Mold for core making equipment and curing method and application of mold

Abstract

The invention discloses a mold for core making equipment and a curing method and application of the mold, and belongs to the technical field of core making machine molds. The curing method comprises the following steps that sand shooting forming is conducted, specifically, in the mold closing state, molding sand is shot into a mold cavity from a sand shooting nozzle in a mold body to be used for forming a sand core; and heating and curing are conducted, specifically, a curing medium heated to be in a gaseous state is injected into the cavity through a plurality of air inlet channels, the curing medium makes contact with the peripheral side of the sand core and then is diffused and permeated, the sand core is cured from the periphery of the sand core, and the air inlet ends of the air inlet channels are separated from the sand shooting nozzles. According to the invention, molding sand injected into the mold can be quickly and uniformly attached to the surface of the loose core, and each part of the sand core can be quickly and uniformly cured in a short time, so that the curing speed of large pieces and high pieces is greatly increased, the curing effect and efficiency are improved, the compactness of the sand core can be improved through vibration, and the production efficiency is improved. And the product quality is further improved.

Description

Technical Field

[0001] The invention mainly relates to the technical field of core making machine moulds, and specifically relates to a mould for core making equipment and a curing method and application thereof. Background Art

[0002] Core making machine is a general term for core shooting machine, cold core machine and shell core machine, which mainly includes sand shooting mechanism, mold clamping mechanism, heat curing box and core pulling and demoulding mechanism. The core making machine shoots sand core into the core box at high speed. Under certain temperature conditions, high-temperature gas is used to make the sand core in the core box quickly form and harden to obtain the finished product. A cycle only takes a dozen seconds to dozens of seconds to produce sand cores for casting. The cores made by the core making machine are accurate in size and smooth in surface, and are widely used in the foundry machinery industry.

[0003] Among the molds currently used in core making machines, general cold and hot core molds are generally solidified by injecting gas through the sand shooting port located at the top of the mold to solidify the sand core, that is, sand shooting and gas injection share the same hole. This design method will cause the sand on the mold far away from the sand shooting port to not be cured quickly, making the sand core solidification uneven, greatly reducing the quality of the sand core products, and for those large and high parts, injecting gas from the sand shooting port on the top of the mold will make the gas penetrate into the sand slower and take longer, greatly reducing work efficiency.

[0004] As previously applied for by the applicant, the patent name is a positive and negative pressure sand shooting mechanism for a core making machine, and the patent application number is 2022110845390. In the sand shooting mechanism, both the sand shooting and the curing gas are injected through the sand shooting port on the top, and the curing gas contacts the outer surface of the sand core for curing treatment. Since the curing gas is sprayed in from the top, it is difficult for the curing gas to evenly cure various areas of the sand core, resulting in uneven curing. In particular, for large or high sand cores, the curing effect at the bottom is very poor, and when curing is performed from the upper sand shooting port, it is very likely that the outer surface of the sand core has been completely cured, but the bottom and the inside are still in an incompletely cured state, resulting in uneven curing and poor curing effect.

[0005] In addition, since the curing gas is usually high-temperature hot gas, after being injected from the top sandblasting port, the curing gas is easy to overflow from the sandblasting port after the injection is completed, resulting in a reduction of the curing gas in the cavity, affecting the curing effect, and increasing the curing cost.

[0006] In view of the above problems, the applicant of the present invention has developed a forming and curing mold and a curing method for core making equipment through continuous and in-depth research. The sand shooting port and the curing gas injection port are separated, and the curing effect is significantly improved by changing the curing method, making it more suitable for the curing treatment of large sand cores. Summary of the invention

[0007] In order to solve the above-mentioned technical problems, one of the purposes of the present invention is to provide a mold for core making equipment and a curing method and application thereof, which separates the sand shooting port from the curing gas injection port, and significantly improves the curing effect by changing the curing method, making the curing more uniform and more suitable for the curing treatment of large sand cores.

[0008] The technical solution adopted by the present invention to solve the above technical problems is: In a first aspect, the present invention provides a method for curing a mold for a core making device, comprising the following steps: S1: Sand shooting molding, in the mold closing state, the molding sand is shot into the mold cavity from the sand shooting nozzle on the mold body to form the sand core; S2: Heating and curing, using multiple air inlet channels to inject the solidifying medium heated to a gaseous state into the mold cavity, diffuse and penetrate after contacting the surrounding side of the sand core, and solidify the sand core from all sides, and the air inlet end of the air inlet channel is separated from the sand shooting nozzle.

[0009] In some achievable embodiments of the first aspect, the solidifying medium heated to a gaseous state is injected into the inner cavity of the sand core through the plurality of air inlet channels, diffuses and penetrates into the inner wall of the sand core after contacting the inner wall, and solidifies the sand core from the inside.

[0010] In some achievable methods of the first aspect, before the sand core is formed, the interior of the cavity is vacuumed under negative pressure using the air inlet channel on the core pulling assembly, so that the molding sand in the cavity quickly adheres to the outer wall of the core pulling assembly and fills the interior of the cavity.

