Sand mold for casting

Abstract

The utility model belongs to the technical field of casting, and provides a sand mold for casting, which comprises a positioning sand core, a precoated sand shell and a random tool, the positioning sand core is used for forming an appearance structure of a casting, the precoated sand shell is used for forming an internal structure of the casting, and the positioning sand core and the precoated sand shell are assembled to form an integral cavity of the casting; the precoated sand shell is matched with the shape follow-up tool in a shape follow-up manner; the shape follow-up tool is used for supporting the precoated sand shell. By additionally arranging the precoated sand shell and the follow-up tool, the durability and the precision of the sand mold are remarkably improved; the follow-up tool has an obvious chilling effect in the pouring process, namely, the effect of a chilling block is achieved, meanwhile, due to the existence of the precoated sand shell, the defects of metal mold casting are overcome, white cast and the like of a casting are avoided, and the comprehensive strength of the casting is remarkably improved. In addition, through reasonable sand core assembly sequence and clearance arrangement, the stability and precision of the sand mold in the casting process are ensured, the manufacturing steps are simple and clear, the operation is easy, and the practical value is very high.

Description

Technical Field

[0001] The utility model belongs to the technical field of casting, provides a sand mold for casting and a manufacturing method thereof, and mainly relates to a sand mold for sand-coated casting of a ductile iron body casting and a manufacturing method thereof. Background Art

[0002] Iron mold sand casting refers to the process of covering the inner cavity of a metal mold (iron mold) with a thin layer of molding sand to form a mold, and then pouring to form a casting. The thickness of the sand layer is generally 10mm to 15mm. For compression casting products, the size of the middle mold cavity is relatively high, and the height dimension deviation is large during the production process. A positioning technology is required to make the castings produced meet the qualified standards. At present, the core head positioning of the casting follow-up tooling is used for sand core positioning, which will cause dimensional deviation during the casting process. The follow-up tooling is very heavy, and it is impossible to achieve the positioning correction of the sand core alone. Mechanical processing is required to achieve positioning. The follow-up tooling is a special-shaped part with high processing difficulty and high production cost. In addition, during the casting process, the follow-up tooling is repeatedly heated and easily deformed by heat. In the later stages of the production process, it becomes particularly difficult to control the quality of the casting products. Therefore, it is urgent to solve the positioning problem in the sand covering molding process to improve the quality of castings. Summary of the invention

[0003] Based on the above problems, it is necessary to propose a sand mold for casting and a method for making the same, which can improve the durability and precision of the sand mold by adding a coated sand shell and a mold-adapting tool. This new sand mold and its method for making it can not only effectively solve the problems of easy wear and deformation of traditional sand molds, but also improve casting efficiency and product quality.

[0004] A sand mold for casting, comprising a positioning sand core, a coated sand shell and a mold-adapting tool; the positioning sand core is used to form the outer structure of the casting, the coated sand shell is used to form the internal structure of the casting, the positioning sand core and the coated sand shell are assembled to form an overall mold cavity of the casting; the coated sand shell and the mold-adapting tool are arranged to match the mold; the mold-adapting tool is used to support the coated sand shell.

[0005] Furthermore, the casting sand mold also includes a positioning piece; the positioning piece is arranged inside the mold-adapting tooling to support the mold-adapting tooling.

[0006] Furthermore, a groove is provided on the positioning sand core, and the groove is used to place the positioning piece.

[0007] Furthermore, the positioning sand core includes a first sand core, a second sand core, a third sand core and a fourth sand core, and the first sand core, the second sand core, the third sand core and the fourth sand core are assembled to form an outer shape structure of the casting.

[0008] Furthermore, a groove is provided on the first sand core, and the groove is used to place the positioning piece.

[0009] Furthermore, the first sand core, the second sand core, the third sand core and the fourth sand core are respectively provided with positioning structures that cooperate with each other.

