Preparation method of shell containing multi-angle special-shaped pipe cavity

Abstract

The invention provides a preparation method of a shell containing a multi-angle special-shaped pipe cavity, which comprises the following steps: combining and assembling a mold core and a plurality of block wax molds, so that the mold core is arranged in the multi-angle special-shaped pipe cavity defined by the plurality of block wax molds, partial areas of at least partial pipe bodies of the mold core are the same as the inner diameters of the multi-angle special-shaped pipe cavities in the corresponding positions so as to be precisely matched, and the rest partial areas of at least partial pipe bodies are arranged in the multi-angle special-shaped pipe cavities in a suspended mode to obtain a casting wax film; a surface layer shell and a back layer shell are prepared on the surface of a casting wax film in sequence, and then sectional continuous dewaxing roasting is adopted to prepare the shell. According to the invention, a multi-dimensional matching relationship is formed by the plurality of pipe bodies distributed at multiple angles of the mold core and the block wax mold, so that the accurate matching of the block wax mold and the mold core is ensured, and the dimensional accuracy of the inner cavity of a later casting can be ensured by utilizing the dimensional accuracy of the mold core.

Description

Technical Field

[0001] The invention relates to the technical field of casting shell preparation, and in particular to a method for preparing a shell containing a multi-angle special-shaped cavity. Background Art

[0002] Since titanium alloy precision castings are prepared by investment casting, which is also called lost wax casting, it usually refers to using fusible materials to make casting patterns, coating the surface of the patterns with several layers of refractory materials to make shells, melting the patterns to discharge the shells, and obtaining the shells after high-temperature roasting. The castings are obtained by pouring molten metal into the shells, which generally includes the processes of wax pressing, shell preparation, dewaxing, pouring molten metal, and post-processing. Therefore, the quality of titanium alloy shells has an important influence on the forming of titanium alloy castings.

[0003] For titanium alloy precision castings, due to the need for unified structure and function, the internal structure is complex and often contains blind cavity structures. Ceramic cores are required to form complex inner cavities. After the casting is poured, the cores are removed to form the inner cavity structure of the casting. Therefore, during the wax pressing process of the casting, it is necessary to place the core in the wax pressing mold and then inject wax to form a wax mold with a core. For castings with complex inner cavities, it is usually necessary to prepare block wax molds in different areas and then splice them into an integral wax mold. Since the integral wax mold is spliced ​​together by multiple parts, when the block wax mold and the multi-angle tubular core are matched, due to the problem of manufacturing dimensional accuracy between the block wax mold and the core, assembly dislocation is prone to occur during splicing, resulting in the inability of the block wax mold to be accurately assembled with the core, thereby affecting the dimensional accuracy of the casting. For wax molds with cores inside, during the wax pressing process, they are easily impacted by the wax liquid, causing the core to shift and break. At the same time, since the shell needs to be made through high-temperature baking, the high-temperature baking process has a certain impact on the core. For the shell with a core inside, after dewaxing, the core is only connected to the shell by the fixed end, and the rest is a suspended structure. During high-temperature baking, it is prone to cracking or deviation due to thermal expansion and contraction. The baking process needs to be controlled to stabilize the quality of the shell and core. Summary of the invention

[0004] In order to overcome the deficiencies in the prior art, the main purpose of the present invention is to provide a method for preparing a mold shell containing a multi-angle special-shaped tube cavity, in which a plurality of tube bodies distributed at multi-angles of a core are utilized to form a multi-dimensional matching relationship with a block wax mold, thereby ensuring the precise matching between the block wax mold and the core, and utilizing the dimensional accuracy of the core to ensure the dimensional accuracy of the inner cavity of the later casting.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a method for preparing a mold shell containing a multi-angle special-shaped tubular cavity, which comprises the following steps: preparing a core according to the tubular cavity structure of a casting, the core comprising a plurality of tubular bodies distributed at multiple angles; designing a plurality of block wax molds according to the tubular cavity structure of the casting, and assembling the core and the plurality of block wax molds in combination, so that the core is placed in a multi-angle special-shaped tubular cavity formed by the plurality of block wax molds to obtain a casting wax film; wherein, at least a portion of the tubular body of the core has the same inner diameter as the multi-angle special-shaped tubular cavity at a corresponding position for precise matching, and at least a portion of the remaining portion of the tubular body is suspended in the multi-angle special-shaped tubular cavity; preparing a surface layer mold shell and a back layer mold shell in sequence on the surface of the casting wax film, and then adopting a segmented continuous dewaxing and roasting method to obtain the mold shell containing the multi-angle special-shaped tubular cavity.

[0006] In some embodiments of the present invention, the surface shell preparation includes: coating the surface of the casting wax mold with a surface layer slurry, and then removing excess surface layer slurry; then performing surface sanding and drying to form the surface shell.

[0007] In some embodiments of the present invention, the preparation of the back layer mold shell includes: coating the surface of the surface layer mold shell with a back layer slurry and removing excess back layer slurry; then performing back layer sanding, and after drying, forming a first layer of back layer mold shell; repeating the steps of coating the back layer slurry and back layer sanding in the preparation of the back layer mold shell multiple times to form a multi-layer back layer mold shell.

[0008] In some embodiments of the present invention, the segmented continuous dewaxing and roasting includes: dewaxing, heating to a first roasting temperature, keeping warm, so that the wax liquid flows out from the dewaxing port; roasting, heating to a second, third, and fourth roasting temperature in sequence, and keeping warm at the second, third, and fourth roasting temperatures, respectively, and then cooling and taking out of the furnace.