[0011] In some achievable embodiments of the first aspect, the curing medium includes at least one of a curing agent and a curing accelerator; And / or, the curing agent includes at least one of air, carbon dioxide, hexamethylenetetramine and citric acid; And / or, the curing accelerator includes at least one of an amine curing accelerator, an acid anhydride curing accelerator, a metal salt curing accelerator and a silane coupling agent.

[0012] In some achievable methods of the first aspect, in the heating and curing step, heated air is injected into the mold cavity to cure the sand core from the inside. After curing, the mold is opened and the core pulling assembly is removed to obtain a cured sand core.

[0013] In some achievable methods of the first aspect, in the heating and curing step, a curing agent or a curing accelerator heated to a gaseous state is first injected into the mold cavity, and diffuses and penetrates after contacting the side wall of the inner cavity of the sand core, and is cured from the inside of the sand core to achieve one-time curing; The heated air is then injected into the mold cavity, diffuses and penetrates into the sand core cavity side wall after contacting it, and solidifies it from the inside of the sand core to achieve secondary solidification. After the solidification is completed, the mold is opened, and the core pulling assembly is taken out to obtain the solidified sand core.

[0014] In some achievable methods of the first aspect, in the heating and curing step, after the curing agent or curing accelerator heated to a gaseous state is mixed with the heated air, the mixed gas is injected into the mold cavity to cure the sand core from the inside. After the curing is completed, the mold is opened and the core pulling assembly is taken out to obtain the cured sand core.

[0015] In some achievable embodiments of the first aspect, the temperature of the heated air is 170° C. to 300° C.; And / or, the pressure of the heated air is 0.1 MPa~0.8 MPa In a second aspect, the present invention provides an application of a method for curing a mold for a core-making device, wherein the method for curing a mold for a core-making device is used to cure the molding sand; The curing method is applicable to hot core or cold core process; And / or, the curing method is applicable to core making machines, core shooting machines, cold core machines and various core making equipment.

[0016] In a third aspect, the present invention provides a molding and curing mold for a core making device, wherein the curing method of the mold for the core making device is used to cure the molding sand, wherein the mold comprises a core pulling assembly and a mold body, wherein the core pulling assembly and the mold body cooperate to form a cavity, and the cavity is used to form a sand core; The mold body is provided with a sand-shooting nozzle, and the sand-shooting nozzle is located at the top of the mold cavity; An air inlet channel is provided on the core pulling assembly, and the air outlet end of the air inlet channel is located in the inner cavity of the sand core. The air inlet channel is used to introduce gas into the inner cavity of the sand core and solidify the gas from the inside of the sand core.

[0017] In some achievable embodiments of the third aspect, the core pulling assembly includes a first core pulling assembly arranged along a first direction, the first core pulling assembly being used to form a first inner cavity of the sand core; A first air outlet is provided on the circumferential side wall of the first core puller, a first air inlet is provided on the end surface of the first core puller in contact with the outside, and a first air inlet channel is formed between the first air inlet and the first air outlet; And / or, the number of the first air outlet is not limited to one.

[0018] In some achievable embodiments of the third aspect, the core pulling assembly includes a second core pulling assembly arranged along a second direction, and the second core pulling assembly is used to form a second inner cavity of the sand core; A second air outlet is provided on the circumferential side wall of the second core puller, a second air inlet communicating with the outside is provided at the axial end of the second core puller, and a second air inlet channel is formed between the second air inlet and the second air outlet; And / or, the number of the second air outlet is not limited to one.

[0019] In some achievable embodiments of the third aspect, the second core pullers are a pair, symmetrically disposed on both sides of the first core pullers; And / or, the second core pulling device comprises a core pulling body, the core pulling body is a cylindrical structure, and a second air outlet is provided on an end surface of the core pulling body located inside the cavity; And / or, the core-pulling body comprises an air inlet end face, the air inlet end face is used to close the inner cavity of the core-pulling body from the outside, and a second air inlet is provided on the air inlet end face.

[0020] In some achievable methods of the third aspect, an air intake pipe is installed in the inner cavity of the core pulling body, and the second air inlet and the second air outlet are connected through the air intake pipe; The number of the air intake duct is not limited to one; And / or, when the number of the air intake pipes exceeds one, the air intake end of each of the air intake pipes is connected to the second air intake port.

[0021] In some achievable embodiments of the third aspect, a third air outlet is provided through the circumferential side wall of the air inlet duct; And / or, the number of the third air outlet is not limited to one.

[0022] In some achievable embodiments of the third aspect, there is a gap between the air intake duct and the core pulling body, and a third air outlet is provided on the side of the air intake duct away from the air intake end face, or the side of the air intake duct away from the air intake end face is open.