[0010] Furthermore, the first sand core is respectively assembled with the coated sand shell, the mold-adapting tooling and the positioning piece into an integrated structure.

[0011] Furthermore, the first sand core and the accompanying tooling are respectively provided with mutually matching positioning structures.

[0012] Furthermore, the coated sand shell is made by using a mold, and the mold is a sand mold.

[0013] Furthermore, the portable tooling is made of metal.

[0014] The production steps of the above-mentioned casting sand mold include:

[0015] The first step is to make the first sand core, the second sand core, the third sand core, the fourth sand core and a sand mold; the sand mold is used to form the coated sand shell; a groove is set on the first sand core, and the groove is matched with the positioning piece.

[0016] The second step is to make the mold according to the casting structure; assemble the first sand core, the mold, the mold-adapting tool and the positioning piece as a whole, place the positioning piece in the groove, the gap between the mold-adapting tool and the mold is 10mm to 15mm, fill the gap with resin sand and compact it to form the coated sand shell; the gap between the sand core 1 and the mold-adapting tool is 10mm to 15mm wide and 20mm to 25mm deep, fill the gap with resin sand and compact it; the interior of the mold-adapting tool is a hollow structure, the positioning piece is arranged inside the mold-adapting tool, and the rest is filled with resin sand and compacted;

[0017] The third step is to remove the mold after the resin sand in the gap between the mold-adapting tool and the mold is hardened, that is, after the coated sand shell is hardened, so that the first sand core, the coated sand shell, the mold-adapting tool and the positioning piece are integrated;

[0018] The fourth step is to assemble the second sand core, the third sand core and the fourth sand core in sequence according to the sand core assembly sequence to form a casting cavity.

[0019] The utility model provides a sand mold for casting. By adding a coated sand shell and a mold-adapting tool, the coated sand shell is used to form the internal structure of the casting, the positioning sand core and the coated sand shell are assembled to form the overall cavity of the casting, the coated sand shell and the mold-adapting tool are matched with the mold, and the coated sand shell and the mold-adapting tool are significantly improved in durability and precision of the sand mold; wherein the mold-adapting tool has an obvious chilling effect during the pouring process, that is, it plays the role of a cold iron, and at the same time, due to the existence of the coated sand shell, the defects of metal mold casting are avoided, and the casting is prevented from having white spots, etc., and the comprehensive strength of the casting is significantly improved. The utility model also ensures the stability and precision of the sand mold during the casting process through a reasonable sand core assembly sequence and gap setting, the production steps are simple and clear, easy to operate, and has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Attached Figure 1 Schematic diagram of the casting structure in the embodiment;

[0021] Attached Figure 2 It is a schematic diagram of the structure of the custom tooling in the embodiment;

[0022] Attached Figure 3 This is a schematic diagram of the first sand core structure in the embodiment;

[0023] Attached Figure 4 This is a schematic diagram of the second sand core structure in the embodiment;

[0024] Attached Figure 5 This is a schematic diagram of the third sand core structure in the embodiment;

[0025] Attached Figure 6 This is a schematic diagram of the fourth sand core structure in the embodiment;

[0026] Attached Figure 7 It is a schematic diagram of the assembly structure of the first sand core, the mold, the mold-adapting tooling and the positioning piece in the embodiment;

[0027] Attached Figure 8 It is a schematic diagram of the assembly structure of the first sand core, the coated sand shell, the mold-matching tooling and the positioning piece in the embodiment;

[0028] Attached Fig. 9 Schematic diagram of the structure of the sand mold for casting in the embodiment;

[0029] 10-positioning sand core; 20-coated sand shell; 30-mold-based tooling; 40-integral cavity of casting; 50-positioning piece; 60-mold; 101-first sand core; 102-second sand core; 103-third sand core; 104-fourth sand core; DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present technical solution, a more comprehensive description will be given below, and preferred embodiments are provided. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly and comprehensively understood.

