Rapid manufacturing process of 3D printing sand mold outer mold for static pressure molding line

Abstract

The invention discloses a rapid manufacturing process of a 3D printing sand mold outer mold for a static pressure molding line, and relates to the technical field of casting. The process is different from conventional metal mold and wood mold manufacturing processes, an outer mold body blank is rapidly manufactured through the 3D printing technology, and then hardening and surface smoothing treatment are conducted through hardening liquid. Through hardening of the hardening liquid, the surface strength and hardness of the outer mold body can be greatly improved, the outer mold body can completely bear the molding pressure (1.2 Mpa) of a static pressure molding line, the hardened sand mold can pass through at least 300 molds without deformation, and the dimensional tolerance stability is good. The surface of the outer mold body is smooth through surface smoothing treatment, and the sand scrabbling defect is avoided. Surface treatment is matched with surface hardening, the manufacturing period of the outer mold can be shortened, the manufacturing cost of the outer mold can be reduced, and meanwhile the use requirement of a static pressure molding line can be met.

Description

Technical Field

[0001] The invention relates to the technical field of casting, in particular to a rapid production process of a 3D printed sand mold outer mold for a static pressure molding line. Background Art

[0002] Static pressure molding line is an automatic casting equipment. Its principle is to preliminarily compact the molding sand through the airflow pre-compacting effect, and then finally compact the molding sand through the air pressure head. This method has good filling of the molding sand during molding, and the overall compactness of the sand mold is high and evenly distributed. It is mainly used for the production of castings with complex structures and large production batches.

[0003] However, for products with small quantities, if a static pressure molding line is used, a formal mold is required. The production cycle of a formal mold is long and the production cost is very high. Therefore, for small batch products, the production cost will increase significantly.

[0004] Although the emerging 3D sand molds can meet the needs of small-batch production, due to the high degree of automation of molten iron transfer and pouring equipment in the foundry workshop and the high safety and environmental protection requirements, the 3D sand molds printed for new products cannot be placed outside the molding line of the foundry workshop production site for pouring, and can only be poured in the pouring section area specified on the static pressure molding line. On the static pressure molding line, a metal pattern needs to be made to complete the molding of the sand box, and then the 3D printed sand core can be placed and poured in the specified pouring section area on the production line. In this way, it is still necessary to make metal molds for small-batch products, which is costly and has a long cycle. Summary of the invention

[0005] In response to the above problems, the present application provides a rapid production process for a 3D printed sand mold outer mold for a static pressure molding line, which can shorten the production cycle of the outer mold, reduce the production cost of the outer mold, and at the same time meet the use requirements of the static pressure molding line.

[0006] The technical solution adopted by the present invention to solve the technical problem is:

[0007] A rapid production process of a 3D printed sand mold outer mold for a static pressure molding line, comprising the following steps:

[0008] S1. Design the external model;

[0009] S2, printing the outer model by 3D printing;

[0010] S3, hardening test;

[0011] 3.1 Print the 8-shaped test block by 3D printing, and the material of the 8-shaped test block is the same as that of the outer mold body;

[0012] 3.2 Apply hardening liquid on the 8-shaped test block;

[0013] 3.3 After the hardening liquid applied by brushing is completely hardened, a tensile strength test is performed;

[0014] (1) If the tensile strength is greater than or equal to the preset value, proceed to the next step;

[0015] (2) If the tensile strength is less than the preset value, repeat steps 3.1, 3.2 and 3.3, and add one application of hardening liquid in step 3.2. The interval between two adjacent applications of hardening liquid is T;

[0016] S4, according to the number of times of applying the hardening liquid determined in step S3, the surface of the outer mold body obtained in step S2 is overall applied with the hardening liquid a corresponding number of times;

[0017] S5. Apply the hardening liquid locally to the gas needle installation position, riser fixing rod installation position and corners;

[0018] S6, using putty to scrape the hardened surface of the outer mold body to obtain an atomic putty layer;

[0019] S7. Use sandpaper to grind the surface of the outer mold until it is smooth;

[0020] S8. Glue the outer mold body to the mold plate and install the air needle.

[0021] Furthermore, the outer mold body is formed by 3D printing using hot phenolic resin, furan resin, silica sand, old sand or regenerated sand.

[0022] Furthermore, the outer mold body is 3D printed using hot phenolic resin, and is cured by heating in a microwave oven after printing.

[0023] Furthermore, the preset value described in step 3.3 is 10 MPa.

[0024] Furthermore, the hardening liquid is formed by mixing epoxy resin and curing agent in proportion.

[0025] Furthermore, the hardening liquid is formed by mixing epoxy resin and curing agent in a mass ratio of 2:1.

[0026] Furthermore, the number of times the hardening liquid is locally applied is 0.5-1.2 times the number of times the hardening liquid is applied in step S3.