[0023] In some achievable modes of the third aspect, a vibrator is provided at an end of the first core pulling device facing away from the sand shooting nozzle; And / or, the number of the vibrators is not limited to one.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention realizes rapid sandblasting from the upper part of the mold body into the mold cavity formed between the core pulling and the mold body through multiple sand blasting nozzles on the two mold bodies, and multiple air outlets on the first core pulling assembly and the second core pulling assembly realize negative pressure vacuum treatment of the inner cavity of the core pulling assembly from different directions and different parts. Under the negative pressure state, the molding sand in the mold cavity can quickly adhere to and fill various parts of the surface of the core pulling, shortening the time and making the distribution more uniform. Then, the positive pressure heated gas is injected into the inner cavity of the core pulling assembly, and enters the interior of the sand core through the air outlet, and diffuses and penetrates into the inner wall of the sand core to achieve heating and curing of the sand core. When a curing agent is used, the curing agent will expand due to heat, accelerate penetration and diffusion, further improve the reinforcement effect, and improve the quality of the product.

[0025] (2) The present invention realizes rapid negative pressure vacuuming and positive pressure injection of a large amount of hot air in the inner cavity of the core pulling assembly through the design of multiple air inlet channels. The multiple air outlets on the first core pulling and the second core pulling greatly accelerate the speed of curing the molding sand. At the same time, the degree of curing of the sand in each part of the mold cavity is the same, which is more uniform, thereby improving the curing effect and product quality. It is more suitable for large and high parts. Compared with the traditional core making machine mold, gas can only be injected from the sand shooting port on the top of the mold. The gas has poor penetration effect in the sand, which will cause slow speed, uneven diffusion, and long time. It also avoids the defect that the molding sand far away from the sand shooting port cannot be better cured, and can quickly and evenly cure all parts of the sand core in a short time.

[0026] (3) The present invention achieves micro-vibration of different positions of the mold by arranging a vibrator on the bottom plate to improve the fluidity of the sand, thereby improving the compactness of the sand core and further improving the quality of the sand core product.

[0027] (4) Since the traditional core making process is slow because it is solidified by gas from the sand injection port or solidified by heating alone, the present invention uses hot air positive pressure injection into the mold cavity. Since the air pressure in the mold cavity is removed during negative pressure vacuuming, the hot air can quickly solidify the sand mold and the sand core. Since the negative pressure vacuuming quickly adsorbs the sand into the mold, the sand mold has a good density, and then the hot air is solidified by positive pressure from multiple directions, the solidification is uniform and fast, so the quality of the molded sand is good and the speed is fast.

[0028] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of a mold for a core making device in an embodiment of the present invention; Figure 2 It is a structural schematic diagram of a core pulling assembly in a mold according to an embodiment of the present invention; Figure 3 It is a schematic diagram of the overall decomposition structure of the mold in an embodiment of the present invention; Figure 4 Schematic diagram of the connection structure of the first core pulling in the mold of the embodiment of the present invention; Figure 5 for Figure 3 A magnified schematic diagram of area A; Figure 6 A schematic diagram of the structure of a sand core prepared according to an embodiment of the present invention; Figure 7 This is a schematic structural diagram of a sand core prepared in an embodiment of the present invention from another perspective. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 1. Core pulling assembly; 11. Bottom plate; 111. First air inlet; 12. First core pulling; 121. Positioning block; 122. Sealing pad; 123. First air outlet; 13. Arc bracket; 14. Second core pulling; 15. Air inlet end face; 16. Second air inlet; 18. Second air outlet; 19. Exhaust plug; 2. Mold body; 21. Sandblasting nozzle; 22. Positioning groove; 23. Arc groove; 3. Positioning frame; 4. Vibrator; 5. Sand core; 51. First cavity; 52. Second cavity. DETAILED DESCRIPTION

[0031] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings, but the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.

[0032] It should be noted that when an element is referred to as being "fixed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly connected by technicians in the technical field to which the present invention belongs. The terminology used in the specification of the present invention is for the purpose of describing specific embodiments and is not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0034] Embodiment: To solve the problem that in the traditional sand-shooting mechanism, both the sand-shooting and the curing gas are injected through the sand-shooting port at the top, which leads to the poor curing effect, uneven curing, difficulty in complete curing inside, and easy overflow of curing gas in the part of the sand core far away from the sand-shooting port. The embodiment of the present invention provides a forming and curing mold for a core-making device, which is designed by separating the sand-shooting port from the curing gas injection port, and arranging the gas outlet end inside the inner cavity of the sand core 5, so that it is injected from the inside of the sand core 5 and contacts with the inner wall of the sand core 5 for curing, and the curing gas is uniformly infiltrated from the inside to the outside, which not only has a better curing effect and a more uniform curing, but also can seal the curing gas inside the sand core 5, effectively preventing it from overflowing from the sand-shooting port, significantly improving the curing effect, and making the curing more uniform, and more suitable for the curing of large sand cores 5.