[0009] In some embodiments of the present invention, the first calcination temperature is 100° C. to 200° C., and the holding time at the first calcination temperature is 3 h to 6 h.

[0010] In some embodiments of the present invention, the wax liquid flows out from the wax outlet in the middle or side of the bottom area of ​​the mold shell.

[0011] In some embodiments of the present invention, the second calcination temperature is 400° C. to 500° C., and the holding time at the second calcination temperature is ≥ 3 h, preferably 3 h to 6 h.

[0012] In some embodiments of the present invention, the third calcination temperature is 650° C. to 750° C., and the holding time at the third calcination temperature is ≥ 3 h, preferably 3 h to 6 h.

[0013] In some embodiments of the present invention, the fourth calcination temperature is 950° C. to 1200° C., and the holding time at the fourth calcination temperature is ≥ 3 h, preferably 3 h to 8 h.

[0014] In some embodiments of the present invention, the furnace is cooled to room temperature before being taken out of the furnace, or the furnace is cooled to below 300° C. before being taken out of the furnace.

[0015] In some embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the tube body is ≤10mm, the spacing between the suspended portion of the tube body and the wall of the multi-angle special-shaped tube cavity at the corresponding position is ≤1mm; when the wall thickness of the casting wax mold corresponding to the suspended portion of the tube body is >10mm, the spacing between the suspended portion of the tube body and the wall of the multi-angle special-shaped tube cavity at the corresponding position is ≤2mm.

[0016] In some embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the tube body is ≤3 mm, the spacing between the suspended portion of the tube body and the cavity wall of the multi-angle special-shaped tube cavity at the corresponding position is ≤0.5 mm.

[0017] In some embodiments of the present invention, designing a plurality of block wax molds according to the casting tube cavity structure includes: dividing the plurality of tubes of the core into X tubes, Y tubes, and Z tubes according to the extension direction of the tubes; using a plane formed by the center lines of the X tubes and the Y tubes as a first dividing plane, and using a plane formed by the center lines of the X tubes and a portion of the Z tubes connected to the X tubes as a second dividing plane to separate the plurality of block wax molds at corresponding positions of the casting wax mold, and respectively serving as a bottom wax mold, a rear wax mold, and a front wax mold.

[0018] In some embodiments of the present invention, the X tube body, the Y tube body, and the Z tube body represent the three-dimensional directions of the coordinate axes X-axis, Y-axis, and Z-axis where the tube body is located, and there is at least one X tube body, Y tube body, and Z tube body respectively.

[0019] In some embodiments of the present invention, a first pipeline groove is provided on the base wax mold, a second pipeline groove is provided on the rear wax mold, and a third pipeline groove is provided on the front wax mold; the first pipeline groove, the second pipeline groove and the third pipeline groove together form the multi-angle special-shaped lumen.

[0020] In some embodiments of the present invention, the combined assembly of the core and the plurality of segmented wax molds includes: placing the X tube body, the Y tube body and part of the Z tube body of the core in the first pipeline groove of the bottom wax mold respectively to position them in the X, Y and Z directions; assembling the front wax mold and the rear wax mold onto the bottom wax mold respectively, and the front wax mold and the rear wax mold are arranged in a matched manner so that part of the second pipeline groove and part of the third pipeline groove are combined to form a tube cavity for sleeve-connecting part of the Z tube body, and the first pipeline groove and part of the third pipeline groove and part of the second pipeline groove are combined to form a tube cavity for sleeve-connecting the X tube body, the Y tube body and part of the Z tube body.

[0021] In some embodiments of the present invention, the Z tube body further comprises a Z1 tube body connected to the Y tube body, and the rear wax mold is further provided with a sleeve cavity for sleeve-connecting the Z1 tube body;

[0022] In some embodiments of the present invention, a partial area of ​​the Z1 tube body has the same inner diameter as the sleeve lumen at a corresponding position for precise matching, and the remaining area of ​​the Z1 tube body is suspended in the sleeve lumen.

[0023] In some embodiments of the present invention, at least a portion of the tube body of the core passes through the inner cavity of the mold shell and is exposed outside the mold shell.

[0024] In some embodiments of the present invention, the shell preparation method further comprises: after the dewaxing and roasting, performing quality inspection on the core; and performing air blowing and cleaning on the inside of the shell.

[0025] In some embodiments of the present invention, an endoscope is used to inspect the interior of the mold shell.

[0026] Advantages of the present invention:

[0027] In the present invention, the multiple tubes of the core distributed at multiple angles form a multi-dimensional matching relationship with the block wax mold, which not only ensures the precise matching between the block wax mold and the core, but also can use the dimensional accuracy of the core to ensure the dimensional accuracy of the inner cavity of the later casting.

[0028] The preparation method of the present invention adopts that at least part of the tube body of the core is suspended in the multi-angle special-shaped tube cavity, which can avoid the problem that the core cannot be assembled with the multi-angle tube cavity in a certain dimension due to the multiple tube bodies distributed at multiple angles.

[0029] The present invention utilizes the plane formed by the center lines of the X tube body, Y tube body, and Z tube body of the core as the dividing plane of the wax mold, and divides the wax mold containing the multi-angle tube cavity into the front wax mold, the rear wax mold, and the bottom wax mold. Therefore, the mutual splicing of the front wax mold, the rear wax mold, and the bottom wax mold necessarily involves the positioning of the wax mold in the three-dimensional directions of X, Y, and Z, which is conducive to ensuring that the wax mold containing the multi-angle core is accurately positioned in the three-dimensional directions during the splicing process. In addition, the accurate positioning of the complex inner cavity of the shell is ensured.

