A medium-temperature wax silica sol investment casting process

Abstract

The present invention relates to the field of precision casting technology, and in particular to a medium-temperature wax silica sol investment casting process. The process includes the preparation of a wax mold: fixing the formed wax mold on a gate rod; molding of a shell: selecting a gate rod to be fixed in a rotary shell making machine, and subjecting the shell to coating, sanding and drying treatments on the rotary shell making machine, and circulating this sequence 4-6 times to obtain a preliminary shell; demolding of the shell: placing the preliminary shell in a sealed container for steaming and dewaxing, and then depressurizing and changing water for secondary dewaxing; roasting of the shell: placing the preheated shell in a roasting furnace, gradually heating it to 900-1100°C and maintaining it for 40-50 minutes to obtain a molded shell; molding of castings: injecting molten metal into the molded shell, and then cooling and shelling it to obtain a finished workpiece. The present invention provides a rotary shell making machine, which realizes automatic shelling in the shell molding stage, reduces the cost of manual participation, and realizes single-person operation; combined with the molding shell characteristics of the rotary shell making machine, performs secondary dewaxing to ensure that the wax mold is cleanly separated.

Description

Technical Field

[0001] The invention relates to the technical field of precision casting, in particular to a medium-temperature wax silica sol investment casting process. Background Art

[0002] Investment casting is also known as precision casting because the resulting castings have a high degree of dimensional accuracy and surface finish. Medium-temperature wax silica sol investment casting involves making a wax pattern using wax with a melting point of 50-100°C. This is then coated and dried multiple times with a coating composed primarily of silica sol, and finally fired to form a high-temperature resistant ceramic mold for casting and cooling. Because investment casting involves complex production steps, a long production cycle, and high labor costs, it is mostly contracted to large enterprises. However, there are still some castings in the market that are difficult to produce in the quantity required by large enterprises due to small batch sizes. Therefore, a medium-temperature wax silica sol investment casting process is needed that can accommodate the small-scale, low-cost precision casting needs of small and medium-sized enterprises. Summary of the Invention

[0003] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the structures particularly pointed out in the description and the drawings.

[0004] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a medium-temperature wax silica sol investment precision casting process, which has the advantages of low production cost, low labor cost, support for small-scale production, high degree of automation, and high casting precision.

[0005] To achieve the above objectives, the technical solution of the present invention is: a medium-temperature wax silica sol investment casting process, which includes the following steps:

[0006] Preparation of wax pattern: The wax pattern of the target shape is pressed through the mold, and then the wax pattern is fixed on the gate rod.

[0007] Shell molding: 8-10 groups of gate rods are selected and fixed in the rotary shell making machine in sequence. After the rotary shell making machine is coated, sanded and dried, the initial shell product is obtained by cycling this sequence 4-6 times.

[0008] Demolding of the mold shell: Place the initial mold shell in a sealed container for 10-20 minutes of steaming and dewaxing, then release the pressure and change the water for a second dewaxing of 8-12 minutes.

[0009] Firing of the shell: preheat the dewaxed shell, then place the preheated shell in a baking furnace, gradually heat it to 900-1100°C and maintain it for 40-50 minutes, then gradually cool it down to obtain a molded shell.

[0010] Molding of castings: The molten metal is injected into the mold shell, cooled and shelled to obtain the finished workpiece.

[0011] In some embodiments, the rotary shell making machine includes a housing, a hoisting assembly, a coating box, a loading flask, and a drying gallery. The housing is a closed, hollow rectangular parallelepiped. The hoisting assembly includes a circular track connected to the inner top of the housing and several moving assemblies. The moving assembly includes a driving member positioned above the circular track, a telescopic rod extending through the circular track and connected to the driving member, a rotating rod connected to the other end of the telescopic rod, an arc-shaped adjusting member, and a locking disk. The driving member houses a drive motor connected to at least two rollers that contact the circular track. The rotating rod includes a main connecting section and a free section rotatably connected to the main connecting section. One end of the arc-shaped adjusting member is connected to the side wall of the main connecting section and is connected to a first rotating motor. The other end of the arc-shaped adjusting member is connected to the side wall of the free section. The first rotating motor drives the arc-shaped adjusting member to rotate, causing the free section to deflect. One end of the free end is connected to the locking disk, which is used to connect to the gate rod. The paint box and the upper flask are sequentially arranged at the bottom of the housing, and the drying gallery is a strip-shaped space in the housing except for the paint box and the upper flask. A far-infrared drying tube is arranged in the drying gallery, and a dehumidifier is connected to the top of the drying gallery.