[0035] Specifically, the molding and curing mold in the embodiment of the present invention is specifically referred to in the attached Figure 1-5 As shown, the mold includes a core pulling assembly 1 and a mold body 2, the core pulling assembly 1 and the mold body 2 cooperate to form a cavity, the cavity is used to form a sand core 5, and the mold body 2 is provided with a sand shooting nozzle 21, and the sand shooting nozzle 21 is located at the top of the cavity. Figure 2 As shown, the mold body 2 is a symmetrical two-half design. In the mold closing state, Figure 1 As shown, the mold body 2 structure is enclosed to form an integral whole.

[0036] The mold cavity is formed by the outer wall of the core pulling assembly 1 and the inner wall of the mold body 2. In the mold closing state, the molding sand is injected into the mold cavity from the sand injection nozzle 21 at the top to form the required sand core. It can be understood that the structures of the core pulling assembly 1 and the mold body 2 are different, and sand cores of different structures can be formed, and there are no excessive restrictions on this.

[0037] In this embodiment, the core pulling assembly 1 is provided with an air inlet channel, the air inlet end of the air inlet channel is separated from the sand-shooting nozzle 21 at the top or side, and the air outlet end of the air inlet channel is located in the inner cavity of the sand core 5. The air inlet channel is used to introduce the heated solidified gas into the inner cavity of the sand core 5, and solidify it from the inside of the sand core 5, so as to achieve diffusion and penetration from the inside of the sand core 5 to the outside, avoid the problem of incomplete solidification inside the sand core 5, and achieve better solidification effect and more uniform solidification. Since in the mold-closing state, after the solidified gas enters the inner cavity of the sand core 5, it will be enclosed in the inner cavity of the sand core 5, and the problem of solidified gas overflow and waste will not be caused.

[0038] It should be noted that there can be multiple air inlet channels. When there are multiple air inlet channels, the sand core 5 can be jet-cured from multiple directions, which improves the curing efficiency and has a better curing effect.

[0039] In some achievable embodiments, the core pulling assembly 1 includes a first core pulling assembly 12 arranged along a first direction, and the first core pulling assembly 12 is used to form a first inner cavity 51 of the sand core 5. Figure 2 In the orientation shown in , the first direction here refers to the vertical height direction.

[0040] In this embodiment, a first air outlet 123 is provided on the circumferential side wall of the first core pull 12, a first air inlet 111 is provided on the end surface of the first core pull 12 in contact with the outside, and a first air inlet channel is formed between the first air inlet 111 and the first air outlet 123, and the first air inlet channel realizes the curing process from the bottom of the sand core 5, which can meet the curing requirements of large or high-molded sand cores 5. The number of the first air outlets 123 is not limited to one, and when there are multiple first air outlets 123, they can be more evenly distributed on the outer circumferential side wall of the first core pull 12.

[0041] Specifically, the first core pulling body 12 includes a first core pulling body having a cavity structure in the first direction, a bottom plate 11 is provided at the bottom of the first core pulling body, and a plurality of first air inlets 111 are provided on the bottom plate 11. An arc bracket 13 is provided at the top of the first core pulling body, and the arc bracket 13 is used to support the second core pulling body 14. The arc brackets 13 are a pair, symmetrically arranged on both sides of the top of the first core pulling body, and an arc groove 23 is provided at a position corresponding to the arc bracket 13 on the mold body 2. In the mold closing state, the arc bracket 13 is embedded in the arc groove 23, and the stability of the internal structure connection of the mold is improved through the mutual cooperation between the arc groove 23 and the arc bracket 13.

[0042] Please refer to the attached Figure 2 and 3 As shown, attached Figure 2 and 3 As shown, the two side walls of the first core pulling body are provided with positioning blocks 122, the inner wall of the mold body 2 is provided with a positioning groove 22 matching the positioning block 122, and the positioning block 222 is embedded in the positioning groove 22 to achieve the connection stability between the core pulling assembly 1 and the mold body 2 in the mold closing state.

[0043] In some achievable embodiments, the core pulling assembly 1 includes a second core pulling assembly 14 arranged along the second direction, the second core pulling assembly 14 is used to form the second inner cavity 52 of the sand core 5, and the second inner cavity 52 of the sand core 5 is connected to the first inner cavity 51. Figure 2 In the orientation shown in , the second direction here refers to the horizontal direction.

[0044] In this embodiment, a second air outlet 18 is provided on the circumferential side wall of the second core pull 14, and a second air inlet 16 communicating with the outside is provided at the axial end of the second core pull 14, and a second air inlet channel is formed between the second air inlet 16 and the second air outlet 18. The second air inlet channel realizes the curing treatment from the upper part of the sand core 5, and the sand core 5 is cured from different height positions, so the curing is more uniform and the curing effect is better. The simultaneous jet curing of multiple parts can also significantly improve the curing efficiency. The number of the second air outlets 18 is not limited to one. When there are multiple second air outlets 18, they can be evenly distributed on the circumferential side wall of the second core pull 14.