[0030] The dewaxing temperature in the present invention is higher than the conventional electric dewaxing temperature, so that the wax liquid can be quickly removed from the inside of the shell, reducing the influence of the wax liquid removal process on the position deviation of the core. At the same time, increasing the first roasting temperature has a preheating effect on the shell, which is conducive to reducing the second roasting insulation time.

[0031] The dewaxing and firing processes of the shell of the present invention are carried out continuously. By continuously and stage-by-stage increasing the firing temperature, on the one hand, the wax liquid inside the shell is removed and the shell is ceramicized by high-temperature firing. On the other hand, since the shell is gradually heated, the deformation or positional displacement of the core caused by thermal expansion and contraction of the core during the heating process can be reduced. At the same time, continuous dewaxing and firing can improve the heating efficiency and effectively reduce the heating and heat preservation time of each stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only used for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. In the accompanying drawings:

[0033] Figure 1 A schematic diagram of the structure of the core in the embodiment provided by the present invention;

[0034] Figure 2 A schematic diagram of the structure of the bottom wax mold in the embodiment provided by the present invention;

[0035] Figure 3 A schematic diagram of the structure of the bottom wax mold and the core after being assembled in the embodiment provided by the present invention;

[0036] Figure 4 A schematic structural diagram of the front wax mold in the embodiment provided by the present invention;

[0037] Figure 5 A schematic diagram of the structure of the core, the bottom wax mold and the front wax mold after being assembled in the embodiment provided by the present invention;

[0038] Figure 6 Schematic diagram of the rear wax mold structure in the embodiment provided by the present invention Figure 1 ;

[0039] Figure 7 Schematic diagram of the rear wax mold structure in the embodiment provided by the present invention Figure 2 ;

[0040] Figure 8 This is a schematic diagram of the casting wax mold structure in the embodiment provided by the present invention.

[0041] In the figure:

[0042] 1. Core; 11. X tube body; 12. Y tube body; 13. Z1 tube body; 14. Z2 tube body; 15. Z3 tube body; 16. Z4 tube body;

[0043] 2. Base wax mold; 21. First pipeline groove; 22. First positioning protrusion; 23. Second positioning protrusion;

[0044] 3. rear wax model; 31. second pipeline groove; 32. sleeve tube cavity;

[0045] 4. front wax model; 41. third pipeline groove;

[0046] 5. Splice the top surface. DETAILED DESCRIPTION

[0047] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0048] Reference Figure 1-Figure 8 As shown, the method for preparing a mold shell containing a multi-angle special-shaped cavity in an embodiment of the present invention is carried out according to the following steps.

[0049] (1) Preparation of core 1.

[0050] In the embodiment of the present invention, the core 1 is prepared according to the casting lumen structure.

[0051] In the embodiment of the present invention, the core 1 includes a plurality of tubes distributed at multiple angles. The plurality of tubes are distributed at different orientations of X, Y, and Z three dimensions. It can be understood that the core 1 is a multi-angle pipe-like structure.

[0052] Figure 1 A specific structural schematic diagram of a core 1 is shown in FIG.

[0053] The multiple tubes constituting the core 1 are divided into an X tube 11 , a Y tube 12 , and a Z tube according to the tube extension direction, wherein the Z tube includes a Z1 tube 13 , a Z2 tube 14 , a Z3 tube 15 and a Z4 tube 16 .

[0054] In the embodiment of the present invention, the Z1 tube body 13 is connected to the Y tube body 12, the Z2 tube body 14 is connected to the X tube body 11, and the Z1 tube body 13 and the Z2 tube body 14 are not arranged in the same direction.

[0055] In the embodiment of the present invention, the Z3 tube body 15 is connected to the connection between the X tube body 11 and the Y tube body 12 , and the Z4 tube body 16 is connected to the connection between the X tube body 11 and the Y tube body 12 .

[0056] In some embodiments of the present invention, the X tube body 11 includes an X1 tube body and an X2 tube body; the Y tube body 12 includes a Y1 tube body and a Y2 tube body.

[0057] (2) Design multiple wax molds based on the casting lumen structure.

[0058] The casting wax mold containing multi-angle special-shaped cavities in the present invention is manufactured by assembling a plurality of divided wax molds and a core 1.

[0059] In an embodiment of the present invention, a pipeline groove is formed on each block wax mold, and multiple block wax molds are combined to form a multi-angle special-shaped tube cavity, and the core 1 is placed in the multi-angle special-shaped tube cavity, thereby obtaining a casting wax film containing a multi-angle special-shaped tube cavity.

[0060] In certain embodiments of the present invention, designing a plurality of block wax molds according to the casting tube cavity structure includes the following steps: dividing a plurality of tubes of the core 1 into an X tube, a Y tube, and a Z tube according to the extension direction of the tubes; using a plane formed by the center lines of the X tube and the Y tube as a first dividing plane to separate the bottom wax mold 2 at a corresponding position of the casting wax mold; and using a plane formed by the center lines of the X tube and a portion of the Z tube connected to the X tube as a second dividing plane to separate the remaining wax mold at a corresponding position of the casting wax mold to obtain a rear wax mold 3 and a front wax mold 4.

[0061] Therefore, the mutual splicing of the front wax mold 4, the rear wax mold 3 and the bottom wax mold 2 inevitably involves the positioning of the wax mold in the three-dimensional directions of X, Y and Z, which is conducive to ensuring that the wax mold containing the multi-angle core is accurately positioned in the three-dimensional directions during the splicing process.

[0062] The bottom wax mold 2 is formed with a first pipeline groove 21, the rear wax mold 3 is formed with a second pipeline groove 31, and the front wax mold 4 is formed with a third pipeline groove 41. The core 1 is assembled with the bottom wax mold 2, the rear wax mold 3 and the front wax mold 4, and the core 1 is placed in a multi-angle special-shaped tube cavity surrounded by the first pipeline groove 21, the second pipeline groove 31 and the third pipeline groove 41.

