Mould and process for sand casting
By applying the tilt casting process in sand casting, using resin sand casting and rotating metal gate basins, the problems of wall thickness difference and heat joints of complex new shell castings are solved, and high-quality production of castings and material savings are achieved.
Patent Information
- Application Number
- CN202411274315.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2024-12-17
AI Technical Summary
When the existing metal-type tilt casting process produces complex new shells, it leads to cracks at the intersection of casting wall thickness differences and shrinkage defects at the hot joints, which is difficult to effectively solve.
The molds and processes of sand casting, including resin sand casting molds and rotary metal gate basins, realize the complex shape production of castings through a tilt casting machine, and use the inner and outer surfaces of the core to place cold iron to achieve simultaneous solidification of different wall thickness parts. , and replenish the heat shrink joint through the dark emanation mouth.
It effectively eliminates crack defects caused by poor wall thickness of castings, improves the yield rate of castings, reduces the difficulty of core making and raw material costs, and reduces the occurrence of rolling gas and secondary slag production.
Smart Images
Figure CN119140759A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of casting, and in particular to a sand casting mold and process. Background Art
[0002] In the production process of aluminum alloy casting, it can be divided into two categories according to the casting mold classification: sand casting and metal casting. According to the casting process method, it can be divided into gravity casting, counter-gravity casting, differential pressure casting, etc. Metal mold gravity casting is a process method commonly used at home and abroad. Metal mold tilting casting is a new casting process method that has emerged in recent years. Its unique process design has greatly improved the process yield, production efficiency and quality of castings compared to ordinary gravity casting methods.
[0003] The existing metal mold tilting pouring process is usually suitable for some castings with relatively simple shapes and uniform wall thickness, but has certain limitations for the production of some complex castings, especially the trial production of new shells. Due to the complex shape of the new shell, the large difference in thin wall, the large number of cores and the presence of multiple hot spots inside the casting, the existing metal mold tilting pouring process method is used for production, and the obtained castings have multiple cracks at the intersection of the wall thickness difference, and shrinkage defects of varying degrees appear at the hot spots. After multiple process adjustments, the defects have not been effectively eliminated. Summary of the invention
[0004] The technical problem to be solved by the present invention is that the existing metal mold tilting casting process produces a complex new shell, and cracks appear at the intersection of the wall thickness difference of the obtained casting, and shrinkage defects appear at the hot joint.
[0005] In order to solve the above technical problems, according to one aspect of the present invention, a sand casting mold is provided.
[0006] The sand casting mold comprises a pouring machine bottom plate, a mold pressing plate, a mold and a core. The core is installed inside the mold. The mold pressing plate presses the mold and the inner core to the pouring machine bottom plate.
[0007] Wherein, the casting mold is a resin sand mold, including an upper casting mold and a lower casting mold,
[0008] The lower mold is located between the bottom plate of the casting machine and the upper mold. The upper mold and the lower mold are molded together to form a mold cavity. The surface of the upper mold is provided with a first pouring port, and the first pouring port is connected to the mold cavity.
[0009] The bottom plate of the pouring machine is provided with guide columns, and the mold also includes a metal pouring basin, which is installed on the guide columns and rotates with the guide columns as the axis; a second pouring port is provided on the side of the metal pouring basin, and the second pouring port is connected with the first pouring port during pouring.
[0010] Preferably, the number of the casting platens is two.
[0011] Preferably, the core is a sand core, the lower casting mold is provided with a sand core seat, and the sand core is installed in the sand core seat.
[0012] Furthermore, there are multiple sand cores.
[0013] Preferably, the mold further comprises a positioning block, which is fixed on the bottom plate of the pouring machine and is used for installation and positioning of the casting mold.
[0014] Preferably, the mold further comprises a sealing strip, and the sealing strip is provided between the upper casting mold and the lower casting mold for sealing connection.
[0015] Preferably, the mold further comprises a fastener, and the mold pressing plate presses the mold and the inner core to the bottom plate of the casting machine through the fastener.