[0045] Preferably, in this embodiment, the second core pull 14 is a pair, symmetrically arranged on both sides of the first core pull 12. The second core pull 14 includes a second core pull body, the second core pull body is a cylindrical structure, and the end surface of the second core pull body located inside the cavity is provided with a second gas outlet 18, ensuring that the second core pull body has multiple gas outlets in different directions, the gas outlet is more uniform, and multi-channel and multi-directional gas diffusion and penetration can be achieved to improve the curing effect.

[0046] like Figure 2 As shown, in this embodiment, the second core pulling body includes an air inlet end face 15, and the air inlet end face 15 is used to close the inner cavity of the second core pulling body from the outside, and a second air inlet port 16 is provided on the air inlet end face 15. The number of the second air inlet ports 16 here is not limited to one, which facilitates the realization of multiple air inlet channels.

[0047] Furthermore, in this embodiment, an air intake pipe is installed in the inner cavity of the second core-pulling body, and the second air inlet 16 and the second air outlet 18 are connected through the air intake pipe. Figure 2 As shown, the air inlet channel can be a cylindrical structure matched with the inner cavity of the second core-pulling body, or can be other structural forms, as long as the air inlet channel has a certain inner cavity and can transport solidified gas into the inner cavity of the second core-pulling body. The number of the air inlet pipes is not limited to one. When the number of the air inlet pipes exceeds one, the air inlet end of each of the air inlet pipes is connected to the second air inlet port 16.

[0048] In this embodiment, the circumferential side wall of the air inlet duct is provided with a third air outlet, and the number of the third air outlet is not limited to one. Alternatively, there is a gap between the air inlet duct and the core pulling body, and the side of the air inlet duct away from the air inlet end face 15 is provided with a third air outlet, or the side of the air inlet duct away from the air inlet end face 15 is open.

[0049] It should be noted that the air inlet pipe transports the solidified gas into the inner cavity of the second core pulling body, and it can be output from the circumferential side wall openings of the air inlet pipe, or from the open-designed air outlet pipe of the air inlet pipe, or from the through hole on the end face of the closed air outlet pipe. Any of the three forms can be selected, or they can be combined in any way, as long as the solidified gas in the air inlet pipe is transported to the inner cavity of the second core pulling body and output through the second air outlet 18 on the second core pulling body.

[0050] In some feasible embodiments, a vibrator 4 is provided at the end of the first core pulling 12 away from the sand shooting nozzle 21, and the number of the vibrator 4 is not limited to one. The vibration of the vibrator 4 can not only improve the fluidity of the sand, but also vibrate and compact the molding sand injected into the mold cavity, thereby improving the compactness and quality of the sand core product.

[0051] In this embodiment, the first core puller 12 and the bottom plate 11 are connected by bolts, and a circle of sealing gasket 122 is provided at the lower edge of the bottom of the first core puller 12. The sealing gasket 122 improves the sealing of the connection between the first core puller 12 and the bottom plate 11, thereby avoiding sand leakage.

[0052] Preferably, in the present embodiment, each of the first air outlet 123 and the second air outlet 18 may be provided with an exhaust plug 19. When the inner cavity of the core pulling assembly is evacuated at negative pressure or injected with positive pressure high-temperature gas, sand is prevented from passing through the first air outlet 123 and the second air outlet 18 with the air flow. On the premise of achieving ventilation to the interior of the sand core 5, the sand is isolated, the air and sand are separated, and the sand is prevented from entering the internal cavity of the core pulling assembly.

[0053] On the other hand, the present invention provides a method for curing a mold for a core making device, wherein the molding sand is cured using the above-mentioned molding curing mold, and the curing method comprises the following steps: S1: Sand shooting molding, in the mold closing state, molding sand is shot into the mold cavity from the sand shooting nozzle 21 on the mold body 2 to form a sand core 5 (which can be called a sand mold); S2: Heating and curing, using multiple air inlet channels to inject the curing medium heated to a gaseous state into the mold cavity, diffuse and penetrate after contacting the sides of the sand core 5, and uniformly cure the sand core 5 from all sides, and the air inlet end of the air inlet channel is separated from the sand shooting nozzle 21. In the traditional process, due to gas curing through the sand shooting nozzle 21 or single heating curing, not only the curing is uneven and the curing speed is slow, but also the part of the sand core far away from the sand shooting nozzle 21 will be incompletely cured, especially for large or high-profile sand core products. In this embodiment, multiple air inlet channels are used to simultaneously intake air into the mold cavity, and the sand core 5 is sprayed with hot gas for curing from different directions, which can effectively solve the problems of uneven and incomplete curing and slow curing speed, and effectively improve the quality of sand core products.

[0054] In some practicable embodiments, the solidifying medium heated to a gaseous state is injected into the inner cavity of the sand core 5 through the plurality of air inlet channels, diffuses and penetrates after contacting the inner wall thereof, and solidifies the sand core 5 from the inside. In practice, due to the different structures of the prepared sand core products, the air inlet channels can be provided on the core pulling assembly 1 or the mold.

