  190 , or the like are provided, and for filling a first cavity C 1  and a second cavity C 2 , a plunger P, a main sleeve  141 , a main runner  142 , an auxiliary sleeve  143 , and an auxiliary runner  144  are constituted. 
     As illustrated in  FIGS. 3 and 4 , according to the present disclosure, one main sleeve  141  configured to inject molten metal is formed to penetrate a lower portion of the fixed mold  111  to extend to a lower side of the medium mold  121 , and the plunger P is provided in the main sleeve  141  to pressurize the injected molten metal such that the molten metal is injected into the cavity. 
     According to the present disclosure, for filling a double cavity, the main runner  142  is formed to extend upward from the main sleeve  141 , and the auxiliary sleeve  143  branched to both directions from an upper end of the main runner  142  is formed. 
     Further, the auxiliary runners  144  are formed upward from the auxiliary sleeves  143  of both sides, respectively, and therefore, each auxiliary runner  144  communicates with the first cavity C 1  and the second cavity C 2 . 
     Therefore, two products may be produced by simultaneously filling two cavities C 1 , C 2  with the molten metal injected by one main sleeve  141 . 
     Furthermore, each auxiliary runner  144  is formed in a double, and each of the first cavity C 1  and the second cavity C 2  may be formed as a double cavity. In this case, molten metal is injected from a total of four auxiliary runners to fill four cavities such that four products may be produced. 
     Here, after the molten metal is filled and solidified, the product may not be taken out due to the shape of the auxiliary sleeve  143 , and to solve such a problem, the present disclosure includes bisected sleeve cores  122  inside a lower portion of the medium mold  121 , and the core cylinder  180  is connected to each of the bisected sleeve cores  122  and configured such that the bisected sleeve core  122  may be away from each other and opened by the hydraulic pressure of the core cylinder  180 . 
     In other words, as illustrated in  FIGS. 2 and 5 , a pair of sleeve cores  122  are formed with core cavities with the shape corresponding to the main sleeve  141 , the main runner  142 , and the auxiliary sleeve  143  upon engagement, and therefore, becomes the form into which the main sleeve  141 , the main runner  142 , and the auxiliary sleeve  143  are inserted into the core cavity upon engagement. 
     In other words, the main sleeve  141  is formed to the inside of the engaged sleeve core  122 , the main runner  142  is connected to the main sleeve  141  to be formed between the sleeve cores  122 , and the auxiliary sleeve  143  branched from the main runner  142  is formed to penetrate the sleeve core  122 . 
     Further, the end of the auxiliary sleeve  143  is formed outside the sleeve core  122 , and therefore, the auxiliary runner  144  is formed. 
     As illustrated, a core cylinder  180  is coupled to both sides of the medium mold  121  perpendicular to a longitudinal direction of the main sleeve  141 , and each one end thereof is connected to the sleeve core  122  to open the sleeve core  122  to both sides of the medium mold  121  perpendicular to the longitudinal direction of the main sleeve  141 . 
     At this time, as illustrated in  FIGS. 1 and 6 , the auxiliary sleeve  143  may be cut after the molten metal is solidified by a pair of hydraulic cutters  190  coupled to an upper end of the medium mold  121 . 
     In other words, the sleeve core  122  is opened, a cutting blade  191  connected to each of the pair of hydraulic cutter  190  operated by the hydraulic pressure to move upward or downward is formed toward the sleeve core  122  from the upper end of the medium mold  121 , and after the sleeve core  122  is opened, the cutting blade  191  moves downward to cut the auxiliary sleeve  143 . 
     The cutting blade  191  is disposed at a position of cutting each of the symmetric points of the auxiliary sleeve  143  with respect to the branched point of the auxiliary sleeve  143 . 
     Therefore, the sleeve core  122  is opened and the auxiliary sleeve  143  is cut by the hydraulic cutter  190  before the solidification is completed, and the mold is opened such that the product may be taken out after avoiding an under-cut shape of the casting product to complete the casting. 