[0016] Furthermore, the fastener includes a locking screw and a locking nut, one end of the locking screw is inserted into the casting machine base plate, and the other end is inserted into the mold pressure plate; the locking nut is installed on the locking screw at one end of the mold pressure plate to lock the mold and the internal core.
[0017] Preferably, the number of the fasteners is 4, and the 4 fasteners are respectively located at the periphery of the mold and are used to fix the mold on the bottom plate of the casting machine.
[0018] According to another aspect of the present invention, a process for sand casting is provided, wherein the mold is the above-mentioned mold, and the process comprises the following steps:
[0019] The first step is to preheat the mold and then spray or brush the mold cavity with paint;
[0020] The second step is to preheat the mold again, and then close the lower mold with the upper mold for a predetermined time to make the temperature of the mold uniform;
[0021] The third step is to preheat the metal pouring basin to a predetermined temperature, place the lower mold on the bottom plate of the casting machine, place the core, place a sealing strip on the surface of the lower mold, place the upper mold on the sealing strip to close the mold with the lower mold, connect the second pouring port with the first pouring port, and use the mold pressing plate to press the mold and the inner core to the bottom plate of the casting machine;
[0022] In the fourth step, the molten metal passes through the metal pouring basin, the second pouring port, the first pouring port in turn, and enters the mold cavity, and the mold is tilted after a predetermined time.
[0023] Compared with the prior art, the technical solution provided by the embodiments of the present invention can at least achieve the following beneficial effects:
[0024] First, the tilting pouring is applied to the production of sand casting to solve the crack and shrinkage problems caused by complex casting structure, large difference in wall thickness and uneven distribution of internal hot spots. Sand casting makes full use of the advantage of placing chillers on the inner and outer surfaces of the core to achieve simultaneous solidification of parts with different wall thicknesses, eliminate crack defects caused by wall thickness difference in castings, and realize shrinkage compensation of hot spots by setting blind risers;
[0025] Second, the tilting pouring machine can tilt to fill the mold quickly and smoothly, reducing the probability of air entrainment and secondary slag formation during the filling process, which can effectively improve the casting yield;
[0026] Third, the casting mold is a resin sand mold, and the pouring basin is made of metal. The separate design of the metal pouring basin and the casting mold reduces the difficulty of core making of the casting mold, reduces the weight and volume of the casting mold, and reduces the cost of raw material investment. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.
[0028] Figure 1 A front view of a mold structure for sand casting provided in this embodiment;
[0029] Figure 2 for Figure 1 The mold structure shown is a cross-sectional view along line AA. DETAILED DESCRIPTION
[0030] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0031] Unless otherwise defined, the technical or scientific terms used herein shall have the common meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "a" do not indicate a quantity limitation, but indicate the existence of at least one.
[0032] refer to Figure 1 and Figure 2 This embodiment provides a sand casting mold, including a pouring machine bottom plate 1, a casting mold and a core, the core is installed inside the casting mold, and the casting mold is fixed to the pouring machine bottom plate 1 by fasteners.
[0033] The casting bottom plate 1 is L-shaped, and includes a horizontal plate 11 and a vertical plate 12 . The horizontal plate 11 and the vertical plate 12 are vertically connected to each other to form an integrated structure.
[0034] The casting mold is a resin sand mold, including an upper casting mold 3 and a lower casting mold 2, wherein the lower casting mold 2 is located between the pouring machine bottom plate 1 and the upper casting mold 3. Specifically, the bottom surface of the lower casting mold 2 is placed on the horizontal plate, and the side surface of the lower casting mold 2 abuts against the vertical plate; the upper casting mold 3 is placed on the side of the lower casting mold 2 away from the horizontal plate, and the side surface of the upper casting mold 3 abuts against the vertical plate.
[0035] Among them, Resin Sand Mold: Resin Sand Mold is made of resin (such as phenolic resin) as a binder mixed with sand particles. Resin Sand Mold has good air permeability and fire resistance, suitable for various casting alloys. Resin Sand Mold has high strength and hardness after curing, and can withstand the impact and pressure of molten metal. Resin Sand Mold can produce complex shapes, suitable for single piece or small batch production.