[0055] In this embodiment, the curing medium includes at least one of a curing agent and a curing accelerator, wherein the curing agent includes at least one of air, carbon dioxide, hexamethylenetetramine and citric acid; and / or the curing accelerator includes at least one of an amine curing accelerator, an acid anhydride curing accelerator, a metal salt curing accelerator and a silane coupling agent.

[0056] There are three specific curing methods: (1) The first curing method includes the following steps: S1: In the mold closing state, the molding sand is injected into the mold cavity from the sand injection nozzle on the mold body to form the sand core 5; S2: The heated air is injected into the mold cavity by using the air inlet channel on the core pulling assembly, and diffuses and penetrates into the inner side wall of the sand core 5 after contacting it, and solidifies it from the inside of the sand core 5. After solidification, the mold is opened, and the core pulling assembly is taken out to obtain the solidified sand core 5.

[0057] Specifically, the heated air is injected into the inner cavity of the sand core 5 through multiple first air inlet channels and the second air inlet channel, which greatly accelerates the curing speed of the molding sand. At the same time, the degree of curing of the sand in each place in the mold cavity is the same, which is more uniform, thereby improving the curing effect and product quality, and is more suitable for large and high parts. Compared with the traditional core making machine mold, gas can only be injected from the sand shooting nozzle on the top of the mold. The gas has poor penetration effect in the sand, which will cause slow speed, uneven diffusion, and long time. It also avoids the defect that the molding sand far away from the sand shooting port cannot be better cured, and can achieve rapid and uniform curing of various parts of the sand core 5 in a short time.

[0058] In addition, since the solidified air inlet channel is directly connected to the mold, no extra moving structure is required, which greatly saves core making time and manufacturing costs. It can also be solidified by heating the gas to promote the acceleration of the reaction speed of the curing agent in the sand mold.

[0059] (2) The second curing method includes the following steps: S1: In the mold closing state, the molding sand is injected into the mold cavity from the sand injection nozzle on the mold body to form the sand core 5; S2: using the air inlet channel on the core pulling assembly to first inject the heated gaseous curing agent or curing accelerator into the mold cavity, and diffuse and penetrate into the inner cavity side wall of the sand core 5 after contacting it, and then curing it from the inside of the sand core 5 to achieve one-time curing; S3: The heated air is then injected into the mold cavity, and diffuses and penetrates into the inner side wall of the sand core 5 after contacting it, and solidifies it from the inside of the sand core 5 to achieve secondary solidification. After the solidification is completed, the mold is opened, and the core pulling assembly is taken out to obtain the solidified sand core 5.

[0060] Specifically, carbon dioxide heated to a gaseous state (in practice, other gaseous curing agents or curing accelerators, such as triethylamine, etc., can also be selected according to actual conditions) and heated air are injected into the inner cavity of the sand core in two batches through multiple first air inlet channels and second air inlet channels. When the curing agent is heated to a gaseous state, its volume continues to expand, reducing the amount of curing agent or curing accelerator used and increasing the contact area with the sand core. It is first introduced into the inner cavity of the sand core 5 to complete a primary curing, and then the heated air is introduced to perform a secondary curing on the sand core 5, which has a better curing effect.

[0061] (3) The third curing method includes the following steps: S1: In the mold closing state, the molding sand is injected into the mold cavity from the sand injection nozzle on the mold body to form the sand core 5; S2: After mixing the curing agent or curing accelerator heated to a gaseous state with air, the mixed gas is injected into the mold cavity through the air inlet channel on the core pulling assembly, and diffuses and penetrates into the inner cavity side wall of the sand core 5 after contacting it, and solidifies it from the inside of the sand core 5. After the curing is completed, the mold is opened, and the core pulling assembly is taken out to obtain the solidified sand core 5.

[0062] Specifically, the carbon dioxide heated to a gaseous state (in practice, other gaseous curing agents or curing accelerators, such as triethylamine, etc., can also be selected according to actual conditions) and the heated air are mixed and injected into the inner cavity of the sand core 5 through multiple first air inlet channels and the second air inlet channels. When the curing agent is heated to a gaseous state, its volume continues to expand, increasing the contact area with the sand core 5. After mixing with the hot air, it can effectively improve the curing effect.

[0063] Preferably, in the above three curing methods, before the sand core 5 is formed, the air inlet channel on the core pulling assembly is used to perform negative pressure vacuum treatment on the inside of the cavity. In practice, negative pressure vacuum treatment can be performed before or during sand shooting, so that the molding sand in the cavity quickly adheres to the outer wall of the core pulling assembly, and at the same time, various parts in the cavity are enriched, which not only makes the molding sand more evenly distributed, but also improves the quality of the subsequent molded products, and can effectively shorten the molding time and improve the molding efficiency. Then, the heated curing gas with positive pressure is used to heat and cure the inside of the sand core 5, which greatly accelerates the curing speed and improves the curing effect, especially for large and high-end products. The curing effect is more obvious, because the sand is shot from the top nozzle and the curing is performed from the outside of the sand core 5, the diffusion and penetration effect of the gas is poor, the speed is slow, and it is easy to cause the sand core part near the sand shooting nozzle to be over-cured, while the part far away from the sand shooting nozzle has not yet reached complete curing. In addition, it is easy to have the problem of incomplete internal curing and product quality problems.