[0012] In some embodiments, the paint box includes a paint box body, a partition arranged in the paint box body and forming a first accommodating cavity with the bottom of the paint box body, an ultrasonic generator arranged in the first accommodating cavity, and several vibrating rods arranged above the partition and connected to the ultrasonic generator.

[0013] In some embodiments, the end of the vibrating rod away from the partition is U-shaped.

[0014] In some embodiments, the cope flask includes a cope flask body, a baffle plate obliquely disposed within the cope flask body and forming a second accommodating cavity with the bottom of the cope flask body, and a hammering assembly disposed within the second accommodating cavity. The hammering assembly includes a second rotary motor disposed on a sidewall of the accommodating cavity, a rotary shaft coaxially disposed with the rotary motor, and a plurality of hammering rods connected at one end to the sidewall of the rotary shaft. The positions on the baffle plate corresponding to the hammering rods are secured by elastic fabric.

[0015] In some embodiments, the far-infrared drying tubes are vertically symmetrically distributed along the side walls of the drying gallery. On a single side wall, the distribution density of the far-infrared drying tubes in the middle is greater than the distribution density of the far-infrared drying tubes at the two side positions.

[0016] In some embodiments, a sphere is provided at one end of the main connecting section, and a ball sleeve is provided at one end of the free section, and the sphere and the ball sleeve are engaged to achieve a rotational connection.

[0017] In some embodiments, the rotary shell making machine further includes an operation window, which is provided on a side wall of the shell and is located between the drying gallery and the coating box.

[0018] In some embodiments, the number of the movable components is 8-10, the gate rod is connected to the movable component every 1-2 hours, and the residence time of a single movable component in the drying gallery is set to 3-5 hours.

[0019] In some embodiments, the housing is provided with a cleaning pipe at a position corresponding to the operating window, and the cleaning pipe is connected to a water tank to spray cleaning liquid into the housing.

[0020] By adopting the above technical solution, the beneficial effects of the present invention are:

[0021] 1. The present invention is equipped with a rotary shell making machine to realize automatic shell forming in the shell forming stage, reduce labor participation costs, and realize single-person operation; combined with the shell forming characteristics of the rotary shell making machine, secondary dewaxing is carried out to ensure that the wax mold is cleanly separated.

[0022] 2. The present invention integrates the coating, sanding and drying steps in the shell forming process by setting up a rotary shell making machine to form a closed loop, which facilitates its automated shell forming; the moving component of the wax mold is controlled by a single drive component, which facilitates the control of the running speed and residence time of a single gate rod, thereby improving the control accuracy; the wax mold adopts immersion coating, and an arc-shaped adjusting component is provided so that the free end drives the wax mold into the coating box at an inclined angle to prevent the generation of bubbles in the shell.

[0023] 3. Add an ultrasonic vibration device in the paint box to reduce the sinking of refractory materials.

[0024] 4. By setting up an upper sand box with an elastic bottom, the hammer rod hits the elastic cloth to make the sand jump in the upper surface cavity of the upper sand box, ensuring that the sand can fully contact the wax model coated with paint.

[0025] 5. By setting up unevenly distributed far-infrared drying tubes, the temperature in the drying corridor can be increased, maintained and decreased as the shell moves, thereby improving the shell forming rate.

[0026] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0027] Undoubtedly, these and other objects of the present invention will become more apparent after the following detailed description of the preferred embodiment is described with reference to the various figures and drawings.

[0028] In order to make the above and other objects, features and advantages of the present invention more obvious and easy to understand, one or more preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention but do not constitute a limitation of the present invention.

[0030] In the drawings, like components are given like reference numerals, and the drawings are schematic and not necessarily drawn to scale.

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only one or several embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on such drawings without paying any creative work.

[0032] Figure 1 This is a schematic diagram of the overall structure of a rotary shell making machine for a medium-temperature wax silica sol investment casting process of the present invention;

[0033] Figure 2 A cross-sectional view of the back portion of a shell in a rotary shell making machine for a medium-temperature wax silica sol investment casting process according to the present invention;

[0034] Figure 3 This is a partial structural diagram of the hoisting assembly in a rotary shell making machine for a medium-temperature wax silica sol investment casting process of the present invention;

[0035] Figure 4 This is a rear view of a moving component in a rotary shell making machine for a medium-temperature wax silica sol investment casting process of the present invention;

[0036] Figure 5 This is an exploded view of a coating box in a rotary shell making machine for a medium-temperature wax silica sol investment casting process of the present invention;