     Next, as illustrated in  FIG. 7 , the lower side of the medium mold  121  is coupled with the sliding shoe (guide shoe)  160  to prevent the conduction of the medium mold  121  upon the mold-opening. In other words, the mold support device  130  at the operation mold  112  side moves on a movable rail (not illustrated), and the sliding shoe  160  to which a low friction material movable on the movable rail is applied is mounted, thereby facilitating the movement in a direction in which the mold of the medium mold  121  is opened or closed despite the increased weight of the mold. 
     Further, to prevent the medium mold  121  from being separated upon opening in a state where the medium mold  121  is coupled to the fixed mold  111 , the medium mold  121  is coupled to one side of the fixed mold  111  and extends toward the operation mold  112 , and the guide rail  171  having a guide hole formed in a longitudinal direction is mounted. Further, the stopper  172  inserted into the guide hole of the guide rail  171  is coupled to protrude from one side of the medium mold  121 , and therefore the stopper  172  is blocked by the guide rail  171  when the mold is opened, thereby preventing the medium mold  121  from being separated. 
     A pair of guide rail  171  and stopper  172  may be formed on the upper and lower portions of the serial multi-cavity high pressure casting apparatus. 
     Further, the operation mold  112  may be engaged and may perform the mold assembly and the mold-opening operation in a state of being coupled to the medium mold  121 , and additionally, may be separated from the medium mold  121  to perform the mold-opening operation. 
     To this end, the hydraulic fastener  150  including a locking block coupled to one side of the operation mold  112  and one side of the medium mold  121  together is constituted, and the operation mold  112  may be separated from the medium mold  121  due to the hydraulic release of the hydraulic fastener  150 . 
     As described above, it is possible to secure operational stability by sequentially opening the mold. 
     Furthermore, the present disclosure makes the mold structure compact to secure a taken-out space. 
     In other words, the conventional mold has the mold structure in which the mold and the holder are assembled in consideration of durability and maintainability, in which the mold structure is complicated and the size thereof is increased by constituting the separate components of the mold and the holder. 
     However, there is a need for minimizing the size of the mold because the taken-out space is insufficient if the three stage mold is opened when the thickness of the mold is increased, and the present disclosure may drive the optimization of the size of the mold through the mold design standardization and the structural analysis, thereby deleting a holder part including a pocket part. 
     In other words, it is possible to minimize the size of the mold by the integrated mold structure (holderless), thereby securing the taken-out space of the product. 
     A high pressure casting method using the serial multi-cavity high pressure casting apparatus having the above configuration will be described with reference to  FIG. 8 . 
     First, the molten metal is injected into the main sleeve  141  in a state where the fixed mold  111 , the medium mold  121 , and the operation mold  112  are engaged, and the molten metal is filled in the first cavity C 1  and the second cavity C 2  by moving the plunger P forward through the main sleeve  141 , the main runner  142 , and the auxiliary sleeve  143 , and the auxiliary runner  144 . 
     Further, when the molten metal is filled and then solidified to complete the casting, the medium mold  121  performs the opening operation at S 11 . In other words, the operation mold  112  coupled to the medium mold  121  moves backward together and therefore, the first cavity C 1  is opened. 
     Then, the sleeve core  122  performs the opening operation by the operation of the core cylinder  180  at S 12 , and the hydraulic cutter is operated at S 13  to cut the auxiliary sleeve  143 . 
     Further, by releasing the hydraulic fastener  150  at S 14 , when the locking block is opened, the operation mold  112  is released from the constraint of the medium mold  121  to control the operation mold to be open at S 15 . 
     As described above, the casting product is taken out from the first cavity C 1  and the second cavity C 2  in a state where the second cavity C 2  is also opened at S 16 . 
     Then, the sleeve core  122  is also controlled to be closed again by the operation of the core cylinder  180  at S 17 , and the mold is sequentially closed at S 18 . 
     The present disclosure has been described above with reference to the exemplary drawings, but is not limited to the described exemplary embodiment, and it will be apparent to those skilled in the art that various modifications and changes are made without departing the spirit and scope of the present disclosure. Therefore, the modified examples or the changed examples are included in the claims of the present disclosure, and the scope of the present disclosure should be interpreted based on the appended claims.