[0064] In this embodiment, a curing method using negative pressure vacuuming and positive pressure input of a gaseous curing medium is used, which has the following advantages: 1. Since the traditional core making process is a single sand shooting through the sand shooting port, air pressure resistance is generated in the mold cavity, so the molding speed is slow. In this embodiment, the gas in the mold cavity and the gas during sand shooting are quickly extracted out of the mold by negative pressure vacuuming, and the sand is also quickly adsorbed to various parts of the mold to form a rapid molding.

[0065] 2. Since the traditional core making process is slow because it is solidified by gas from the sand injection port or solidified by heating alone, in this embodiment, hot air is injected into the mold cavity by positive pressure. Since the air pressure in the mold cavity is removed during negative pressure vacuuming, the hot air can quickly solidify the sand mold and sand core. Since the negative pressure vacuuming quickly adsorbs the sand to the mold, the sand mold has a good density, and then the hot air is solidified by positive pressure from multiple directions, the solidification is uniform and fast, so the quality of the molded sand mold is good and the speed is fast.

[0066] 3. The exhaust channel of the mold through the positive and negative pressure process is not easy to be blocked and the exhaust is unobstructed because the carbon deposits and residual resin in the exhaust channel are cleaned during the positive and negative pressure process.

[0067] 4. When sand shooting, the sand shooting pressure can be greatly reduced due to the assistance of negative pressure vacuum pumping, so the carbon deposits on the mold and the mold wear can be reduced, thereby greatly improving the service life of the mold. It can also effectively clean or reduce the carbon deposits and waste sand on the mold, keep the mold clean, thereby ensuring the quality of the sand mold or sand core, and reducing the mold cleaning process or cleaning time.

[0068] In some feasible implementations, the temperature of the heated air is 170°C to 300°C, and the pressure of the heated air is 0.1 MPa to 0.8 MPa, which is the safe operating pressure range of hot air to ensure the safety of the curing operation.

[0069] The curing agent includes at least one of carbon dioxide, hexamethylenetetramine, citric acid and silane coupling agent. After the curing agent is heated and expanded, its volume will greatly increase, increasing the contact area with the sand core 5, so that the sand core can be quickly cured, the strength and stability of the sand core 5 can be enhanced, and its moisture resistance and high temperature resistance can be improved. At the same time, the porosity in the sand core 5 can be reduced, and the surface quality of the casting can be improved.

[0070] Finally, an embodiment of the present invention further provides an application of a method for curing a mold for a core-making device, wherein the method for curing a mold for a core-making device is used to cure the molding sand; The curing method is applicable to hot core or cold core processes, and the curing method is applicable to core making machines, core shooting machines, cold core machines and various core making equipment.

[0071] The above is an exemplary description of the present invention in combination with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for curing a mold for a core making device, characterized in that: The following steps are involved: S1: sand shooting molding, in the mold closing state, molding sand is shot into the mold cavity from the sand shooting nozzle (21) on the mold body (2) to form a sand core (5); S2: Heating and curing, using a plurality of air inlet channels to inject the curing medium heated to a gaseous state into the cavity, diffuse and penetrate into the sand core (5) after contacting the circumference of the sand core (5), and cure the sand core (5) from all sides, and the air inlet end of the air inlet channel is separated from the sand shooting nozzle (21).

2. The method for curing a mold for a core making device according to claim 1, characterized in that: The solidifying medium heated to a gaseous state is injected into the inner cavity of the sand core (5) through the plurality of air inlet channels, diffuses and penetrates after contacting the inner wall thereof, and solidifies the sand core (5) from the inside thereof.

3. The method for curing a mold for a core making device according to claim 1, characterized in that: The curing medium includes at least one of a curing agent and a curing accelerator; And / or, the curing agent includes at least one of carbon dioxide, hexamethylenetetramine and citric acid; And / or, the curing accelerator includes at least one of an amine curing accelerator, an acid anhydride curing accelerator, a metal salt curing accelerator and a silane coupling agent.

4. The method for curing a mold for a core making device according to claim 1, characterized in that: In the heating and curing step, heated air is injected into the mold cavity to cure the sand core (5) from the inside. After curing is completed, the mold is opened and the core pulling assembly (1) is taken out to obtain a cured sand core (5).

5. The method for curing a mold for a core making device according to claim 1, characterized in that: In the heating and curing step, a curing agent or curing accelerator heated to a gaseous state is first injected into the mold cavity, and diffuses and penetrates into the inner cavity side wall of the sand core (5) after contacting the inner cavity side wall, and is cured from the inside of the sand core (5), thereby achieving one-step curing; The heated air is then injected into the mold cavity and diffuses and penetrates into the inner wall of the sand core (5) after contacting the inner wall, thereby curing the sand core (5) from the inside to achieve secondary curing. After the curing is completed, the mold is opened and the core pulling assembly (1) is removed to obtain a cured sand core (5).