[0031] The present embodiment mainly relates to an iron mold coated sand casting method, provides a casting sand mold and a manufacturing method thereof, and solves the problem of dimensional deviation due to difficult positioning during the sand coating molding process.

[0032] A sand mold for casting, see attached Figures 1 to 9 As shown, the casting sand mold includes a positioning sand core 10, a coated sand shell 20 and a mold-matching tooling 30; the positioning sand core 10 is used to form the outer structure of the casting, the coated sand shell 20 is used to form the internal structure of the casting, and the positioning sand core 10 and the coated sand shell 20 are assembled to form an overall mold cavity 40 of the casting; the coated sand shell 20 and the mold-matching tooling 30 are matched and arranged; the mold-matching tooling 30 is used to support the coated sand shell 20.

[0033] During the casting process, the design of this sand mold is intended to ensure high precision and high quality of the casting. The precise shape of the positioning sand core 10 ensures that the outer structure of the casting meets the design requirements, and its sturdy structure can effectively support and maintain the shape of the sand mold until the casting process is completed. In addition, the matching design of the coated sand shell 20 and the mold-matching tooling 30 not only ensures the stability of the casting process, but also greatly improves the precision of the casting. The design of the mold-matching tooling 30 takes into account various factors in the casting process, such as temperature changes, sand mold shrinkage, etc., to ensure that during the casting process, the coated sand shell 20 can be effectively supported to avoid deformation or displacement.

[0034] Specifically, the casting sand mold further includes a positioning member 50 ; the positioning member 50 is disposed inside the mold-adapting tool 30 , and is used to support the mold-adapting tool 30 , and acts as a core bone. A groove is disposed on the positioning sand core 10 , and the groove is used to place the positioning member 50 .

[0035] It should be noted that the positioning member 50 is made of high-strength material, such as steel or cast iron, preferably steel bars; this ensures that it can withstand high temperature and pressure during the casting process. Its shape and size are customized according to the requirements of the specific casting to ensure that the mold-following fixture 30 can be accurately supported to prevent the casting from being deformed or shifted during the casting process; at the same time, the overall stability of the sand mold is enhanced, and the casting stress can be effectively dispersed to reduce the deformation and breakage risks of the sand mold. During the molding process, the positioning member 50 is closely matched with the positioning sand core 10 through the groove to ensure the accurate position of the mold-following fixture 30 in the sand mold. This close fit not only improves the precision and quality of the casting, but also simplifies the positioning and alignment steps during the casting process.

[0036] In one embodiment, the positioning sand core 10 includes a first sand core 101, a second sand core 102, a third sand core 103 and a fourth sand core 104, which are assembled to form the outer structure of the casting. A groove is provided on the first sand core 101, and the groove is used to place the positioning member 50. The design of the groove takes into account both the size and shape of the positioning member 50 and the stability of its placement, ensuring that the positioning member 50 can be firmly fixed in the groove throughout the casting process; the gap between the positioning member 50 and the first sand core 101 is 1 mm to 3 mm.

[0037] Specifically, mutually matching positioning structures are respectively provided on the first sand core 101, the second sand core 102, the third sand core 103 and the fourth sand core 104. The first sand core 101 is respectively assembled with the coated sand shell 20, the form-fitting tool 30 and the positioning piece 50 into an integrated structure, which can solve the defect of large dimensional deviation. The first sand core 101 and the form-fitting tool 30 are respectively provided with mutually matching positioning structures.

[0038] The coated sand shell 20 is manufactured by using a mold 60 . The mold 60 is a sand mold manufactured by using a 3D printing method to ensure the accuracy of the mold 60 .

[0039] It should be noted that the portable tooling 30 is made of metal. The metal material can withstand extreme working environments such as high temperature and high pressure, ensuring that the tooling always maintains stable performance during use. In addition, the metal material also has good corrosion resistance and wear resistance, which can effectively extend the service life of the tooling.