[0063] (3) Assemble the core 1 and a plurality of wax mold blocks to prepare a casting wax film.

[0064] In an embodiment of the present invention, at least a portion of the tube body of the core 1 has the same inner diameter as the multi-angle special-shaped tube cavity at the corresponding position for precise matching, and at least the remaining portion of the tube body is suspended in the multi-angle special-shaped tube cavity.

[0065] The present invention adopts a method in which at least part of the tube body of the core 1 is suspended in the multi-angle special-shaped tube cavity, which can avoid the problem that the core 1 cannot be assembled with the multi-angle tube cavity in a certain dimension due to the multiple tube bodies distributed at multiple angles.

[0066] In the present invention, the multi-angle distributed tube body of the core 1 forms a multi-dimensional matching relationship with the block wax mold, which can ensure the precise matching between the block wax mold and the core 1, and can also use the dimensional accuracy of the core 1 to ensure the dimensional accuracy of the inner cavity of the later casting.

[0067] In certain embodiments of the present invention, the inner diameter of at least part of the tube body of the core 1 at the port is the same as the inner diameter of the multi-angle special-shaped tube cavity for precise matching, and the rest of at least part of the tube body is suspended in the multi-angle tube cavity.

[0068] The present invention adopts a method in which the port of the multi-angle special-shaped tubular cavity is precisely matched with the port of at least part of the tube body of the core 1, and the remaining area of ​​at least part of the tube body is suspended in the multi-angle special-shaped tubular cavity. This can avoid the problem that the core 1 cannot be assembled with the multi-angle tubular cavity in a certain dimension due to having multiple tube bodies distributed at multiple angles.

[0069] In an embodiment of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the tube body is ≤10mm, the spacing between the suspended portion of the tube body and the cavity wall of the multi-angle special-shaped tube cavity at the corresponding position is ≤1mm. It can also be understood that the spacing between the suspended portion of the tube body and the groove walls of the first pipe groove 21, the second pipe groove 31, and the third pipe groove 41 at the corresponding position is ≤1mm.

[0070] In an embodiment of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the tube body is greater than 10 mm, the spacing between the suspended portion of the tube body and the cavity wall of the multi-angle special-shaped tube cavity at the corresponding position is ≤2 mm. It can also be understood that the spacing between the suspended portion of the tube body and the groove walls of the first pipe groove 21, the second pipe groove 31, and the third pipe groove 41 at the corresponding position is ≤2 mm.

[0071] In certain embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the tube body is ≤3 mm, the spacing between the suspended portion of the tube body and the cavity wall of the multi-angle special-shaped tube cavity at the corresponding position is ≤0.5 mm. It can also be understood that the spacing between the suspended portion of the tube body and the groove walls of the first pipe groove 21, the second pipe groove 31, and the third pipe groove 41 at the corresponding position is ≤0.5 mm.

[0072] In an embodiment of the present invention, the spacing design between the suspended part of the pipe body and the cavity wall of the multi-angle special-shaped pipe cavity at the corresponding position can meet the assembly requirements of the core 1 and also meet the requirements of the shrinkage and deformation of the wax mold.

[0073] It is worth mentioning that in the present invention, the spacing between the suspended part of the pipe body and the cavity wall of the multi-angle special-shaped pipe cavity can also be designed according to the proportional relationship between the spacing d between the suspended part of the pipe body and the cavity wall of the multi-angle special-shaped pipe cavity and the wall thickness x of the wax mold corresponding to the suspended part of the pipe body.

[0074] Among them, the proportional relationship formula is: d = kx;

[0075] In the formula, k is the proportionality coefficient, d is the spacing between the suspended part of the pipe body and the cavity wall of the multi-angle special-shaped pipe cavity at the corresponding position, and x is the wall thickness of the wax mold.

[0076] In some embodiments of the present invention, when 1mm ≤ x ≤ 8mm, 0.4 ≤ k ≤ 0.5.

[0077] In some embodiments of the present invention, when 8mm < x ≤ 20mm, 0.1 ≤ k ≤ 0.15.

[0078] In some embodiments of the present invention, the length of the pipe body with the same inner diameter at the port of the pipe body ≥ 8mm to ensure high-precision fitting.

[0079] As an implementation manner of the present invention, the combined assembly of the core 1 and multiple segmented wax molds includes the following steps:

[0080] (3-1) Assemble the core 1 onto the bottom wax mold 2 to obtain a combined structure of the core 1 and the bottom wax mold 2.

[0081] Figure 3 Fig. shows a schematic structural diagram of a bottom wax mold 2, Figure 4 Fig. shows a schematic diagram of the combined structure of assembling the core 1 onto the bottom wax mold 2.

[0082] In an embodiment of the present invention, place the core 1 corresponding to the first pipe groove 21 of the bottom wax mold 2, place part of the pipe body in the first pipe groove 21, and achieve positioning in the X, Y, and Z directions to prevent the core 1 from sliding in the first pipe groove 21.

[0083] In some embodiments of the present invention, place the X pipe body 11, Y pipe body 12, and part of the Z pipe body of the core 1 corresponding to the first pipe groove 21 of the bottom wax mold 2 for positioning in the X, Y, and Z directions.