[0027] Furthermore, the thickness of the putty layer is 0.4-0.6 mm.

[0028] Furthermore, the putty layer is applied in two steps.

[0029] Furthermore, in step S7, the outer mold body is polished using 600-mesh sandpaper.

[0030] The beneficial effects of the present invention are:

[0031] The embodiment of the present application provides a rapid production process for a 3D printed sand mold outer mold for a static pressure molding line. The outer mold body is printed by 3D printing, and hardened by a hardening liquid and the surface is smoothed, so that the surface of the treated outer mold body is smooth and there will be no sand removal defects. The surface treatment combined with the surface hardening can ensure that the outer mold will not deform or crack after being placed for 3 years, and effectively shorten the production cycle (2 weeks), while also effectively reducing the production cost (the production cost is reduced to one tenth of the original cost). BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A top view of a rapid outer mold produced by a 3D printing sand mold outer mold rapid production process for a static pressure molding line provided by the present application;

[0033] Figure 2 for Figure 1 AA section view in.

[0034] In the figure: 1. mold plate; 2. outer mold body; 3. air needle; 4. insulation riser fixing rod; 5. putty layer; 6. hardening layer; 7. corner. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described in detail below in conjunction with the drawings in the embodiments of the present application, and the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by those skilled in the art without creative work on the basis of the embodiments of the present application shall belong to the protection scope of the present application.

[0036] like Figure 1 and Figure 2 As shown, a rapid production process of a 3D printed sand mold outer mold for a static pressure molding line includes the following steps:

[0037] S1. Design the outer mold body 2 according to the casting process, and determine the installation position of the gas needle 3 and the installation position of the insulation riser fixing rod 4. The installation position of the gas needle 3 and the installation position of the insulation riser fixing rod 4 are subjected to greater force during molding on the static pressure molding line, so special attention should be paid during the later curing.

[0038] S2. Print out the outer model 2 by 3D printing.

[0039] The outer mold body 2 is formed by 3D printing using hot phenolic resin, furan resin, silica sand, old sand or regenerated sand.

[0040] As a specific implementation, the outer mold body 2 described in this embodiment is 3D printed using hot phenolic resin, and is cured by heating in a microwave oven after printing.

[0041] S3. Hardening test.

[0042] 3.1 The 8-shaped test block is printed by 3D printing, and the material of the 8-shaped test block is the same as that of the outer mold body 2.

[0043] 3.2 Apply hardening liquid on the 8-shaped test block.

[0044] 3.3 After the applied hardening liquid has completely hardened, carry out a tensile strength test.

[0045] (1) If the tensile strength is greater than or equal to the preset value, proceed to the next step.

[0046] (2) If the tensile strength is less than the preset value, repeat the operations of steps 3.1, 3.2 and 3.3, and add one hardening liquid brushing operation in step 3.2. The interval time between two adjacent hardening liquid brushings is T.

[0047] As a specific implementation, the preset value described in this embodiment is 10 MPa, that is, after the 8-shaped test block is hardened, its tensile strength should reach 10 MPa.

[0048] As a specific implementation, in step 3.2 of this embodiment, if the number of times the hardening liquid is applied is greater than 2, the time interval between two adjacent hardening liquid applications is less than 10 minutes. After the last application of the hardening liquid, the hardening needs to be hardened for 10 hours so that the applied hardening liquid is completely hardened.

[0049] As a specific implementation, the hardening liquid described in this embodiment is formed by mixing epoxy resin and curing agent in a certain proportion. For example, the mixing ratio of the epoxy resin and curing agent is 2:1 by mass.

[0050] S4. According to the number of times of applying the hardening liquid determined in step S3, the surface of the outer mold body 2 obtained in step S2 is overall applied with the hardening liquid a corresponding number of times, and the interval between two adjacent overall applications of the hardening liquid is T, which is the same as the interval between two adjacent applications of the hardening liquid in step S3.

[0051] S5. Apply hardening liquid locally to the installation position of the air needle 3, the installation position of the riser fixing rod and the corner 7 to strengthen the strength of the parts. The number of times of local hardening liquid application is 0.5-2 times of the number of times of local hardening liquid application determined in step S3, and the time interval between steps S4 and S5, and the interval between two adjacent local hardening liquid applications are both T, which is the same as the interval between two adjacent local hardening liquid applications in step S3. After the last local hardening liquid application, harden for 10 hours, so that the applied hardening liquid is completely hardened to obtain a hardened layer 6.

[0052] As a specific implementation, in this embodiment, the number of times the hardening liquid is locally applied is 1 times the number of times the hardening liquid is applied in step S3, that is, the number of times the hardening liquid is locally applied is the same as the number of times the hardening liquid is applied as a whole.