[0037] Figure 6 This is an exploded view of the upper sand box in a rotary shell making machine for a medium-temperature wax silica sol investment casting process of the present invention;

[0038] Description of main reference numerals:

[0039] 1. Shell;

[0040] 2. Hoisting components;

[0041] 21. Circular track;

[0042] 22. Mobile components;

[0043] 221. Driving parts;

[0044] 221a. Roller;

[0045] 222. Telescopic rod;

[0046] 223. Rotating rod;

[0047] 223a. Main connecting section, 223b. Free section;

[0048] 224. Arc-shaped adjustment member;

[0049] 224a. A first rotating motor;

[0050] 225. Locking disk;

[0051] 3. Paint box;

[0052] 31. Paint box;

[0053] 32. Partition;

[0054] 33. Ultrasonic generator;

[0055] 34. Vibrator;

[0056] 4. Sand loading box;

[0057] 41. Upper sand box body;

[0058] 42. Hammering components;

[0059] 421. Second rotating motor;

[0060] 422. Rotation axis;

[0061] 423. Hammering stick;

[0062] 43. Blocking plate;

[0063] 431. Stretch fabric;

[0064] 5. Drying gallery;

[0065] 51. Far infrared drying tube;

[0066] 6. Dehumidifier;

[0067] 7. Operation window;

[0068] 8. Clean the tube. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but are not intended to limit the present invention.

[0070] In addition, in the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0071] In the present invention, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed connections, removable connections, or integration; they may refer to direct connections or indirect connections through an intermediate medium; they may refer to internal communication between two components or interactions between two components. However, the term "direct connection" indicates that the two connected entities are not connected through a transitional structure, but are connected solely through a connecting structure to form a single entity. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0072] Reference Figure 1 The present invention provides a technical solution: a medium-temperature wax silica sol investment precision casting process, which relies on the cooperation of the rotary shell making machine. The rotary shell making machine includes a shell 1, a hoisting assembly 2, a coating box 3, a sand box 4, a drying corridor 5, an operation window 7 and a cleaning pipe 8.

[0073] The housing 1 is formed as a closed hollow rectangular parallelepiped.

[0074] Reference Figure 3 The hoisting assembly 2 includes a circular track 21 and 8-10 moving assemblies 22. The circular track 21 is connected to the inner top of the shell 1, and the circular track 21 keeps a certain distance from the top of the shell 1. The moving assembly 22 includes a driving member 221, a telescopic rod 222, a rotating rod 223, an arc-shaped adjusting member 224 and a locking plate 225. The driving member 221 is located above the circular track 21, referring to Figure 4The driving member 221 is provided with a driving motor, which is a conventional motor that can control the operation of the rollers 221a. The driving motor is connected to four rollers 221a, and the rollers 221a are in contact with the annular track 21. One end of the telescopic rod 222 passes through the annular track 21 and is connected to the driving member 221. The telescopic rod 222 is preferably an electric telescopic rod 222. The other end of the telescopic rod 222 is connected to one end of the rotating rod 223. The rotating rod 223 includes a main connecting section 223a and a free section 223b. A ball is provided at one end of the main connecting section 223a, and a ball sleeve is provided at one end of the free section 223b. The ball and the ball sleeve are engaged to achieve a rotatable connection between the main connecting section 223a and the free section 223b. Optionally, the main connecting section 223a and the free section 223b can also be hinged. One end of the arc-shaped adjusting member 224 is connected to the side wall of the main connecting section 223a and is connected to a first rotary motor 224a. The other end of the arc-shaped adjusting member 224 is hinged to the side wall of the free section 223b. The first rotary motor 224a drives the arc-shaped adjusting member 224 to rotate, causing the free section 223b to deflect. One end of the free end is connected to a locking plate 225, which is used to connect to the gate rod. The locking plate 225 is a conventional gate rod fixing structure. Optionally, a rotary motor can be connected between the locking plate 225 and the free section 223b to enable the locking plate 225 to rotate.

[0075] The paint box 3 and the upper flask 4 are sequentially arranged at the bottom of the housing 1, and the housing 1 is provided with a glass door that can be moved horizontally at the positions of the paint box 3 and the upper flask 4. Figure 5 The paint box 3 includes a paint box body 31, a partition 32, an ultrasonic generator 33, and four vibrating rods 34. The partition 32 is arranged in the paint box body 31 and forms a first accommodating cavity with the bottom of the paint box body 31. The ultrasonic generator 33 is arranged in the first accommodating cavity. The end of the vibrating rod 34 away from the partition 32 is U-shaped. The four vibrating rods 34 are respectively arranged at the four corners above the partition 32 and connected to the ultrasonic generator 33.