[0084] As some embodiments of the present invention, the X tube body 11, the Y tube body 12 and the Z2 tube body 14 of the core 1 are placed in the first pipeline groove 21 of the bottom wax mold 2, and the X tube body 11 and the Y tube body 12 are respectively matched with the partial area of ​​the first pipeline groove 21 (which can be called the first core groove) to be positioned in the X and Y directions; the Z2 tube body 14 is matched with the partial area of ​​the first pipeline groove 21 (which can be called the first positioning groove) to be positioned in the Z direction. At this time, the core 1 is positioned in the three directions of X, Y and Z by the X tube body 11, the Y tube body 12 and the Z2 tube body 14 to prevent the core 1 from sliding in the first pipeline groove 21.

[0085] It is worth mentioning that the inner diameters of the ports of the X tube body 11 and the Y tube body 12 of the core 1 are the same as the inner diameters of the ports of the first pipe groove 21 at the corresponding positions, which are precisely matched.

[0086] The inner diameter of the rest of the X tube body 11 and the Y tube body 12 of the core 1 is smaller than the inner diameter of the first conduit groove 21 at the corresponding position. When the core 1 is assembled to the first conduit groove 21, the X tube body 11 and the Y tube body 12 are fixed only at the end of the first conduit groove 21, and the rest of the X tube body 11 and the Y tube body 12 are suspended in the first conduit groove 21.

[0087] In certain embodiments of the present invention, the inner diameter of the Z2 tube body 14 is identical to the inner diameter of the first pipe groove 21 at the corresponding position for precise matching, thereby ensuring accurate positioning in the Z direction.

[0088] In certain embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X-tube body 11 and the Y-tube body 12 is ≤10 mm, the spacing between the suspended portion of the X-tube body 11 and the Y-tube body 12 and the cavity wall of the multi-angle special-shaped cavity at the corresponding position is ≤1 mm, which can also be understood as the spacing between the suspended portion of the X-tube body 11 and the Y-tube body 12 and the groove wall of the first pipeline groove 21 at the corresponding position is ≤1 mm.

[0089] In certain embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X-tube body 11 and the Y-tube body 12 is greater than 10 mm, the spacing between the suspended portion of the X-tube body 11 and the Y-tube body 12 and the cavity wall of the multi-angle special-shaped cavity at the corresponding position is ≤2 mm, which can also be understood as the spacing between the suspended portion of the X-tube body 11 and the Y-tube body 12 and the groove wall of the first pipeline groove 21 at the corresponding position is ≤2 mm.

[0090] In certain embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X-tube body 11 and the Y-tube body 12 is ≤3 mm, the spacing between the suspended portion of the X-tube body 11 and the Y-tube body 12 and the cavity wall of the multi-angle special-shaped cavity at the corresponding position is ≤0.5 mm, which can also be understood as the spacing between the suspended portion of the X-tube body 11 and the Y-tube body 12 and the groove wall of the first pipeline groove 21 at the corresponding position is ≤0.5 mm.

[0091] (3-2) Assemble the front wax mold 4 onto the bottom wax mold 2 to obtain a combined structure of the core 1, the bottom wax mold 2 and the front wax mold 4.

[0092] Figure 5 A schematic diagram of the structure of a front wax mold 4 is shown. The structure after the core 1, the bottom wax mold 2 and the front wax mold 4 are assembled is as shown in FIG. Figure 6 shown.

[0093] In an embodiment of the present invention, the third pipe groove 41 of the front wax mold 4 is arranged corresponding to a portion of the pipe body, and the front wax mold 4 is assembled on the bottom wax mold 2 .

[0094] In some embodiments of the present invention, a partial area of ​​the third pipe groove 41 corresponds to a partial area of ​​the first pipe groove 21 and is enclosed for sleeve connection with the X tube body 11 and the Y tube body 12 .

[0095] In some embodiments of the present invention, a partial area of ​​the third pipe groove 41 is arranged corresponding to the Z3 pipe body 15 and the Z4 pipe body 16 .

[0096] The front wax mold 4 is assembled on the bottom wax mold 2 after cooperating with the X tube body 11, Y tube body 12, and Z2 tube body 14 of the core 1. Therefore, the front wax mold 4 and the bottom wax mold 2 are positioned in the X and Y directions, and the front wax mold 4 cannot move in the X and Y directions, thereby ensuring accurate assembly in the X and Y directions.

[0097] It is worth mentioning that the inner diameter of the port of the third pipe groove 41 of the front wax mold 4 is the same as the inner diameter of the port of the corresponding matching pipe body, which is a precise match.

[0098] The inner diameter of the rest of the third conduit groove 41 is larger than the inner diameter of the corresponding tube body. After the front wax model 4 is assembled on the bottom wax model 2, the X tube body 11, the Y tube body 12 and part of the Z tube body, such as the Z3 tube body 15 and the Z4 tube body 16, are fixed only through the end of the third conduit groove 41, and the rest of the X tube body 11, the Y tube body 12 and part of the Z tube body are suspended in the third conduit groove 41.

[0099] In certain embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 is ≤10 mm, the spacing between the suspended portion of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 and the groove wall of the third pipeline groove 41 at the corresponding position is ≤1 mm.

[0100] In certain embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portions of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 is greater than 10 mm, the spacing between the suspended portions of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 and the groove wall of the third pipeline groove 41 at the corresponding position is ≤2 mm.

[0101] In certain embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 is ≤3 mm, the spacing between the suspended portion of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 and the groove wall of the third pipeline groove 41 at the corresponding position is ≤0.5 mm.

[0102] In an embodiment of the present invention, a second positioning protrusion 23 is further provided on the bottom wax mold 2 , and the second positioning protrusion 23 is used for positioning and assembling with the front wax mold 4 , so that the front wax mold 4 and the bottom wax mold 2 form a positioning assembly.