6. The method for curing a mold for a core making device according to claim 1, characterized in that: In the heating and curing step, a curing agent or curing accelerator heated to a gaseous state is mixed with heated air, and the mixed gas is injected into the mold cavity to cure the sand core (5) from the inside. After the curing is completed, the mold is opened and the core pulling assembly (1) is taken out to obtain a cured sand core (5).

7. The method for curing a mold for a core making device according to any one of claims 1 to 6, characterized in that: Before the sand core (5) is formed, the air inlet channel on the core pulling component (1) is used to perform negative pressure vacuum treatment on the inside of the cavity, so that the molding sand in the cavity quickly adheres to the outer wall of the core pulling component (1) and fills the inside of the cavity.

8. The method for curing a mold for a core making device according to claim 7, characterized in that: The temperature of the heated air is 170°C to 300°C; And / or, the pressure of the heated air is 0.1 MPa~0.8 MPa.

9. Application of a method for curing a mold for a core making device, characterized in that: The molding sand is solidified by using the solidification method for the mold for core making equipment as described in any one of claims 1 to 8; The curing method is applicable to hot core or cold core process; And / or, the curing method is applicable to core making machines, core shooting machines, cold core machines and various core making equipment.

10. A forming and curing mold for a core-making device, wherein the molding sand is cured by the curing method for a mold for a core-making device according to any one of claims 1 to 8, wherein: The mold comprises a core pulling assembly (1) and a mold body (2), wherein the core pulling assembly (1) and the mold body (2) cooperate to form a mold cavity, and the mold cavity is used to form a sand core (5); The mold body (2) is provided with a sand-shooting nozzle (21), and the sand-shooting nozzle (21) is located at the top or side of the mold cavity; The core pulling assembly (1) is provided with an air inlet channel, the air outlet end of the air inlet channel is located in the inner cavity of the sand core (5), and the air inlet channel is used to introduce gas into the inner cavity of the sand core (5) and solidify the gas from inside the sand core (5).

11. The forming and curing mold for core making equipment according to claim 10, characterized in that: The core pulling assembly (1) comprises a first core pulling (12) arranged along a first direction, the first core pulling (12) being used to form a first inner cavity (51) of the sand core (5); A first air outlet (123) is provided on the circumferential side wall of the first core puller (12), a first air inlet (111) is provided on the end surface of the first core puller (12) in contact with the outside, and a first air inlet channel is formed between the first air inlet (111) and the first air outlet (123); And / or, the number of the first air outlet (123) is not limited to one.

12. The forming and curing mold for core making equipment according to claim 10 or 11, characterized in that: The core pulling assembly (1) comprises a second core pulling (14) arranged along a second direction, the second core pulling (14) being used to form a second inner cavity (52) of the sand core (5); A second air outlet (18) is provided on the circumferential side wall of the second core puller (14), a second air inlet (16) communicating with the outside is provided at the axial end of the second core puller (14), and a second air inlet channel is formed between the second air inlet (16) and the second air outlet (18); And / or, the number of the second air outlet (18) is not limited to one.

13. The forming and curing mold for core making equipment according to claim 12, characterized in that: The second core pullers (14) are a pair and are symmetrically arranged on both sides of the first core puller (12); And / or, the second core pulling device (14) comprises a core pulling body, the core pulling body is a cylindrical structure, and a second air outlet (18) is provided on an end surface of the core pulling body located inside the cavity; And / or, the core pulling body comprises an air inlet end surface (15), the air inlet end surface (15) is used to close the inner cavity of the core pulling body from the outside, and a second air inlet (16) is provided on the air inlet end surface (15).

14. The forming and curing mold for core making equipment according to claim 13, characterized in that: An air intake pipe is installed in the inner cavity of the core pulling body, and the second air intake port (16) and the second air outlet port (18) are connected via the air intake pipe; The number of the air intake duct is not limited to one; And / or, when the number of the air intake pipelines exceeds one, the air intake end of each of the air intake pipelines is connected to the second air intake port (16).

15. The forming and curing mold for core making equipment according to claim 14, characterized in that: The circumferential side wall of the air inlet duct is provided with a third air outlet penetrating therethrough; And / or, the number of the third air outlet is not limited to one.

16. The forming and curing mold for core making equipment according to claim 14, characterized in that: There is a gap between the air intake duct and the core pulling body, and a third air outlet is provided on the side of the air intake duct away from the air intake end face (15), or the side of the air intake duct away from the air intake end face (15) is open.

17. The forming and curing mold for core making equipment according to claim 11, characterized in that: A vibrator (4) is provided at the end of the first core pulling (12) facing away from the sand shooting nozzle (21); And / or, the number of the vibrators (4) is not limited to one.

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