[0076] Reference Figure 6The upper flask 4 includes an upper flask body 41, a hammer assembly 42, and a blocking plate 43. The blocking plate 43 is obliquely disposed within the upper flask body 41 and forms a second accommodating chamber with the bottom of the upper flask body 41. The hammer assembly 42 is disposed within the second accommodating chamber. The hammer assembly 42 includes a second rotary motor 421, a rotating shaft 422, and a plurality of hammer rods 423. The second rotary motor 421 is disposed on the side wall of the accommodating chamber. The rotating shaft 422 is coaxial with the rotary motor. One end of the hammer rod 423 is connected to the side wall of the rotating shaft 422. The hammer rods 423 are evenly arranged in groups of three around the side wall of the rotating shaft 422, with adjacent groups of hammer rods 423 staggered. The positions on the blocking plate 43 corresponding to the hammer rods 423 are fixed by elastic fabric 431.

[0077] The drying gallery 5 is a strip-shaped space in the housing 1 except for the coating box 3 and the upper sand box 4. The drying gallery 5 is provided with far-infrared drying tubes 51, which are vertically symmetrically distributed along the side walls on both sides of the drying gallery 5. Figure 2 On a single side wall, the distribution density of the far-infrared drying tubes 51 in the middle position is greater than the distribution density of the far-infrared drying tubes 51 at both sides, and a dehumidifier 6 is connected to the top of the drying gallery 5.

[0078] The operation window 7 is provided on the side wall of the housing 1 and is located between the drying gallery 5 and the paint box 3 .

[0079] The housing 1 is provided with a cleaning pipe 8 at a position corresponding to the operation window 7 . The cleaning pipe 8 is connected to a water tank and can spray cleaning liquid into the housing 1 .

[0080] In summary, a medium-temperature wax silica sol investment casting process specifically includes the following steps:

[0081] Preparation of wax pattern: The wax pattern of the target shape is pressed through the mold, and then the wax pattern is fixed on the gate rod.

[0082] Shell Molding: Select 8-10 groups of sprue rods in the operation window 7 and secure them to the moving assembly 22 every 1-2 hours. Upon entering the shell 1, the sprue rods are first cleaned of grease and grease by the cleaning tube 8. Then, they are moved. As the wax pattern approaches the coating tank 3, the arc-shaped manipulator 224 rotates, causing the free section 223b to deflect. This causes the wax pattern to descend while tilting and rotating into the coating for coating. The arc-shaped manipulator 224 continues to rotate, while the telescopic rod 222 retracts, allowing the coated wax pattern to exit the coating tank 3 and continue to move above the upper flask 4. The arc-shaped manipulator 224 continues to rotate, tilting the free end parallel to the partition plate 32. The hammer rod 423 is then activated to strike the elastic cloth 431, dispersing the sand and contacting it with the wax pattern. Finally, the mold enters the drying gallery 5 for drying. This cycle repeats 4-6 times to produce a preliminary shell. The residence time of a single moving assembly 22 in the drying gallery 5 is set to 3-5 hours.

[0083] Demolding of the mold shell: Place the initial mold shell in a sealed container for 10-20 minutes of steaming and dewaxing, then release the pressure and change the water for a second dewaxing of 8-12 minutes.

[0084] Firing of the shell: preheat the dewaxed shell, then place the preheated shell in a baking furnace, gradually heat it to 900-1100°C and maintain it for 40-50 minutes, then gradually cool it down to obtain a molded shell.

[0085] Molding of castings: The molten metal is injected into the mold shell, cooled and shelled to obtain the finished workpiece.

[0086] It should be understood that the embodiments disclosed herein are not limited to the specific processing steps or materials disclosed herein, but should extend to equivalent substitutions of such features understood by those skilled in the relevant art. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0087] The "embodiment" mentioned in the specification means that a particular feature or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present invention. Therefore, the phrase or "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0088] Furthermore, the described features or characteristics may be combined in any other suitable manner into one or more embodiments. In the above description, some specific details, such as thickness, quantity, etc., are provided to provide a comprehensive understanding of the embodiments of the present invention. However, those skilled in the relevant art will appreciate that the present invention may be implemented without one or more of the above specific details or may be implemented using other methods, components, materials, etc.