[0036] The upper mold 3 and the lower mold 2 are molded together to form a mold cavity. A first pouring port is provided on the surface of the upper mold 3, and the first pouring port is connected to the mold cavity.
[0037] The mold further comprises a positioning block 8 , which is fixed on the bottom plate 1 of the pouring machine and is used for installing and positioning the mold, especially for installing and positioning the lower mold 2 .
[0038] The lower mold 2 is mainly used to install and fix the intermediate core. Specifically, the core is a sand core. The lower mold 2 is provided with a sand core seat, and the sand core is installed in the sand core seat. The number of the sand cores in this embodiment is 2, including a first sand core 91 and a second sand core 92.
[0039] The mold further comprises a sealing strip, which is arranged between the upper casting mold 3 and the lower casting mold 2 for sealing connection.
[0040] The upper mold 3 covers the lower mold 2 and is mainly used to form a sealed cavity after the upper mold 3 and the lower mold 2 are molded together, and to fix the upper part of the sand core.
[0041] The guide column 6 is fixedly installed on the vertical plate 12, and the guide column 6 is perpendicular to the horizontal plate 11. A metal pouring basin 7 is installed on the guide column 6, and the metal pouring basin 7 rotates along the horizontal plate direction with the guide column as the axis. The pouring basin 7 is a metal structure with a groove, and the bottom plate of the metal pouring basin 7 abuts the vertical plate 12, and the side of the metal pouring basin 7 abuts the upper casting mold 3. The side of the metal pouring basin 7 is provided with a second pouring port, and the metal pouring basin 7 is rotated to the casting mold pouring position. During pouring, the second pouring port is connected with the first pouring port; after pouring is completed or before pouring, the metal pouring basin 7 can be rotated to other positions. Using a metal pouring basin 7 instead of a sand mold pouring basin can greatly reduce the amount of resin sand used, which reduces the cost of raw materials and also improves production efficiency.
[0042] The mold further comprises a mold pressing plate 10, and the mold pressing plate 10 presses the mold and the inner core against the pouring machine bottom plate 1. In this embodiment, the number of the mold pressing plates is two.
[0043] Specifically, the mold pressing plate 10 is arranged on the surface of the upper mold 3, and presses the mold and the internal core with the casting machine bottom plate 1 through fasteners. The fasteners include a locking screw 4 and a locking nut 5. The number of the fasteners in this embodiment is 4, and the 4 fasteners are respectively located around the mold, and are used to fix the mold on the casting machine bottom plate 1. Specifically, one end of the locking screw 4 is inserted into the casting machine bottom plate 1, and the other end is inserted into the mold pressing plate 10. The locking nut 5 is installed on the locking screw 4 installed at one end of the mold pressing plate 10, and is used to lock the mold.
[0044] The mold is used in a sand casting process, comprising the following steps:
[0045] The first step is to preheat the mold and then spray or brush the mold cavity with paint. The specific preheating temperature can be about 120°C.
[0046] In the second step, after the mold is preheated again, the lower mold is molded with the upper mold for a predetermined time to make the mold temperature uniform. The specific re-preheating temperature can be referenced to 240° C. and the predetermined time is 30 minutes.
[0047] The third step is to preheat the pouring basin 7 to a predetermined temperature. The metal pouring basin can be preheated to a certain temperature to reduce the temperature loss of the molten metal before entering the mold and ensure the filling quality; place the lower mold 3 on the bottom plate 1 of the casting machine, and lower the core into the lower mold; place the upper mold and the lower mold to form the mold cavity, the second pouring gate is connected to the first pouring gate, and the mold pressing plate 10 presses the mold and the internal core to the bottom plate 1 of the casting machine.
[0048] In order to fix the mold, the mold pressure plate 10 is arranged on the surface of the upper mold 3, one end of the locking screw 4 is inserted into the casting machine bottom plate 1, and the other end is inserted into the mold pressure plate 10, and the locking nut 5 is installed on the locking screw 4 installed at one end of the mold pressure plate 10 to lock the mold.