[0053] S6 , after the hardening liquid applied in steps S4 and S5 is completely hardened, use putty to scrape the hardened surface of the outer mold body 2 to obtain a putty layer 5 .

[0054] As a specific implementation, the thickness of the putty layer 5 in this embodiment is 0.4-0.6 mm, so as not to affect the casting tolerance. The fillet part should be slightly thicker than other parts to resist the scouring of the molding sand during the molding process.

[0055] Preferably, the putty layer 5 has a thickness of 0.5 mm, and the putty layer 5 is scraped twice, that is, scraped twice.

[0056] S7. Use sandpaper to grind the surface of the outer mold body 2 until it is smooth.

[0057] As a specific implementation, in this embodiment, 600-grit sandpaper is used to grind the outer mold body 2.

[0058] S8, bonding the outer mold body 2 to the mold plate 1, and installing the air needle 3. Exemplarily, the outer mold body 2 is bonded to the mold plate 1 by a chemical adhesive.

[0059] Other embodiments obtained by those skilled in the art by combining, splitting, reorganizing, etc. the embodiments of the present application on the basis of the embodiments provided in the present application do not exceed the protection scope of the present application.

[0060] The above specific implementation methods have detailed the purpose, technical solutions and beneficial effects of the embodiments of the present application. The above are only specific implementation methods of the embodiments of the present application and are not used to limit the protection scope of the embodiments of the present application. That is, any modifications, equivalent substitutions, improvements, etc. made on the basis of the embodiments of the present application should be included in the protection scope of the embodiments of the present application.

Claims

1. A rapid production process of 3D printed sand mold outer mold for static pressure molding line, characterized by: The following steps are included: S1. Design the outer model (2); S2, printing an outer model (2) by 3D printing; S3, hardening test; 3.1 Printing an 8-shaped test block by 3D printing, wherein the material of the 8-shaped test block is the same as that of the outer mold body (2); 3.2 Apply hardening liquid on the 8-shaped test block; 3.3 After the hardening liquid applied by brushing is completely hardened, carry out the tensile strength test; (1) If the tensile strength is greater than or equal to the preset value, proceed to the next step; (2) If the tensile strength is less than the preset value, repeat the operations of steps 3.1, 3.2 and 3.3, and add one application of hardening liquid in step 3.2, and the interval between two adjacent applications of hardening liquid is T; S4, according to the number of times of applying the hardening liquid determined in step S3, the surface of the outer mold body (2) obtained in step S2 is entirely applied with the hardening liquid for a corresponding number of times; S5, locally brushing the hardening liquid on the installation position of the gas needle (3), the installation position of the riser fixing rod and the corner (7); S6, using atomic putty to scrape the surface of the hardened outer mold body (2) to obtain an atomic putty layer (5); S7, using sandpaper to grind the surface of the outer mold body (2) until it is smooth; S8. Bond the outer mold body (2) to the mold plate (1) and install the air needle (3).

2. The rapid production process of a 3D printed sand mold outer mold for a static pressure molding line according to claim 1, characterized in that: The outer mold body (2) is formed by 3D printing using hot phenolic resin, furan resin, silica sand, old sand or regenerated sand.

3. The rapid production process of a 3D printing sand mold outer mold for a static pressure molding line according to claim 2, characterized in that: The outer mold body (2) is 3D printed using hot phenolic resin and is cured by heating in a microwave oven after printing.

4. The rapid production process of a 3D printing sand mold outer mold for a static pressure molding line according to claim 1, characterized in that: The preset value described in step 3.3 is 10 MPa.

5. The rapid production process of a 3D printing sand mold outer mold for a static pressure molding line according to claim 1, characterized in that: The hardening liquid is prepared by mixing epoxy resin and curing agent in a certain proportion.

6. A rapid production process of a 3D printed sand mold outer mold for a static pressure molding line according to claim 5, characterized in that: The hardening liquid is prepared by mixing epoxy resin and curing agent in a mass ratio of 2:

1.

7. The rapid production process of a 3D printing sand mold outer mold for a static pressure molding line according to claim 1, characterized in that: The number of times the hardening liquid is locally applied is 0.5-1.2 times the number of times the hardening liquid is applied in step S3.

8. The rapid production process of a 3D printing sand mold outer mold for a static pressure molding line according to claim 1, characterized in that: The thickness of the putty layer (5) is 0.4-0.6 mm.

9. The rapid production process of a 3D printing sand mold outer mold for a static pressure molding line according to claim 1, characterized in that: The putty layer (5) is scraped and coated twice.

10. The rapid production process of 3D printing sand mold outer mold for static pressure molding line according to claim 1, characterized in that: In step S7, the outer mold body (2) is polished using 600-mesh sandpaper.

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