Claims

1. A medium temperature wax silica sol investment casting process, characterized in that: The following steps are involved: Preparation of wax pattern: Press the wax pattern of target shape through the mold, and then fix the wax pattern on the gate rod; Shell molding: 8-10 groups of gate rods are selected and fixed in a rotary shell making machine in sequence. After the rotary shell making machine is coated, sanded and dried, the initial shell product is obtained by repeating this process 4-6 times. Demolding of the shell: Place the initial shell in a sealed container for 10-20 minutes of steaming and dewaxing, then release the pressure and change the water for a second dewaxing of 8-12 minutes; Firing of the shell: preheat the dewaxed shell, then place the preheated shell in a baking furnace, gradually raise the temperature to 900-1100℃ and maintain it for 40-50 minutes, then gradually cool it down to obtain a molded shell; Molding of castings: The molten metal is poured into the mold shell, cooled and shelled to obtain the finished workpiece; The rotary shell making machine includes a shell, a hoisting assembly, a coating box, an upper sand box and a drying gallery. The shell is a hollow rectangular parallelepiped formed by closing. The hoisting assembly includes a ring track and several moving assemblies. The ring track is connected to the inner top of the shell. The moving assembly includes a driving member, a telescopic rod, a rotating rod, an arc-shaped adjusting member and a locking disk. The driving member is arranged above the ring track. A driving motor is provided in the driving member. The driving motor is connected to at least two rollers. The rollers are in contact with the ring track. One end of the telescopic rod passes through the ring track and is connected to the driving member. One end of the rotating rod is connected to the other end of the telescopic rod. The rotating rod includes a main connecting section and a free section, the main connecting section and the free section are rotatably connected, one end of the arc-shaped adjusting member is connected to the side wall of the main connecting section and is connected to a first rotating motor, the other end of the arc-shaped adjusting member is connected to the side wall of the free section, the first rotating motor drives the arc-shaped adjusting member to rotate and drive the free section to deflect, one end of the free section is connected to a locking disk, and the locking disk is used to connect a gate rod, the paint box and the upper sand box are sequentially arranged at the bottom of the shell, the drying gallery is a strip-shaped space in the shell except for the paint box and the upper sand box, a far-infrared drying tube is provided in the drying gallery, and a dehumidifier is connected to the top of the drying gallery; The upper sand box includes an upper sand box body, a hammering assembly and a blocking plate. The blocking plate is obliquely arranged in the upper sand box body and forms a second accommodating cavity with the bottom of the upper sand box body. The hammering assembly is arranged in the second accommodating cavity. The hammering assembly includes a second rotating motor, a rotating shaft and a plurality of hammering rods. The second rotating motor is arranged on the side wall of the accommodating cavity. The rotating shaft is coaxially arranged with the rotating motor. One end of the hammering rod is connected to the side wall of the rotating shaft. The position on the blocking plate corresponding to the hammering rod is fixed by elastic cloth.

2. The medium temperature wax silica sol investment casting process according to claim 1, characterized in that: The paint box includes a paint box body, a partition, an ultrasonic generator and several vibrating rods. The partition is arranged in the paint box body and forms a first accommodating cavity with the bottom of the paint box body. The ultrasonic generator is arranged in the first accommodating cavity. Several vibrating rods are arranged above the partition and connected to the ultrasonic generator.

3. The medium temperature wax silica sol investment casting process according to claim 2, characterized in that: One end of the vibrating rod away from the partition is U-shaped.

4. The medium temperature wax silica sol investment casting process according to claim 2, characterized in that: The far-infrared drying tubes are vertically symmetrically distributed along the side walls of the drying gallery. On a single side wall, the distribution density of the far-infrared drying tubes in the middle is greater than that of the far-infrared drying tubes on both sides.

5. The medium temperature wax silica sol investment casting process according to claim 1, characterized in that: One end of the main connecting section is provided with a sphere, and one end of the free section is provided with a ball sleeve. The sphere and the ball sleeve are engaged with each other to realize rotational connection.

6. The medium temperature wax silica sol investment casting process according to claim 1, characterized in that: The rotary shell making machine further comprises an operation window, which is arranged on the side wall of the shell and is located between the drying gallery and the coating box.

7. The medium temperature wax silica sol investment casting process according to claim 1, characterized in that: There are 8-10 groups of mobile components, and the gate rods are connected to the mobile components every 1-2 hours. The residence time of a single mobile component in the drying gallery is set to 3-5 hours.

8. The medium temperature wax silica sol investment casting process according to claim 6, characterized in that: The shell is provided with a cleaning pipe at a position corresponding to the operation window. The cleaning pipe is connected to the water tank and can spray cleaning liquid into the shell.

Images