[0049] The pouring basin 7 is rotated to the casting gate position, so that the second pouring gate is connected with the first pouring gate, and the first pouring gate is connected with the mold cavity.
[0050] In the fourth step, the molten metal passes through the metal pouring basin, the second pouring port, the first pouring port and enters the mold cavity in sequence, and the mold is tilted after a predetermined time. The temperature of the molten metal reaches 710°C during pouring, and the predetermined time is within the last 40s-50s.
[0051] The above steps are the sand casting process described in this embodiment. The production of castings is to use a tilting pouring machine to complete sand casting under the premise of meeting various performance requirements of sand casting. The specific process also includes other existing technologies, which will not be described in detail here.
[0052] The present invention applies tilting pouring to the production of sand casting, which not only highlights the advantages of tilting pouring, but also gives play to the unique process characteristics of sand casting. The use of tilting pouring not only simplifies the design of the pouring system and optimizes the complementary effect of the pouring and riser, but also can effectively reduce the amount of aluminum alloy compared with the usual sand casting.
[0053] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the protection scope of the present invention. The protection scope of the present invention is determined by the appended claims.
Claims
1. A sand casting mold, comprising a pouring machine bottom plate, a mold pressing plate, a mold and a core, wherein the core is installed inside the mold, and the mold pressing plate presses the mold and the inner core to the pouring machine bottom plate. in, The casting mold is a resin sand mold, including an upper casting mold and a lower casting mold. The lower mold is located between the bottom plate of the casting machine and the upper mold. The upper mold and the lower mold are molded together to form a mold cavity. The surface of the upper mold is provided with a first pouring port, and the first pouring port is connected to the mold cavity. The bottom plate of the pouring machine is provided with guide columns, and the mold also includes a metal pouring basin, which is installed on the guide columns and rotates with the guide columns as the axis; a second pouring port is provided on the side of the metal pouring basin, and the second pouring port is connected with the first pouring port during pouring.
2. The sand casting mold according to claim 1, wherein: The number of the casting platens is two.
3. The sand casting mold according to claim 1, wherein: The mold core is a sand core, the lower casting mold is provided with a sand core seat, and the sand core is installed in the sand core seat.
4. The sand casting mold according to claim 3, wherein: The number of the sand cores is multiple.
5. The sand casting mold according to claim 1, wherein: The mold also includes a positioning block, which is fixed on the bottom plate of the pouring machine and is used for installing and positioning the casting mold.
6. The sand casting mold according to claim 1, wherein: The mold further comprises a sealing strip, which is arranged between the upper casting mold and the lower casting mold for sealing connection.
7. The sand casting mold according to claim 1, wherein: The mold further comprises a fastener, and the mold pressing plate presses the mold and the inner core to the bottom plate of the casting machine through the fastener.
8. The sand casting mold according to claim 7, wherein: The fastener includes a locking screw and a locking nut, one end of the locking screw is inserted into the casting machine bottom plate, and the other end is inserted into the casting mold pressure plate; the locking nut is installed on the locking screw at one end of the casting mold pressure plate to lock the casting and the internal core.
9. The sand casting mold according to claim 7, wherein: The number of the fasteners is 4, and the 4 fasteners are respectively located around the periphery of the mold.
10. A sand casting process, wherein: The mold is a mold as described in any one of claims 1 to 9, comprising the following steps: The first step is to preheat the mold and then spray or brush the mold cavity with paint; The second step is to preheat the mold again, and then close the lower mold with the upper mold for a predetermined time to make the temperature of the mold uniform; The third step is to preheat the metal pouring basin to a predetermined temperature, place the lower mold on the bottom plate of the pouring machine, and lower the core into the lower mold; place the upper mold and the lower mold together to form the mold cavity, the second pouring port is connected to the first pouring port, and the mold pressing plate presses the mold and the internal core to the bottom plate of the pouring machine; In the fourth step, the molten metal passes through the metal pouring basin, the second pouring port, the first pouring port in turn, and enters the mold cavity, and the mold is tilted after a predetermined time.