[0103] (3-3) Assemble the rear wax mold 3 onto the bottom wax mold 2 to obtain a combined structure of the core 1, the bottom wax mold 2, the front wax mold 4 and the rear wax mold 3.

[0104] Figure 7 A schematic diagram of the structure of a rear wax mold 3 is shown. Figure 1 , Figure 8 A schematic diagram of the structure of a rear wax mold 3 is shown. Figure 2 The overall structure after assembling the core 1, the bottom wax mold 2, the front wax mold 4 and the rear wax mold 3 is as follows Figure 8 shown.

[0105] In an embodiment of the present invention, the second pipeline groove 31 of the rear wax mold 3 is placed corresponding to the partial tube body of the core 1, and the rear wax mold 3 is assembled on the bottom wax mold 2, and the front wax mold 4 is arranged in a matched manner with the rear wax mold 3, so that the partial second pipeline groove 31 of the rear wax mold 3 and the partial third pipeline groove 41 of the front wax mold 4 are combined to form a tube cavity for sleeve-connecting the partial Z tube body, such as the Z3 tube body 15 and the Z4 tube body 16, and at the same time, the first pipeline groove 21 of the bottom wax mold 2 and the partial third pipeline groove 41 and the partial second pipeline groove 31 are combined to form a tube cavity for sleeve-connecting the X tube body 11, the Y tube body 12 and the partial Z tube body, such as the Z2 tube body 14.

[0106] The rear wax mold 3 is assembled on the bottom wax mold 2 and the front wax mold 4 after cooperating with the X tube body 11, Y tube body 12, and Z4 tube body 16 of the core 1. Therefore, the rear wax mold 3 is positioned with the front wax mold 4 and the bottom wax mold 2 in the X and Y directions, and the rear wax mold 3 cannot move in the X and Y directions, thereby ensuring accurate assembly in the X and Y directions.

[0107] It is worth mentioning that the inner diameter of the port of the second pipe groove 31 of the rear wax mold 3 is the same as the inner diameter of the port of the corresponding matching pipe body, which is a precise match.

[0108] The inner diameter of the rest of the second pipe groove 31 is larger than the inner diameter of the corresponding tube body. When the rear wax model 3 is assembled on the bottom wax model 2, the X tube body 11, the Y tube body 12 and part of the Z tube body, such as the Z3 tube body 15 and the Z4 tube body 16, are fixed only through the port of the second pipe groove 31, and the rest of the X tube body 11, the Y tube body 12 and part of the Z tube body are suspended in the second pipe groove 31.

[0109] In some embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 is ≤10 mm, the spacing between the suspended portion of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 and the groove wall of the second pipeline groove 31 at the corresponding position is ≤1 mm.

[0110] In certain embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 is greater than 10 mm, the spacing between the suspended portion of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 and the groove wall of the second pipeline groove 31 at the corresponding position is ≤2 mm.

[0111] In some embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 is ≤3 mm, the spacing between the suspended portion of the X tube body 11, the Y tube body 12, the Z3 tube body 15, and the Z4 tube body 16 and the groove wall of the second pipeline groove 31 at the corresponding position is ≤0.5 mm.

[0112] In some embodiments of the present invention, the inner diameter of the Z2 tube body 14 is the same as the inner diameter of the second pipe groove 31 at the corresponding position for precise matching.

[0113] Of course, it can be understood that the inner diameter of the Z2 tube body 14 is the same as the inner diameter of the multi-angle special-shaped tube cavity at the corresponding position to precisely match.

[0114] In the embodiment of the present invention, at least one sleeve cavity 32 is further provided on the rear wax mold 3, and the sleeve cavity 32 is sleeved on the corresponding Z tube body. Through the sleeve cavity 32, the front wax mold 4 and the rear wax mold 3 are fixed as a whole, and the front wax mold 4 and the rear wax mold 3 are restricted from moving in the Z direction, so as to ensure the integrity of the sequentially spliced ​​front wax mold 4 and the rear wax mold 3, and form the positioning of the front wax mold 4 and the rear wax mold 3 in the Z direction.

[0115] As an embodiment of the present invention, the rear wax mold 3 is provided with a sleeve cavity 32 for sleeve-connecting the Z1 tube body 13 .

[0116] It is worth mentioning that a part of the Z1 tube body 13 has the same inner diameter as the sleeve lumen 32 at the corresponding position for precise matching, and the rest of the Z1 tube body 13 is suspended in the sleeve lumen 32 .

[0117] In the embodiment of the present invention, at least part of the tube body of the core 1 passes through the multi-angle special-shaped tube cavity and is exposed outside the casting wax mold, that is, part of the tube body of the core 1 is exposed outside the casting wax mold.

[0118] (3-4) Melt at least part of the joints between the bottom wax mold 2, the rear wax mold 3, and the front wax mold 4, and fuse them together.

[0119] In an embodiment of the present invention, after the overall assembly is completed, a cover is set outside the position where the core 1 and the block wax mold are spliced ​​and the casting wax mold is exposed. The material of the cover is an elastic material that can tightly fix at least two block wax molds and the core 1.

[0120] Then, at the joint top surface 5, the wax model in the local area of ​​the joint seam is melted, the joint seam is fused together, and the divided wax models are joined into a whole.

[0121] Finally remove the cover.

[0122] In an embodiment of the present invention, the tool for melting the joint seam can be an electric soldering iron.

[0123] (4) The surface layer shell and the back layer shell are prepared in sequence on the surface of the casting wax film.

[0124] The surface shell preparation includes: coating the surface of the casting wax mold with a surface layer slurry, and then removing excess surface layer slurry; then performing surface sanding, and after drying, forming a surface shell.