[0040] The steps of making the casting sand mold provided in the above embodiment include:

[0041] The first step is to make a first sand core 101 , a second sand core 102 , a third sand core 103 , a fourth sand core 104 and a sand mold; the sand mold is used to form a coated sand shell 20 ; a groove is set on the first sand core 101 , and the groove is matched with the positioning piece 50 .

[0042] The second step is to make a mold 60 according to the structure of the casting; assemble the first sand core 101, the mold 60, the mold-adapting tool 30 and the positioning piece 50 as a whole, place the positioning piece 50 in the groove, and the gap between the mold-adapting tool 30 and the mold 60 is 10mm to 15mm, fill the gap with resin sand and compact it to form a coated sand shell 20; the gap between the sand core 1 and the mold-adapting tool 30 is 10mm to 15mm wide and 20mm to 25mm deep, and fill the gap with resin sand and compact it; the interior of the mold-adapting tool 30 is a hollow structure, the positioning piece 50 is arranged inside the mold-adapting tool 30, and the rest of the part is filled and compacted with resin sand;

[0043] Step 3: After the resin sand in the gap between the form-fitting tool 30 and the mold 60 is hardened, that is, after the coated sand shell 20 is hardened, the mold 60 is removed to make the first sand core 101, the coated sand shell 20, the form-fitting tool 30 and the positioning piece 50 a whole;

[0044] In the fourth step, according to the sand core assembly sequence, the second sand core 102, the third sand core 103 and the fourth sand core 104 are assembled in sequence to form an integral mold cavity 40 of the casting.

[0045] The above embodiments solve the problem of difficult positioning of ultra-high coated sand castings, and fundamentally solve the problem that the larger the size, the greater the dimensional deviation. At the same time, it has the excellent performance of coated sand casting, with a 10-15mm sand isolation layer, and rapid quenching from the inside, so that the internal structure crystals are refined, the structure is dense and defect-free, thereby reducing the problem of pressure leakage in the inner cavity of the vacuum compressor body, and also reducing the number of internal direct cooling cold irons and related hidden risers, improving the efficiency of later cleaning. At the same time, the use of 3D printing and manual molds can also greatly improve production efficiency. Reduce costs and significantly reduce the processing costs of processing the bottom positioning of the conformal tooling due to dimensional deviations caused by casting. This method is suitable for the production of some similar products.

[0046] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A sand mold for casting, characterized in that: The casting sand mold comprises a positioning sand core, a coated sand shell and a mold-adapting tool; the positioning sand core is used to form the outer structure of the casting, the coated sand shell is used to form the internal structure of the casting, the positioning sand core and the coated sand shell are assembled to form an overall mold cavity of the casting; the coated sand shell and the mold-adapting tool are arranged to match the mold.

2. The casting sand mold according to claim 1, characterized in that: The casting sand mold further comprises a positioning piece; the positioning piece is arranged inside the mold-adapting tooling and is used to support the mold-adapting tooling.

3. The casting sand mold according to claim 2, characterized in that: The positioning sand core is provided with a groove, and the groove is used for placing the positioning piece.

4. The casting sand mold according to claim 2 or 3, characterized in that: The positioning sand core comprises a first sand core, a second sand core, a third sand core and a fourth sand core, and the first sand core, the second sand core, the third sand core and the fourth sand core are assembled to form the outer shape structure of the casting.

5. The casting sand mold according to claim 4, characterized in that: The first sand core is provided with a groove, and the groove is used for placing the positioning piece.

6. The casting sand mold according to claim 4, characterized in that: The first sand core, the second sand core, the third sand core and the fourth sand core are respectively provided with positioning structures that cooperate with each other.

7. The casting sand mold according to claim 4, characterized in that: The first sand core is respectively assembled with the coated sand shell, the mold-adapting tooling and the positioning piece into an integrated structure.

8. The casting sand mold according to claim 4, characterized in that: The first sand core and the accompanying tooling are respectively provided with mutually matching positioning structures.

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