[0125] The preparation of the back layer mold shell includes: coating the surface of the surface layer mold shell with the back layer slurry and removing the excess back layer slurry; then performing back layer sanding and drying to form the first layer of back layer mold shell; repeating the steps of coating the back layer slurry and back layer sanding in the preparation of the back layer mold shell multiple times to form a multi-layer back layer mold shell.

[0126] It is worth mentioning that during the coating of the surface layer slurry and the back layer slurry, the tube body that passes through the multi-angle special-shaped tube cavity and is exposed outside the casting wax mold is protected, and this part of the tube body of the core 1 is always kept exposed outside the shell.

[0127] It should be noted that before applying the surface layer slurry to prepare the surface layer shell, the surface of the wax mold can be cleaned to remove surface stains.

[0128] (5) A segmented continuous dewaxing and roasting process is used to produce a shell having a multi-angle special-shaped cavity.

[0129] (5-1) Dewaxing, heating to the first roasting temperature, keeping the temperature, and allowing the wax liquid to flow out from the dewaxing port.

[0130] In an embodiment of the present invention, the first roasting temperature is 100°C to 200°C, for example, it can be one of 100°C, 110°C, 117°C, 120°C, 150°C, 180°C, 200°C or any value that satisfies the above range; the holding time is 3h to 6h, for example, it can be one of 3h, 4h, 5h, 6h or any value that satisfies the above range. The dewaxing temperature is higher than the conventional electric dewaxing temperature, so that the wax liquid can be quickly removed from the inside of the shell, reducing the influence of the wax liquid removal process on the core position deviation. At the same time, increasing the first roasting temperature preheats the shell, which is conducive to reducing the second roasting holding time.

[0131] In an embodiment of the present invention, the wax liquid flows out from the wax outlet in the middle or side of the bottom area of ​​the mold shell; the wax liquid relies on gravity to flow out from the wax outlet in the middle or side of the bottom area of ​​the mold shell, avoiding surface or local cracking of the internal core caused by tilting of the mold shell.

[0132] (5-2) Calcination.

[0133] In the embodiment of the present invention, in order to avoid the core 1 from cracking due to rapid sintering, a segmented continuous firing method is adopted, the temperature is raised to the second, third and fourth firing temperatures, and the temperature is kept at the second, third and fourth firing temperatures respectively, and then cooled and taken out of the furnace.

[0134] In an embodiment of the present invention, the second roasting temperature is 400°C to 500°C, for example, it can be one of 400°C, 420°C, 450°C, 480°C, 500°C or any numerical value satisfying the above range; the holding time at the second roasting temperature is ≥3h, for example, it can be 3h to 6h; specifically, the holding time can be one of 3h, 4h, 5h, 6h or any numerical value satisfying the above range.

[0135] In an embodiment of the present invention, the third roasting temperature is 650°C to 750°C, for example, it can be one of 650°C, 680°C, 700°C, 720°C, 750°C or any numerical value satisfying the above range; the holding time at the third roasting temperature is ≥3h, for example, it can be 3h to 6h; specifically, the holding time can be one of 3h, 4h, 5h, 6h or any numerical value satisfying the above range.

[0136] In an embodiment of the present invention, the fourth roasting temperature is 950°C to 1200°C, for example, it can be one of 950°C, 980°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C or any numerical value satisfying the above range; the holding time at the fourth roasting temperature is ≥3h, for example, it can be 3h to 8h; specifically, the holding time can be one of 3h, 4h, 5h, 6h, 7h, 8h or any numerical value satisfying the above range.

[0137] In the embodiment of the present invention, the furnace is cooled to room temperature before being taken out of the furnace, or the furnace is cooled to below 300° C. The room temperature refers to a temperature range of 20° C. to 30° C.

[0138] Since the dewaxing and firing process of the shell is carried out continuously, by continuously increasing the firing temperature in stages, on the one hand, the wax liquid inside the shell is removed and the shell is ceramicized by high-temperature firing. On the other hand, since the shell is gradually heated, the core deformation or position displacement caused by thermal expansion and contraction of the core during the heating process can be reduced. At the same time, continuous dewaxing and firing can improve heating efficiency and effectively reduce the heating and heat preservation time of each stage.

[0139] (6) After the shell is dewaxed and fired, the surface of the core 1 is inspected with an endoscope to prevent cracks on the surface of the core 1.

[0140] (7) Use an air gun to blow air to clean the inside of the shell.

[0141] It should be noted that the terms "comprises" and any variations thereof in the specification and claims of the present invention are intended to cover non-exclusive inclusions. For example, the inclusion of a series of components is not necessarily limited to those components explicitly listed, but may include other components that are not explicitly listed or inherent to the components.

[0142] In the present invention, the directions or positional relationships indicated by the terms "upper", "lower", "bottom", "top", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0143] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0144] In addition, the descriptions of "first", "second", etc. involved in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0145] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0146] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for preparing a shell mold containing a multi-angle special-shaped cavity, characterized in that: The following steps are involved: Prepare a core according to the casting lumen structure, wherein the core comprises a plurality of tubes distributed at multiple angles; According to the casting lumen structure, a plurality of segmented wax molds are designed, and the core is assembled with the plurality of segmented wax molds, so that the core is placed in a multi-angle special-shaped lumen formed by the plurality of segmented wax molds to obtain a casting wax film; wherein, at least a portion of the tubular body of the core has the same inner diameter as the multi-angle special-shaped lumen at a corresponding position for precise matching, and at least a portion of the remaining portion of the tubular body is suspended in the multi-angle special-shaped lumen; A surface layer shell and a back layer shell are prepared in sequence on the surface of the casting wax film, and then a segmented continuous dewaxing and roasting process is adopted to obtain the shell containing multi-angle special-shaped cavities.

2. The method for preparing a mold shell having a multi-angle special-shaped cavity according to claim 1, characterized in that: The surface shell preparation comprises: The surface of the casting wax mold is coated with a surface layer slurry, and then the excess surface layer slurry is removed; thereafter, the surface layer is sanded and dried to form the surface layer shell.

3. The method for preparing a mold shell having a multi-angle special-shaped cavity according to claim 2, characterized in that: The back layer shell preparation comprises: The surface of the surface shell is coated with a back layer slurry, and excess back layer slurry is removed; the back layer is then sanded and dried to form a first back layer shell; The steps of coating the back layer slurry and sprinkling the back layer with sand in the preparation of the back layer shell are repeated many times to form a multi-layer back layer shell.

4. The method for preparing a mold shell having a multi-angle special-shaped cavity according to claim 1, characterized in that: The segmented continuous dewaxing and roasting comprises: Dewaxing, heating to the first roasting temperature, keeping the temperature, so that the wax liquid flows out from the dewaxing port; Roasting, heating to the second, third and fourth roasting temperatures in sequence, and keeping the temperature at the second, third and fourth roasting temperatures respectively, and then cooling and taking out of the furnace; Preferably, the first roasting temperature is 100°C to 200°C, and the holding time at the first roasting temperature is 3h to 6h; Preferably, the wax liquid flows out from the wax outlet in the middle or side of the bottom area of ​​the shell; Preferably, the second calcination temperature is 400°C to 500°C, and the holding time at the second calcination temperature is ≥ 3h, preferably 3h to 6h; Preferably, the third roasting temperature is 650° C. to 750° C., and the holding time at the third roasting temperature is ≥ 3 h, preferably 3 h to 6 h; Preferably, the fourth roasting temperature is 950° C. to 1200° C., and the holding time at the fourth roasting temperature is ≥ 3 h, preferably 3 h to 8 h; Preferably, the sintered steel is taken out of the furnace after being cooled to room temperature, or taken out of the furnace after being cooled to below 300° C.

5. The method for preparing a mold shell having a multi-angle special-shaped cavity according to claim 1, characterized in that: When the wall thickness of the casting wax mold corresponding to the suspended portion of the tube body is ≤10 mm, the distance between the suspended portion of the tube body and the cavity wall of the multi-angle special-shaped tube cavity at the corresponding position is ≤1 mm; When the wall thickness of the casting wax mold corresponding to the suspended portion of the tube body is greater than 10 mm, the distance between the suspended portion of the tube body and the cavity wall of the multi-angle special-shaped tube cavity at the corresponding position is ≤ 2 mm; Preferably, when the wall thickness of the casting wax mold corresponding to the suspended portion of the tube body is ≤3 mm, the spacing between the suspended portion of the tube body and the cavity wall of the multi-angle special-shaped cavity at the corresponding position is ≤0.5 mm.

6. The method for preparing a mold shell having a multi-angle special-shaped cavity according to claim 1, characterized in that: Design multiple wax models based on the casting lumen structure including: Dividing the multiple tube bodies of the core into X tube body, Y tube body and Z tube body according to the extension direction of the tube body; The plurality of block wax molds are obtained by dividing the corresponding positions of the casting wax mold using the plane formed by the center lines of the X tube body and the Y tube body as the first dividing plane, and using the plane formed by the center lines of the X tube body and the part of the Z tube body connected to the X tube body as the second dividing plane, and serving as the bottom wax mold, the rear wax mold and the front wax mold respectively; Preferably, a first pipeline groove is provided on the bottom wax mold, a second pipeline groove is provided on the rear wax mold, and a third pipeline groove is provided on the front wax mold; the first pipeline groove, the second pipeline groove and the third pipeline groove together form the multi-angle special-shaped lumen.

7. The method for preparing a mold shell having a multi-angle special-shaped cavity according to claim 6, characterized in that: The assembly of the core and the plurality of wax mold blocks comprises: Placing the X tube body, the Y tube body and part of the Z tube body of the core in the first channel groove of the bottom wax mold to position them in the X, Y and Z directions; The front wax mold and the rear wax mold are respectively assembled onto the bottom wax mold, and the front wax mold is matched with the rear wax mold so that part of the second pipeline groove and part of the third pipeline groove are combined to form a tube cavity for sleeve-connecting part of the Z tube body, and the first pipeline groove and part of the third pipeline groove and part of the second pipeline groove are combined to form a tube cavity for sleeve-connecting the X tube body, the Y tube body and part of the Z tube body.

8. The method for preparing a mold shell having a multi-angle special-shaped cavity according to claim 7, characterized in that: The Z tube body also includes a Z1 tube body connected to the Y tube body, and the rear wax mold is also provided with a sleeve cavity for sleeve-connecting the Z1 tube body; Preferably, a partial area of ​​the Z1 tube body has the same inner diameter as the sleeve lumen at the corresponding position for precise matching, and the remaining partial area of ​​the Z1 tube body is suspended in the sleeve lumen.

9. The method for preparing a mold shell having a multi-angle special-shaped cavity according to claim 1, characterized in that: At least a portion of the tube body of the core passes through the inner cavity of the shell and is exposed outside the shell.

10. The method for preparing a mold shell having a multi-angle special-shaped cavity according to claim 1, characterized in that: The shell preparation method further comprises: After the dewaxing and roasting, the core is inspected for quality; and the inside of the shell is cleaned; Preferably, an endoscope is used to inspect the interior of the mold shell.

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